Prantik Kundu¹, Valur Olafsson², Souheil Inati³, Peter Bandettini^1,3, and Thomas Liu^4
1Section on Functional Imaging Methods, NIMH, Bethesda, MD, United States, ²UCSD, San Diego, CA, United States, ³fMRI Core Facility, NIMH, Bethesda, MD, United States, ⁴Center for Functional MRI, UCSD, San Diego, CA, United States

We demonstrate that a multi-echo (ME) approach to simultaneous multi-slice (SMS) fMRI acquisition (TR<1s) enables robust solutions to current challenges in SMS data analysis using spatial ICA for connectivity analysis and denoising. Unlike single-echo SMS acquisition, which currently requires arbitrary dimensionality estimation and denoising that is dependent on a group-level templates, the ME approach instead uses direct BOLD/non-BOLD dimensionality detection and component classification. We show here that: ME-ICA on ME-SMS data enables stable high dimensionality estimates for resting and video paradigms; BOLD components of cortex and subcortex show clear TE-dependence; and importantly, SMS related artifacts show clear [non-BOLD] TE-independence.

Ruo-Ning Sun¹, Ying-Hua Chu¹, Yi-Cheng Hsu¹, and Fa-Hsuan Lin^1,2
1Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, ²Aalto University, Finland

Volumetric magnetic resonance inverse imaging (InI) typically only samples the central partition in a 3D k-space in order to achieve massively accelerated acquisition. However, considering the physiological noise scaled with the image pixel size, sampling InI at the central partition, corresponding the largest voxel size, may not be optimal. Using empirical data and quantifying the InI reconstruction by time domain signal-to-noise ratio (tSNR), we found that the optimal sampling partition for about 35% of the cortical locations is the first slow spatial harmonic (1/128 mm-1 with 256 mm FOV and 4 mm partition thickness).

Hendrik Mandelkow¹, Jacco A de Zwart¹, and Jeff H Duyn^1
1Advanced MRI, LFMI, NINDS, National Institutes of Health, Bethesda, MD, United States

Information-theoretic approaches to BOLD fMRI analysis, like multivariate pattern analysis (MVPA), suggest that distinctive local patterns of BOLD signal on a spatial scale of millimetres carry information that allows the classification or decoding of perceptual stimuli. In this study high-resolution BOLD fMRI experiments at 7T indicate that the single-trial discriminability of naturalistic movie stimuli peaks at a spatial resolution of 2-3mm, well above the resolution limit for BOLD fMRI, but below the resolution of most fMRI experiments.

Xiujuan Geng¹, Hong Gu², Yihong Yang², and Li-Hai Tan^1
1University of Hong Kong, Hong Kong, China, ²National Institute on Drug Abuse, Maryland, United States

Recent multiband EPI acquisition techniques show advantages in spontaneous brain functional connectivity analyses and diffusion imaging. In this work, we investigated the potentials of fast imaging in task-based fMRI studies. Particularly, we utilized conventional and multiband (MB) EPI techniques to study brain functional mapping under phonological processing with rhyming judgment tasks. Despite the lower spatial SNR per image volume due to the faster TR acquisitions, the MB EPI produces stronger statistical power in activation detection because of higher temporal sampling rate. Results also demonstrated that the MB technique produces stronger or similar detection power with much reduced acquisition time.

Klaudius Kalcher^1,2, Roland Boubela^1,2, Christian Nasel³, and Ewald Moser^1,2
1MR Center of Excellence, Medical University of Vienna, Vienna, Austria, ²Department for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria, ³Department of Radiology, State Clinical Center Danube District, Tulln, Lower Austria, Austria

Functional MRI at 3 T has become a workhorse for the neurosciences, e.g., neurology, psychology, and psychiatry, enabling non-invasive investigation of brain function and connectivity. However, BOLD-based fMRI is a rather indirect measure of brain function, confounded by fluctuation related signals, e.g. head or brain motion, brain pulsation, blood flow, intermixed with susceptibility differences close or distant to the region of neuronal activity. Here we explore recent technical and methodological advancements aimed at disentangling these various components, employing fast multiband sequences to critically sample them and temporal ICA to separate these different signal sources from the measured data.

Brice Fernandez¹ and Michael Czisch^2
1Applications and Workflows Europe, GE Healthcare, Munich, Germany, ²Neuroimaging Research Group, Max Planck Institute of Psychiatry, Munich, Germany

For functional MRI, the use of a single-shot multi-echo EPI (MEPI) has been shown to be an advantageous acquisition scheme. Among others factors, MEPI increases fMRI BOLD sensitivity and offers increased robustness to sample-induced susceptibility gradients. In addition, parallel imaging has been shown to significantly reduce EPI distortions but suffers from SNR loss. However, the limit of BOLD sensitivity as a function of the susceptibility gradients is unknown. Here, we investigate the BOLD sensitivity as a function of the susceptibility gradients using simulations and considering a MEPI acquisition protocol with a high acceleration factor, and an echo combination method.

Christoph Juchem¹, Peter Herman¹, Basavaraju G Sanganahalli¹, Terence W Nixon¹, Peter B Brown¹, Scott McIntyre¹, Fahmeed Hyder¹, and Robin A de Graaf^1
1Diagnostic Radiology, Yale University, New Haven, CT, United States

The in vivo rat model is a work horse in neuroscientific and preclinical MR research, however, excellent magnetic field homogeneity is required for meaningful results. The benefits of Dynamic Multi-Coil Technique (DYNAMITE) shimming for echo-planar imaging (EPI) of the rat brain at 11.7 Tesla are presented. Improved field homogeneity along with the achievable large brain coverage will be crucial when signal pathways, cortical circuitry, the brain's default network or multi-modal integration are studied. Along with the efficiency gains demonstrated recently, DYNAMITE shimming has the potential to replace conventional shim systems in small bore animal scanners.

Vimal Singh¹ and David Ress^2
1Electrical Engineering, University of Texas at Austin, Austin, TX, United States, ²Neuroscience, Baylor College of Medicine, Houston, TX, United States

Functional MRI in human superior colliculus (SC) requires high resolution. Dual-echo spiral has been used for high-resolution applications in cortex. Here we tune and evaluate various dual-echo spiral variants for sub-cortical application: single-echo spiral in, and dual-echo spiral in-in, in-out, and out-out. The functional signal-to-noise ratio of the activity evoked by visual stimulation was used as a performance metric. This metric was first used to find the optimal echo time for each variant. Then, using the optimal TE, each variant was compared to single-echo spiral out as a reference. Best performance was obtained for dual-echo spiral out.

Wietske van der zwaag¹, Mayur Narsude¹, Roberto Martuzzi², and José P Marques^3
1CIBM, EPFL, Lausanne, Switzerland, ²LNCO, EPFL, Lausanne, Switzerland, ³UNIL, Lausanne, Switzerland

This study aimed to demonstrate that with a fast BOLD sensitive fMRI acquisition, 3D-EPI-CAIPI with TR=400ms, subtle temporal effects, such as those involved in multisensory facilitation in the primary sensory cortices, can successfully be investigated. Differences in time-to-peak for the BOLD responses mono- or multisensory stimulation could be shown in auditory, visual and motor cortices, with audiovisual stimulation always leading to a faster response than auditory-only or visual-only stimuli. No such effect could be demonstrated for the same stimulus paradigm in otherwise comparable TR=2s data.

Valentin G. Kemper¹, Federico De Martino¹, An T. Vu², David A. Feinberg³, Essa Yacoub², and Rainer Goebel^1
1Department of Cognitive Neuroscience, Maastricht University, Maastricht, Limburg, Netherlands, ²Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, United States, ³Helen Wills Institute of Neuroscience, University of California, Berkeley, United States

Variable flip angle (VFA) refocusing schemes for Inner-Volume 3D-GRASE were designed to improve spatial coverage and point-spread along the partition direction in high-resolution functional MRI at 7T. Phase graph theory was used to calculate signal contributions from spin-echoes and stimulated echoes along the echo train. The simulations yield point-spread functions, which are in good agreement with such estimated from non-phase encoded acquisitions. In a simple visual activation experiment, almost twice the number of slices were acquired per echo train while maintaining the temporal signal to noise ratio, functional sensitivity, and point-spread properties of a reference acquisition with conventional 180° refocusing.

Valentin G. Kemper¹, Federico De Martino¹, An T. Vu², Benedikt A. Poser¹, David A. Feinberg^3,4, Essa Yacoub², and Rainer Goebel^1
1Department of Cognitive Neuroscience, Maastricht University, Maastricht, Limburg, Netherlands, ²Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, United States, ³Helen Wills Institute of Neuroscience, University of California, Berkeley, United States, ⁴Advanced MRI Technologies, California, United States

3D Inner Volume GRASE (3D-GRASE) and Spin-Echo EPI (2D SE-EPI) sequences were compared with regard to sensitivity and resolution in the context of sub-millimeter functional MRI at 7 T. Theoretical simulations, acquisitions with phase encoding turned off, and analysis of residual noise correlations showed that the point spread in slice direction in 3D-GRASE is comparable to the point spread of 2D SE-EPI in phase encoding direction with commonly employed acquisition parameters and reconstructions. t-values of functional activity in a simple visual activation experiment were higher in 3D-GRASE acquisitions due to better temporal signal to noise ratio.

David G Norris^1,2, Jenni Schulz¹, and Rasim Boyacioglu^1
1Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen, Netherlands, ²Erwin L Hahn Institute, University Duisberg-Essen, Essen, Germany

We demonstrate the application of echo shifted EPI, combined with in plane acceleration using GRAPPA, and multiband imaging. GRAPPA reduces the echo train length, so that the effective TE is close to the optimum for performing fMRI at 3T. Using an isotropic spatial resolution of 3.5mm, GRAPPA factor 3, and MB3 whole brain coverage at 3T was possible with TE 30ms, and TR 224ms. Image quality was comparable to that obtained using multiband but no echo shifting. This approach will greatly improve the efficiency of fMRI, particularly at lower field strengths and course to intermediate spatial resolutions.

Mark Chiew¹, Stephen M Smith¹, Nadine N Graedel¹, Thomas Blumensath², and Karla L Miller^1
1FMRIB Centre, University of Oxford, Oxford, Oxfordshire, United Kingdom, ²IVSR, University of Southampton, Southampton, Hampshire, United Kingdom

In this abstract, we demonstrate the k-t FASTER method for rank-constrained acceleration of FMRI data acquisition on prospectively under-sampled in vivo data. A 3D EPI acquisition scheme with 4.27x acceleration via pseudo-random under-sampling of the kz dimension was used to achieve whole brain sampling at 2mm isotropic resolution with TR = 975 ms without the use of coil sensitivity information. Results show high fidelity reconstructions of resting state networks in comparison to an un-accelerated 3D EPI acquisition of equal duration.

Yun-An Huang^1,2, Shih-Hsien Yang³, Tzu-Hao Harry Chao⁴, Edzer L. Wu⁵, Der-Yow Chen⁶, Kuan-Hung Cho⁷, Yeun-Chung Chang⁸, Changwei W. Wu³, Li-Wei Kuo⁹, and Jyh-Horng Chen^1,2
1Department of Electrical Engineering, National Taiwan University, Taipei, Taipei, Taiwan, ²Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taipei, Taiwan, ³Graduate Institute of Biomedical Engineering, National Central University, Taoyuan, Taiwan, ⁴Department of Life Science, National Taiwan University, Taipei, Taiwan, ⁵Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan, ⁶Department of Psychology, National Cheng Kung University, Tainan, Taiwan, ⁷Institute of Brain Science, National Yang Ming University, Taipei, Taiwan, ⁸College of Medicine, National Taiwan University, Taipei, Taiwan, ⁹Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli County, Taiwan

Functional MRI (fMRI) has been widely used to discover the brain functions by examining the T2* weighted blood-oxygen-level-dependent (BOLD) signals. However, higher spatial or temporal resolution is urgently needed for investigating the hemodynamic responses from subtle neural activities. In this study, single carrier Wideband MRI with 2-fold acceleration was employing on the conventional gradient echo sequence (WB-GRE) in rat fMRI experiments with electrical stimulation to forepaws. Our preliminary results show WB-GRE could provide higher spatial or temporal resolution. Also, the capability of using Wideband technology on fMRI to map the functional activation with enhanced spatial resolution has been demonstrated.

Hing-Chiu Chang¹, Shayan Guhaniyogi¹, Ying-Hui Chou¹, and Nan-Kuei Chen^1
1Brain Imaging and Analysis Center, Duke University Medical Center, Durham, North Carolina, United States

Interleaved EPI based fMRI is highly susceptible to unstable aliasing artifacts across the FOV as a result of B0 drifting over time, physiological noises and subject motion. The recently developed multiplexed sensitivity-encoding (MUSE) post-processing algorithm can suppress the in-plane aliasing artifacts resulting from time-domain signal instabilities during dynamic scans. In this study, the MUSE algorithm is further developed and generalized to accommodate high-throughput fMRI data obtained with multi-band interleaved EPI pulse sequence, suppressing both in-plane and through-plane aliasing artifacts and improving image throughput.

Philipp Ehses^1,2, G. Shajan¹, and Klaus Scheffler^1,2
1High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, ²Dept. of Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany

Increasing acquisition speed is beneficial in fMRI since it increases statistical power and allows the separation of physiological noise from the time series. An effective means to achieve this speed is to combine EPI with parallel imaging. 3D EPI allows very high parallel imaging factors since acceleration can be performed in both phase-encoding directions. Non-Cartesian parallel imaging can potentially allow even higher acceleration by exploiting coil sensitivities in all three dimensions. To this end, a 3D radial EPI sequence was developed and first results with up to 8-fold radial GRAPPA acceleration are presented from finger tapping experiments at 9.4T.

Jun Hua^1,2, James J Pekar^1,2, Peter C.M. van Zijl^1,2, Qin Qin^1,2, Craig K Jones^1,2, and Jeffrey M Yau^3
1The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, ²F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, ³Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States

Localized BOLD activations in visual/motor cortex are typically observed during visual/motor tasks. Recent studies show that BOLD activities can be detected in many other regions during such tasks. Here, we performed whole-brain fMRI experiments with simultaneous flashing-checkerboard and finger-tapping using GRE-EPI, SE-EPI and T2-prepared SE-BOLD fMRI. Robust activations outside visual/motor cortex can be detected by T2prep-BOLD, but not GRE/SE-EPI. CNR in these regions was greater in T2prep-BOLD, mainly due to much reduced dropout and distortion compared to EPI. This implies that important information might be missed in these regions with GRE/SE-EPI, especially for cognitive fMRI studies with sophisticated tasks.

Iris Asllani^1,2, Shazia Dharssi³, Richard P Sloan³, and Scott A Small^3
1Biomedical Engineering, Rochester Institute of Technology, Rochester, NY, United States, ²Rochester Center for Brain Imaging, University of Rochester, NY, United States, ³Columbia University, NY, United States

To study the effects of normal aging and disease progression on the brain function, we need to develop fMRI methods that provide both quantifiable and reliable measures of metabolism over the time-scales involved in these processes. To this end, we have developed an fMRI method that combines ASL perfusion fMRI with steady state contrast enhanced (SSCE) fMRI to image CBF and CBV, concomitantly. Here we report on the test-retest reliability of this method by comparing CBF and CBV images acquired on older subjects at two time-points, 90 days apart.

Nadine N Graedel¹, Mark Chiew¹, Stuart Clare¹, and Karla L Miller^1
1FMRIB Center, University of Oxford, Oxford, Oxfordshire, United Kingdom

3D EPI provides a number of advantages over 2D multi-slice acquisition for high-resolution fMRI. However, the temporal signal characteristics of 3D sampling have not been fully characterized, particularly with respect to the interaction of physiological noise and acceleration. In this work we looked at the effect of varying slice acceleration factors on temporal SNR at different resolutions for in vivo and phantom acquisitions. We found a significantly different behavior of the in vivo tSNR compared to predictions based on thermal noise considerations alone. We present an investigation into potential sources of these effects.

Marta Morgado Correia¹, Arjen Alink¹, and Nikolaus Kriegeskorte^1
1MRC Cognition and Brain Sciences Unit, Cambridge, Cambridgeshire, United Kingdom

High resolution fMRI has the potential to reveal brain activity patterns in greater spatial detail, which promises more precise localisation and the elucidation of population-code information residing in fine-grained columnar patterns of neuronal activity. However, there are significant challenges of acquiring high resolution data at 3T. In this study we compared three fMRI resolutions (1.6mm, 2mm, and 3mm isotropic) in terms of their decoding accuracy of checkerboard-like response patterns in early visual cortex at different spatial scales.

Nicholas P Blockley^1
1FMRIB Centre, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, Oxon, United Kingdom

The reversible transverse relaxation rate, R₂, is sensitive to mesoscopic magnetic field inhomogeneity resulting from subvoxel differences in magnetic susceptibility. This sensitivity has been exploited to measure tissue iron concentration, resting oxygen extraction fraction (qBOLD) and changes in oxygen metabolism (calibrated BOLD). However, R₂ is also sensitive to macroscopic magnetic field inhomogeneity that left uncorrected will reduce the specificity of these applications. In this work we combined an echo planar Asymmetric Spin Echo (ASE) pulse sequence with the Gradient Echo Slice Excitation Profile Imaging (GESEPI) technique to provide compensation for through-slice magnetic field gradients during image acquisition.

Yasha Khatamian¹ and J. Jean Chen^1
1Rotman Research Institute, Toronto, ON, Canada

This study investigated the effects of respiratory noise on gradient-echo vs. spin-echo BOLD acquired in the resting-state. Correlations were calculated between gradient-/spin-echo scans and the raw respiration volume over time signal as well as this same signal convolved with a respiration response function. Spin-echo showed weaker and less structured correlations to the respiration volume over time signal, supporting the idea that the effects of this signal are more prominent in gradient-echo scans and have a potential macrovascular origin. The findings presented here further support the benefits of using spin-echo BOLD as an alternative in resting-state functional MRI studies.

Boris Keil¹, Filip Grigorov², Andre J van der Kouwe¹, Lawrence L Wald^1,3, and Reza Farivar^2
1A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States, ²McGill Vision Research Unit, McGill University, Montreal, QC, Canada, ³Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, United States

A dense, form-optimized 32-channel visual cortex array coil was constructed and compared to a commercial 32-channel brain coil at 3T. The array coil provides substantial gain in cortical SNR in accelerated imaging acquisitions. The coil allows for sub-millimeter functional imaging using a conventional sequence, and the resulting images empowered high-resolution mapping and measurement of visually-driven activity with minimal pre-processing.

Shih-Hsien Yang¹, Yun-An Huang², Tzu-Hao Harry Chao³, Der-Yow Chen⁴, Kuan-Hung Cho⁵, Li-Wei Kuo⁶, Jyh-Horng Chen², and Changwei W. Wu^1
1Graduate Institute of Biomedical Engineering, National Central University, Taoyuan, Taiwan, ²Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan, ³Department of Life Science, National Taiwan University, Taipei, Taiwan, ⁴Department of Psychology, National Cheng Kung University, Tainan, Taiwan, ⁵Institute of Brain Science, National Yang-Ming University, Taipei, Taiwan, ⁶Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, Miaoli, Taiwan

The blood-oxygenation-level-dependent (BOLD) fMRI has been widely implemented to study brain functions. However, the BOLD contrast still suffers the low temporal resolution and low sensitivity. Here, we applied single carrier Wideband (WB) MRI technique on gradient echo imaging (GRE) sequence in fMRI studies, in order to reduce the scan time and enhance the T2* sensitivity. By examining the simulated BOLD contrast from different inhaled gas, this study demonstrated the reduced scan time and enhanced sensitivity of the Wideband MRI technique.

Alexandru V Avram¹ and Peter J Basser^1
1Section on Tissue Biophysics and Biomimetics, National Institutes of Health, Bethesda, MD, United States

Quantifying voxel-averaged measures of cytoarchitecture and tissue microstructure can provide valuable information about functional organization of normal and pathological brain tissue. In this study, we apply the recently developed MAP-MRI framework to derive microscopic descriptors of brain tissue and estimate average axon diameters (AAD) in healthy volunteers. We quantify AAD variations along white matter pathways and discuss the feasibility of estimating conduction delays along these fibers. Finally, we propose a new measure for quantifying whole-brain functional connectivity at a millisecond-scale called Latency Matrix.

Satomi Higuchi¹, Ikuko Uwano¹, Kohsuke Kudo^1,2, Jonathan Goodwin^1,2, Fumio Yamashita¹, Kenji Ito¹, Taisuke Harada^1,2, and Makoto Sasaki^1
1Division of Ultrahigh Field MRI, Iwate Medical University, Yahaba, Iwate, Japan, ²Department of Diagnostic and Interventional Radiology, Hokkaido University Hospital, Sapporo, Hokkaido, Japan

Ultra-high field MRI offers potential benefit for functional imaging due to enhanced BOLD effect. However, signal intensity inhomogeneity is severe at ultrahigh field MRI. Therefore, we tested the effect of signal inhomogeneity correction for detection of BOLD signal changes, and found that brain regions affected by coil insensitivity and susceptibility artefact showed underestimated BOLD signal, whereas regions closest to the surface coil such as visual cortex, showed overestimated BOLD signal. These results highlight the need for pre-processing of ultra-high field fMRI data to correct for inhomogeneity of signal intensity, prior to model estimation.

Luis Miguel Lacerda^1,2, André Santos Ribeiro^2,3, Nuno Andre da Silva^2,4, Rafael Neto Henriques^2,5, and Hugo Alexandre Ferreira^2
1Centre for Neuroimaging Sciences, Institute of Psychiatry, King's College London, London, Denmark Hill, United Kingdom, ²Institute of Biophysics and Biomedical Engineering, Faculty of Sciences of the University of Lisbon, Lisbon, Portugal, ³2Centre for Neuropsychopharmacology, Division of Brain Sciences, Department of Medicine, Imperial College London, London, London, United Kingdom, ⁴Forschungszentrum Jülich GmbH, Institute of Neuroscience and Medicine - 4, Jülich, Germany, ⁵Cognition and Brain Science Unit, Medical Research Council, Cambridge, United Kingdom

In this work we present the Multimodal Imaging Brain Connectivity Analysis (MIBCA) toolbox. This application is an easy-to-use interface for automatic MRI and PET data pre-processing, group analysis, and visualization of connectivity and complexity data using graph theory analysis. Here, software features are demonstrated using a multimodal dataset comprised of volumetric T1-weighted, DTI, BOLD and FDG PET data for studying anatomical, structural, functional and effective connectivities. We believe this toolbox can greatly accelerate research in brain connectivity.

Laleh Golestanirad^1,2, Tom Schweizer³, Sunit Das³, Fred Tam⁴, and Simon Graham^1
1Medical Biophysics, University of Toronto, Toronto, Ontario, Canada, ²Laboratory of Electromagnetics and Acoustics, Ecole Polytechniqe Federale de Lausanne, Lausanne, Vaud, Switzerland, ³St Michael Hospital, Toronto, Ontario, Canada, ⁴Sunnybrook Research Institute, Toronto, Ontario, Canada

Neuropsychological tests involving word generation are very commonly applied in patients with brain disease. In this work we present, for the first time, an fMRI study of a written version of the phonemic fluency task that can reliably reproduce all the previously reported activation. AS additional validation we also show that the cerebellar activation foci associated with the written phonemic fluency task which is agree with previously reported lesion analysis results.

Jun Lv¹, Dongdong Liu², Jing Ma³, JUE ZHANG^1,2, Xiaoying Wang^1,4, and Jing Fang^1,2
1Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, Beijing, China, ²College of Enigneering, Peking University, Beijing, Beijing, China, ³Dept. of Pulmonary Medicine, Peking University First Hospital, Beijing, China, ⁴Dept. of Radiology, Peking University First Hospital, Beijing, Beijing, China

Graph theoretical analysis of functional magnetic resonance imaging (fMRI) time series has revealed a small-world organization of slow-frequency blood oxygen level dependent (BOLD) signal fluctuations during wakeful resting. The purpose of this study was to use this approach to explore the changes of paralimbic-limbic cortex during slow wave sleep which are reflected in small-world properties and functional connectivity of our brain network. Our result suggested that paralimbic-limbic cortex was getting more independent when human sleep. It means that our brain owns a kind of defense mechanism responsible for suppressing the external environment interference which may strongly explain why sleep insufficiency has adverse impact on memory. Thus, our study provides a new insight for revealing the significance of sleep on memory process.

Jong-Su Baeck¹, Yang-Tae Kim², Yeon Sung Jung³, Jeehye Seo¹, Seong-Uk Jin¹, Mun Han¹, and Yongmin Chang^1,4
1Department of Medical & Biological Engineering, Kyungpook National University, Daegu, Korea, ²Department of Psychiatry, Keimyung University Dongsan Medical Center, Daegu, Daegu, Korea, ³Department of Marketing, School of Business Administration, Dankook University, Gyeong-gi, Korea, ⁴Department of Radiology, College of Medicine, Kyungpook National University, Daegu, Korea

The strong point of the advertising strategy using celebrity power is to imprint the products in minds of consumers quickly and to attract attention. In this study, we examined the neural response to have an effect of celebrity on favorableness toward the car. Combination of a celebrity face and a car showed higher activation in orbitofrontal cortex (OFC), temporal pole and insula compared to a combination of ordinary face and a car. Our fMRI findings therefore support celebrity power on car advertising and provide neural mechanisms in relation to it.

Marie-Claire Reville¹, Ian Frampton², Jonathan Fulford³, Matthew Holland², Shanker Venkatasubramanian⁴, Benjamin Rock⁵, Michael Depledge⁶, and Mathew White^2
1Psychology, University of Exeter, Exeter, Devon, United Kingdom, ²European Centre for Environment and Human Health, University of Exeter Medical School, Truro, Cornwall, United Kingdom, ³MR Research Centre, University of Exeter Medical School, Exeter, Devon, United Kingdom, ⁴University of Exeter Medical School, European Centre for Environment and Human Health, Truro, Cornwall, United Kingdom, ⁵Department of Nuclear Medicine, Royal Cornwall Hospitals NHS Trust, Truro, Cornwall, United Kingdom,⁶European Centre for Environment and Human Health, University of Exeter Medical School, Exeter, Devon, United Kingdom

Why do people prefer rural environments and feel better in them? To explore this, 28 participants viewed rural and urban images while their brain was scanned with a fMRI scanner. Results indicate that there are brain regions with significant additional activation in response to urban as opposed to rural image viewing. When images were matched on attractiveness ratings, the amount of activation difference in urban over rural image viewing generally decreased. This suggests that to some extent features of the images are influencing the activation differences. Future research should investigate this further by focusing on factors associated with attractiveness.

Jang Woo Park¹, Sungmook Choi², Yang-Tae Kim³, Jeehye Seo¹, Seong-Uk Jin¹, Mun Han¹, Kyung Eun Jang¹, Kyung Jin Suh*⁴, and Yongmin Chang*^5
1Department of Medical & Biological Engineering, Kyungpook National University, Daegu, Daegu, Korea, ²Department of English Education, Kyungpook National University, Daegu, Korea, ³Department of Psychiatry, School of Medicine, Keimyung University, Daegu, Korea, ⁴Department of Radiology, College of Medicine, Dongguk University, Gyungju, Korea, ⁵Department of Molecular Medicine and Radiology, School of Medicine, Kyungpook National University, Daegu, Korea

In recent decades, several behavioral research studies have demonstrated that use of text-congruous illustrations help to reading comprehension, whereas use of text-incongruous illustrations leads to unfavorable outcomes. However, the neural underpinning of such text-illustration effects is still poorly understood. This study performed fMRI for comparison of the brain activity while 30 Korean female university students read 45 short passages in English with text only and with text-congruous and text-incongruous illustrations. The result of this study show that text-congruous illustrations increase brain areas of attention, motivation, and reward, but text-incongruous illustrations reduce reader's attention and motivation to read text.

Seong-Uk Jin¹, Jang Woo Park¹, Jeehye Seo¹, Jong Su Baeck¹, Mun Han¹, Kyung Eun Jang¹, and Yongmin Chang*^1,2
1Department of Medical & Biological Engineering, Kyungpook National University, Daegu, Korea, ²Department of Molecular Medicine & Diagnostic Radiology, Kyungpook National University, Daegu, Korea

Neuronavigated low-frequency repetitive transcranial magnetic stimulation is known to produce local and interhemisperic neuromodulatory effects on cortical excitability with accuracy in targeting of a given cortical region. However there have been few studies about the duration and extent of neuromodulatory effect in neuronavigated rTMS using functional magnetic resonance image (fMRI). Navigated rTMS on primary motor cortex lead to robust modulation not only at the ipsilateral motor network, but also at the contralateral (unstimulated) hemisphere for more than 20 minutes. Our findings highlight the duration and extent of interhemispheric neuromodulation effects of rTMS with serial consecutive fMRI for the first time.

Kyung Eun Jang¹, Jeehye Seo¹, Seong-Uk Jin¹, Jang Woo Park¹, Mun Han¹, Yang-Tae Kim², Kyung Jin Suh*³, and Yongmin Chang*^1,4
1Department of Medical & Biological Engineering, Kyungpook National University, Daegu, Korea, ²Department of Psychiatry, School of Medicine, Keimyung University, Daegu, Korea, ³Department of Radiology, College of Medicine, Dongguk University, Gyungju, Gyeongsangbuk-do, Korea, ⁴Department of Radiology and Molecular Medicine, Kyungpook National University, Daegu, Korea

Recently, there is a growing interest in training effect of working memory. It has been demonstrated that training induced improvement in working memory was shown in several domains such as updating, shifting, and inhibition. Furthermore, some studies suggest transfer effects of working memory training to cognitive reasoning and fluid intelligence. These findings could be attributable to improvements in general working memory capacity by training program. To the best of our knowledge, the plastic changes in neural networks associated with visuospatial working memory after sports training have been seldom studied. In the present study, we are aimed to investigate the dynamic neural changes in neural activation related to transfer effects of shooting training on visuospatial working memory, using fMRI. We used the difficult version of the judgment of line orientation (JLO) task, which is a well-established visuospatial task to assess angular orientation of lines. Overall, our finding of greater activations in fronto-parietal networks and basal ganglia during the JLO after training suggest not only dynamic neural changes in relation to training but also transfer effects of training to visuospatial working memory. Transfer effects of training to non-trained tasks might be explained by the underlying similarities neural networks as well as neurotransmitter. Thus, higher activity of fronto-parietal networks in this study might provide the basis for transfer effects of shooting training to the JLO task and increased activity of striatum together with increased release of dopamine might also provide a more general mechanism that mediates transfer effects of shooting training to the JLO task.

S. Senthil Kumaran¹, Sunita Gudwani¹, and Rajesh Sagar^2
1Department of NMR, All India Institute of Medical Sciences, New Delhi, Delhi, India, ²Department of Psychiatry, All India Institute of Medical Sciences, New Delhi, Delhi, India

The grapheme (text) to phoneme (sound) conversion involves both fast and slow routes functioning parallel while reading meaningful words. Lexical decisions to pseudowords proceeds slowly and exhaustively than that to words. Neural processing while reading pseudowords involves successful mapping of orthographic forms that recruits inferior frontal gyrus (BA44 and 45), insula, thalamus and caudate nucleus. The current study not only documents the role of these areas but also provides evidence that the need for exhaustive search of mental lexicon during pseudoword reading does not affect the reaction time supersedes the slow.

S SENTHIL KUMARAN¹, Sunita Gudwani¹, Sambhu Prasad², and Rajesh Sagar^2
1Department of NMR, ALL INDIA INSTITUTE OF MEDICAL SCIENCES, New Delhi, Delhi, India, ²Department of Psychiatry, ALL INDIA INSTITUTE OF MEDICAL SCIENCES, New Delhi, Delhi, India

Dyslexia is primarily reading problem in children with normal intelligence. The text interpretation is affected due to uncoordinated interface between phonological and orthographic decoding. Our study aims at exploring the intricacies of these aspects by non-meaningful, meaningful and rhyming tasks. The clinical information when complemented with these results would aim towards more precise, efficient and targeted therapeutic management.

Kapil Chaudhary¹, S SENTHIL KUMARAN², Poodipedi Sarat Chandra³, and Manjari Tripathi^1
1Neurology, All India Institute of Medical Science, New Delhi, Delhi, India, ²Department of NMR, ALL INDIA INSTITUTE OF MEDICAL SCIENCES, New Delhi, Delhi, India,³Neurosurgery, All India Institute of Medical Science, New Delhi, Delhi, India

Hippocampal sclerosis (HS) and malformations of cortical development (MCDs) are most common structural abnormalities in patients with chronic intractable epilepsy. Chronic intractable epilepsy is common cause of mesial temporal sclerosis which can affect mesial temporal structures and mesial frontal region associated language areas. Our result has suggested that LTLE patients showed atypical language reorganization in comparison to RTLE and ETLE group after surgery. In this study we used maximum componants of language (semantic, semantic decision task, lexical and comprehension language). Study is helpful for determine effectiveness of fMRI language paradigm, surgery planning, language reorganisation (Pre & post surgery) in LTLE, RTLE and ETLE patients.

Duc Ha Hoang¹, Anne Pagnier², Emilie Cousin³, Karine Guichardet², Isabelle Schiff², Fanny Dubois-Teklali², and Alexandre Krainik^4
1Grenoble Institute of Neurosciences, Grenoble, France, ²Department of Pediatrics - Grenoble University Hospital, Grenoble, France, ³Laboratoratory of Psychology and Neurocognition - University Pierre Mendès, Grenoble, France, ⁴Department of Neuroradiology and MRI - Grenoble University Hospital, Grenoble, France

Survivors with medulloblastoma demonstrated working memory (WM) deficit, leading to an impairment of school performance. The purpose is to describe the cerebellar involvement in specific cognitive deficits observed in children with medulloblastoma • 9 healthy volunteers children and 5 patients with cerebellar medulloblastoma. Using BOLD fMRI, SPM8 • 4/5 patients had a WM deficit following a resection of left posterior cerebellar lobe (CrusI/II, lobule VIIb/VIII) and inferior vermis; the only patient without WM deficit was the only one without cerebellar hemispheric lesion. BOLD activations were found in the left posterior cerebellar lobe • The left posterior cerebellar lobe may involve the visuospatial WM

Paola Valsasina¹, Maria A. Rocca¹, Alvino Bisecco¹, Khaled Abdel-Aziz², Frederik Barkhof³, Christian Enzinger⁴, Franz Fazekas⁵, Antonio Gallo⁶, Hanneke Hulst³, Xavier Montalban⁷, Nils Muhlert², Gianna C Riccitelli¹, Alex Rovira⁸, Gioacchino Tedeschi⁶, Giancarlo Comi⁹, and Massimo Filippi^1
1Neuroimaging Research Unit, Institute of Experimental Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, MI, Italy, ²Dept. Brain Repair and Rehabilitation, Institute of Neurology, UCL, London, GB, United Kingdom, ³Department of Radiology, Free University Medical Centre, Amsterdam, NL, Netherlands, ⁴Division of Neuroradiology, Medical University of Graz, Graz, AT, Austria, ⁵Department of Neurology, Medical University of Graz, Graz, AT, Austria, ⁶Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, Second University of Naples, Naples, NA, Italy, ⁷Department of Neurology-Neuroimmunology, Vall d’Hebron University Hospital, Barcelona, CT, Spain, ⁸Department of Radiology, Vall d’Hebron University Hospital, Barcelona, CT, Spain, ⁹Department of Neurology, San Raffaele Scientific Institute, Vita-Salute San Raffaele University, Milan, MI, Italy

Functional MRI (fMRI) during a n-Back task was applied in a multicenter study to assess the functional correlates of frontal lobe dysfunction in multiple sclerosis (MS) patients with/without cognitive impairment. Twenty MS patients (47%) were cognitively impaired (CI). With increasing n-back load, CI patients had a distributed reduced fMRI activity (in bilateral parietal and frontal regions, and bilateral insula) and fMRI deactivations (in the bilateral precuneus, posterior cingulate cortex and parahyppocampal gyrus) compared to healthy controls and cognitively preserved patients. Preserved fMRI activity of the frontal lobe is associated with a better cognitive profile in MS.

Jiu Chen¹ and Zhi-jun Zhang^1
1Neurologic Department, Affiliated ZhongDa Hospital, Neuropsychiatric Institute and Medical School of Southeast University, nanjing, jiangsu, China

The study showed that amnestic mild cognitive impairment (aMCI) had the deficits of gray matter (GM) volume on the network of cerebellum-limbic system, and suggests an apolipoprotein E (APOE)-specific effect of age with GM volume on the occipito-insula-frontal neural circuit. Moreover, the results suggest that GM deficits could be accelerated by the combined effect of the aging process and the presence of the APOE ¦Å4 allele. Conversely, the APOE ¦Å2 possibly reflects a protective morphometric main effect, which increases with age in aMCI. The relationship of GM alterations with neuropsychological test supported that GM atrophy was the basis of cognitive impairment in aMCI.

Edward Challis^1,2, Barbara Spano³, Laura Serra³, Marco Bozzali³, Seb Oliver¹, and Mara Cercignani^2
1Physics and Astronomy, University of Sussex, Brighton, Sussex, United Kingdom, ²Clinical Imaging Sciences Centre, Brighton and Sussex Medical School, Brighton, Sussex, United Kingdom, ³Neuroimaging Laboratory, IRCSS Santa Lucia, Rome, Italy

Statistical machine learning techniques are seeing increased interest by the neuroimaging community. Simultaneously clinicians and researchers are also studying the functional connectivity patterns of brains and how these relations might change in conditions like Alzheimer’s disease or clinical depression. In this study we investigate the performance of Gaussian process classifiers to perform patient stratification from functional connectivity patterns of brains at rest. The majority of previous approaches to such problems have focused on using support vector machines to perform classification in this setting. Our results confirm that Gaussian process classifiers form a promising direction for future research.

Lijia Ma¹, Min Guan¹, Liang Li², Li Tong², Yong Zhang³, Dandan Zheng³, Bin Yan², Meiyun Wang¹, and Dapeng Shi^1
1Radiology, People's Hospital of Zhengzhou University, ZhengZhou, HeNan, China, ²National digital swiching system engineering and technological research center, HeNan, China, ³GE Healthcare, Beijing, China

Previous studies found that by using real-time functional MRI (rtfMRI) neurofeedback, subjects could learn to control activation in the target brain region.We hypothesize that through rtfMRI neurofeedback,PHN patients could learn to control the activation in rACC,a region involved in pain perception and regulation.5 PHN patients performed a corresponding imagery task and were instructed to increase and decrease activation in rACC using rtfMRI neurofeedback.3/5 patients learned to change their fMRI signal with intermittent feedback training.Also there was a corresponding change in the perception of pain.This investigation may provide an alternative way for treatment of severe, chronic clinical pain in the future.

Tamar M van Veenendaal¹, Dominique M IJff², Richard HC Lazeron², Walter H Backes¹, Paul AM Hofman¹, Marielle CG Vlooswijk³, Anton de Louw², Albert P Aldenkamp², and Jacobus FA Jansen^1
1Radiology, Maastricht University Medical Centre, Maastricht, Netherlands, ²Epilepsy Centre Kempenhaeghe, Heeze, Netherlands, ³Neurology, Maastricht University Medical Centre, Maastricht, Netherlands

Cognitive adverse events often arise when antiepileptic drugs (AEDs) are used to treat epilepsy. We hypothesize that these cognitive problems are accompanied with a less efficient brain network and test this using graph theoretical measures on resting-state fMRI data. The normalized characteristic path length and clustering coefficient of a ‘low risk’ group (epilepsy patients using AEDs associated with mild cognitive side effects) was compared to a ‘high risk’ group (patients using AEDs associated with more severe cognitive side effects). A significant association was found between risk group the clustering coefficient of the frontal areas, but not of the whole brain.

Jun Chen¹, Jinhuan Liu¹, Zihu Tan², Ni Li², Yilin Zhao¹, Dongjie Huang¹, Qizhong Xu¹, and Liang Zhang^1
1Department of Radiology, Renmin Hospital of Wuhan University, Wuhan, Hubei Province, China, ²Department of Geriatrics, Hubei Hospital of Traditional Chinese Medicine, Wuhan, Hubei Province, China

Sudden changes of the brain could signify some underlying dangers for the patients with aphasia from apoplexy. Therefore, rapid detection of sudden changes of the brain is crucial for survival. Acupuncture is a complementary and alternative medicine (CAM) modality that is practiced in many parts of the world for a variety of ailments1. The efficacy of acupuncture is already accepted for postoperative and chemotherapy nausea and vomiting and in postoperative dental pain. The acupoints are arranged on so-called ¡°meridians¡±, which represent a network of channels each connected to a functional organic system. However, the scientific basis of acupuncture remains unclear. Functional MRI (fMRI) is an established clinical diagnostic method as well as an indispensable tool in clinical research2. It has been utilized for language and other cortical function localization3, which can significantly improve our understanding of the functions of different language center. This work focused on analyzing the rehabilitative action involved in acupuncture and the early phase fMRI signal to evaluate the underlying neural recovery.

Adnan Alahmadi^1,2, Rebecca Samson¹, David Gasston³, Matteo Pardini^1,4, Karl Friston⁵, Ahmed Toosy^1,6, and Claudia A.M. Wheeler-Kingshott^1
1NMR Research Unit, Department of Neuroinflammation, Queen Square MS Centre, UCL Institute of Neurology, London, United Kingdom, ²Department of Diagnostic Radiology, Faculty of Applied Medical Science, KAU, Jeddah, Saudi Arabia, ³Department of Neuroimaging, Institute of Psychiatry, King's College London, London, United Kingdom,⁴Department of Neurosciences, Ophthalmology and Genetics, University of Genoa, Genoa, Italy, ⁵Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, London, United Kingdom, ⁶NMR Research Unit, Department of Brain Repair and Rehabilitation, Queen Square MS Centre, UCL, London, United Kingdom

We have investigated non-linear responses in BOLD using a parametric fMRI power grip motor experiment with five target grip force levels in healthy volunteers. We have demonstrated the ability to detect a complex BOLD response to grip force modulation, affecting different brain regions. The study showed linear and non-linear BOLD responses to varying grip forces in the primary motor cortex and non-linear responses (up to the 4th order) in other motor and non-motor areas. We concluded that BOLD signal and force have a complicated relationship that is far from a simple correlation and further physiological confirmations are warranted.

Toshiharu Nakai¹, Ayuko Tanaka¹, Mitsunobu Kunimi¹, Sachiko Kiyama¹, and Yoshiaki Shiraishi^2
1NeuroImaging & Informatics, NCGG, Ohbu, Aichi, Japan, ²Computer Science and Engineering, NITECH, Nagoya, Aichi, Japan

An event-related fMRI using virtual performance of a hand manipulation test for elderly was designed to investigate the neural basis of potential cognitive decline. Precise timing of three visuo-motor operations to transfer a target object to the goal was recorded by using turnkeys to define the time series of the events. It was demonstrated that activation of dorsal visual pathway was augmented in the elderly group when the visuo-motor performance was switched, suggesting that‘switching cost’ may be a more sensitive index as age related change than the other cognitive processing used for three steps of visuo-motor task.

Jan Rydlo¹, Filip Spaniel², Ibrahim Ibrahim¹, and Jaroslav Tintera^1
1Institute for Clinical and Experimental Medicine, Prague, Czech Republic, Czech Republic, ²Prague Psychiatric Center, Prague, Czech Republic, Czech Republic

Our study deals with differences in activation of self-reference patterns between patients with first episode of schizophrenia and healthy subjects. The paradigm to activate self-reference pattern, performed by a joystick, allows to manipulate the experience of movement control by visual feedback. Controls showed increased activation compared to patients in anterior cingulate, mediofrontal cortex, precuneus. Patients did not activate midline cortical structures during the self-reference experiment.

Cecil Chern-Chyi Yen¹, Camille Toarmino², David A. Leopold³, Cory T. Miller², and Afonso C. Silva^1
1CMU/LFMI/NINDS, National Institues of Health, Bethesda, Maryland, United States, ²Psychology, University of California San Diego, La Jolla, California, United States,³SCNI/LN/NIMH, National Institutes of Health, Bethesda, Maryland, United States

The tonopotic organization of the auditory cortex has been a great interest for neuroscientists to understand the encoding of sounds in the brain. An auditory experimental design consisting of three random frequency ranges and a continuous sampling scheme was presented to study the tonotopic organization in awake marmoset, which had been shown to have great potential as a novel animal model for auditory studies. For the first time, we demonstrated the robust BOLD fMRI response as well as the tonotopic map in auditory cortex of awake marmosets.

Keren Yang¹, Rosa Sanchez Panchuelo¹, Denis Schluppeck², Richard W. Bowtell¹, and Susan T. Francis^1
1Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom, ²School of Psychology, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom

We use ultra-high field (7 Tesla) fMRI to assess orientation mapping in dorsal and ventral visual areas (V1, V2, V3). Within visual areas, the phase value of orientation maps are compared with those of angular-position from retinotopic maps, and are shown to display a high correlation (P<0.0001). Repeatability is shown to be high for both retinotopic and orientation maps. BOLD CNR is assessed as a function of number of repeat scans of orientation maps, with CNR being a factor of ~4 lower for orientation maps compared to retinotopic maps.

Patrick P. Gao^1,2, Jevin W. Zhang^1,2, Iris Y. Zhou^1,2, Joe S. Cheng^1,2, Dan H. Sanes³, and Ed X. Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, HKSAR, China, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, HKSAR, China, ³Department of Biology, New York University, New York, NY, United States

Ultrahigh frequencies (UHFs) are important for social communication of many species (e.g. higher than 40/60 kHz for rats/mice, respectively). While lower frequencies are known to be represented as tonotopy in the auditory system, it remains largely unclear how the UHFs are encoded and processed. In the auditory pathway, the inferior colliculus (IC) is a midbrain nucleus targeted by both ascending and descending auditory projections, thus a key station for auditory information processing. In this study, non-invasive BOLD fMRI was applied to investigate the underlying mechanisms of UHF encoding in the IC.

Condon Lau¹, Jevin W Zhang^2,3, Wing-Ho Yung⁴, and Ed X Wu^2,3
1Division of Biomedical Engineering, HKUST, Kowloon, Hong Kong, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, Hong Kong,³Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, Hong Kong, ⁴School of Biomedical Sciences, The Chinese University of Hong Kong, New Territories, Hong Kong

The brain depends on an adequate oxygen supply and hypoxia occurs when the supply is inadequate. Chronic hypoxia is a significant feature of multiple health conditions and occupations that have been associated with hearing disorders. We employed BOLD fMRI to investigate the effects of chronic intermittent hypoxia on central auditory physiology in an animal hypoxia model. Larger fMRI responses are observed in both auditory cortex hemispheres of hypoxia subjects. This difference may be related to earlier auditory evoked potential observations which suggested an abnormal stimulus classification response. Future fMRI studies can examine auditory physiology changes in human subjects at risk of chronic hypoxia.

Ankeeta Sharma¹, Senthil Kumaran¹, and Rohit Saxena^2
1Department of NMR, All India Institute of Medical Sciences, New Delhi, Delhi, India, ²Dr. Rajendra Prasad Centre For Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, Delhi, India

Objects have characteristic attributes (such as two or three-dimensional shape, textute, depth etc) that can be perceived both visually and haptically. Therefore, object-related brain areas may hold a representation of objects in both modalities. Humans have an exceptional ability to estimate the shape of objects from a combination of visual cues such as shading, texture etc. In the human brain, the ventral object visual pathway can generate distinct representations for a virtually unlimited type of texture and depth cues. Haptic perceptionof object or shape categories evokes distinct patterns of neural activation in ventral occipito- temporal cortexthat are widely distributed.

Mahta Karimpoor^1,2, Fred Tam³, Tom Schweizer^4,5, Corinne Fischer^6,7, and Simon Graham^1,2
1Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada, ²Medical Biophysics, University of Toronto, Toronto, Ontario, Canada, ³Medical Biophysics, Sunnybrook Research Institute, Toronto, Ontario, Canada, ⁴Neurosurgery, Keenan Research Centre in the Li Ka Shing Knowledge Institute, Toronto, Ontario, Canada,⁵Neuroscience Research Program, St. Michael's Hospital, Toronto, Ontario, Canada, ⁶Keenan Research Centre in the Li Ka Shing Knowledge Institute, Toronto, Ontario, Canada, ⁷Geriatric Psychiatry, St. Michael's Hospital, Toronto, Ontario, Canada

Neuropsychological (NP) tests are commonly used to detect abnormal brain function. Functional MRI may help to characterize brain activity underlying NP test performance, toward increasing test sensitivity and specificity. Here, we refine an fMRI-compatible tablet device for studying NP tests which require a touch screen computer. Using the paired associates learning (PAL) NP test as an example, it is shown that integrating video data to provide users with visual feedback of hand position during tablet responses, instead of having them rely primarily on proprioceptive inputs, produces activation maps where the learning and memory contributions to PAL are more readily identified.

Shin-Lei Peng^1,2, Lin-Yi Huang¹, Sheng-Min Huang¹, Yi-Chun Wu³, Fu-Chan Wei⁴, Chih-Jen Wen⁴, Hui-Yu Cheng⁴, Chih-Hung Lin⁴, and Fu-Nien Wang^1
1Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan, ²Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States, ³Molecular Imaging Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan, ⁴Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan

In this study, we investigated the age-related change in the BOLD response to whisker pad stimulation by including 3- and 9-month-old rats. Results showed that BOLD responses to a whisker pad stimulus were similar in the spatial extent, signal changes and hemodynamic response between 3M and 9M rats. These results indicate that rodent fMRI studies are feasible in populations composed of rats aging up to 9-month-old. The further age-related correlation is not needed in the rodent fMRI studies.

Shwan Kaka¹ and Martyn Paley^1
1Academic Radiology, University of Sheffield, Sheffield, Yorkshire, United Kingdom

The aim of this study was to investigate whether fMRI responses can be measured during median nerve activity. The median nerve was stimulated at the threshold of action potential generation using transcutaneous electrical nerve stimulation (TENS). Evidence of fMRI responses in the median nerve during wrist stimulation by TENS was observed at relatively high stimulation frequencies (2.5 and 3.5 Hz).

Michela Fratini¹, Marta Moraschi^1,2, Bruno Maraviglia¹, Federico Giove^1,3, Paul Summers⁴, Stefania Favilla⁴, and Carlo Adolfo Porro^4
1Fermi Center, Rome, Rome, Italy, ²Fondazione Santa Lucia, Rome, Italy, ³Dipartimento di Fisica, Sapienza Universita` di Roma, Rome, Italy, ⁴Dipartimento di Scienze Biomediche, Univ. Modena e Reggio Emilia, Modena, Italy

Spinal cord fMRI may be of immediate application in neuroradiology, and in particular for the assessment and follow-up of spinal injuries, pain, and neurodegenerative diseases. However, the exact features of functional response, and the biophysical origin of the signal, are still unclear. In this framework, we parametrically studied the connection between stimulation strength and functional response using controlled motor task (isometric task). We observe a strong parametric dependence of functional response in the spinal cord on the stimulation strength. Such a dependence confirms the physiological origin of the response, and is of great help in model-based fMRI inference.

Yuji Komaki^1,2, Keigo Hikishima^1,2, Shinsuke Shibata¹, Masaya Nakamura¹, and Hideyuki Okano^1
1Keio University, Shinjuku, Tokyo, Japan, ²Central Institute for Experimental Animals, Kawasaki, Kanagawa, Japan

For better understanding of the neuropathic pain, one of the crucial tasks is to develop the evaluation of the pain with high objectivity. The neuropathic pain model with surgical manipulation and with inheritable genetic modification was compared with intact mice using tactile like stimulus for peripheral nerve fibers. The resulting analysis showed, for intact mice, the only S1 was activated. In comparison with intact model, models of neuropathic pain showed the significantly high BOLD activities in ACC and thalamus. Therefore abnormally connection of A-fiber was considered as a possible cause of neuropathic pain.

Tomokazu Murase¹, Masahiro Umeda², Masaki Fukunaga³, Katsuya Maruyama⁴, Yuko Kawai², Yasuharu Watanabe², Chuzo Tanaka¹, and Toshihiro Higuchi^1
1Neurosurgery, Meiji University of Integrated Medicine, Nantan-shi, Kyoto, Japan, ²Medical Informatics, Meiji University of Integrated Medicine, Kyoto, Japan, ³Biofunctional Imaging, Immunology Frontier Research Center, Osaka University, Osaka, Japan, ⁴Research&Collaboraton, Siemens Japan K.K., Tokyo, Japan

We used MB-EPI and deconvolution analysis to examine the temporal signal change, at a high time resolution, in brain activity caused by acupuncture stimulation. For statistical analysis, 3dDeconvolve, which is part of the AFNI package, was used to extract the impulse response functions (IRFs) of the fMRI signals on a voxel-wise basis. Delayed and long-sustained increases of the signal induced by the real acupuncture were observed after stimulation. Especially, in real acupuncture, significantly delayed and long-sustained increases of BOLD signals were observed in several brain regions related to pain perception than those observed in sham acupuncture and palm scrubbing.

Christian Sprenger¹, Jürgen Finsterbusch¹, and Christian Büchel^1
1Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany

With blood-oxygenation level-dependent functional MRI (fMRI) the central nervous system can be investigated in vivo, e.g., to study the representation and modulation of pain. Many fMRI studies on the brain'’s role in pain processing have been performed and recently interest in the spinal cord’'s involvement has increased. However, to study the functional interplay between the brain and the spinal cord in pain processing, both regions must be covered in a single measurement. Here, first results of a combined fMRI study to investigate the processing of painful thermal stimuli in the brain and the spinal cord are presented.

Naoya Yuzuriha¹, Sosuke Yoshinaga¹, Makoto Hirakane¹, Kazunari Kimura¹, Shigeto Iwamoto¹, Hiroshi Sato², Akihiko Fujikawa³, Masayasu Takahashi⁴, and Hiroaki Terasawa^1
1Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan, ²Bruker Biospin K.K., Yokohama, Kanagawa, Japan, ³Bioimaging Research Labs, Astellas Pharma Inc., Tsukuba, Ibaraki, Japan, ⁴Pharmacology Research Labs, Astellas Pharma Inc., Tsukuba, Ibaraki, Japan

The aim of this study is to establish an experimental system applicable for the elucidation of the pathogenic mechanism underlying allodynia. Using a BOLD-fMRI method, the brain activation caused by allodynic pain with green laser stimuli of fibromyalgia-model or normal rats was evaluated. In the fibromyalgia-model rats, positive BOLD responses were observed in the cingulate cortex, the primary somatosensory cortex, the secondary somatosensory cortex, the insula cortex, and the thalamus. We successfully observed allodynia in the animal model of fibromyalgia. The green laser greatly facilitates the elucidation of the allodynia-specific neural circuits.

Jennifer Wegrzyk¹, Jean-Philippe Ranjeva¹, Sylviane Confort-Gouny¹, Hélène Boudinet^1,2, David Bendahan¹, and Julien Gondin^1
1Aix-Marseille Université, CNRS, CRMBM (Centre de Résonance Magnétique Biologique et Médicale) UMR 7339, Marseille, France, ²CEMEREM, APHM, Pôle Imagerie, Marseille, France

In this BOLD fMRI study we illustrated that cerebral activation patterns in healthy subjects were significantly different between two neuromuscular stimulation protocols (using either “conventional” or “wide-pulse, high-frequency” parameters) and voluntary contractions. Plantar flexions were performed under isometric conditions at a given submaximal intensity level inside a 1.5T scanner. The results show that the brain activation was higher for “wide-pulse, high-frequency” as compared to conventional neuromuscular electrostimulation and closer to the physiological brain activation pattern of voluntary contractions.

I-Jung Chen¹, Yeh-Hsiung Cheng², Tzu-Cheng Chao^1,2, and Ming-Long Wu^1,2
1Department of Computer Science and Information Engineering, National Cheng Kung University, Tainan, Taiwan, ²Institute of Medical Informatics, National Cheng Kung University, Tainan, Taiwan

In most fMRI studies, repetition time (TR) of 2-3 seconds is typically used to detect neuronal activities. However, for fMRI studies targeting effective connectivity (EC), such long TR might be unfavorable for detecting causal relationship among brain regions. In this study, effect of TR on detectability of EC using conditional Granger causality analysis (CGCA) is investigated. Results from auditory-motor fMRI experiments show that short TR (<1 second) is preferred for analyzing effective connectivity among brain regions, which gives an important hint that current fMRI protocols might need to be adjusted to better study causal relationships in human brain.

Liang Li¹, Li Tong¹, Bin Yan¹, Ying Zeng¹, Linyuan Wang¹, and Jianxin Li^1
1China National Digital Switching System Engineering and Technological Research Center, zhengzhou, Henan, China

We propose a new activation detection method for rt-fMRI data based on robust kalman filter. The This method adds a variation to the update step in the extended kalman filter to fit the unexpected noise in the general linear model, then solving the variation using the convex optimization, finally and use the solved variation to modify the kalman filter . The method can be used in the Functional localization run to find the brain regions associate with the tasks in real time. In clinical application, The method can be used in the functional localization run to obtain the brain regions associate with the tasks in real time, the algorithm can be used in the functional location run especially for the subjects who could not keep peace during the experiments .

Yong Zhang¹, Dapeng Shi², Min Guan², Lijia Ma², and Chunyan Shen^2
1GE Healthcare, Shanghai, Shanghai, China, ²Henan Provincial People's Hospital, Zhengzhou, Henan, China

This preliminary study investigated perfusion changes associated with real-time fMRI neurofeedback training targeting motor cortex. Six right-handed healthy volunteers underwent five days¡¯ neurofeedback training to self-regulate the brain activity within the left motor cortex using the finger tapping imagery task for the dominant right hand. Pre- to post-training comparison revealed increased CBF in the left motor and somatosensory cortex as well as the visual cortex but decreased CBF in the right anterior dorsolateral prefrontal cortex (DLPFC), which might provide interesting insight into the mechanism of neurofeedback training.

Willem M Otte^1,2, Pascal Bieleveld³, Eric van Diessen², Umesh S Rudrapatna⁴, Kees P Braun², and Rick M Dijkhuizen^1
1Image Sciences Institute, University Medical Center Utrecht, Utrecht, Utrecht, Netherlands, ²Department of Pediatric Neurology, University Medical Center Utrecht, Utrecht, Utrecht, Netherlands, ³Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands, ⁴Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut, United States

Using resting-state fMRI and minimum-spanning tree analysis the functional hippocampal network organization was characterized in relation to the extent of spatial memory, following experimental hemispherectomy in rats. The data sheds new light on patterns of change in functional network organization in the contralateral hippocampus in relation to changes in spatial memory after hemispherectomy. Improved spatial memory after hemispherectomy related to decreased diameter and increased leaf number of the network’s minimum-spanning tree, indicating a shift towards a more star-like network. This supports the hypothesis that reorganization of hippocampal neural networks contributes to consolidation of spatial learning and memory after hemispherectomy.

Daehun Kang^1,2, Yul-Wan Sung¹, Uk-Su Choi³, and Seiji Ogawa^1
1Kansei Fukushi Research Center, Tohoku Fukushi University, Sendai, Miyagi, Japan, ²Graduate School of Information Sciences, Tohoku University, Sendai, Miyagi, Japan,³Neuroscience Research Institute, Gachon University of Medicine and Science, Incheon, Korea

A functional area of a human brain is usually activated by multiple stimuli, and category-selective areas (i.e. fusiform face area & parahippocampal place area) are also activated by a non-preferred stimulus as well as the preferred stimulus. With using conventional fMRI method, it is difficult to know whether all of the neurons in activated areas respond to both the preferred and non-preferred stimuli or whether a part of neuronal population is separately activated by each stimulus. In the present study, we measured fMRI responses using multi-echo-train echo-planar-imaging to discriminate the neuronal populations in a functional area.

Sarah Sonnay¹, João M.N. Duarte^1,2, Rolf Gruetter^1,3, and Nathalie Just^1,2
1LIFMET, EPFL, Lausanne, Switzerland, ²Radiology, University of Lausanne, Lausanne, Switzerland, ³Radiology, Universities of Geneva and Lausanne, Geneva/Lausanne, Switzerland

Brain circuitry can be studied with BOLD fMRI, but long stimulation paradigms might be needed to investigate long-term neuronal modifications. The aim of the study was to develop a method to activate the rat brain for 2 hours. SD rats (n=10,322±13g) under α-chloralose anesthesia underwent electrical stimulation of the forepaw. BOLD fMRI was performed at 9.4T using GE-EPI. We observed sustained and localized BOLD responses with minimum activated volume loss during 2 hour-stimulation in varying the frequency at regular intervals and in using small ISI. We conclude that the applied paradigm increases the statistical power for connectivity analysis.

Joe S. Cheng^1,2, Jevin W. Zhang^1,2, Patrick P. Gao^1,2, Adrian Tsang^1,2, Iris Y. Zhou^1,2, and Ed X. Wu^1,3
1Department of Electrical and Electronic Engineering, the University of Hong Kong, Hong Kong, Hong Kong, ²Laboratory of Biomedical Imaging and Signal Processing, the University of Hong Kong, Hong Kong, Hong Kong, Hong Kong, ³Laboratory of Biomedical Imaging and Signal Processing, the University of Hong Kong, hong kong, Hong Kong, Hong Kong

The direction of frequency-modulation (FM) sweep is an important acoustic cue for human language and animal vocal communications. To investigate FM direction processing in development and disease models, an in vivo and non-invasive technique with high spatial resolution is desired. Therefore, we investigated the FM direction selectivity in the rat subcortex using. The BOLD signal changes during upward sweeps were significantly higher than those during downward sweeps in the dorsal CIC, while dorsal nuclei of later lemniscus didn¡¦t show any directional selectivity. Therefore, fMRI proves a feasible tool to probe the FM sweep direction selectivity in the subcortical structures.

Jevin W. Zhang^1,2, Shu-juan Fan^1,2, Patrick P. Gao^1,2, Joe S. Cheng^1,2, Dan H. Sanes³, and Ed X. Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, the University of Hong Kong, Hong Kong, Hong Kong, China, ²Department of Electrical and Electronic Engineering, the University of Hong Kong, Hong Kong SAR, China, ³Center for Neural Science, New York University, New York, New York, United States

bSSFP fMRI with swept source imaging paradigm was applied on the experimental and age-matched control group to examine the effect of bilateral auditory cortex ablation on the tonotopic organization in inferior colliculus (IC). The differences between the changes of encoded frequency along the tonotopic axis suggested the tuning curve bandwidth center was shifted toward different directions for neurons at different portions of the IC. This study clearly demonstrated that cortical input can modulate the tonotopic organization in IC.

Erik Beall¹, Mark Lowe¹, and Mingyi Li^1
1Imaging Institute, Cleveland Clinic, Cleveland, OH, United States

Intrinsic connectivity is attractive over seeded connectivity methods as there is no need for localization. However, to-date the measures used for intrinsic connectivity as described in the literature suffer several limitations. We were inspired to apply a Gaussian normalization process by a recent method using the distribution of correlation at each voxel. The new method is very attractive from a theoretical standpoint, as it only depends on the shape of the t-score distribution at each voxel and an appropriately-fitted theoretical Gaussian. Our results support the use of this new measure.

Soroosh Afyouni^1,2, Joanne R Hale², Stephen D Mayhew², Theodoros N Arvanitis^1,3, and Andrew P Bagshaw^2
1Institute of Digital Healthcare, WMG, University of Warwick, Coventry, West Midlands, United Kingdom, ²School of Psychology, University of Birmingham, Birmingham, West Midlands, United Kingdom, ³Birmingham Children’s Hospital NHS Foundation Trust, Birmingham, West Midlands, United Kingdom

This study investigated the dynamics of hub regions within the default mode network (DMN) of the human brain. Volunteers underwent a 15-minute fMRI scan and dynamic functional connectivity (FC) was calculated using a 240s sliding window within eight DMN regions of interest. To identify hub regions, both binarized and weighted degree and betweenness centrality metrics were calculated from adjacency matrices obtained using regularized inverse covariance and integrated over a range of thresholds. The posterior cingulate cortex had the highest centrality across the entire scan, consistent with studies using stationary FC which have identified it as the primary DMN hub.

Yue Zhang¹, Jing Liu², Longchuan Li³, Minyi Du⁴, Wenxue Fang⁴, Dongxin Wang⁴, Xuexiang Jiang², Xiaoping Hu³, Jue Zhang¹, Xiaoying Wang², and Jing Fang^1
1College of Engineering, Peking University, Beijing, Beijing, China, ²Department of Radiology, Peking University First Hospital, Beijing, Beijing, China, ³Biomedical Imaging Technology Center, Department of Biomedical Engineering, Georgia Institute of Technology / Emory University, Atlanta, Georgia, United States, ⁴Department of Anesthesiology, Peking University First Hospital, Beijing, Beijing, China

Understanding the effect of postherpetic neuralgia (PHN) pain on brain activity is important for clinic strategies. This is the first study, to our knowledge, to relate PHN pain to small-world properties of brain functional networks. Functional magnetic resonance imaging was used to construct brain functional networks during the resting state. Sixteen patients with PHN pain and sixteen age-matched controls were analyzed (8 males, 8 females for both groups). Decreased local efficiency for PHN in comparison with the healthy controls was found. Moreover, regional nodal efficiency was found to be profoundly affected for PHN.

Ashish Anil Rao¹, Ek Tsoon Tan², Rakesh Mullick¹, and Suresh Emmanuel Joel^1
1General Electric Global Research, Bangalore, Karnataka, India, ²General Electric Global Research, New York, United States

Investigation and understanding of both intra and inter-subject variability of functional connectivity metrics is critical to be able to use it meaningfully in research and the clinic. Here we report an investigatoin of intra and inter-subject reproducibility of functional networks obtained using spatial ICA. We find that higher-order networks and primary networks have different characteristics of reproducibility and may have implications for their use in studying state, trait or disease.

Zhaohua Ding^1,2, Ran Xu¹, Victoria L Morgan^1,3, Adam W Anderson^1,3, and John C Gore^1,3
1Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, ²Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, United States, ³Biomedical Engieering, Vanderbilt University, Nashville, TN, United States

Synopsis: Resting state functional magnetic resonance imaging (MRI) has been conventionally used to study functional connectivity between cortical regions. We present here a novel technique that may be used to depict functional pathways of the human brain. A key concept proposed is spatio-temporal correlation tensor, which is constructed on the basis of spatio-temporal analyses of resting state MRI signals. Our in vivo experiments demonstrate that the technique holds a great potential of directly mapping structure-function relations in the human brain.

Mauro DiNuzzo^1,2, Daniele Mascali^1,2, Marta Moraschi^1,3, Michela Fratini^1,3, Tommaso Gili³, Girolamo Garreffa^1,3, Bruno Maraviglia^1,3, Laura Serra³, Marco Bozzali³, and Federico Giove^1,2
1MARBILab, Enrico Fermi Center, Rome, Rome, Italy, ²Department of Physics, U Sapienza, Rome, Rome, Italy, ³Santa Lucia Foundation IRCCS, Rome, Italy

We computed the maximum positive and minimum negative values of the cross-correlation to obtain a delay-independent measure of the correlation between brain voxels and a seed region. Using standard delay-sensitive analysis based on correlation coefficient, we confirmed previous studies that demonstrated decrease in spatial extension and amplitude of the default-mode network (DMN) areas in Alzheimer’s disease patients. However, this trend could not be observed with cross-correlation analysis, indicating that the loss of correlation of the DMN is possibly the result of an increase in the delay of the propagation of oscillations rather than a decrease in the strength of mutual responses.

Molly G Bright¹ and Kevin Murphy^1
1CUBRIC, School of Psychology, Cardiff University, Cardiff, Cardiff, United Kingdom

We observe structure similar to functional connectivity networks within the data we typically remove from fMRI time series during noise correction. Physiological and head motion regressors were used to extract “noise” variance from resting-state BOLD fMRI data in a general linear model. Independent component analysis identified several key networks, including the default mode network, in the noise datasets. These structures are also observed when using random noise regressors uncoupled to physiology or motion, indicating that this phenomenon is inherent to the removal of any regressors of similar frequencies.

Luis Hernandez-Garcia¹, Alejandro Veloz-Baeza², and Magnus Ulfarsson^3
1University of Michigan, Ann Arbor, Michigan, United States, ²University of Valparaiso, Valparaiso, Chile, ³University of Iceland, Reykjavik, Iceland

We present a novel framework for analyzing the hierarchical relationships between nodes in a brain network in terms of how 'necessary' and 'sufficient' they are for each other. Here, we characterize and demonstrate the feasibility of this framework in simulated and experimental BOLD FMRI data.

Arun Niranjan¹, Jack A. Wells¹, and Mark F. Lythgoe^1
1Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom

Resting state functional connectivity MRI (fcMRI) has been applied in humans and rats, in order to gain a deeper understanding of brain function. Despite a degree of reported application of fcMRI in the mouse brain, significant technical challenges remain that are currently holding back the widespread utility of fcMRI to investigate functional changes in genetic mouse models of neurological disease. In this work, we aim to provide an experimental platform for investigating resting state fcMRI in the mouse brain, and show both phantom and in vivo evidence for parameter choices.

Kay Jann¹, Dylan Gee², Emily Kilroy³, Simon Schwab⁴, Tyrone Cannon⁵, and Danny JJ Wang^1
1Department of Neurology, University of California, Los Angeles, Los Angeles, California, United States, ²Department of Psychology, University of California, Los Angeles, Los Angeles, California, United States, ³Division of Occupational Science, University of Southern California, Los Angeles, California, United States, ⁴Department of Psychiatric Neurophysiology, University Hospital of Psychiatry / University of Bern, Bern, Switzerland, ⁵Department of Psychology, Yale University, New Haven, Connecticut, United States

The purpose of this study was to investigate the similarity and reliability of resting brain networks between BOLD and ASL based rs-fMRI. A 2x2x2 factorial design was applied where 10 subjects underwent repeated BOLD and ASL rs-fMRI scans on two occasions on two separate MRI scanners respectively. While BOLD-networks showed excellent test-retest-reliability across sessions and scanners in their spatial pattern, ASL-networks showed reduced yet still adequate repeatability as well as highly reproducible network CBF measurements. The combination of ASL and -BOLD rs-fMRI provides a powerful tool to fully characterize the spatiotemporal and quantitative properties of resting brain networks.

Hengtai Jan¹, Shih-Yen Lin^1,2, Kuan-Hung Cho³, Yi-Ping Chao⁴, and Li-Wei Kuo^1
1Division of Medical Engineering Research, National Health Research Institutes, Zhunan, Miaoli County, Taiwan, ²Department of Computer Science, National Chiao Tung University, Hsinchu, Taiwan, ³Institute of Brain Science, National Yang-Ming University, Taipei, Taipei, Taiwan, ⁴Department of Computer Science and Information Engineering, Chang Gung University, Kwei-Shan, Taoyuan County, Taiwan

Previous brain network studies have widely reported both structural and functional brain networks show small-world characteristics. However, the strengths of small-worldness may vary due to several factors, such as cortical parcellation number (scale), connectivity measure, and selection of sparsity. The relationship between small-worldness and these factors is still unclear. Therefore, in this study, we aimed to investigate (1) the dependence of small-worldness on the sparsity in either structural or functional networks at multiple scales and (2) the correlation of small-worldness between structural and functional networks. Our results suggest the coherence between functional and structural networks may exist under certain sparsities.

Xiaoyun Liang¹, Alan Connelly^1,2, and Fernando Calamante^1,2
1Brain Research Institute, Florey Institute of Neuroscience and Mental Health, Melbourne, VIC, Australia, ²Department of Medicine, Austin Health and Northern Health, University of Melbourne, Melbourne, VIC, Australia

In this study, a neural mass model has been employed to simulate brain activity at two different levels: neural and BOLD signal. Disrupted network efficiencies have been systematically investigated by simulating each lesioned brain region separately. The relationships between disrupted network efficiencies and degree, betweenness centrality and vulnerability have been studied. Our simulated results indicate that damages to ‘hub’ regions lead to lower global, but not local efficiency. Overall, our simulated results show that the NMM can predict disrupted network efficiencies and unravel their relationships with network metrics.

Zhifeng Liang¹, Xiao Liu², and Nanyin Zhang^1
1Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, United States, ²Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, Bethesda, MD, United States

Little is known about the dynamic properties of resting-state functional connectivity in animals. Here we studied nonstationary properties of spontaneous BOLD fluctuations in awake rat brains. Averages of 15% resting-state fMRI frames based on the BOLD amplitude of primary somatosensory and infralimbic cortices closely resembled seed-based functional connectivity patterns. k-means clustering further revealed distinct time varying co-activation patterns. Importantly, those CAPs have consistent temporal evolutions. Therefore, the current study revealed robust spatial and temporal patterns of dynamic neural circuitries in awake rat brains.

Xiaoyun Liang¹, Alan Connelly^1,2, and Fernando Calamante^1,2
1Brain Research Institute, Florey Institute of Neuroscience and Mental Health, Melbourne, VIC, Australia, ²Department of Medicine, Austin Health and Northern Health, University of Melbourne, Melbourne, VIC, Australia

In this study, we proposed a joint sparsity constraint method, JGMSS, to directly estimate networks at group-level. Simulated results demonstrate that JGMSS can achieve consistently higher accuracy and sensitivity than the previosuly proposed elastic net (EN) method. Estimated functional connectivity from in vivo data shows much less network variability across the selected range of threshold than EN does, suggesting that JGMSS is largely independent of threshold. Overall, JGMSS can robustly and reliably estimate functional connectivity at group-level.

Chantal Delon-Martin^1,2, Hugo Lafaye de Micheaux^1,2, Sonia Pellissier^1,3, Amandine Rubio^2,4, Bruno Bonaz^1,5, and Sophie Achard^6
1U836, INSERM, Grenoble Cédex 9, France, ²GIN, UJF, Grenoble, France, ³LPPA, Université de Savoie, Le Bourget du Lac, France, ⁴Gastro-entérologie pédiatrique, CHU, Grenoble, France, ⁵Hépato-gastroentérologie, CHU, Grenoble, France, ⁶GIPSA-Lab, CNRS, Grenoble, France

Aim : Does autonomic nervous system impact on resting-state functional connectivity ? Methods : We acquired the heart rate variability as a measure of ANS simultaneously with rs-fcMRI. We measured the correlation between LF-component of HRV and each region time-course. We measured the HRV impact on the connectivity of each region with all other regions. Results : We evidenced that the HRV correlates negatively with the time-course of brain regions and biases the connectivity measures between brain regions. Conclusion : In rs-fcMRI, the impact of ANS has to be taken into account for proper interpretation of results from group studies.

Roberta Sclocco¹, Elisa Marchetta^2,3, Viviana Casaleggi¹, Marco Tettamanti⁴, Anna Maria Bianchi¹, and Giovanna Rizzo^3
1Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy, ²Department of Neuroradiology, San Raffaele Scientific Institute, Milano, Italy,³Istituto di Bioimmagini e Fisiologia Molecolare, CNR, Segrate (MI), Italy, ⁴Nuclear Medicine Department & Division of Neuroscience, San Raffaele Scientific Institute, Milano, Italy

The investigation of brain connectivity through spectral Granger causality indices relies on the estimation of the coefficients of a multivariate autoregressive model (MVAR). In the original formulation, though, the estimated model only includes lagged terms, therefore omitting the potential contribution of instantaneous correlations between the analyzed time series. In this work, we applied a method for removing zero-lag interactions on BOLD fMRI time series from a public dataset, and our results showed how this procedure is able to improve the estimation of the causal relationships, allowing to correctly identify the driving node of the network.

Renaud Lopes¹, Pierre Besson¹, Patrice Jissendi¹, and Xavier Leclerc^1
1CLAIR "Center of Lille Advanced Imaging Research" - IMPRT Platform, University hospital of Lille, Lille, France

Recently, ultrafast fMRI sequences significantly increase the temporal resolution of whole brain fMRI but they decrease the spatial signal-to-noise ratio. The aim of this study was to investigate the benefit of ultrafast acquisitions to be used to substantially shorten the total acquisition time. This study showed that ultrafast fMRI sequence can be useful to decrease the acquisition timing without loss of information. The reduced scan time could help the clinical acceptance of resting-state fMRI protocols.

Hongjian He¹, Song Chen¹, Han Zhang², and Jianhui Zhong^1
1Zhejiang University, Hangzhou, Zhejiang, China, ²Hangzhou Normal University, Hangzhou, Zhejiang, China

Correlation between task-induced activity amplitude and resting-state signal sub-frequency band power as a function of frequency is investigated across subjects. The preliminary shows that rest-task coupling relationship is is both non-stationary over frequency and region-dependent.

Tianyi Qian¹ and Hesheng Liu^2
1Siemens Healthcare, MR Collaborations NE Asia, Beijing, China, ²Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States

The multiband/slice acceleration EPI technique can provide high temporal or spatial resolution BOLD image for fMRI study. By analyzing the resting-state fMRI in high temporal resolution (TR=645ms), the temporal dynamics within the DMN and the behavior of its subsystems has been observed in this study.

Wen-Chau Wu^1,2
1Graduate Institute of Oncology, National Taiwan University, Taipei, Taiwan, ²Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan

Several recent studies showed that caffeine altered BOLD signals and some examined the effect from a perspective of signal processing and global contrast modulation. Since caffeine has known pharmacological effects on human behavior, we hypothesized that in addition to the reported global effect, caffeine's influence on resting-state BOLD signals might be spatially differential and could be detected. In this study, the hypothesis was tested in the visual cortex under the eyes-open condition. Results showed that caffeine slightly decreased the connection between visual cortex and the lateral geniculate nucleus whereas the integration of extrastriate visual areas was increased.

Zhifeng Liang¹, Ziyu Cao², Liqin Yang², Fuchun Lin², Nanyin Zhang¹, and Hao Lei^2
1Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, United States, ²State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan, Hubei, China

It is intriguing to explore the relationship among different connectivity measures in the brain. The current study compared the volume based connectivity and functional connectivity from 152 (volume based dataset) and 42 (functional dataset) rats, and revealed significant correlation between those two connectivity measures. Although both connectivity measures were negatively correlated with physical distances between ROIs, their robust correlation still remains after regression of physical distances.

Saskia Klein¹, Lars Kasper¹, S. Johanna Vannesjo¹, Simon Gross¹, Benjamin Dietrich¹, Christoph Barmet^1,2, Maximilian Haeberlin¹, David O. Brunner¹, Bertram J. Wilm¹, and Klaas P. Prüssmann^1
1Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Zurich, Switzerland, ²Skope Magnetic Resonance Technologies LLC, Zurich, Switzerland

We used concurrent magnetic field monitoring in-vivo to measure system and physiological fluctuations in the encoding fields of multiple EPI time series. Principal component analysis disentangled these fluctuations based on their frequency components in the projections. Despite the robust detection of physiologically induced field fluctuations, the observed SFNR losses are small at 3T. However, correcting for system-induced fluctuations in the encoding fields using concurrent magnetic field monitoring increased the SFNR considerably.

Arno Solin¹, Simo Särkkä¹, Aapo Nummenmaa², Aki Vehtari¹, Toni Auranen³, and Fa-Hsuan Lin^1,4
1Department of Biomedical Engineering and Computational Science, Aalto University, Espoo, Finland, ²Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, United States, ³Advanced Magnetic Imaging Centre, Aalto NeuroImaging, Aalto University, Espoo, Finland, ⁴Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan

We present how the DRIFTER method for removal and modeling of physiological noise can be extended to complex-valued images and raw k-space data. We compare the amplitude maps of the reconstructed cardiac noise component in fast fMRI data. The experiments suggest that catching the noise at an early stage of data processing can give better estimates of the noise influence in the data. Consequently, also the actual data component can be improved by removing the physiological noise before image reconstruction, which eliminates aliasing of the structural noise in the image data.

Ali M Golestani^1,2 and J Jean Chen^1,2
1Rotman Research Institute, Baycrest, Toronto, ON, Canada, ²University of Toronto, Toronto, ON, Canada

Physiological signals have an effect on resting state BOLD, that typically described by transfer functions, estimated from datasets with typically repetition times of 2 s, preventing accurate sampling of all signal components. In this study we assess whether such limitations affect the estimation of the BOLD hemodynamic response function to physiological signals by using typical (TR = 2 s) and high temporal resolution (TR < 400 ms) data. We found that data acquired at typical temporal resolution produced transfer functions that are similar to those based on high temporal resolution data, suggesting the estimation to be insensitive to sampling rate.

Jaakko Paasonen¹, Raimo Salo¹, Joanna K Huttunen¹, and Olli Gröhn^1
1Department of Neurobiology, A.I.Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland

Resting state fMRI is an attractive tool in preclinical research, but translational value of results may be hindered by anesthesia. Our aim was to investigate the possible differences in the resting state of rat brain under five different anesthetics. Data were measured from n = 52 rats and analyzed with independent component analysis. Three cortical and one striatal component were chosen for further comparison. Significant spatial and spectral differences were seen between groups in all cortical components, but not in striatal component. Therefore the anesthetic in animal resting state studies should be carefully selected, especially when investigating the cortical networks.

Diana Platas^1,2, Benito de Celis Alonso³, Silvia Hidalgo Tobón^4,5, Fernando Chico⁴, Jairo Muñoz-Delgado⁶, and Kimberley Phillips^2
1Universidad Nacional Autónoma de México, Mexico DF, Mexico DF, Mexico, ²Trinity University, Texas, United States, ³Faculty of Physics and Mathematics, BUAP, Puebla, Mexico, ⁴Hospital Infantil de Mexico, Federico Gómez, Mexico DF, Mexico, ⁵Universidad Autónoma Metropolitana, Campus Iztapalpa, Mexico DF, Mexico, ⁶Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico DF, Mexico

Resting state functional images (RsfMRI) measured in absence of a task, aim at detecting low frequency fluctuations (LFFs, less than 0.1 Hz) in the Blood Oxygen Level Dependent (BOLD) signals [1]. Functional connectivity is defined for these studies as the temporal correlations between different brain regions [2,3]. Functional communication between brain regions plays a fundamental role in cognitive processes. Here we have used resting-state areas of the brain to examine intrinsic connectivity networks in a seldom-used primate species, the spider monkey (Ateles geoffroyi). Human working memory has been intensively studied but little is known about its evolution. Comparison of connectivity maps in spider monkeys is an initial stage to approach working memory evolution in primates, and thus closes the gap between RsfMRI and cognitive data.

Elisabeth Jonckers¹, Geert De Groof¹, and Annemie Van der Linden^1
1Biomedical Sciences, Bio-imaging Lab, University of Antwerp, Wilrijk, Antwerpen, Belgium

Songbirds show extensive neuroplasticity over the seasons in the song control system related to their song behavior. In this experiment we used resting state fMRI to asses plasticity in the auditory network. The fact that female starlings select mates based on song characteristics possibly indicate an increased relevance for auditory discrimination in breeding season compared to non-breeding season. In this study we investigated if this increased discrimination is reflected in an increased local functional connectivity (FC) within the major auditory areas.

Noora Pauliina Tuovinen¹, Andac Hamamci¹, Francesco de Pasquale¹, and Umberto Sabatini^1
1Radiologia, Fondazione Santa Lucia, Rome, Lazio, Italy

For studying integration of fMRI into radiotherapy planning, rest and finger tapping scans were acquired on a tumor patient. Glioblastoma multiforme and surgical cavity were near the motor cortex. We hypothesized that resting state could complement information gathered during task. The data was analyzed and registered using tools provided by FSL. On the unaffected hemisphere motor areas overlapped, whereas the affected hemisphere motor area was only easily recognizable from resting-state. Tumor's proximity to activation region sometimes complicates the identification. Resting state might be able to give information not otherwise available. This study will be further validated with larger patient sample.

Hu Liu¹, Guoguang Fan¹, and Ke Xu^1
1Department of Radiology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning, China

An improved understanding of the cerebellum, especially the cerebello-thalamo-cortical (CTC) circuit in Parkinson¡¯s disease (PD)-related changes, is essential for a better understanding of the pathophysiology of the disorder. Previous study describes a relationship between the anterior lobe of the cerebellum and motor function, and between the posterior lobe and executive function. Using functional connectivity method we found increased functional connectivity of the cerebellar posterior lobe in the resting state. This alteration may play a compensatory role in cognitive or executive functions of PD patients.

Yuzheng Hu¹, Hong Gu¹, Betty Jo Salmeron¹, Xia Liang¹, Elliot Stein¹, and Yihong Yang^1
1Neuroimaging Research Branch, National Institute on Drug Abuse, NIH, Baltimore, MD, United States

Accumulative evidence has indicated the involvement of the insular system in drug addiction by its fundamental role in interoception. However, relationship between the interoception, neurobiological measures of insula and addiction behaviors remains unclear. To address this question, the current study employed Toronto Alexithymia Scale and resting-state functional connectivity method to cocaine dependents and well-matched controls. Altered insula-cingulate and insula-frontal functional connectivity, abnormal alexithymic trait and dis-association between insula-cingulate functional connectivity and alexithymia were observed in chronic cocaine users. These findings may shield insight on the neurobiological bases of drug addiction.

Yanjun Diao¹, Xiaojing Long¹, Chunxiang Jiang¹, Li Yi², Yu Chen², and Lijuan Zhang^1
1SIAT,Chinese Academy of Sciences, Shenzhen, Guangdong, China, ²Neurology,Peking University Shenzhen Hospital, Shenzhen, Guangdong, China

Extensive involvement of brain functional networks as a result of single IS lesion was observed in this study. The clinical relevance of the network involvement needs further investigation. This preliminary study may provide valuable reference into the cerebral functional network research during the rehabilitation of ischemic stroke.

Chunxiang Jiang¹, Yanjun Diao¹, Xiaojing Long¹, Dai Shan¹, Weiqi Liao¹, and Lijuan Zhang*^1
1Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China

We explored the diurnal alteration of human brain in the aspect of network degree centrality based on resting-state functional magnetic resonance imaging.Functional connectivity of human brain manifests a dynamic property.The pattern of diurnal network centrality provides an informative reference for characterizing the functional substrate in neuropsychological and psychiatric disorders that circadian rhythm matters.

Tanzil Mahmud Arefin^1,2, Anna Mechling^2,3, Sami Ben Hamida⁴, Hsu-Lei Lee², Dominik V. Elverfeldt², Jürgen Hennig², Brigitte Kieffer⁴, and Laura-Adela Harsan^2
1Computational Neuroscience, Bernstein Center Freiburg, Freiburg, Baden-Württemberg, Germany, ²Medical Physics, University Medical Center Freiburg, Freiburg, Baden-Württemberg, Germany, ³Department of Biology, University of Freiburg, Freiburg, Baden-Württemberg, Germany, ⁴IGBMC, Illkirch, Alsace, France

Functional communication between brain regions plays a key role in complex cognitive process. Emerging studies show that rsfMRI can reveal the modifications in functional brain connectivity due to psychiatric disorders or drug effects. This study was aimed to scrutinize the functional connectivity modifications in GPR88 Knock Out (KO) mice using rsfMRI technique, which has not been examined yet and might be interesting in the perspective of neurological or psychiatric disorders and drug research.

Alex TL Leong^1,2, Russell W. Chan^1,2, Iris Y. Zhou^1,2, Adrian Tsang^1,2, and Ed X. Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China

This exploratory study is done to expand the possibility that vertebrates other than mammals possess similar primitive brain functions that has withstood the rigors of evolution. Resting-state modality which is commonly used to explore such a possibility in mammals is employed on the crucian carp, cyprinus carpio L. Long-range networks which are key to resting-state networks has been discovered and with very close anatomical specificity to previous axonal projection studies. This provides us motivation to believe that resting-state network is a basic global brain phenomenon in vertebrates.

Axel P. Mathieu^1,2, Maxime J. Parent³, Blandine Courcot^1,2, Jamie Near^1,2, and Pedro Rosa-Neto^3
1Brain Imaging Centre, Douglas Mental Health Research Centre, Montreal, QC, Canada, ²Department of Psychiatry, McGill University, Montreal, QC, Canada, ³Translational Neuroimaging Laboratory, McGill Centre for Studies on Aging, Montreal, QC, Canada

Functional connectivity as measured by resting-state functional Magnetic Resonance Imaging (rsfMRI) is a promising early biomarker for several neurodegenerative diseases. Since anesthesia is known to affect this measure, it is preferable when studying animal models to forego anesthesia entirely. Here, we demonstrate the feasibility of acquiring rsfMRI data in conscious rats by training them in a custom-designed restraining apparatus. After 4 days of training, head movements did not differ significantly from those observed while the rats are under isoflurane anesthesia. Additionally, rsfMRI connectivity was demonstrably stronger in awake rats. This shows great potential for completely conscious animal rsfMRI acquisition.

Elisabeth Jonckers¹, Verner P. Bingman², Geert De Groof¹, Onur Güntürkün³, and Annemie Van der Linden^1
1Biomedical Sciences, bio-imaging Lab, University of Antwerp, Wilrijk, Antwerpen, Belgium, ²Department of Psychology, Bowling Green State University, Bowling Green, Ohio, United States, ³Department of Biopsychology, Institute of Cognitive Neuroscience, Ruhr-University Bochum, Bochum, Germany

Both brain hemispheres exhibit strong, but not complete, bilateral symmetry in both structure and function. Nevertheless some brain functions are lateralized. Earlier we have shown the usefulness of rsfMRI to study lateralization in the brain by applying this technique to a well-known model of lateralization, the visual system of the awake pigeon. In this study we wanted to extend this application to another avian brain region, the hippocampus, of which a large body of data has accumulated demonstrating its functional lateralization.

Hang Joon Jo¹, Stephen J Gotts², Brian E Russ³, David A Leopold³, and Peter A Bandettini^1
1Section on Functional Imaging Methods, Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, MD, United States, ²Section on Cognitive Neuropsychology, Laboratory of Brain and Cognition, National Institute of Mental Health, MD, United States, ³Section on Cognitive Neurophysiology and Imaging, Laboratory of Neuropsychology, National Institute of Mental Health, MD, United States

In our previous study, we reported that the resting brain activity of one hemisphere was maximally correlated with locations close to the corresponding anatomical location in nearly half of the cortex in the human brain, locations which are strongly reminiscent of the locations of callosal connections revealed by horseradish peroxidase tracing in monkeys, particularly in occipital, temporal, and parietal cortex. To examine this phenomenon more directly in macaque monkeys, we present that the maximum correlations of resting-state FMRI for individual monkeys can reflect the locations of axonal connections that were revealed by the existing studies of anatomical tracing experiments.

Wolfgang Weber-Fahr¹, Claudia Falfán-Melgoza¹, Marcus Meinhardt², Sandra Dieter², Santiago Canals³, Alexander Sartorius¹, and Wolfgang Sommer^2
1RG Translational Imaging, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany, ²Department of Psychopharmacology, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany, ³CSIC-UMH, Instituto de Neurociencias, Sant Joan d'Alacant, Spain

In this study we aimed to investigate the brain networks in a rat model of alcohol abstinence with MEMRI and rsfMRI. 21 rats of which 11 underwent 8 weeks of Ethanol exposure were scanned after 2 week withdrawal at a 9.4T scanner. Additionally to rsfMRI; T1-maps were acquired for 12 rats before and after subcutanious osmotic Mn2+ pump implantation. ICA showed an increased interoceptive network component in the cingulate cortex of rats in withdrawal. Even though both methods rely on fundamentally different approaches, an overlapping area of increased Mn2+ uptake was found in the MEMRI data.

Zhixin Li¹ and Christopher P Pawela^1,2
1Plastic Surgery, Medical College of Wisconsin, Milwaukee, WI, United States, ²Biophysics, Medical College of Wisconsin, WI, United States

Mapping the genomic influence of a single chromosome on the alterations of functional connectivity due to somatosensory stimulation using fMRI and fcMRI

Yang Fan¹, Linlin Zhu², Qihong Zou¹, Zhendong Niu², and Jia-Hong Gao^1
1Center for MRI Research, Peking University, Beijing, China, ²School of Computer Science and Technology, Beijing Institute of Technology, Beijing, China

A fundamental feature of the human brain is the presence of both structural and functional asymmetries between two hemispheres at both macroscopic and microscopic dimensions. Previous studies have revealed the functional lateralization of language network. This kind of functional brain asymmetry was stable among different group of subjects. However, whether it is reliable in the same subject across time, which may be important to a few neuropsychiatric disorders, is still undetermined. In the present study, we examined the test-retest (TRT) reliability of the asymmetry of language network and prove its temporal stability.

Carlo Nicolini¹, Adam Liska¹, Francesco Sforazzini¹, Alberto Galbusera¹, Angelo Bifone¹, and Alessandro Gozzi^1
1MRI Laboratory, Istituto Italiano di Tecnologia, Centre for Neuroscience and Cognitive Sciences, Rovereto, Trento, Italy

We recently described the presence of distributed intrinsic connectivity networks in the mouse brain homologous to those observed in primates and humans. Here we used complex network analysis to describe the functional topology of the resting mouse brain. We found that the mouse brain can be segregated into four stable and anatomically plausible communities that can be associated to known distributed brain functions and related to known connectional partitions of the human brain. These initial results suggest that the mouse brain conserves fundamental topological properties that are also seen in higher species.

Oscar San Emeterio Nateras^1,2, Carlos Bazan III¹, Fang Yu¹, Jinqi Li², Cristal G Franklin², Wei Zhou^1,2, Sunil K Valaparla^1,2, Jack L Lancaster^1,2, and Timothy Q Duong^1,2
1Radiology, University of Texas Health Science Center, San Antonio, TX, United States, ²Research Imaging Institute, San Antonio, TX, United States

This study demonstrates a novel rsfMRI application to investigate the spinal cord. We found extensive functional networks in the spinal C1-C4, and they included some unilateral, bilateral and top-down functional connectivity. Future studies will improve spatial resolution and to map connectivity of the entire spinal cord to the brain.

Yu-Han Hong¹, Hui-Yu Wang¹, You-Yin Chen², Yeu-Sheng Tyan^1,3, and Jun-Cheng Weng^1,3
1School of Medical Imaging and Radiological Sciences, Chung Shan Medical University, Taichung, Taiwan, ²Department of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan, ³Department of Medical Imaging, Chung Shan Medical University Hospital, Taichung, Taiwan

At present, resting state functional MRI (rsfMRI) is increasingly used in human and rodent neuropathological research. Therefore, the purpose of this study was to find a stable and reliable analysis method of rsfMRI for human and rat, and to compare the region correlation and power spectrum in human and rat brain networks using seed regions and independent component analysis (ICA). By acquiring rsfMRI data with a comparable protocol (e.g. anesthesia for rat), scanning and analysis, in both humans and rats we were able to compare findings obtained in both species. The outcome of rsfMRI is different for humans and rats and depends strongly on the seed position in the seed regions functional connectivity analysis, and the applied number of components in the ICA. The most important difference was the power spectrum of several networks, such as visual, motor, default mode, amygdala, hippocampus and thalamus, in the rat shifted to lower frequency regime compared to human brain. Furthermore, a higher number of components was needed for the ICA analysis to separate different cortical regions in rats as compared to humans.

Han Yuan¹, Callen Johnson^1,2, Raquel Phillips¹, Vadim Zotev¹, Masaya Misaki¹, and Jerzy Bodurka^1,3
1Laureate Institute for Brain Research, Tulsa, OK, United States, ²Department of Physics, University of Tulsa, Tulsa, OK, United States, ³College of Engineering, University of Oklahoma, Norman, OK, United States

We investigated the resting state brain dynamics using single-shot multi-echo EPI sequence with simultaneously acquired electroencephalography (EEG) and respiratory data. Multi-echo EPI images were decomposed into linearly weighted components based on differentiated TE-dependent signals using spatial independent component analysis (ICA). The BOLD signal of neuronal or non-neuronal/physiological origin was differentiated by comparing the time course of EPI independent components with the variations of EEG alpha power and respiratory volumes. Results show that the multi-echo ICA approach based on the multimodal data is able to decompose the BOLD signals into components of neuronal and non-neuronal origin, and thus can be used to remove the physiological noise of BOLD signals.

Yi-Ching Lynn Ho¹, Way Cherng Chen¹, Hui Chien Tay¹, Fatima Nasrallah¹, and Kai-Hsiang Chuang^1
1Singapore Bioimaging Consortium, Agency for Science, Technology & Research (A*STAR), Singapore, Singapore

The increasing use of resting-state fMRI to study brain development and disease progression raises the question of how functional connectivity changes in response to alterations in structural connectivity. Using the cuprizone mouse model of reversible demyelination, we tracked the relationship of S1 functional connectivity to corpus callosum myelination, which was assessed with histology. Results showed different temporal progression of the impairment and the recovery of structural and functional connectivity.

Jung Hwan Kim¹ and David Ress^1,2
1Neuroscience, Baylor College of Medicine, Houston, TX, United States, ²Neuroscience, The University of Texas at Austin, Austin, TX, United States

We present a novel convection-diffusion oxygen transport model to understand the BOLD hemodynamic response function (HRF). A lumped-linear flow model described the CBF response produced by arterial dilation. The CMRO2 response was assumed to have a gamma-function form. The model successfully fit the HRF evoked in human visual cortex and measured using high-resolution fMRI. Results show how CBF and CMRO2 compete with each other to shape the BOLD HRF. The predicted flow and CMRO2 amplitudes agree with previous measurements. Our model provides a detail theoretical framework to understand neurovascular and neurometabolic coupling in the brain.

Marco Palombo¹, Emiliano Macaluso², Marco Bozzali², and Silvia Capuani^1
1Physics Department, Sapienza University, Rome, Rome, Italy, ²NeuroImaging Laboratory, Santa Lucia Foundation, Rome, Italy

We investigated the signal source and spatial specificity of DW fMRI changes in the visual cortex using Gaussian and non-Gaussian diffusion methods. In particular we exploited the strong dependence of non-Gaussian  parameter on local magnetic susceptibility in order to show: 1) vascular contribution (in capillaries and small veils) is predominant in the ADC variations found in Gaussian diffusion fMRI; 2) non-Gaussian diffusion fMRI is more sensitive and spatially localized to the signal source than Gaussian diffusion fMRI ; 3) it is possible to use non-Gaussian diffusion fMRI to localize brain activation areas more accurately than usual BOLD fMRI.

Irati Markuerkiaga¹, Markus Barth¹, and David Norris^1
1Donders Institute for Cognitive Neuroscience, Nijmegen, Netherlands

In this work we present a cortical vasculature model based on reported experimental data and simulate the fMRI signal across layers for examining the depth dependent point spread function (PSF). This is necessary to determine the spatial resolution achievable by high resolution fMRI sequences for identifying layer specific functional activation.

Louis Gagnon^1,2, Sava Sakadzic¹, Frederic Lesage², Joseph J Musacchia¹, Joel Lefebvre², Qianqian Fang¹, Meryem A Yucel¹, Karleyton C Evans¹, Emiri T Mandeville¹, Julien Cohen-Adad², Jonathan R Polimeni¹, Mohammad A Yaseen¹, Eng H Lo¹, Douglas Greve¹, Richard B Buxton³, Anders Dale³, Anna Devor³, and David A Boas^1
1Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachussetts General Hospital, Charlestown, MA, United States, ²Department of Electrical Engineering, Ecole Polytechnique de Montreal, Montreal, QC, Canada, ³Department of Radiology and Neuroscience, UCSD, LaJolla, CA, United States

We modeled the BOLD response using a set of in vivo vascular measurements obtained with oxygen-sensitive two-photon microscopy. Our model predicted that the folded cortical orientation relative to the main magnetic field can affect the amplitude of the BOLD response by up to 40%. Experimental BOLD measurements during a hypercapnic challenge confirmed this hypothesis. We proposed a method to correct for this confounding effect.

Laurentius Huber¹, Aneurin Kennerley², Dimo Ivanov³, Claudine Gauthier¹, Harald E. Möller¹, and Robert Turner^1
1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, ²Department of Psychology, The University of Sheffield, United Kingdom, ³Psychology and Neuroscience, Maastricht University, Netherlands

Inter-trial variation of stimulus-induced fMRI signal response is investigated with respect to BOLD and its underlying CBV changes with a recently developed multi-echo VASO sequence. The most striking result is that the post-stimulus CBV has a post stimulus undershoot (PSU) followed by an overshoot in an oscillating manner. The characteristic time course of the well described BOLD PSU appears only after averaging across trials. Mechanisms underlying inter-trial variations can be investigated by means of correlating several separate features of individual trials, e.g. initial response vs. PSU amplitude.

Cecil Chern-Chyi Yen¹, Daniel Papoti¹, and Afonso C. Silva^1
1CMU/LFMI/NINDS, National Institues of Health, Bethesda, Maryland, United States

The spatiotemporal characteristic of the BOLD signal across cortical layers has not been well understood due to the neurophysiological effects of general anesthetics in animal model or the limitations of spatiotemporal resolution of the human fMRI. To bridge the gap, a dual-echo EPI sequence with high spatiotemporal resolution was used to separate the laminar BOLD response and non-BOLD response in awake marmoset model. We had shown the spatiotemporal characteristic of the laminar BOLD response without complications of anesthesia and non-BOLD contribution.

Florian Schmid¹, Lydia Wachsmuth¹, Miriam Schwalm², Albrecht Stroh², and Cornelius Faber^1
1Department of Clinical Radiology, University of Münster, Münster, Germany, ²Research Group Molecular Imaging and Optogenetics, Johannes Gutenberg-University Mainz, Mainz, Germany

We utilize optogenetic tools for a temporally and spatially defined modulation of components of the cortico-thalamic and the thalamo-cortical neuronal network in naïve rats and use BOLD fMRI as a global, noninvasive readout. Our results show positive BOLD activation of S1 sensory cortex upon optogenetic stimulation of S1 or the posterior thalamic nuclei group, and negative BOLD response upon inhibitory stimulation.

Teng-Chieh Cheng¹, Yi-Jui Liu¹, Yi-Hsiung Lee², Kuo-Fang Shao³, Chao-Chun Lin⁴, Chia-Wei Lin⁴, and Wu-Chung Shen^4
1Department of Automatic Control Engineering, Feng Chia University, Taichung, Taiwan, ²Ph.D. Program of Electrical and Communications Engineering, Feng Chia University, Taichung, Taiwan, ³Master's Program in Biomedical Informatics and Biomedical Engineering, Feng Chia University, Taichung, Taiwan, ⁴Department of Radiology, China Medical University Hospital, Taichung, Taiwan

Neuron activity can be measured by BOLD signal in fMRI study, but BOLD signals could be altered solely by hypercapnia. However, no reports have explored the changes of hemodynamic response function (HRF) in terms of the degrees of hypercapnia. In this study, we investigated the HRF variate from short to long time stimulus within different CO2 concentration inhalation. Our results show the peak of HRF curve is decreased and time-to-peak is ascended with inhaled CO2 fractions. We conclude the restriction of HRF by cerebrovascular reserve is related to CO2 concentration and independent with visual stimulus duration under the steady-state hypercapnia.

Yuhan Ma¹, Avery J.L. Berman¹, and G. Bruce Pike^1,2
1McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada, ²Hotchkiss Brain Institute and Department of Radiology, University of Calgary, Calgary, Alberta, Canada

We investigated the effect of dissolved oxygen in arterial blood plasma on BOLD signal during the hyperoxia calibrated BOLD method by examining the relaxation rates of bovine blood plasma under various partial pressures of oxygen. The R₁ of plasma linearly increases with oxygen concentration, whereas R₂ and R₂^* are unaffected. Therefore, dissolved oxygen in arterial plasma should not induce significant BOLD contrast through R₂ and R₂^* effects. This study verifies that under hyperoxia, BOLD signal contrast arises from dHb in venous and capillary blood - the fundamental basis of the calibrated BOLD method - and not dissolved oxygen in arteries.

Alexander Poplawsky¹, Mitsuhiro Fukuda¹, Xiaopeng Zong², and Seong-Gi Kim^1,3
1Radiology, University of Pittsburgh, Pittsburgh, PA, United States, ²Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, NC, United States,³Biological Sciences, Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), SKKU, Suwon, Korea

We used high-resolution fMRI in the olfactory bulb model to determine whether inhibitory neurons contribute to the hemodynamic response. Odor and micro-stimulation of the anterior commissure (AC) were used to preferentially evoke excitatory and inhibitory processes, respectively. For both BOLD and CBV fMRI, we measured hemodynamic responses in bulb layers corresponding to inhibitory neuron activity. Of particular interest, the combined odor plus AC stimulations revealed a relative increase in fMRI changes at layers corresponding to the net increase in total synaptic activity (excitatory + inhibitory). Our data show that excitatory and inhibitory activities contribute to hemodynamic responses in the bulb.

Steffen N Krieger^1,2, Claudine J Gauthier², Dimo Ivanov³, Laurentius Huber², Elisabeth Roggenhofer², Bernhard Sehm², Robert Turner², and Gary F Egan^1
1Monash Biomedical Imaging, Monash University, Melbourne, Victoria, Australia, ²Max-Plank Institute for Human Cognitive and Brain Sciences, Leipzig, Saxonia, Germany,³Maastricht University, Netherlands

Calibrated BOLD might be a powerful alternative to classic functional MRI techniques especially as CMRO2 has been found to be more spatially specific when mapping cerebral functional activation compared to BOLD. However, the application of calibrated BOLD at ultra-high field strengths and in combination with more complex cognitive study designs might have been inhibited by the limited knowledge about stability. This study provides evidence that CMRO2 is a reliable biomarker for cognitive studies even when used at ultra-high magnetic fields. The calibrated BOLD technique might be a viable alternative to classic BOLD approaches.

Isabelle Lajoie¹, Felipe B Tancredi¹, Danny J Wang², and Richard D Hoge^1
1Centre de recherche de l'IUGM, Montreal, Quebec, Canada, ²Neurology, University of California, Los Angeles, CA, United States

We describe here an optimized protocol for the acquisition and processing of MRI data for the quantification of oxidative metabolism (CMRO2) using the QUantitativeO2 (QUO2) method with fixed concentrations of respirator gases and a DE-pCASL sequence. We assessed the reproducibility of the method and obtained respective inter-session coefficients of variation (CV) of 10%, 15%, and 17% for M (extrapolated maximum BOLD signal), OEF0 (Oxygen Extraction Fraction) and CMRO20. In future work, we will extend the protocol to MRI scanners from multiple scanner vendors and verify that equivalent results can be obtained at different scanning sites.

Felipe B Tancredi^1,2, Isabelle Lajoie^1,2, and Richard D Hoge^1,2
1Institut de génie biomédical, Université de Montréal, Montreal, Quebec, Canada, ²Centre de recherche de l'IUGM, Montreal, Quebec, Canada

Respiratory manipulations inducing global changes in CBF and BOLD have been used to measure cerebral vascular reactivity and metabolism. Respiratory stimulus is commonly achieved by delivering predetermined concentrations of gases for inspiration, yielding end-tidal (ET) values that are used for retrospective normalization of the fMRI signal. The simplest method has been to administer O2/CO2 mixtures through low-cost oxygen masks. However, control over the administered dose have been difficult using this approach – which hampers reproducibility of ET responses. We have designed a breathing apparatus allowing precise adjustments in FiO2/FiCO2 and good intra-subject reproducibility of ET levels.

Esben Thade Petersen^1,2, Jill De Vis¹, Thomas Alderliesten³, C.A.T. van den Berg², and Jeroen Hendrikse^1
1Department of Radiology, UMC, Utrecht, Netherlands, ²Department of Radiotherapy, UMC, Utrecht, Netherlands, ³Department of Neonatology, UMC, Utrecht, Netherlands

In this work we present a method which allows simultaneous full brain measurement of blood-volume, oxygenation and hematocrit. The sequence is based on a T1 and T2 Prepared Velocity Selective Labeling Module. Blood oxygen saturation is an important parameter in neuroscience and for the management of diseases such as stroke or cancer. The sequence was tested using a hypercapnic challenge, which alters the oxygenation levels across the brain. Initial results are promising and further validation work is ongoing in healthy subjects using the reactivity challenge while simultaneously monitoring frontal lobe oxygenation by means of Near InfraRed Spectroscopy.

Farshad Moradi¹, Aaron Simon², and Richard B Buxton^1,2
1Radiology, UCSD, San Diego, California, United States, ²Center for Functional MRI, University of California, San Diego, California, United States

BOLD dynamics is complicated by nonlinear changes in vascular volumes and saturations linked to blood flow. We introduce a theoretical framework by integrating a detailed model of BOLD signal (Griffeth & Buxton 2011) with multi-compartmental balloon model of vascular tree. Simulations were used to examine the effects of vascular viscoelastic properties and transit time of blood. The new model is then used to estimate dynamic oxygen metabolism changes from experimentally measured flow and BOLD signals. Taking into account transient changes in blood volume distribution increases temporal accuracy of CMRO2 estimates compared to applying steady-state analysis to dynamic data.

Damon P Cardenas¹, Eric Muir¹, Shiliang huang², and Timothy Duong^1
1Radiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas, United States, ²MRI, Research Imaging Institute, San Antonio, Texas, United States

There are substantial interests in the effects of oxygen availability on neurovascular coupling and the response of cerebral blood flow (CBF) to neural activation. We evaluated forepaw-evoked CBF responses in rats under i) normobaric air, ii) normobaric oxygen, iii) hyperbaric air, and iv) hyperbaric oxygen (HBO). Basal CBF was not different under the four conditions, despite substantial increase of oxygen. Stimulus-evoked CBF was increased at moderately high [O2] compared to normobaric air, but returned to normal at very high [O2] under HBO, suggesting CBF responses are in some way regulated by oxygen-sensitive mechanisms.

Xinyuan Miao¹, Hong Gu², Lirong Yan³, Hanzhang Lu⁴, Danny JJ Wang³, Xiaohong Joe Zhou⁵, Yan Zhuo¹, and Yihong Yang^2
1Institute of Biophysics, Chinese Academy of Sciences, Beijing, Beijing, China, ²National Institutes of Health, National Institute on Drug Abuse, MD, United States,³Department of Neurology, UCLA, Los Angeles, CA, United States, ⁴University of Texas Southwestern Medical Center, Dallas, TX, United States, ⁵Center for Magnetic Resonance Research and Department of Radiology, University of Illinois at Chicago, Chicago, IL, United States

We developed a CBV-based imaging technique to detect intrinsic brain activity. Spontaneous fluctuations of CBV-weighted signal were measured by whole-brain, 3D-GRASE VASO imaging. Brain networks were detected reliably by the VASO technique. Frequency analyses showed that the VASO signal appeared to contain more high-frequency oscillations, compared to BOLD. Susceptibility artifacts were substantially alleviated in the VASO images and functional connectivity between striatum and orbital frontal cortex was detected robustly by the VASO but not BOLD. These results suggest that the 3D-GRASE VASO imaging may become an attractive technique for assessing brain functions in regions that precluded by traditional BOLD techniques.

Mukund Balasubramanian¹, Robert V. Mulkern¹, William M. Wells², Padmavathi Sundaram¹, and Darren B. Orbach^1
1Department of Radiology, Boston Children's Hospital, Boston, Massachusetts, United States, ²Department of Radiology, Brigham and Women's Hospital, Boston, Massachusetts, United States

Understanding the behavior of ionic volume currents in strong magnetic fields could facilitate efforts to use MRI to detect signals more tightly coupled to neuronal activity. However, studies on this topic are controversial: two competing mechanisms have been proposed to account for the behavior of these currents. One of these mechanisms, magnetohydrodynamic flow, predicts a slow evolution of phase signals (on the order of one minute for 0.9% saline at 3T) that is dependent on both field strength and conductivity. Here, we test and confirm these predictions using 0.9% and 3.6% saline current phantoms scanned at 1.5T and 3T.

Simon Schwab¹, Yosuke Morishima¹, Thomas Koenig¹, Thomas Dierks¹, Andrea Federspiel¹, and Kay Jann^2
1University Hospital of Psychiatry, Department of Psychiatric Neurophysiology / University of Bern, Bern, Switzerland, ²Department of Neurology, University of California, Los Angeles, California, United States

In the present work, we aimed to compare two sets of HRFs for microstate-informed resting-state fMRI analysis: the standard canonical HRF (CA), and the HRFs extended by the two temporal and dispersion derivatives (CA+). Fourteen healthy subjects underwent simultaneous EEG/fMRI. We have found that the extended model CA+ shows lower residuals for visual and right auditory areas across subjects. These findings provide further support that the canonical HRF alone may be insufficient to explain BOLD responses varying across brain regions and subjects. However, further investigation is needed to reduce residuals by using more flexible HRF models.

Maria Giulia Preti^1,2, Nora Leonardi^1,2, F. Isik Karahanoglu^1,2, Frédéric Grouiller³, Mélanie Genetti⁴, Margitta Seeck⁵, Serge Vulliemoz⁵, and Dimitri Van De Ville^1,2
1Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, VD, Switzerland, ²Medical Imaging Processing Lab, University of Geneva, Geneva, Switzerland, ³Department of Radiology and Medical Informatics, Geneva University Hospitals, Geneva, Switzerland, ⁴Functional Brain Mapping Lab, University Hospital and Faculty of Medicine of Geneva, Geneva, Switzerland, ⁵EEG and Epilepsy Unit, Neurology and Functional Brain Mapping Lab, University Hospital and Faculty of Medicine of Geneva, Geneva, Switzerland

Focal epilepsy is characterized by a not yet fully understood abnormal brain network organization that can be addressed with the integration of EEG, revealing the epileptic activity, and dynamic functional connectivity, exploring the connections’ dynamics during resting-state functional magnetic resonance imaging. We proposed a new method to combine the two techniques using partial least squares regression, aiming to assess the functional subnetworks related to epileptic activity. Results for one subject were consistent with previous literature, encouraging a new spectrum of future analysis with this method.

Štefan Holiga¹, Karsten Mueller¹, Dušan Urgošík², Robert Jech³, and Harald E. Möller^1
1Nuclear Magnetic Resonance Unit, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, ²Department of Radiation and Stereotactic Neurosurgery, Na Homolce Hospital, Prague, Czech Republic, ³Department of Neurology and Center of Clinical Neuroscience, First Faculty of Medicine, Charles University in Prague, Czech Republic

Deep-brain stimulation (DBS) is a rapidly evolving neurosurgical treatment approach for a variety of disabling neurological and psychiatric symptoms, offering a range of fundamental research questions. Several functional MRI (fMRI) studies already revealed neural correlates of its striking therapeutic benefit on patients with fully-implanted and active DBS-hardware under strictly controlled safety standards. In this work we underline the importance of adhering to rigorous data-analysis standards, too. In particular, we demonstrate the DBS-hardware-related signal distortion artifact problem empirically, present the risk of false-positive fMRI findings and accordingly call for extremely cautious means of analyzing fMRI of patients with implanted electrodes.

Joao Jorge^1,2, Frederic Grouiller³, Robert Stoermer⁴, Christoph Michel⁵, Patricia Figueiredo², Wietske van der Zwaag¹, and Rolf Gruetter^1
1Center for Biomedical Imaging, University of Lausanne/Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland, ²Institute for Systems and Robotics, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Lisbon, Portugal, ³Department of Radiology and Medical Informatics, Geneva University Hospital, University of Geneva, Geneva, Switzerland, ⁴Brain Products, GmbH, Gilching, Germany, ⁵Geneva University Hospital, Geneva, Switzerland

Simultaneous EEG-fMRI acquisitions are prone to specific artifacts that can seriously compromise data quality. In particular, mechanically-propagated scanner vibrations can significantly affect EEG recordings performed at ultra-high fields. In this work, we explored the advantages of a head-only MRI scanner for simultaneous EEG-fMRI acquisition, at 7 Tesla, using an optimized EEG setup with short cable lengths (~12cm from cap to amplifiers). The effects of cable length and type on EEG noise sensitivity were assessed. Following tests on safety and MR image quality, simultaneous acquisitions were performed on human subjects under visual stimulation, yielding reliable VEPs and occipital BOLD responses.

Vadim Zotev¹, Kymberly D Young¹, Raquel Phillips¹, Han Yuan¹, Masaya Misaki¹, and Jerzy Bodurka^1,2
1Laureate Institute for Brain Research, Tulsa, OK, United States, ²College of Engineering, University of Oklahoma, Tulsa, OK, United States

We have performed the first study utilizing real-time fMRI neurofeedback (rtfMRI-nf) with simultaneous EEG to elucidate correlations between BOLD activity of the thalamus and posterior EEG alpha rhythm. Ten healthy participants learned to self-regulate fMRI activity of the anterior and mediodorsal nuclei of the thalamus using rtfMRI-nf during a task involving retrieval of happy autobiographical memories. We observed a significant enhancement in temporal correlation between thalamic BOLD activity and EEG alpha rhythm during the rtfMRI-nf training. Our results suggest that rtfMRI-nf with simultaneous EEG is a powerful tool for studying relationships between electrophysiology and hemodynamics of the human brain.

Johan N van der Meer¹, André Pampel², Jennifer R Ramautar³, German Gomez-Herrero³, Jöran Lepsien², Harald Möller², and Martin Walter^1
1Clinical Affective Neuroimaging Laboratory, Department of Behavioral Neurology, Leibniz Institute for Neurobiology, Magdeburg, Germany, ²Nuclear Magnetic Resonance Unit, Max Planck institute for human cognitive and brain sciences, Leipzig, Germany, ³Department of Sleep and Cognition, Netherlands Institute for Neuroscience, Amsterdam, Netherlands

During simultaneous EEG-fMRI measurements, investigators routinely shuts down the helium pump to avoid the pump artifact in the EEG; however, this potentially harms the scanner. In this work, we investigate if this He pump artifact is really detrimental for the EEG. We performed EEG-fMRI with a reversal checkerboard task while the He pump was off and on and compare EEG quality markers between these two conditions. We also recorded EEG outside the scanner. We found (1) the He pump did not have discernable impact on EEG quality, (2) The quality during scanning is much lower during scanning as compared to outside.

Ana Beatriz Solana^1,2, Juan Antonio Hernández-Tamames^3,4, José Luis Ortiz¹, Elena Molina³, Eva Manzanedo³, Fernando O. Zelaya⁵, and Francisco del Pozo^1
1Center for Biomedical Technology, Pozuelo de Alarcón, Madrid, Spain, ²DBT, Global Research Center, General Electric, Munich, Munich, Germany, ³Universidad Rey Juan Carlos, Madrid, Spain, ⁴Fundación Reina Sofía, Madrid, Spain, ⁵King's College London, London, United Kingdom

A new spiral fMRI sequence, called SpRETI, is developed to include the following characteristics: 1) reduced EEG gradient-induced artifacts during simultaneous EEG-fMRI; 2) real time data storage to avoid loss of data; and, 3) acquisition of an optimized B0map inside the pulse sequence. SpRETI performance was tested calculating the gradient-induced artifact characteristics in the EEG, and its removal, and the BOLD contrast in a motor and visual tasks. Results were compared with EPI and other two spiral EPI sequences. SpRETI showed the best performance for simultaneous EEG-fMRI: lowest EEG gradient-induced artifact and a similar BOLD contrast.

Frédéric Grouiller¹, Suzanne Heinzer², Bénédicte Delattre^1,2, François Lazeyras¹, Giannarita Iannotti^3,4, Laurent Spinelli³, Francesca Pittau³, Margitta Seeck³, Osman Ratib¹, Maria Isabel Vargas¹, Valentina Garibotto¹, and Serge Vulliémoz^3
1Department of Radiology and Medical Informatics, Geneva University Hospital, Geneva, Switzerland, ²Philips AG Healthcare, Zürich, Switzerland, ³EEG and Epilepsy Unit, Department of Neurology, Geneva University Hospital, Geneva, Switzerland, ⁴Functional Brain Mapping Laboratory, University of Geneva, Geneva, Switzerland

We report the feasibility to record in a single session combined EEG-PET, MRI, EEG-fMRI and ESI using high-density EEG and a PET-MRI hybrid scanner. This whole multimodal procedure could be performed in less than two hours with good patient comfort. This single-session quadrimodal imaging could be of great interest for epilepsy presurgical mapping and may replace four separated exams usually performed to identify the epileptic focus. It may improve significantly the patient workflow in epilepsy unit and reduce the cost of presurgical epilepsy evaluations.

Chi Wah Wong¹, Valur Olafsson^1,2, Omer Tal¹, and Thomas Liu^1
1Center for Functional MRI, University of California San Diego, La Jolla, CA, United States, ²Neuroscience Imaging Center, University of Pittsburgh, PA, United States

A prior study has shown that the global signal amplitude in resting-state fMRI is negatively correlated with a measure of EEG vigilance in the eyes-closed (EC) condition but not in the eyes-open (EO) condition. In this study, we used simultaneous EEG-fMRI to identify brain regions in which the BOLD signal amplitudes are correlated with EEG vigilance. We then compared the spatial distribution between the EC and EO conditions. We found that the BOLD signal amplitude in the motor cortex, middle temporal gyrus, basal ganglia and cuneus are more negatively correlated with EEG vigilance in EC than EO.

David Carmichael¹, Umair J Chaudhary², Rachel C Thornton², Roman Rodionov², Serge Vulliemoz³, Andrew W McEvoy⁴, Beate Diehl², Matthew C Walker², John S Duncan², and Louis Lemieux^2
1Imaging and Biophysics, UCL Institute of Child Health, London, United Kingdom, ²UCL Institute of Neurology, London, United Kingdom, ³EEG and Epilepsy Unit, University Hospital and Functional Brain Mapping Lab, Geneva, Switzerland, ⁴Victor Horsley Department of Surgery, National Hospital for Neurology and Neurosurgery, London, United Kingdom

We used the recently developed method of combined intracranial EEG and fMRI (icEEG-fMRI) in a patient with epilepsy who had a focal electrographic seizure during scanning. We used an expert visually coded model and a quantitative model of spectral dynamics during the seizure obtained by frequency transformation followed by convolution by a haemodynamic response function and principle component analysis (PCA). Both models gave a similar widespread network of changes including in the right temporal lobe where the seizure onset was recorded. The quantitative model had greater statistical power and included a cluster proximal to the electrode that recorded seizure onset.

Qingfei Luo¹, Xiaoshan Huang², and Gary H. Glover^1
1Radiology, Stanford University, Stanford, CA, United States, ²Biomedical Engineering, Tsinghua University, Beijing, China

The previous ballistocardiogram (BCG) artifact removal methods based on a reference layer used either a customized electrode system or complicated experimental procedures. In this work, we propose a practical and efficient reference layer method and compare its performance with the most popular method (optimal basis sets (OBS)) on alpha-wave and sensory-evoked EEG signals. By designing the reference layer as a reusable cap, this method can be used directly with a standard EEG cap and without any hard modification. The comparison results showed that it has better performance than the OBS in removing the BCG artifact.

Chi Wah Wong¹, Valur Olafsson^1,2, Omer Tal¹, and Thomas Liu^1
1Center for Functional MRI, University of California San Diego, La Jolla, CA, United States, ²Neuroscience Imaging Center, University of Pittsburgh, PA, United States

A prior study has shown that the resting-state fMRI global signal amplitude is inversely correlated with a measure of EEG vigilance. In this study, we applied a sliding window approach to examine how the temporal dynamics of the global signal amplitude are related to the dynamics of network topology and EEG vigilance. We found that the temporal variations in the global signal amplitude are positively correlated with the time-varying clustering coefficient and negatively correlated with time-varying measures of characteristic path length and EEG vigilance.

Catie Chang¹, David A Leopold², Marieke L Scholvinck³, and Jeff H Duyn^1
1Advanced MRI Section, Laboratory of Functional and Molecular Imaging, NINDS, NIH, Bethesda, MD, United States, ²Section on Cognitive Neurophysiology and Imaging, Laboratory of Neuropsychology, NIMH, MD, United States, ³Ernst Strüngmann Institute for Neuroscience in Cooperation with Max Planck Society, Frankfurt am Main, Germany

The neural correlates of spontaneous hemodynamic fluctuations (“resting-state fMRI”) are not fully understood. Using simultaneous LFP-fMRI data acquired from awake macaques in the resting state, we examined the relationship between the low (< 8 Hz) and high (40-80 Hz) frequency bands of the local field potential in terms of their correlations with the fMRI signal. We observed that fluctuations in the power of the low and high frequency bands were weakly correlated with one another and provided complementary information about fMRI signals, suggesting that the correlation of LFP with BOLD arises from at least two distinct processes.