ISMRM 21st Annual Meeting & Exhibition 20-26 April 2013 Salt Lake City, Utah, USA

TRADITIONAL POSTER SESSION • FUNCTIONAL MRI
2227 -2239 Functional Connectivity: Acquisitions & Artifacts
2240 -2245 Functional Connectivity: Electrophysiological Correlates
2246 -2261 Functional Connectivity Analysis
2262 -2274 Functional Connectivity: Biomarkers
2275 -2284 fMRI Acquisition: Methods & Protocols
2285 -2297 fMRI: Analysis of Activation
2298 -2326 Animal fMRI Studies
2327 -2350 Human fMRI Studies

TRADITIONAL POSTER SESSION • FUNCTIONAL MRI
Thursday, 25 April 2013 (10:30-12:30) Exhibition Hall
Functional Connectivity: Acquisitions & Artifacts

2227.   Evaluation of Dual-Echo Pseudo-Continuous ASL for Resting-State BOLD Functional Connectivity Measurement
Tim X. Liu1, Sungho Tak1, Danny J.J. Wang2, Lirong Yan2, and J. Jean Chen1
1Rotman Research Institute, Baycrest, University of Toronto, Toronto, ON, Canada, 2Neurology, University of California, Los Angeles, CA, United States

 
Dual-echo pseudo-continuous ASL (pCASL) was recently introduced for simultaneously measuring dynamic BOLD and CBF, but its potential to reliably measure resting-state BOLD connectivity is still unestablished, due to potential ASL contamination in pCASL-based BOLD, and to its much longer repetition time. Our study shows, for the first time, that pCASL BOLD provides highly comparable connectivity results to conventional BOLD in terms of accuracy and reproducibility, despite its significantly longer repetition time. Using dual-echo pCASL, one can technically acquire the equivalent of 12 minutes of data (6 for BOLD and ASL each) in 8 minutes, allowing >30% cost and time savings.

 
2228.   The Application of Accelerated Functional Connectivity Magnetic Resonance Imaging to Study the Higher Frequency Band Resting State Functional Connectivity (R-fcMRI) and the Improvement for the Individual R-fcMRI Repeatability
Guangyu Chen1, Andrew S. Nencka1, Guangyu Chen1, and Shi-Jiang Li1,2
1Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, 2Psychiatry and Behavioral Medicine, Medical College of Wisconsin, Milwaukee, WI, United States

 
By increasing the acquisition frequency of resting-state fMRI data from 0.5Hz to 2Hz, we found that the resting-state default mode network still exists in the higher frequency band of the BOLD signal. Including the higher frequency band functional connectivity can increase the individual resting-state functional connectivity repeatability within and between sessions.

 
2229.   Artificial Correlations Induced by SENSE and GRAPPA Corrupt fcMRI Conclusions
Iain P. Bruce1 and Daniel B. Rowe1,2
1Department of Mathematics, Statistics, and Computer Science, Marquette University, Milwaukee, Wisconsin, United States, 2Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States

 
In fcMRI, parallel MR image reconstruction models such as SENSE and GRAPPA can be used to reduce data acquisition time in an effort to both increase spatiotemporal resolution and more rapidly measure changes in the BOLD contrast. However, the correlations induced by these models can change the correlation coefficients between previously aliased voxels in sub-sampled data by contrast to data that was fully sampled. Depending on the sign of the induced correlation relative to the correlation inherent in the acquired data, this can result in either Type I or II errors in fcMRI when the hypothesis assumes no correlation exists.

 
2230.   Minimizing Spurious Functional Connectivity Findings from Resting State fMRI
Prantik Kundu1, Noah Brenowitz1, Souheil J. Inati2, Ziad S. Saad3, Petra Vertes4, Yulia Worbe4, Valerie Voon4, Ed Bullmore4, and Peter A. Bandettini5
1Section on Functional Imaging Mehthods, NIMH, Bethesda, MD, United States, 2Functional MRI Core Facility, NIMH, Bethesda, MD, United States, 3Scientific and Statistical Computing Core, NIMH, Bethesda, MD, United States, 4Dept. of Psychiatry, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom, 5Functional MRI Core Facility, National Institute of Mental Health, Bethesda, MD, United States

 
We present a solution to the critical problem for resting state fMRI (rs-fMRI) that functional connectivity estimates are severely biased by any level of in-scanner subject head movement. We show that separating BOLD from non-BOLD signals using T2* decay analysis of multi-echo fMRI and independent components analysis (ME-ICA) entirely removes both linear and non-linear manifestations of motion artifact. This denoising is achieved without arbitrary processing such as data censoring or band pass filtering, making ME-ICA the first physically and statistically principled approach for comprehensive denoising of rs-fMRI data. Our study gives a deeper understanding of rs-fMRI while solving a critical problem for this exciting methodology.

 
2231.   Venous Suppression in Resting State FMRI: Implications for Correlation Analysis
Andrew T. Curtis1, R. Matthew Hutchison1, and Ravi S. Menon1
1Medical Biophysics, University of Western Ontario, London, Ontario, Canada

 
A phase regressor technique is applied to resting state fMRI data to suppress venous contributions. Resulting seed-based correlation maps demonstrate substantial differences in spatial organization and correlation values.

 
2232.   Temporal Processing of fMRI Data Induces Functional Correlations and Potentially Alters Functional Activations
M. Muge Karaman1, Andrew S. Nencka2, and Daniel B. Rowe1,2
1Department of Mathematics, Statistics, and Computer Science, Marquette University, Milwaukee, WI, United States, 2Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States

 
Temporal processing is a common practice in fMRI and functional connectivity MRI studies as a way to “improve” the resulting images. However, such processing alters the signal and noise properties of the data and could have severe effect on the statistical maps, including functional activations, computed from the processed images. We develop a mathematical framework that allows one to analytically analyze the effects of time series preprocessing, and thus contributes to produce more accurate functional activations. This exact method considers linear operators to perform spatial processing, reconstruction and Fourier anomalies correction, and temporal processing on the acquired signal measurements.

 
2233.   Resting-State Functional Connectivity Mapping Using Cerebral Blood Flow: Comparison with Simultaneously Acquired BOLD in High-Susceptibility Regions
Sungho Tak1, Danny J.J. Wang2, Lirong Yan2, and J. Jean Chen3
1Rotman Research Institute at Baycrest Centre, University of Toronto, Toronto, ON, Canada, 2Neurology, University of California, Los Angeles (UCLA), Los Angeles, CA, United States, 3University of Toronto, Toronto, ON, Canada

 
In this study, we investigated cerebral blood flow (CBF)-based functional connectivity of the default mode network and the medial temporal regions using the dual-echo pseudo-continuous spin labeling (pCASL) technique. CBF and BOLD were measured simultaneously, and CBF-based connectivity revealed the entire default-mode network. Furthermore, as CBF is less sensitive to susceptibility effects than conventional BOLD, we were able to observe significant connectivity between the entorhinal cortex, medial orbitofrontal cortex and the parahippocampal cortex using fluctuations in CBF. These regions are anatomically connected within the medial temporal lobe, but are not observed using BOLD connectivity.

 
2234.   Resting-State Functional Connectivity Mapping in Humans Using Spin-Echo EPI BOLD
Yasha Khatamian1 and J. Jean Chen2
1Rotman Research Institute, Toronto, ON, Canada, 2University of Toronto, Toronto, ON, Canada

 
This study investigated the use of spin-echo vs. gradient-echo BOLD for mapping resting-state functional connectivity in humans. We performed connectivity analyses to the posterior cingulate cortex, parahippocampal cortex, and head of the caudate. While spin echo provided robust connectivity maps overall, its sensitivity to the default mode network was lower than gradient echo. Importantly, spin echo was able to map connectivity in regions affected by susceptibility artifacts, such as the subcortical nuclei and the medial temporal lobes. Therefore, spin-echo BOLD may be a good alternative to gradient echo for resting-state functional studies.

 
2235.   Quantitative Measurement of Signal Fluctuations in ASL from Resting State Functional Networks
Weiying Dai1, Ajit Shankaranarayanan2, Gottfried Schlaug3, and David C. Alsop1
1Radiology, Beth Israel Deaconess Medical Center & Harvard Medical School, Boston, MA, United States, 2Global Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States, 3Neurology, Beth Israel Deaconess Medical Center & Harvard Medical School, Boston, MA, United States

 
We report quantitative measurement of signal fluctuation from resting state networks in volumetric arterial spin labeling (ASL) perfusion images of normal volunteers. Network fluctuations are much larger than residual noise. The combined signal fluctuation from all the networks is approximately 10% of the mean perfusion signal, but the signal fluctuation amplitude varies between the different networks. Unlike the residual noise, the resting state network fluctuations cannot be reduced by greater smoothing. Resting network quantification with ASL may be useful to further study the physiology of the fluctuations and may enable improved noise reduction and statistical analysis of ASL studies.

 
2236.   
Resting State Neural Network Demonstrated with Cerebral Blood Volume Based fMRI Using the USPIO Agent Ferumoxytol in Humans
Deqiang Qiu1, Greg Zaharchuk1, Thomas Christen1, Wendy W. Ni1, Gary H. Glover1, and Michael E. Moseley1
1Radiology, Stanford University, Stanford, CA, United States

 
In this paper, we present the first study demonstrating the synchronously spontaneous fluctuations of cerebral blood volume (CBV) in humans by using ultrasmall superparamagnetic iron particle (USPIO) for fMRI (termed ICE-BVI). Consistent with previous methods utilizing BOLD and CBF, CBV demonstrates spontaneous fluctuations that are synchronized within putative resting state neural networks. ICE-BVI provides a new means for studying the mechanisms of spontaneous fluctuations, and may improve the sensitivity of detection of resting state neural networks.

 
2237.   Resting State Functional Connectivity in the Human Spinal Cord at 7 Tesla
Robert L. Barry1,2, Seth A. Smith1,2, and John C. Gore2,3
1Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, 2Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, 3Vanderbilt University, Nashville, TN, United States

 
The existence of resting state functional connectivity is well established in the brain, but to date there have been no conclusive investigations in the spinal cord. The advent of 7 Tesla scanners and implementation of multichannel spine coils along with appropriate image acquisitions and corrections provide new opportunities for high-resolution spinal fMRI. This abstract represents the first demonstration of high-resolution resting state functional connectivity in the human spinal cord. Future work will investigate spinal functional connectivity in patients with multiple sclerosis and spinal cord injury, and translate these methods down to 3 Tesla to facilitate widespread development of clinical applications.

 
2238.   Frequency Characteristics of Large Scale Resting State Networks Using 7T Spin Echo EPI
Erik van Oort1,2, Peter J. Koopmans3, Rasim Boyacioglu4, Markus Barth4, Christian F. Beckmann1,2, and David Norris5
1Statistical Imaging Neuroscience, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Nijmegen, Gelderland, Netherlands, 2Statistical Imaging Neuroscience, Radboud University Nijmegen, Donders Center for Cognitive Neuroimaging, Nijmegen, Nederland, Netherlands, 3MR Techniques in Brain Function, Radboud University Nijmegen, Donders Center for Cognitive Neuroimaging, Nijmegen, Nederland, Netherlands, 4MR Techniques in Brain Function, Radboud University, Nijmegen, Nederland, Netherlands, 5MR Techniques in Brain Function, Radboud University Nijmegen, Donders Center for Cognitive Neuroimaging, Nijmegen, Gelderland, Netherlands

 
Frequency characteristics of large scale Resting State Networks were investigated using full brain 7T Spin Echo EPI. Previous results of GE EPI data show peak identifiability and estimation of RSNs at frequencies above 0.1Hz, with decreasing performance at higher frequencies. The SE performance also peaks above 0.1Hz, but plateaus instead of dropping off. This is in accordance with the reported more linear nature of SE EPI, when compared to GE EPI. This causes less attenuation of high frequency contributions in SE EPI, which show in a monotonically rising performance, until reaching a plateau.

 
2239.   Resting State fMRI Using Multi Echo EPI (ME-EPI): A Study of Echo Time Dependence of Sensitivity
Deqiang Qiu1, Thomas Christen1, Jae Mo Park1, Michael E. Moseley1, and Greg Zaharchuk1
1Radiology, Stanford University, Stanford, CA, United States

 
Resting state fMRI (RS-fMRI) using BOLD has attracted significant interests recently. However, the relative sensitivity of RS-fMRI with respect to echo time has not been characterized. In this study, we developed a multi-echo EPI sequence with parallel imaging to study the effect of echo time on the sensitivity of RS-fMRI. We found that the sensitivity of RS-fMRI increases with echo time up to 58ms and has no significantly changes when increasing echo time further to 78ms. The benefits of reduction of EPI-related distortion using parallel imaging as well as combination of multiple echoes are also discussed.

 

TRADITIONAL POSTER SESSION • FUNCTIONAL MRI
Thursday, 25 April 2013 (10:30-12:30) Exhibition Hall
Functional Connectivity: Electrophysiological Correlates

2240.   Stability of Resting-State Brain Activity Fluctuations Across Time: Evidence from fMRI and MEG
Om Bhatt1, Jed Meltzer1, Bernhard Ross1, and J. Jean Chen1
1Rotman Research Institute, Baycrest, University of Toronto, Toronto, ON, Canada

 
Magnetoencephalography (MEG) is potentially valuable in clarifying the physiological mechanisms of resting-state fMRI-based functional connectivity. However, MEG and fMRI experiments cannot be performed simultaneously on the same subject. In this work, we present evidence for a stability of intrinsic brain activity across time. This stability is higher in certain brain regions, and higher during “eyes-open” than in “eyes-closed” resting state. These findings will enhance our ability to capitalize on the spatially resolved neuro-electric information from MEG to inform resting-state fMRI interpretations of brain activity. Future work will address the link between these spectral features and connectivity.

 
2241.   Simultaneous fMRI and EEG Study of Never Resting Brain: Spatial and Temporal Similarity of EEG Microstates Cortical Representation and BOLD Resting State Networks
Han Yuan1, Lei Ding2,3, Min Zhu2, and Jerzy Bodurka1,4
1Laureate Institute for Brain Research, Tulsa, OK, United States, 2School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK, United States,3Bioengineering Center, University of Oklahoma, Norman, OK, United States, 4College of Engineering, University of Oklahoma, Norman, OK, United States

 
We describe a method to derive and characterize the resting state networks (RSNs) independently using EEG microstates. We combined electrophysiological source imaging and independent component analysis to obtain cortical sources of EEG microstates and compared them to the resting state networks independently derived from simultaneously measured BOLD fMRI. Our results revealed for the first time that the EEG-microstate-derived RSNs are of both high spatial similarity and temporal correlation with BOLD fMRI RSNs.

 
2242.   
EEG Correlates of Time-Varying BOLD Functional Connectivity
Catie Chang1, Zhongming Liu2, Michael C. Chen3, Xiao Liu2, and Jeff H. Duyn1
1Advanced MRI Section, LFMI, NINDS, National Institutes of Health, Bethesda, MD, United States, 2Advanced MRI Section, LFMI, NINDS, NIH, Bethesda, MD, United States,3Dept. of Psychology, Stanford University, Stanford, CA, United States

 
While resting-state functional connectivity (FC) has been observed to vary substantially over time-scales of seconds to minutes, the origins and relevance of these dynamics are not well understood. Here, we use simultaneous EEG-fMRI and a sliding-window analysis to investigate the electrophysiological correlates of within-scan fluctuations in FC between default-mode (DMN) and dorsal attention (DAN) networks. Fluctuations in alpha power were significantly correlated with fluctuations in DMN-DAN connectivity as well as in the degree of DMN-DAN anti-correlation. These results suggest an electrical signature of non-stationary DAN-DMN FC, potentially reflecting variations in vigilance or attentional states.

 
2243.   The Electrical Basis of Dynamic Functional Connectivity Measured with Sliding Window Correlation.
Mac Merritt1, Garth Thompson1, Wen-Ju Pan1, Matthew E. Magnuson1, and Shella Keilholz1
1BMED, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States

 
This study uses simultaneous resting state fMRI and microelectrode recording to investigate the relationship between the temporal dynamics of bilateral electrical activity and bilateral blood oxygenation level dependent (BOLD) fluctuations using Sliding Window Correlation. This shows an electrical basis for BOLD signal functional connectivity dynamics that can be observed with sliding window correlation.

 
2244.   Global Reductions in Resting-State BOLD Connectivity Reflect Widespread Decreases in MEG Connectivity
Omer Tal1, Chi Wah Wong1, Valur Olafsson1, Mithun Diwakar2, Roland Lee2, Ming-Xiong Huang2, and Thomas T. Liu1,2
1Center for Functional MRI, University of California, San Diego, La Jolla, CA, United States, 2Radiology, University of California, San Diego, La Jolla, CA, United States

 
It has been previously shown that caffeine reduces resting-state BOLD connectivity throughout the brain. However, given the complex hemodynamic nature of the BOLD signal and caffeine’s effects on both neural activity and the vasculature, it was not clear whether neural or vascular factors were primarily responsible for the observed connectivity changes. In this study, we employ both fMRI and magnetoencephalography (MEG) to show that caffeine-induced reductions in BOLD connectivity reflect widespread decreases in neuro-electric connectivity.

 
2245.   Inter-Subject Variability in the Amplitude of the Resting-State fMRI Global Signal Reflects Differences in EEG Vigilance
Chi Wah Wong1, Valur Olafsson1, Omer Tal1, and Thomas Liu1
1Center for Functional MRI, University of California San Diego, La Jolla, CA, United States

 
The global signal is often considered a confound in resting-state fMRI. However, a recent primate study has shown that the global signal may contain significant contributions from neural sources. In this study, we used simultaneous EEG-fMRI to examine the sources of inter-subject variability in the amplitude of the global signal in humans. We found that the global signal amplitude is negatively correlated with an EEG-based vigilance measure.

 

TRADITIONAL POSTER SESSION • FUNCTIONAL MRI
Thursday, 25 April 2013 (10:30-12:30) Exhibition Hall
Functional Connectivity Analysis

2246.   Connectivity-Based Neurofeedback: Dynamic Causal Modeling for Real-Time FMRI.
Yury Koush1,2, Maria Joao Rosa3, Fabien Robineau4,5, Klaartje Heinen6, Nikolaus Weiskopf7, Patrik Vuilleumier4,5, Dimitri Van de Ville1,2, and Frank Scharnowski1,2
1Department of Radiology and Medical Informatics, CIBM, University of Geneva, Geneva, Switzerland, 2Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 3Computer Science Department, University College London, London, United Kingdom, 4Department of Neuroscience, CMU, University of Geneva, Geneva, Switzerland, 5Geneva Neuroscience Center, Geneva, Switzerland, 6Institute of Cognitive Neuroscience, University College London, London, United Kingdom, 7Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, United Kingdom

 
Neurofeedback based on real-time fMRI is a novel technique that allows to train voluntary control over brain activity. So far, this technique was limited to training localized brain activity within a region of interest. Here, we overcome this limitation by presenting real-time dynamic causal modelling in order to provide neurofeedback information based on connectivity between brain areas rather than activity within a brain area. Being able to train network activity is an important extension of the neurofeedback approach that will contribute to its development as a promising research tool, and will open up a whole new range of medical applications.

 
2247.   Quality Assessment and Consistency of Serial Multi-Center Resting-State fMRI in Alzheimers Disease
David Clayton1, Farshid Faraji1, Douglas Arnold2, Alex De Crespigny3, and Alexandre Coimbra3
1Genentech, Inc., South San Francisco, California, United States, 2NeuroRX Research, Montreal, Quebec, Canada, 3Genentech Inc, South San Francisco, California, United States

 
Several single site resting-state fMRI studies (RS-fMRI) have shown that brain functional connectivity metrics are altered in Alzheimer Disease (AD) patients. Exploratory RS-fMRI was included in two global Phase II studies of a novel AD drug. We report here fMRI data quality control procedures and observed quality metrics from screening and very early on-treatment scans. Subject tolerance and protocol compliance was good. In spite of heterogeneous scanning equipment and variable raw SNR across sites, the data pre-processing pipeline resulted in consistent processed data quality metrics, with few scans that could not be used for subsequent functional connectivity analysis.

 
2248.   A Case for Correcting Attenuation of Correlation in Resting State FMRI
Jacco A. De Zwart1, Peter van Gelderen1, and Jeff H. Duyn1
1Advanced MRI, LFMI, NINDS, National Institutes of Health, Bethesda, MD, United States

 
In low-noise situations the correlation between two signals is underestimated, an effect known as attenuation of correlation. This work shows that this well-established effect can lead to significant underestimation of cross-correlation in resting-state fMRI, where often the ratio between the neurogenic fluctuation of interest and noise level is less than 10. Correction of the cross-correlation value for this effect is well established and straightforward if the noise level is known.

 
2249.   Power-Law Functional Organizations of the Brain in Wake, Anesthesia, and Vegetative State
Xiaolin Liu1, B. Douglas Ward1, Shi-Jiang Li1, and Anthony G. Hudetz2
1Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States, 2Anesthesiology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States

 
Self-organized criticality (SOC) is an attractive model for describing human brain dynamics. One of the most commonly sought empirical signatures of SOC is the power-law probability distributions in a complex system. This study proposes a novel algorithm that determines functional partitions (FPs) of the brain based upon both their anatomical and functional properties. We then show its effectiveness in demonstrating robust power-law distributions in healthy brains and discuss the implications of power-law manifestations in wake, anesthesia, and vegetative states as related to the maintenance and disruption the brain¡¯s self-organizing capability.

 
2250.   Wavelet-Based Clustering and Dynamic Analysis of Resting State Data in the Rat
Shella Keilholz1, Alessio Medda2, Lukas Hoffmann3, Matthew E. Magnuson1, Garth Thompson1, and Wen-Ju Pan1
1Biomedical Engineering, Emory/Georgia Tech, Atlanta, GA, United States, 2Georgia Tech Research Institute, Atlanta, GA, United States, 3Neuroscience Program, Emory University, Atlanta, GA, United States

 
While functional connectivity has typically been calculated over the length of an entire scan, interest has been growing in dynamic analysis methods that can detect changes in connectivity on much shorter time scales. Dynamic connectivity can be examined using sliding window correlation, but the properties of the dynamics depend on the window length, making a data-driven approach more attractive. We have developed an algorithm based on wavelet decomposition that clusters voxels into groups with similar temporal and spectral properties. The resulting clusters agree well with anatomy in the rat and the wavelet decomposition features exhibit sensitivity to network dynamics.

 
2251.   Resting-State fMRI Signal Anti-Correlation Exists in Absence of Global Signal Regression
Xiao Liu1 and Jeff H. Duyn1
1Advanced MRI section, LFMI, NINDS, National Institutes of Health, Bethesda, MD, United States

 
To understand the negative correlation between resting-state fMRI signals and how it could be affected by global signal regression (GSR) procedure, a novel technique was applied to temporally decompose the default mode network (DMN) into multiple co-activation patterns (CAPs). This decomposition of activity patterns during rest suggests that anti-correlation between brain regions is not an artifact of global signal regression but may be caused by brief periods of negatively correlated neuronal activity.

 
2252.   Spontaneous Low-Frequency Functional Connectivity and Temporal Dynamics: Working Memory Vs. Rest
Jingyuan Chen1, Catie Chang2, and Gary H. Glover1,3
1Electrical Engineering, Stanford University, Palo Alto, CA, United States, 2National Institutes of Health, Bethesda, MD, United States, 3Radiology Department, Stanford University, Palo Alto, CA, United States

 
In the current study, we compared the spontaneous temporal behavior of the default-mode network (DMN) at rest and under a sustained 2-back working memory (WM) task load. Results indicated that during sustained WM task: (1) the spontaneous low-frequency temporal connectivity showed similar patterns as the steady-state task-induced activation/deactivation; (2) global variability with posterior cingulate cortex was weaker compared to rest; (3) the DMN and salience network showed significant power reduction compared to rest.

 
2253.   Network Diffusion Models for Functional Brain Connectivity Networks
Farras Abdelnour1, Henning Voss1, and Ashish Raj1
1Radiology, Weill Cornell Medical College, New York, NY, United States

 
We present a simple and intuitive network diffusion model which produces an accurate mathematical description of the structure-function relationship. We hypothesize that resting state functional relationships between brain regions result from this diffusion process applied to the structural network during rest. The network diffusion model applied to the structural networks closely predicts both the spatial and temporal correlation structures seen in the functional networks. We compare our work with published models. The proposed model is simple yet offers improved estimates of functional connectivity.

 
2254.   Resting-State Functional Connectivity of Specialized Occipitotemporal Cortical Regions
Kaundinya Gopinath1, Simon Lacey2, Shaheen Ahmed1, Randall Stilla2, and K. Sathian2
1Department of Radiology & Imaging Sciences, Emory University, Atlanta, GA, United States, 2Department of Neurology, Emory University, Atlanta, GA, United States

 
The human occipitotemporal cortex (OTC) contains a number of regions specialized for processing particular types of sensory stimuli: including the lateral occipital complex (LOC), an object-selective area; the fusiform face area (FFA), a face-selective area; the parahippocampal place area (PPA), a scene-selective area; and the extrastriate body area (EBA), a body part-selective area. This study examined resting-state connectivity patterns of functionally localized LOC, EBA, FFA and PPA. Results indicate that regions of OTC exhibit both common and differential connectivity patterns. The EBA exhibited preferential connectivity with the default mode network, while FFA exhibited increased connectivity with the frontoparietal attention network.

 
2255.   Quantification of Reproducible Spatiotemporal Dynamic Patterns Using Bootstrapping from Randomized Phase Data in the Rodent Model
Matthew E. Magnuson1, Garth Thompson1, Wen-Ju Pan1, and Shella Keilholz1
1Biomedical Engineering, Georgia Institute of Technology / Emory University, Atlanta, GA, United States

 
Dynamic analysis of functional MRI data is gaining traction over the traditional static based analysis, primarily because it provides complex information regarding the spatial and temporal properties of functional activity as opposed to a single average of those dynamic components. Majeed et al. previously published a technique for creating reproducible spatiotemporal dynamic templates from functional data based on a specified window length. In the work presented here we expand on the previous work using a bootstrapping algorithm to statistically threshold the template output allowing for quantification, clustering, and finally inter-subject comparisons.

 
2256.   Effective Brain Connectivity Among Resting-State Networks : A Frequency Dependent Granger Causality Analysis
I-Jung Chen1, Yen-Hsiang Cheng2, Tzu-Cheng Chao1,2, Ping-Hong Lai3,4, Fu-Nien Wang5, and Ming-Long Wu1,2
1Department of Computer Science and Information Engineering, National Cheng Kung University, Tainan, Taiwan, 2Institute of Medical Informatics, National Cheng Kung University, Tainan, Taiwan, 3Department of Radiology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan, 4School of Medicine, National Yang-Ming University, Taipei, Taiwan, 5Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan

 
In general, fMRI analysis includes full spectral width (i.e., bandwidth) without looking into signal changes at different spectral frequency. For a resting-state fMRI (rsfMRI) experiment, low frequency oscillation (0.01 ¡V 0.1Hz) of MRI signals was reported to reveal activities of resting brain networks. In this study, we examined whether effective connectivity among resting brain networks changes at different frequency band. More specifically, conditional Granger Causality (GC) analysis was performed with band pass filtered time series of resting brain networks. The results show that effective connectivity varies in different frequency bands and outflows from each resting-state network present different frequency dependent characteristics.

 
2257.   Functional Parcellation of Cerebellum Based on Resting-State fMRI and Singular Value Decomposition
Chia-Wei Li1 and Jyh-Horng Chen1,2
1Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan, Taiwan, 2Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan, Taiwan

 
Recent researches pointed out that the cerebellum participates in many cognitive processes. In this study, we tried to parcel out the functional separation according to the functional connectivity between cerebellum and cerebrum based on one combined process of data-driven SVD and seed method. Moreover, we also parceled out the energy peaks in frequency domain among those cerebellar functional networks. In the result, fourteen functional patterns show that cerebellum participate in many cognitive processes, including of motor, executive control, memory, language, emotion, thalamic network, visuospatial, and DMN. And most of the energy peaks among those patterns distribute in 0.01~0.04 and 0.06~0.09 (Hz). It could provide one valuable reference for the further investigation about resting-state MRI.

 
2258.   Graph Analysis of Resting-State ASL Data Reveals Nonlinear Correlations Among CBF and Network Metrics
Xiaoyun Liang1, Alan Connelly1,2, and Fernando Calamante1,2
1Brain Research Institute, Florey Institute of Neuroscience and Mental Health, Heidelberg, VIC, Australia, 2Department of Medicine, Austin Health and Northern Health, University of Melbourne, Melbourne, VIC, Australia

 
In this study, investigations on small-world network properties of ASL perfusion data have been conducted. The small-world network properties of ASL data are consistent with previous findings from BOLD data. Interestingly, the outcomes on the relationships between 4 specific network metrics and region-wise CBF demonstrate that consistent nonlinear patterns exist across normal subjects, which is well in line with the previous finding that ‘hub’ regions tend to have higher values for degree, vulnerability and centrality, but lower values for characteristic path length, along with higher metabolic energy consumption (and CBF). This should not only provide useful information to further our understanding of the metabolic energy consumptions with which the brain can maintain normal cognition with the lowest cost, but also have applications for clinical studies on brain disorders.

 
2259.   Mapping Brain Entropy Using Resting State fMRI: Part I
Ze Wang1,2, Anish Mitra3, Marcus Raichle3, Anna Rose Childress1, and John A. Detre2,4
1Dept. of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, United States, 2Dept. of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States, 3Neurology, Washington University in St Louis, St. Louis, Missouri, United States, 4Dept. of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, United States

 
Entropy is a measure of system orderliness, and can be assessed as a quantitative brain status index. Using a large resting fMRI database, we systematically investigated resting brain entropy regarding its age and gender effects, spatial distribution, regional organization, and the hierarchical structure of local BEN communities. In this abstract, we showed high test-retest reproducibility of BEN mapping using resting state fMRI in the whole brain. We also showed a clear BEN contrast between the neocortex versus non-neocortex regions in the resting brain.

 
2260.   Correction of Long-Term Physiological Noise Effects Increases the Reproducibility of Resting-State Networks
Jaemin Shin1,2, Zhi Yang3,4, Audrey Duarte5, and Xiaoping P. Hu1
1Department of Biomedical Engineering, Georgia Tech and Emory University, Atlanta, GA, United States, 2Center for Advanced Brain Imaging, Georgia Tech and Georgia State University, Atlanta, GA, United States, 3Institute of Psychology, Chinese Academy of Sciences, Beijing, China, 4National Institute of Mental Health, Bethesda, MD, United States,5School of Psychology, Georgia Tech, Atlanta, GA, United States

 
Recently, increased attention has been directed at resting-state functional connectivity. However, physiological fluctuations arising from respiratory and cardiac processes are detrimental in resting-state functional connectivity analysis. The present study aims to characterize the effects of physiological noise correction on the derived resting-state networks (RSNs). After correction, it is observed that the reproducibility of RSNs is increased. In particular, a technique that corrects for long-term physiological noise effects as well as short-term effects resulted in the highest reproducibility.

 
2261.   Reliability of Intrinsic Networks Over 128 Weeks
Ann S. Choe1,2, Suresh E. Joel3,4, Craig K. Jones3,4, John Muschelli5, Visar Belegu1,2, John W. McDonald1,2, Brian S. Caffo5, Peter C.M. van Zijl3,4, and James J. Pekar3,4
1Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 2International Center for Spinal Cord Injury, Hugo Moser Research Institute, Kennedy Krieger Institute, Baltimore, MD, United States, 3Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States, 4FM Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, 5Department of Biostatistics, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States

 
Understanding the intra-subject inter-session reproducibility of resting-state fMRI over prolonged time periods is essential. A longitudinal dataset of a healthy subject that covers the span of 128 weeks with weekly repeat measures was used to investigate the stability of network spatial distributions and between network connectivity (BNC), which were found to be stable over 128 weeks. This shows that rs-fMRI outcome measures can be used to reliably monitor disease progression and responses to therapeutic interventions. The most spatially stable network was the primary motor network and BNC was most stable between the secondary visual and salience networks.

 

TRADITIONAL POSTER SESSION • FUNCTIONAL MRI
Thursday, 25 April 2013 (10:30-12:30) Exhibition Hall
Functional Connectivity: Biomarkers

2262.   Some Brains Are More Strongly Functionally Connected Than Others: A Resting-State fMRI Study of Inter and Intra Network Coherence
Izabela Przezdzik1, Andrew P. Bagshaw1, and Stephen D. Mayhew1
1BUIC, School of Psychology, University of Birmingham, Birmingham, United Kingdom

 
We used group ICA to identify the brain’s major bilateral networks and seed-based functional connectivity (FC) to demonstrate that some individual’s brains are more strongly connected than others. We observe that: 1) FC strength within a network is related to FC strength within other networks; 2) FC strength between networks can be predicted from the FC within the seed network; 3) FC within a cortical network is related to the strength of its connectivity with the thalamus. These results provide insight into the collaborative and antagonistic temporal relationships between the networks which form the functional architecture of the human brain.

 
2263.   Within Hemisphere Connectivity Differentiates Humans from Nonhuman Primates: A Resting-State fMRI Study
Hsiao-Ying Wey1,2, Kimberly A. Phillips1,3, Angela R. Laird1, Peter Kochunov1,4, Michael D. Davis1, David C. Glahn1,5, John Blangero6, Timothy O. Duong7, and Peter T. Fox1
1Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States, 2Athinoula A. Martinos Center, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States, 3Department of Psychology, Trinity University, San Antonio, TX, United States,4Maryland Psychiatric Research Center, University of Maryland, Baltimore, MD, United States, 5Department of Psychiatry, Yale University, Hartford, CT, United States,6Department of Genetics, Texas Biomedical Research Institute, San Antonio, TX, United States, 7Research Imaging Institute, UT Health Science Center at San Antonio, San Antonio, TX, United States

 
We aim to investigate evolutionary differences of functional connectivity between humans and nonhuman primates. Specifically, we identified resting-state intrinsic connectivity networks in four primate species (humans, chimpanzees, baboons, and capuchin monkeys) spanning different levels of the evolutionary tree, and we compared similarities and discrepancies of those networks found in humans. We observed similar networks associated with primary functions in both species. Interestingly, all nonhuman primate species displayed lateralized functional networks that were strikingly similar to those observed in humans.

 
2264.   Magnetic Resonance Imaging the Genetic Influence on Intrinsic Resting-State Connectivity in Brown Norway and Dahl Salt-Sensitive Rat Brains
Zhixin Li1, B. Douglas Ward2, Melinda R. Dwinell3, and Christopher P. Pawela1
1Department of Plastic Surgery, Medical College of Wisconsin, Milwaukee, WI, United States, 2Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, 3Human and Molecular Genetics Center, Medical College of Wisconsin, Milwaukee, WI, United States

 
We address for the first time the genetic influences on intrinsic neural connectivity in a resting-state fMRI study of two genetically different inbred rat strains:Brown Norway(BN) and Dahl salt-sensitive(SS) rats.SS rat exhibited differential intrinsic functional connectivity patterns in primary somatosensory and caudate putamen network in comparison to BN rats. These task-specific regional differences in neural network can speculatively suggest an “endophenotype” or imaging marker of genetic component of under specific biological events.

 
2265.   Mapping the Mouse Brain Functional Connectivity Networks: Strain Specific Patterns
Laura-Adela Harsan1, Anna Mechling1, Neele Hübner1, Hsu-Lei Lee1, Jürgen Hennig2, and Dominik von Elverfeldt1
1Medical Physics, University Medical Center, Freiburg, BW, Germany, 2Medical Physics, University Medical Center Freiburg, Freiburg, BW, Germany

 
The intrinsic connectional architecture of functional networks (FN) in the mouse brain remains a significantly underexplored research area. The primary goal of our study is to systematically and comparatively probe using resting state fMRI (rsfMRI) the intrinsic brain functional connectivity of two mouse strains, intensively used in the fundamental and preclinical neuroscience: the C57Bl6/N and the Balbc/J strain. Using Independent Component Analysis (ICA), partial correlation and graph theory, we identify the relevant, influential nodes in each strain and show inter-strain differences in the large scale organization of FN.

 
2266.   Spontaneous BOLD Signal Fluctuations in the Young and Elderly Brain: a Non-Contrast Biomarker of Cerebral Vasomotor Reactivity?
Hesamoddin Jahanian1, Wendy W. Ni1, Thomas Christen1, Manjula K. Tamura2, Michael E. Moseley1, and Greg Zaharchuk1
1Department of Radiology, Stanford University, Stanford, California, United States, 2Division of Nephrology, Stanford University, Stanford, California, United States

 
Spontaneous fluctuations in blood oxygenation level dependent (BOLD) signal have been observed in resting state time series measurements. Although their precise physiological origin is not yet clear, they are likely to arise from oscillations in metabolic-linked brain physiology, arterial vasomotion and hemodynamics. We hypothesized that these physiological fluctuations may reveal cerebrovascular autoregulatory mechanisms and consequently be associated with factors modulating the cerebrovasculature such as aging and hypertension. To test this hypothesis, we compared the magnitude of spontaneous BOLD fluctuations in two populations: 1) young healthy adults and 2) hypertensive elderly subjects with chronic kidney disease (CKD).

 
2267.   ASL Based Functional Connectivity in Schizophrenia Relates to Disease Severity
Nadja Razavi1, Andrea Federspiel1, Thomas Dierks1, Martinus Hauf2, and Kay Jann1
1Dept. of Psychiatric Neurophysiology, University Hospital of Psychiatry / University of Bern, Bern, Bern, Switzerland, 2Institut of Diagnostic and Interventional Neuroradiology, University of Bern / Inselspital, Bern, Bern, Switzerland

 
We measured resting-state DMN activity by pCASL based cerebral blood flow (CBF) and BOLD fMRI data in 11 patients with schizophrenia. We show that both datasets yield spatially similar DMN components and we demonstrate that the spatial similarity of a patient’s CBF-DMN to the respective DMN group component was negatively correlated to the PANSS positive score. In addition, pCASL provides information about the absolute perfusion of the brain and network: Increased CBF in patient’s DMNs (controlled for grey matter CBF), suggested a state of hyperactivity that may be relating to processing errors occurring in schizophrenia.

 
2268.   Identifying Group Differences in Functional Subnetworks: A Novel Whole-Brain Method Applied to Dyslexia
Emily S. Finn1, Xilin Shen2, John M. Holahan3, Xenophon Papademetris2,4, Dustin Scheinost4, Cheryl Lacadie2, Sally E. Shaywitz3, Bennett A. Shaywitz3, and Robert Todd Constable2,4
1Interdepartmental Neuroscience Program, Yale University, New Haven, CT, United States, 2Diagnostic Radiology, Yale University, New Haven, CT, United States, 3Yale Center for Dyslexia and Creativity, Yale University, New Haven, CT, United States, 4Biomedical Engineering, Yale University, New Haven, CT, United States

 
We applied a novel data-driven functional connectivity (FC) analysis to fMRI data from dyslexic vs. non-impaired readers to reveal functional subnetworks involved in successful reading. Our method improves upon previous FC analyses by not requiring a priori seed regions or arbitrary thresholds to determine connectivity. We found a network of occipitoparietal (visual association) and frontal (attention) areas that were better connected in non-impaired readers, suggesting that these subjects are better able to process word shapes and modulate their attention to visual stimuli. We believe this method can be extended to examine differentially connected functional subnetworks in other neural disorders.

 
2269.   Resting State fMRI Revealed Differences in Connectivity to Visual Cortex in Premature Infants with Hypercapnic Ventilation
Xiawei Ou1, George Andrew James2, Zhaohua Ding3, Charles M. Glasier1, Raghu H. Ramakrishnaiah1, and Jeffrey R. Kaiser4
1Radiology, Arkansas Children's Hospital; University of Arkansas for Medical Sciences, Little Rock, AR, United States, 2Brain Imaging Research Center, University of Arkansas for Medical Sciences, Little Rock, AR, United States, 3Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, 4Pediatrics, Arkansas Children's Hospital; University of Arkansas for Medical Sciences, Little Rock, AR, United States

 
We performed resting state fMRI study on extremely low birth-weight (ELBW) infants randomized to groups with or without permissive hypercapnia and compared the functional connectivity in the brain to the primary visual cortex. We found decreased inter-network functional connectivity between visual cortex and motor cortex for the hypercapnic infants. Our findings suggest that hypercapnic ventilation may reduce functional connectivity between brain default networks.

 
2270.   Reproducible Differentiation of Individual Subjects with Minimal Acquisition Time Via Resting State FMRI
Raag D. Airan1, Joshua Vogelstein2,3, Brian S. Caffo4, James J. Pekar1,5, and Haris I. Sair1
1Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, MARYLAND, United States, 2Statistical Sciences, Duke University, Durham, NC, United States,3Applied Mathematics and Statistics, Johns Hopkins University, Baltimore, MARYLAND, United States, 4Biostatistics, Johns Hopkins University, Baltimore, MARYLAND, United States,5F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MARYLAND, United States

 
Resting state fMRI (rs-fMRI) has received much recent attention as a complement to task-based fMRI. While reproducibility of rs-fMRI has been well established at the group level, individual subject level analysis is desired for most clinical applications and is less well characterized. Here we establish the reproducibility of subject-level rs-fMRI data and determine that 7 minutes is sufficient to acquire the maximal rs-fMRI information for differentiating individual subjects. We see strong reproducibility of individual subject data with only 1 minute of acquisition time. Additionally, we find that brain regions yielding the most individual differentiation correspond to higher cortical processing centers.

 
2271.   Resting-State fMRI Activity in the Basal Ganglia Predicts Unsupervised Learning Performance in a Virtual Reality Environment
Valur Olafsson1, Chi Wah Wong1, Markus Plank2, Joe Snider2, Eric Halgren3, Howard Poizner2, and Thomas Liu1
1Center for Functional MRI, UCSD, La Jolla, CA, United States, 2Institute for Neural Computation, UCSD, La Jolla, CA, United States, 3Multimodal Imaging Laboratory, UCSD, La Jolla, CA, United States

 
Learning without feedback is often referred to as unsupervised learning. Prior work suggests that structures in the basal ganglia have a role in unsupervised learning performance. In this study we ran a resting state fMRI study on 10 subjects that had gone through an unsupervised learning task in a complex virtual reality environment and had been assessed on their performance to learn without feedback. We found that there was significant correlation between the performance measures and resting-state fMRI measures from basal ganglia structures. Our results indicate that resting-state measures could be used to predict individual differences in unsupervised learning.

 
2272.   Functional Connectivity and Temporal Patterns of Brain Networks Involved in Alternative Finger Tapping
Huijin Song1, Jeehye Seo1, Seonguk Jin1, Moon Han1, Moonjung Hwang2, Yongmin Chang1,3, and Kyung Jin Suh4
1Medical & Biological Engineering, Kyungpook National University, Daegu, Korea, 2GE healthcare, Seoul, Korea, 3Molecular medicine, Kyungpook National University, Daegu, Korea,4Radiology, School of Medicine, Dongguk University, Gyungju, Korea

 
In the last decades, a few studies showed that the independent component (IC), which extracted from task based fMRI data by independent component analysis (ICA) method, is very similar with the task-evoked brain network. However, previous researchers did not attempt to identify other ICs possibly reflecting brain networks, which were implicitly associated with the task. Therefore, in this study, we aimed to identify not only IC reflecting motor network but also ICs reflecting neural network implicitly involved with alternative finger tapping task using ICA. Furthermore, we also investigated the relation between the temporal patterns of identified ICs and the hemodynamic response of finger tapping task to evaluate the possible difference in the temporal patterns of identified ICs between welders with chronic manganese exposure and healthy controls. Based on our finding that ICA could identify not only IC reflecting motor network but also ICs reflecting neural network implicitly involved with alternative finger tapping task. In addition, the strong correlation of IC reflecting WM with hemodynamic response of alternative finger tapping task suggest that welders required more WM resource for successful complex motor task due to WM deficit.

 
2273.   Increased Functional Connectivity Between Occipitotemporal Cortex and Frontoparietal Attention Network During Visual Processing
Kaundinya Gopinath1, Simon Lacey2, Shaheen Ahmed1, Randall Stilla2, and K. Sathian2
1Department of Radiology & Imaging Sciences, Emory University, Atlanta, GA, United States, 2Department of Neurology, Emory University, Atlanta, GA, United States

 
The human occipitotemporal cortex (OTC) contains a number of regions specialized for processing particular types of sensory stimuli: including the lateral occipital complex (LOC), the fusiform face area (FFA), the parahippocampal place area (PPA), and the extrastriate body area (EBA), exhibiting selectivity for objects, faces, scenes and body-parts, respectively. This study examined functional connectivity patterns of functionally localized LOC, EBA, FFA and PPA, during rest and from residuals of OTC localizer fMRI data. Results indicate increased OTC functional connectivity (in the residuals data) to frontoparietal attention network during visual processing compared to rest, reflecting the attention demands of the task.

 
2274.   Diurnal Variations of Regional Homogeneity in Healthy Human Brain Evaluated Using Resting-State FMRI
Chunxiang Jiang1, Yanjun Diao1, Xiaojing Long1, Weiqi Liao1, and Lijuan Zhang1
1Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China

 
Circadian rhythm of sleep and wakefulness is a fundamental property of human physiology, which is important for sustaining essential body functions. Brain physiology varies according to the rhythm. In this study, we used ReHo(Regional Homogeneity) method to investigate the diurnal changes of neural activity in normal human brain in resting state.

 

TRADITIONAL POSTER SESSION • FUNCTIONAL MRI
Thursday, 25 April 2013 (10:30-12:30) Exhibition Hall
fMRI Acquisition: Methods & Protocols

2275.   MEG & fMRI: Which One Best Spatially Localizes Brain Activity?
Tynan Stevens1,2, Steven Beyea1,2, Ryan D'Arcy3, Tim Bardouille2, and David Clarke1,4
1Dalhousie University, Halifax, Nova Scotia, Canada, 2NRC, Halifax, Nova Scotia, Canada, 3Frasier Health Authority, Surrey, British Columbia, Canada, 4Neurosurgery, Capital District Health, Halifax, Nova Scotia, Canada

 
Functional brain imaging must demonstrate precise functional localization for application to presurgical planning. We investigated two leading candidate technologies - fMRI and MEG - in this context. We implemented a simple grip-force task that has been shown to predominately activate the primary motor region. We evaluated localizing ability using several metrics, including peak activation magnitude (within an anatomically defined ROI), activation extent, laterality, anatomical specificity, and reliability of activated regions. We found that similar peak activation magnitude, lateralization, and reliability could be achieved with either modality. However, fMRI had advantages in terms of specificity to our anatomically defined ROIs.

 
2276.   Activation Extent and Tissue Specificity of High-TSNR BOLD at 7T
Javier Gonzalez-Castillo1, Daniel A. Handwerker1, Colin Hoy1, and Peter A. Bandettini1
1Section on Functional Imaging Methods, National Institute of Mental Health, Bethesda, MD, United States

 
The sensitivity of BOLD fMRI heavily depends on temporal signal-to-noise ratio (TSNR) and versatility of the hemodynamic response model. Recent work demonstrated that with optimal TSNR and using a sufficiently versatile response model it is possible to detect wide spread activations all over the brain in response to a relatively simple visual stimulation plus attention control task using a 3T scanner and 3.75x3.75x3.8mm3 voxels. Here we extent that work on a 7T scanner to evaluate the tissue specificity of high TSNR activations and the effect of higher field strength.

 
2277.   Combined T2*-Weighted Acquisitions of the Human Brain and the Cervical Spinal Cord with a Dynamic Update of the Linear Shims
Jürgen Finsterbusch1,2, Christian Sprenger1,2, and Christian Büchel1,2
1Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, 2Neuroimage Nord, Hamburg-Kiel-Lübeck, Germany

 
Important basic functions of the central nervous system like sensory processing, motor execution or reflexes involve the spinal cord. To investigate the functional relationship between the brain and the spinal cord directly, fMRI acquisitions covering both regions in the same experiment are required. But the demands differ considerably between the two regions, in particular regarding the shim adjustment. With different fields-of-view, in-plane resolutions, and slice thicknesses and using a dynamic coil selection and update of the linear shim terms, combined T2*-weighted acquisitions of the brain and the cervical spinal cord are feasible as is demonstrated in healthy volunteers at 3T.

 
2278.   Development of BOLD-Sensitive Protocols for Imaging the Human Spinal Cord at 7 Tesla
Robert L. Barry1,2, John C. Gore2,3, and Seth A. Smith1,2
1Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, 2Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, 3Vanderbilt University, Nashville, TN, United States

 
Functional imaging of the human spinal cord (spinal fMRI) has been demonstrated by a handful of groups worldwide, and can detect changes in spinal function due to injury and multiple sclerosis. However, to date there have been no reports of human spinal fMRI at any field strength above 3 Tesla. The proposed multi-shot pulse sequence and post-processing methods are designed to obviate or mitigate challenges of ultra-high-field fMRI that include tissue heating (specific absorption rate), T2* blurring, and geometric distortions. To the best of our knowledge, this abstract is the first published demonstration of human spinal fMRI at 7 Tesla.

 
2279.   Short Echo-Time 3D-TSE with and Without VASO Preparation for Functional MRI
Paul Summers1, Armando Bauleo1, Fabiola Cretti2, Fausta Lui1, and Carlo Adolfo Porro1
1University of Modena and Reggio Emilia, Modena, MO, Italy, 2Ospedali Riuniti di Bergamo, Bergamo, BG, Italy

 
We examined short-echo time, 3D turbo-spin echo (TSE) sequences with and without blood-signal nulling for functional contrast that may that compete with vascular space occupancy (VASO) effects. Subjects performed a blocked, self-paced left-hand finger tapping task during acquisition of the images. Functional responses in nearly identical spatial locations were seen that correlated negatively with task performance in the blood.nulled case and positively otherwise. These preliminary results suggest that short echo time, 3D TSE is sensitive to functional signal changes, but do not distinguish between possible sources such as VASO; BOLD; SEEP or inflow in the absence of blood nulling.

 
2280.   High Resolution Frequency-Modulated BSSFP FMRI
Albert Kir1,2, Alan B. McMillan3, Rao P. Gullapalli1,2, and Joel M. Morris4
1Magnetic Resonance Research Center, University of Maryland, School of Medicine, Baltimore, MD, United States, 2Diagnostic Radiology and Nuclear Medicine, University of Maryland, School of Medicine, Baltimore, MD, United States, 3Radiology, University of Wisconsin Madison, School of Medicine and Public Health, Madison, WI, United States,4Communication and Signal Processing Laboratory, University of Maryland, Baltimore County, Baltimore, MD, United States

 
Echo Planar Imaging (EPI) techniques have been traditionally used to perform functional magnetic resonance imaging (fMRI). Due to the issues of signal dropout and/or geometric distortion of EPI-based sequences, balanced steady-state free precession (bSSFP) techniques have been studied as a potential alternative for acquiring fMRI images with improved image signal and spatial resolution. However, depending on the distribution of field inhomogeneity, a bSSFP sequence exhibits geometrically-varying sensitivity to the BOLD signal. In this study, we have implemented a frequency modulated (FM) bSSFP approach to address this issue and demonstrate its application in high-resolution fMRI.

 
2281.   Artifact-Suppressed Alternating SSFP fMRI in Human Subjects Using a Breath Hold Paradigm
Tiffany Jou1, Steve Patterson2, John M. Pauly1, and Chris Bowen2
1Electrical Engineering, Stanford University, Stanford, California, United States, 2Institute for Biodiagnostics (Atlantic), National Research Council Canada, Halifax, Nova Scotia, Canada

 
Results from a rat hypercapnia study suggests that by using RF catalyzation to alternate between two RF phase-cycling steady states, whole-brain BOLD activation from a single run of the functional paradigm is possible. This approach has been coined “alt-SSFP”. Our overall goal was to investigate these possibilities in human studies for the first time. Using human breath holding experiments to perturb BOLD signal, we have shown that alt-SSFP (1) recovers functional sensitivity in regions that suffer signal dropout in GRE-EPI, and (2) exhibits functional sensitivity comparable to the pbSSFP two-acquisition method, but using just a single functional run.

 
2282.   2D Parallel Imaging with RASER for True Whole Brain fMRI at 7 T
Ute Goerke1, Craig Moodie2, Krista Wisner2, and Angus MacDonald III2
1CMRR, University of Minnesota, Minneapolis, Minnesota, United States, 2Psychology, University of Minnesota, Minneapolis, Minnesota, United States

 
As previously reported RASER provides excellent fMRI activation maps in the orbitofrontal cortex (OFC) in humans without suffering from the typical blurring and signal loss of echo-planar images due to magnetic field variations near air-tissue interfaces. In the presented work, a novel 2D parallel imaging approach for RASER is implemented to achieve whole brain coverage with acceptable spatiotemporal resolution for fMRI. In order to demonstrate that the ability to detect activation near air cavities with accelerated RASER is retained a 7 T fMRI study was performed using a working memory task modulated with gains and losses showing reliable activation in the OFC.

 
2283.   Vessel Size Imaging in the Brainstem
Michael Germuska1 and Daniel P. Bulte1
1Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, Oxfordshire, United Kingdom

 
BOLD mediated vessel size imaging (VSI) is preformed in the brainstem. Two different acquisition strategies, dual-echo and multi-echo EPI (MESSER), are compared with and without cardiac gating. The dual-echo acquisition scheme is found to outperform the multi-echo strategy. Both gated acquisitions show an improved performance, as measured by VSI fitting residuals, compared to non-gated acquisitions. The robust performance and small fitting residuals of the gated dual-echo sequence suggests it can be a useful tool for assessing vascular changes in the brainstem.

 
2284.   BOLD Mapping of Finger Movement Compares with the Underlying Electrophysiology; a Combined 7T fMRI and ECoG Study
Jeroen Cornelis Willem Siero1,2, Dora Hermes1,3, Hans Hoogduin2, Peter R. Luijten2, Nick F. Ramsey1, and Natalia Petridou1,2
1Rudolf Magnus Institute, University Medical Center Utrecht, Utrecht, Utrecht, Netherlands, 2Radiology, University Medical Center Utrecht, Utrecht, Utrecht, Netherlands,3Stanford University, Stanford, California, United States

 
BOLD fMRI has the potential to map activation patterns of small neuronal ensembles such as columns. However, to confirm whether BOLD activation maps reflect the underlying neuronal activity patterns, a comparison with electrophysiological data is required. Here, we investigate the spatial representation of finger movements using electrocorticography (ECoG) post-implant and presurgical BOLD fMRI at 7T in the same human subjects. We show that BOLD and high frequency ECoG maps are closely matched; movement of three individual fingers could be distinguished on a spatial span of 12 mm. These results are promising for the spatial correspondence between neuronal and vascular responses.

 

TRADITIONAL POSTER SESSION • FUNCTIONAL MRI
Thursday, 25 April 2013 (10:30-12:30) Exhibition Hall
fMRI: Analysis of Activation

2285.   
Incorporation of Gray Matter T1 and T2* Improves Brain Activation Statistics in FMRI
M. Muge Karaman1, Iain P. Bruce1, and Daniel B. Rowe1,2
1Department of Mathematics, Statistics, and Computer Science, Marquette University, Milwaukee, WI, United States, 2Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States

 
In fMRI, the voxels in gray matter (GM) contain neurons that are to be active while performing a task. We develop a model to determine brain activation by incorporating T1and T2* of GM. The model considers the physical nonlinear signal equation to model MR magnetization rather than using a linear model; utilizes the first scans of the complex-valued fMRI data to estimate each voxel’s T1 and T2*; and incorporates GM T1 and T2* values into the activation statistics. It has been found that the proposed model provides more significant activation statistics compared to the commonly used fMRI activation models.

 
2286.   
Is Quantitative fMRI Really Better Than Plain BOLD in Predicting Cognitive Function?
Peiying Liu1, Chandramallika Basak2, and Hanzhang Lu1
1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, United States, 2Center for Vital Longevity, University of Texas at Dallas, Dallas, Texas, United States

 
Given that the BOLD signal is an indirect measure of neural activity, there have been great efforts recently developing more quantitative fMRI methods, including fMRI normalization using cerebrovascular reactivity. In this work, we compared between the plain BOLD signal and the BOLD signal after normalization with cerebrovascular reactivity. We found the normalized fMRI signal showed a significant correlation with working memory performance across healthy individuals, while the plain BOLD signal showed no correlation. This work provided the first direct evidence that quantitative measure of brain activation after accounting for vascular factors can provide a more accurate predictor of cognitive function.

 
2287.   Default Mode Network and Working Memory Network During an fMRI Working Memory Task: Differences and Correlations with Behavioral Performance
Marta Re1,2, Tommaso Piccoli3,4, Giancarlo Valente3, Vincent Van De Ven3, Alexander Sack3, and Francesco Di Salle3,5
1IRCCS Istituto Scientifico “Eugenio Medea”, Bosisio Parini, Lecco, Italy, 2Dipartimento di Bioingegneria, Politecnico di Milano, Milano, MI, Italy, 3Department of Cognitive Neuroscience, University of Maastricht, Maastricht, Limburg, Netherlands, 4Dipartimento di Biomedicina e Neuroscienze Cliniche, Università degli Studi di Palermo, Palermo, PA, Italy, 5Dipartimento di Medicina e Chirurgia, Università di Salerno, Baronissi, SA, Italy

 
Working memory (WM) load has effects on regional neural activation, but the mechanism through which its modulates brain connectivity is still unclear. Spatial independent component analysis (ICA) is a reliable technique to investigate the networks during an fMRI task. The aim of this work is to use the time course of the WM task involved networks (default mode network and working memory network), selected by means of ICA, for studying: a) how these networks are involved with the complexity of the task and the phase; b) how, in these networks, complexity and phase are correlated with reaction times.

 
2288.   Spatial Heterogeneity Analysis of Brain Activation in Epilepsy
Lalit Gupta1, René M.H. Besseling2,3, Geke M. Overvliet2,4, Paul A.M. Hofman2,4, Anton de Louw2, Maarten Vaessen2,3, Albert P. Aldenkamp2,4, Shrutin Ulman1, Jacobus F.A. Jansen3,4, and Walter H. Backes3,4
1Philips Electronics India Ltd., India, 2Epilepsy center Kempenhaeghe, Heeze, Netherlands, 3Research School for Mental Health & Neuroscience, Maastricht University, Netherlands, 4Maastricht University Medical Center, Maastricht University, Netherlands

 
In many brain diseases it has been observed that spatial patterns in BOLD activation maps appear more (diffusively) distributed than in healthy controls. However, measures that can quantitatively characterize this spatial distributiveness in individual subjects are lacking. We evaluated language activation maps by applying a number of conceptually different spatial heterogeneity measures of activation distribution patterns. For a language task that showed no systematic differences in activation overlap, our findings revealed an increase in spatial heterogeneity of activation patterns in patients with epilepsy relative to healthy controls.

 
2289.   Visual Image Reconstruction of Brain Activities and Retinotopic Mapping: An Optimization Method
Yu-Sheng Tseng1, Yao-Wen Chang1, and Teng-Yi Huang1
1National Taiwan University of Science and Technology, Taipei, Taiwan

 
This study attempts exploiting multi-focal functional MRI(fMRI) for retinotopic mapping, or retinotopy, in the primary visual cortex. We tried to reconstruct visual image according the retinotopy and brain activities obtained by fMRI. We empirically found that the accuracy of the reconstructed visual image largely depended on the threshold selection. Therefore, this study proposed an approach to find the optimal threshold according to a receiver operating characteristic analysis. The results obtained with 10 participatns volunteers using the optimized t thresholds demonstrated an average accuracy of 81%.

 
2290.   Single Trial Characterization of the BOLD Response at 3T Using Structured Sparse Functionals with Paradigm Free Mapping
Cesar Caballero Gaudes1,2, Fikret Isik Karahanoglu3, François Lazeyras2, and Dimitri Van de Ville2,3
1Basque Center on Cognition, Brain and Language, Donostia-San Sebastian, Guipuzcoa, Spain, 2Department of Radiology and Medical Informatics, University of Geneva, Geneva, Geneva, Switzerland, 3Medical Image Processing Lab, Ecole Polytechnique Federale de Lausanne, Lausanne, Vaud, Switzerland

 
Paradigm-free mapping (PFM) enables to map the BOLD response in space and time without prior knowledge of the timing of the events using sparsity-promoting estimators, such as the Dantzig Selector or LASSO. Here, we extend PFM by using hierarchical structured sparsity-promoting estimators (Group-LASSO, Weighted-Fusion and Group-Weighted-Fusion) along with an informed basis set in order to deal with BOLD response variability, and use the monotone fast iterative shrinkage thresholding algorithm to solve this deconvolution problem. Experimental results demonstrate that the new approach has superior abilities to characterize single-trial BOLD responses with no prior timing information at 3T.

 
2291.   Searchlight Goes GPU - Fast Multi-Voxel Pattern Analysis of fMRI Data
Anders Eklund1, Malin Björnsdotter2,3, Johannes Stelzer4, and Stephen LaConte1,5
1Virginia Tech Carilion Research Institute, Roanoke, Virginia, United States, 2University of Gothenburg, Göteborg, Sweden, 3Nanyang Technological University, Singapore, Singapore, 4Max-Planck-Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 5School of Biomedical Engineering & Sciences, Virginia Tech-Wake Forest University, Blacksburg, Virginia, United States

 
The searchlight algorithm is a popular choice for locally-multivariate decoding of fMRI data. A substantial drawback of searchlight is the increase in computational complexity, compared to the univariate general linear model. This is especially true for large searchlight spheres, non-linear classifiers, cross validation schemes and statistical permutation testing. Here we therefore present a graphics processing unit (GPU) implementation of the searchlight algorithm, to enable fast locally-multivariate fMRI analysis. The GPU implementation is 21 times faster than a multithreaded Matlab implementation. This makes it possible to apply 10 000 permutations with leave-one-out cross-validation in about 19 minutes.

 
2292.   Enhanced Phase Regression with Savitzky-Golay Filtering for High-Resolution BOLD FMRI
Robert L. Barry1,2 and John C. Gore2,3
1Vanderbilt University Institute of Imaging Science, Nashville, TN, United States, 2Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, 3Vanderbilt University, Nashville, TN, United States

 
Phase regression exploits the temporal evolution of phase in individual voxels to suppress BOLD fluctuations from larger vessels while preserving signal changes from microvascular effects. However, the efficacy of this algorithm is hindered when the phase time series exhibits low signal-to-noise ratio. We demonstrate that Savitzky-Golay filters may be used to recover the underlying change in phase and completely restore the efficacy of phase regression. This approach is shown to work on data acquired with single-shot and multi-shot pulse sequences, and should be useful for both human and animal gradient-echo fMRI at high spatial resolutions at high- and ultra-high fields.

 
2293.   Reliability of fMRI: Are Group Means Really Representative?
Tynan Stevens1, Steven Beyea2, Ryan D'Arcy3, and David Clarke1
1Dalhousie University, Halifax, Nova Scotia, Canada, 2NRC, Halifax, Nova Scotia, Canada, 3Frasier Health Authority, Surrey, British Columbia, Canada

 
The Rombouts overlap coefficient (Roverlap) is used extensively in fMRI reliability research. While it is widely recognized that this coefficient depends on analysis threshold, existing studies do not agree on the precise relationship between Roverlap and threshold, and so no clear strategy has been employed across studies. We argue that individual variability in the Roverlap-threshold relationship reduces the information available in group level Roverlap results. This variability likely contributes to the inconsistent findings in the literature to date. We thus suggest that control of reliability is best conducted at the individual-level, as group trends may not be truly representative.

 
2294.   Data Downsampling for Time-Efficient and Robust Estimation of ICA Model Order Using Bootstrap Stability Analysis of Principal Components
Waqas Majeed1, Feng Wang2,3, Robert M. Friedman4, Chaohui Tang2,3, and Malcolm J. Avison2,3
1Department of Electrical Engineering, Lahore University of Management Sciences, School of Science and Engineering, Lahore, Punjab, Pakistan, 2Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University, Nashville, TN, United States, 3Department of Radiology, Vanderbilt University, Nashville, TN, United States,4Department of Psychology, Vanderbilt University, Nashville, TN, United States

 
Bootstrap stability analysis (BSA) has previously been shown to be a more robust and accurate method for ICA model order estimation, compared with traditional methods. However, large computational burden associated with BSA makes it impractical. In this work, we demonstrate that BSA can be used on the prefiltered and downsampled data without compromising the results, while reducing the processing time to a great degree.

 
2295.   AutoROI: Fast and Automatic Generation of ROIs for Real-Time fMRI Paradigms
Paul Wighton1 and André J. W. van der Kouwe1
1Department of Radiology, MGH, Martinos Center for Biomedical Imaging, Charlestown, Massachusetts, United States

 
In most real-time fMRI paradigms, suitable regions of interest (ROIs) must be computed quickly after localization scans have been acquired and before the real-time paradigm can begin. We have developed software that can quickly generate ROIs by leveraging existing software packages. We demonstrate our software by computing ROIs: 1) Using a functional localizer 2) using a structural scan and reference data (either an atlas or a previous scan of the subject) and 3) Using a functional localizer constrained by structural data. We validate our software using a finger-tapping paradigm and flashing checkerboard paradigm.

 
2296.   A Retrospective Evaluation of Clinical Functional MRI Quality and Analysis Methods
Victoria L. Morgan1,2, Megan Strother2, and Reid C. Thompson3
1Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States, 2Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States, 3Neurosurgery, Vanderbilt University, Nashville, TN, United States

 
Due to the high variability in the anatomy and physiology of the patients who undergo functional MRI for clinical presurgical mapping of eloquent cortex, it is difficult to determine metrics for quality evaluation and to compare different analysis strategies. In this work we show that increased motion is reflected in decreased temporal signal to noise (tSNR) in both motor and language tasks. However, when performing motor tasks the focal activation is robust across levels of tSNR, motion and analysis methods; but when performing language tasks, the activation levels and spatial maps can be significantly affected by these factors.

 
2297.   A Novel Approach to the Quantitative Estimation of the Oxygen Metabolism Response to a Neural Stimulus That Accounts for Uncertainty Due to Unmeasured Physiological Parameters
Aaron Benjamin Simon1, Valerie E M Griffeth1, and Richard B. Buxton2
1Bioengineering, University of California San Diego, La Jolla, CA, United States, 2Radiology, University of California San Diego, La Jolla, CA, United States

 
We examined whether we could estimate the CMRO2 response to a stimulus, as well as the uncertainty of that estimate, by measuring baseline R2' and the CBF and BOLD responses. We related the three measurements to the CMRO2 response through a detailed, multi-compartment BOLD model and adopted a Bayesian approach to determine how uncertainty in unmeasured physiological parameters of the model affected the precision of the estimate the CMRO2 response. We tested the method with a hypercapnia challenge and found that the estimate agreed well with previous work but that the unmeasured parameters produced considerable uncertainty in the estimate.

 

TRADITIONAL POSTER SESSION • FUNCTIONAL MRI
Thursday, 25 April 2013 (10:30-12:30) Exhibition Hall
Animal fMRI Studies

2298.   Comparison of Six Different Anesthesia Protocols for phMRI
Jaakko Paasonen1, Joanna K. Huttunen1, and Olli Gröhn1
1Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland

 
Anesthesia is one of the most critical factors in designing a phMRI study. We investigated the BOLD signal changes under six different anesthesia protocols with a nicotine challenge in order to find optimal experimental phMRI setup. Nicotine injection in total of 39 rats induced clear cortical signal changes, in all animals, revealing several alternative approaches. However, the choice of anesthetic led to notably different BOLD responses emphasizing the need of optimization of anesthetic conditions for each pharmaceutical agent.

 
2299.   Isoflurane Supplement Prevents Epileptic Activity in fMRI Studies Under Medetomidine Anesthesia
Xiaopeng Zong1, Mitsuhiro Fukuda1, Alberto Vazquez1, and Seong-Gi Kim1
1Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States

 
Dexedetomidine (DEX) is an increasingly popular sedative for fMRI in rodents. To illuminate its effects on neural activity and neurovascular coupling, we carried out electrophysiology, optical imaging, and BOLD fMRI on DEX sedated rats. After continuous DEX infusion for ~2 h, local field potential responses to electrical forelimb stimulation became epileptic with concomitant large increases in cerebral blood flow (CBF). Supplement of ~0.3% isoflurane (ISO) suppressed the generation of the epileptic activity. DEX constricts both arterial and venous vessels at baseline. The DEX+ISO combination yields robust CBF and BOLD fMRI responses, and is a suggested anesthesia for 2-3 h fMRI studies.

 
2300.   Effect of Four Commonly Used Anesthetics on Stimulation-Induced and Resting State fMRI Signal in Mice
Aileen Schröter1, Felix Schlegel1, Aline Seuwen1, Joanes Grandjean1, and Markus Rudin1,2
1Institute for Biomedical Engineering, ETH and University Zürich, Zürich, Zürich, Switzerland, 2Institute of Pharmacology and Toxicology, University Zürich, Zürich, Zürich, Switzerland

 
Functional MR imaging, originally applied in human studies, has been translated back to small animals, which allows performing basic research on animal models of different pathologies. In view of the many transgenic mouse lines the method has been started to be transferred from rats to mice. FMRI in small animals suffers from largely unknown influences of anesthesia, which has been addressed already in studies on rats. However, given species differences, results obtained in rat studies cannot be translated directly to mice. The presented study is characterizing the effects of four anesthetics – isoflurane, urethane, medetomidine, propofol – on fMRI responses in mice.

 
2301.   Subcortical and Cortical Distribution of BOLD Signal from Somatosensory Stimulation in Anaesthetised Rats
Diana Cash1, Tobias C. Wood1, Camilla Simmons1, Aisling L. Dixon1, Steve C.R. Williams1, and Michel B. Mesquita1
1Neuroimaging, King's College, Institute of Psychiatry, London, United Kingdom

 
Forepaw sensory stimulation at 0.5 and 3 Hz in alpha-chloralose-anaesthetized rats was characterized by BOLD-sensitive fMRI. An expected increase in BOLD signal in S1 contralateral cortex was detected at 3Hz, but not at 05Hz where the signal timecourse showed a trend toward decrease. S1 and other areas adjacent to the contralateral S1, as well as the ipsilateral S1 and S2 also showed decreased BOLD signal with both stimulations paradigms. Bilateral subcortical thalamic and striatal BOLD increases were also detected and similar under both stimulation frequencies.

 
2302.   Spontaneous fMRI-BOLD Power Spatial Distribution: Comparison Between Awake State and Under Isoflurane Anesthesia in the Rat
Wen-Ju Pan1, Matthew E. Magnuson1, Garth Thompson1, and Shella Keilholz1
1Biomedical Engineering, Emory University/ Georgia Institute of Technology, Atlanta, GA, United States

 
As a first step toward understanding the difference of brain baseline activity in resting state fMRI between awake and isoflurane-anesthetized states in the rat model, we examined the BOLD spectral powers across brain distributions between the two states, and demonstrated the potential usefulness of mapping low frequency BOLD power to assess brain regional activity.

 
2303.   Two Anesthetics, Two Completely Different Connectivity Results
Erik B. Beall1, John T. Gale2, Ken E. Sakaie1, and Mark J. Lowe1
1Imaging Institute, Cleveland Clinic, Cleveland, OH, United States, 2Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States

 
Studies of resting connectivity under anesthesia have shown modulation of connectivity patterns with a strong dependence on the choice of anesthetic. Propofol appears to have an increasing usage in human and animal anesthesia connectivity studies. However, it is possible propofol is a poor choice. Based on a failure to find reasonable connectivity patterns in a pilot BOLD scan under propofol, we acquired two long scan sessions (separated by several months) under two different anesthetics and found reasonable connectivity patterns under ketamine but a complete absence of connectivity patterns under propofol.

 
2304.   Effects of Different Anesthesia on the Resting-State Networks in Rodents
Johnny Ng1, Jessica Roman1, Edmund Wong1, David Carpenter1, and Cheuk Tang1,2
1Dept. of Radiology, Mount Sinai School of Medicine, New York, NY, United States, 2Dept. of Psychiatry, Mount Sinai School of Medicine, New York, NY, United States

 
Functional imaging in animal models is difficult to perform, especially in awake experiments. Resting-state fMRI is the most convenient way to assess brain function with the animal under anesthesia. The aim of this study is to investigate the effects of three commonly used anesthetic – isoflurane, medetomidine and ketamine – in rodent experiments and their effects on brain function. 14 mice were used in this study. MELODIC ICA and dual-regression analysis were implemented. Increased coactivation has been found in several networks with medetomidine compared with ketamine or isoflurane alone.

 
2305.   Sub-Anesthetic Ketamine Modulates Intrinsic BOLD Connectivity in the Hippocampal-Prefrontal System in the Rat: Dose-Dependence and PK/PD Relationships
Natalia Gass1, Alexander Sartorius1, Adam James Schwarz2,3, Esther Schenker4, Celine Risterucci5, Michael Spedding4, Lei Zheng1, Andreas Meyer-Lindenberg1, and Wolfgang Weber-Fahr1
1Central Institute of Mental Health, Mannheim, Germany, 2Eli Lilly and Company, Indianapolis, Indiana, United States, 3Indiana University, Bloomington, Indiana, United States,4Institut de Recherches Servier, Croissy-sur-Seine, France, 5F. Hoffmann-La Roche, Basel, Switzerland

 
The aim of this work was to systematically characterize the effects of ketamine, a rapidly acting antidepressant, on rsfMRI in rat. Male Sprague-Dawley rats in 4 parallel groups received either vehicle or one of three sub-anesthetic doses of S-ketamine. Three rsfMRI datasets were acquired from each rat: pre-injection and 15 and 30 min post-injection. Pharmacokinetic/pharmacodynamic image and region-of-interest analyses revealed increased functional connectivity between the hippocampus and regions in the prefrontal cortex, and within the prefrontal cortex, that positively correlated with ketamine plasma levels. The observed increases in functional connectivity reveal possible neural mechanisms underlying established behavioral effects of ketamine.

 
2306.   Functional Connectivity in the Mouse Brain Detected Under Different Dosages of Medetomdine
Fatima Nasrallah1, Hui Chien Tay1, Krzysztof Pyka1, and Kai-Hsiang Chuang1
1Magnetic Resonance Imaging Group, A*Star Biomedical Research Institutes, Singapore, Singapore, Singapore

 
Consistent functional networks have been identified in the resting brain of humans, monkeys, and rats. Since most transgenic models of neurodegenerative diseases are only available in mouse, efforts have been made to detect the resting-state networks in mice. Here we demonstrated, as in other species, robust functional connectivity in the mouse brain and showed, that opposed to what has been shown in the rat, functional connectivity is preserved under high dosages of the commonly used sedative medetomidine.

 
2307.   BOLD fMRI Response of the Rat Brain to Hyperosmotic Saline Infusion
Bianca Gonzales Cerqueira1, Glenn M. Toney2, and Timothy O. Duong3
1Research Imaging Institute, Univ. of TX Health Science Center, San Antonio, Texas, United States, 2Physiology, Univ. of TX Health Science Center, San Antonio, Texas, United States, 3Research Imaging Institute, UT Health Science Center at San Antonio, San Antonio, Texas, United States

 
Rat brain BOLD fMRI response to an infusion of alternating isotonic and hypertonic saline was studied. Previous studies have demonstrated that osmosensitive areas of the brain such as the organum vasculosum laminae terminalis can detect small changes in plasma osmolarity and project to the hypothalamic paraventricular nucleus which is involved in sympathetic activation. Increased sympathetic activation is of interest due to its role in many forms of hypertension. There was an significant (p=0.029) increase in average percent change of hypertonic saline (13.79%) compared to isotonic saline (-0.85%) in the anterior medial hypothalamus, which includes osmosensitive areas of the brain. This study demonstrates that non-invasive functional imagining can translated to longitudinal studies of sympathetic activation and hypertension.

 
2308.   Differential BOLD and Blood Flow Response During and Immediately After Transient Carotid Occlusion
Guang Li1, Jeffrey W. Kiel2, Damon P. Cardenas3, De La Garza H. Bryan4, and Timothy O. Duong4
1Department of Radiology, UT Health Science Center at San Antonio, San Antonio, TX, United States, 2Department of Ophthalmology, UT Health Science Center at San Antonio, San Antonio, TX, United States, 3Department of Biomedical Engineering, UT Health Science Center at San Antonio, San Antonio, TX, United States, 4Research Imaging Institute, UT Health Science Center at San Antonio, San Antonio, TX, United States

 
While post-occlusion reactive hyperemia has been attributed to metabolic local control (matching of blood flow (BF) to local metabolic demands) in various tissues, post-occlusion reactive hyperemia in the retina has not yet been studied. We found differential BOLD and BF responses in the retinal and choroidal circulations in the retina during and immediately after transient carotid occlusion. Reactive hyperemia was detected in the retina but not in the choroid, suggesting that the retinal circulation is under metabolic local control but the choroid is not. These findings provide novel insights in the hemodynamic regulation of the retinal and the choroidal circulations.

 
2309.   Effect of Occlusion Durations on Postocclusion Reactive Hyperemia in Rat Retina
Guang Li1, Jeffrey W. Kiel2, Damon P. Cardenas3, De La Garza H. Bryan4, and Timothy O. Duong4
1Department of Radiology, UT Health Science Center at San Antonio, San Antonio, TX, United States, 2Department of Ophthalmology, UT Health Science Center at San Antonio, San Antonio, TX, United States, 3Department of Biomedical Engineering, UT Health Science Center at San Antonio, San Antonio, TX, United States, 4Research Imaging Institute, UT Health Science Center at San Antonio, San Antonio, TX, United States

 
Reactive hyperemia has been attributed to metabolic local control in which BF is trying to match local metabolic demands. In the retina, reactive hyperemia and the effect of occlusion duration on reactive hyperemia have not yet been studied. This study used BOLD and laser speckle BF measurements to investigate reactive hyperemia after graded occlusion durations and probe the reactive hyperemia capacity reserve in the retina. We found that the retinal circulation is under metabolic control but it has smaller capacity for reactive hyperemia compared to other organs (i.e., brain, intestine, heart, etc).

 
2310.   Effect of Metabolic Rate on Postocclusion Reactive Hyperemia in Rat Retina
Guang Li1, Jeffrey W. Kiel2, Damon P. Cardenas3, De La Garza H. Bryan4, and Timothy O. Duong4
1Department of Radiology, UT Health Science Center at San Antonio, San Antonio, TX, United States, 2Department of Ophthalmology, UT Health Science Center at San Antonio, San Antonio, TX, United States, 3Department of Biomedical Engineering, UT Health Science Center at San Antonio, San Antonio, TX, United States, 4Research Imaging Institute, UT Health Science Center at San Antonio, San Antonio, TX, United States

 
Reactive hyperemia and its modulation by varying metabolic demands have not been studied in the retina. We investigated the reactive hyperemia and hemodynamic reserve in the rat retina by measuring blood flow and oxygenation under dark, constant light and flicker. Our results showed that changes in metabolic rate by light conditions did not affect the reactive hyperemia likley because of the small BF reserve in the retinal circulation, suggesting that metabolic autoregulation in the retina is less able to compensate for increased metabolism.

 
2311.   A Protocol for Longitudinal BOLD-FMRI Imaging Deep Brain Stimulation Response in the Rat Brain
Tzu-Hao Chao1, Jyh-Horng Chen2, and Chen-Tung Yen1
1Institute of Zoology, National Taiwan University, Taipei, Taiwan, 2Interdisciplinary MRI/MRS Lab, Dept. of Electrical Engineering, National Taiwan University, Taipei, Taiwan

 
The purpose of the present study was to setup a protocol to follow BOLD response by deep brain stimulation longitudinally in the same rat. A pair of tungsten microwire electrode was chronically implanted in the ventroposterior thalamus (VP), and fMRI scan was made under dexmedetomidine anesthesia. We found the electrode caused limited distortion to MR signal in EPI images. VP stimulation-evoked BOLD responses in the primary somatosensory cortex were stable over 2 scan sessions separated by 7 days. Using this protocol, normal and abnormal plasticity change of specific brain pathway can be probed during their development and maintenance stages.

 
2312.   Deep Brain Stimulation fMRI in Mice
Yu-Chieh Jill Kao1, Hsin-Yi Lai1, John Robert Younce1, and Yen-Yu Ian Shih1
1Experimental Neuroimaging Laboraory, Department of Neurology and Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, Chapel Hill, NC, United States, Chapel Hill, NC, United States

 
This is the first study demonstrating the feasibility of deep brain stimulation (DBS) fMRI in mice. Robust CBV response in the somatosensory cortex was observed during DBS at the mouse ventral posteromedial thalamus. Optimal DBS frequency was found at 20 Hz which is similar to that in rats. The proposed mouse DBS fMRI technique provides a new insight into the future investigation of DBS mechanism and assessment of DBS treatment outcome.

 
2313.   Brain Parenchymal fMRI Signals During Cortical Spreading Depression
Joonas Arttu Autio1,2, Artem Shatillo1, Rashid Giniatullin1, and Olli Gröhn1
1Neurobiology, University of Eastern Finland, Kuopio, Kuopio, Finland, 2Radiology, University of Oulu, Oulu, Oulu, Finland

 
Using functional magnetic resonance imaging (fMRI) of the rat brain we found a novel type of parenchymal fMRI signals during large increases in metabolism. Cortical spreading depression (CSD), a self-propagating wave of tissue depolarization, associated with several pathological conditions such as migraine and stroke, was used as paradigm to evoke enhanced brain metabolism. The underlying CSD activated signal changes were investigated using spin-lock (SL), T1 relaxation in the rotating frame (T1ñ), weighted fMRI. Our results show that during CSD propagation SL-fMRI signal is generated by endogenous parenchymal mechanisms.

 
2314.   White-Matter Diffusion fMRI in the Healthy Mouse Optic Nerve
William M. Spees1,2, Tsen-Hsuan Lin3, and Sheng-Kwei Song1,2
1Department of Radiology, Washington University, St. Louis, MO, United States, 2Hope Center for Neurological Disorders, Washington University, St. Louis, MO, United States,3Department of Physics, Washington University, St. Louis, MO, United States

 
Recently, we have implemented diffusion fMRI and demonstrated its utility for detecting white-matter axonal activation in the optic nerve of healthy mice. A robust (27%) and completely reversible stimulus-induced decrease in the apparent diffusion coefficient perpendicular to the axonal fibers was observed with the application of a flashing-light visual stimulus. The change in ADC parallel to the axonal fibers was not statistically significant. The results of hypercapnia experiments suggest minimal contribution from vascular effects.

 
2315.   C7 Nerve Root Sensory Mapping: A 9.4T Bold Functional MRI Investigation
Jacques Machol IV1, Rupeng Li2, Patrick Hettinger1, Nicholas Flugstad1, Ji-Geng Yan1, Hani Matloub1, and James S. Hyde2
1Plastic Surgery, Medical College of Wisconsin, Milwaukee, WI, United States, 2Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States

 
In the case of severe brachial plexus root avulsion injuries, the contralateral C7 (cC7) nerve root is identified as a possible donor for nerve transfer. It is of interest to the peripheral nerve surgeon as to how the cC7 root can serve as a “spare nerve.” This study uses BOLD fMRI to elucidate the linear relationship in the sensory C7 nerve root cortical map makeup of each major upper limb nerve (ulnar, median, radial, and musculocutaneous) by means of sensory stimulation. This investigation helps to expound why C7 is a suitable donor for brachial plexus injury treatment.

 
2316.   Decreased Functional Connectivity in ApoE4 and ApoE-Knockout Mice Revealed by Resting-State fMRI at Ultra-High Field
Valerio Zerbi1, Maarten Van Beek1, Diane Jansen1, Christian F. Beckmann2,3, Amanda J. Kiliaan1, and Arend Heerschap4
1Anatomy, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands, Netherlands, 2Donders Centre for Cognitive Neuroimaging, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands, Netherlands, 3MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, Enschede, Netherlands, Netherlands, 4Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands, Netherlands

 
Cholesterol released from apoE-containing lipoprotein is used for synaptogenesis and synaptic maintenance. The apoE4 isoform is a less potent cholesterol transporter, which in turn is linked to impaired synaptic connectivity. Resting-state fMRI experiments showed marked differentiation in functional networks compared with non-apoE4 carriers. We tested in apoE4 and apoE-ko mice the hypothesis that dysfunctional apoE, and further its absence, are related to reduced brain functional connectivity. Results indicate that apoE4 and, more severely, apoE-ko mice have lower functional connectivity between several brain areas compared to wild-type, providing new evidences of a dependency between the apoE genotype and the functional connectivity.

 
2317.   Neuroimaging Measure as an Endophenotype for Genetic Effects on Electrical Stimulation in Brown Norway and Dahl Salt-Sensitive Rat Strains
Zhixin Li1, B. Douglas Ward2, Melinda R. Dwinell3, and Christopher P. Pawela1,2
1Department of Plastic Surgery, Medical College of Wisconsin, Milwaukee, WI, United States, 2Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, 3Human and Molecular Genetics Center, Medical College of Wisconsin, Milwaukee, WI, United States

 
The goal of study was to reveal the region-specific effects of genetic differences between two inbred rat strains, Brown Norway (BN) and Dahl salt-sensitive on a biologic measure in brain using BOLD-fMRI under a well-established task paradigm. The Differential BOLD response to electrical stimulation in two inbred rat stains were mainly detected in contralateral S1FL, S2, TH, and bilateral CPu regions. These results suggest a new approach to visualize the genetic effects on the brain using neuroimaging measures.

 
2318.   Differentiating BOLD and Non-BOLD Signals in 11.7 Tesla Rat Resting State fMRI
Prantik Kundu1,2, Mathieu David Santin3, Alexandra Petiet3, Peter A. Bandettini4, Ed Bullmore2, and Stéphane Lehéricy3
1Section on Functional Imaging Mehthods, NIMH, Bethesda, MD, United States, 2Dept. of Psychiatry, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom,3UPMC/INSERM UMR_975 CNRS 7225, CENIR,ICM,CRICM, Paris, France, 4Section on Functional Imaging Mehthods, National Institute of Mental Health, Bethesda, MD, United States

 
Rat resting state fMRI (rs-fMRI) is an exciting platform for functional and pharmacological neuroscience, but its capabilities and limits are not yet well understood. Distinguishing neuronally-related BOLD signals from non-BOLD artifact in rat rs-fMRI is an important methodological step. Here we distinguish BOLD and non-BOLD signals in rat rs-fMRI using multi-echo ICA. We show multi-echo ICA of 11.7T rat fMRI data produces consistent components showing clear localization of functionally and neuropharmacologically interesting brain areas.

 
2319.   Asymmetrical Gustatory Cortex But Symmetrical Gustatory Representation in the Left and Right Hemispheres of the Rodent Brain
Ikuhiro Kida1, Yoko Hoshi2, Masahito Nemoto2, Yoshinobu Iguchi2, and Yoshichika Yoshioka3
1Center for Information and Neural Networks, National Institute of Information and Communications Technology, Suita, Osaka, Japan, 2Integrated Neuroscience Research Project, Tokyo Metropolitan Institute of Medical Science, Setagaya-ku, Tokyo, Japan, 3Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan

 
Our previous study using BOLD fMRI demonstrated that tastants evoke bilateral responses in the insular cortices, but that these representations are asymmetrical in rodents. There are two possible interpretations of asymmetrical responses: asymmetrical functional representations or asymmetrical positions of the insular cortices. We performed MRA and optical imaging to measure the anatomical positions and functional representations, respectively, of the insular cortices. We found that the bilateral gustatory cortices have symmetrical functional representations, but contain anatomical asymmetries that result in bilateral asymmetry. This suggests that the cerebral vasculature provides a reliable reference point for functional representations in the gustatory cortex.

 
2320.   Magnetic Resonance Characteristics of Sucrose-Infiltrated ex-vivo Brain Tissue Preparations
Roger J. Mullins1,2, Da Shi1,3, Jiachen Zhuo1, Su Xu1, and Rao P. Gullapalli1
1Diagnostic Radiology and Nuclear Medicine, Core for Translational Research in Imaging @ University of Maryland, Baltimore, Maryland, United States, 2Program in Neuroscience, University of Maryland, Baltimore, Maryland, United States, 3Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, United States

 
It is well known that fixation in paraformaldehyde (PFA) alters MR characteristics, but the extent that sucrose infiltration may affect the MR signal and image quality has not been examined. Scanning ex vivo mouse brains revealed lowered mean, axial and radial diffusivity in brains immersed in 30% sucrose compared to brains in 4% PFA. However, higher T2 relaxation and signal intensity was found in samples immersed in 30% sucrose. Brains immersed in 4% PFA were more similar to in vivo DTI, in terms of T2 relaxation and signal intensity.

 
2321.   
Investigation of Optogenetically Induced Oxytocin Release Within Central Amygdala on BOLD Signals in Rat Brain at 9.4T 
Philipp Lebhardt1,2, Wolfgang Kelsch3, Apar Jain4, Miriam Kernert4, Valery Grinevich4, Gabriele Ende5, Andreas Meyer-Lindenberg2, Alexander Sartorius1,2, and Wolfgang Weber-Fahr1,5
1RG Translational Imaging, Central Institute of Mental Health, Medical Faculty Mannheim / Heidelberg University, Mannheim, Germany, 2Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim / Heidelberg University, Mannheim, Germany, 3RG Developmental Biology, Central Institute of Mental Health, Medical Faculty Mannheim / Heidelberg University, Mannheim, Germany, 4Laboratory of Neuropeptides, German Cancer Research Center DKFZ, CellNetwort Cluster of Excellence, University of Heidelberg, Heidelberg, Germany, 5NeuroImaging, Central Institute of Mental Health, Medical Faculty Mannheim / Heidelberg University, Mannheim, Germany

 
We are presenting preliminary results on a study investigating the BOLD response of the oxytocinergic network in the rat brain stimulated via optogenetics. We selectively expressed Channelrhodopsin-2-mCherry in oxytocin neurons. The guide cannula was implanted into the central amygdala for subsequent stimulation with an implanted optic fiber. Rats were subjected to a fear conditioning protocol and displayed substantial reduced fear response after blue light-evoked axonal oxytocin release within the central amygdala. Using a blocked laser activation fMRI scanning protocol we could show projections from the central amygdala to the superior colliculus in both rats investigated.

 
2322.   Exploring the Mouse Brain Functional Networks After Demyelination: A rs-fMRI Study
Neele Saskia Hübner1,2, Anna Mechling1, Hsu-Lei Lee1, Jürgen Hennig1, Dominik von Elverfeldt1, and Laura-Adela Harsan1
1Department of Radiology - Medical Physics, University Medical Center Freiburg, Freiburg, Germany, 2Faculty of Biology, University of Freiburg, Freiburg, Germany

 
This study demonstrates the potential of resting state functional magnetic resonance imaging for investigating the mouse brain functional networks in normal and pathological conditions. We investigate the impact of experimentally induced demyelination on the functional connectivity of cuprizone demyelinated mice. Data derived from independent component analysis combined with partial correlation analysis and graph theory indicate a complex remodeling of the large scale functional networks in the mouse brain as an effect of demyelinating pathology.

 
2323.   Methylene Blue Potentiates Stimulus-Evoked fMRI Responses and Oxygen Consumption During Hypoxia
Shiliang Huang1, Fang Du2, Yen-Yu Ian Shih2,3, Qiang Shen2, Francisco Gonzalez-Lima4, and Timothy O. Duong2
1University of Texas Health Science Center at San Antonio, San Antonio, TX, United States, 2UT Health Science Center at San Antonio, San Antonio, TX, United States,3University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, 4The University of Texas at Austin, Austin, TX, United States

 
Methylene blue (MB) at low doses has metabolic-enhancing and antioxidant properties and exhibits experimental neurotherapeutic benefits, but little is known about its in vivo effects on cerebral blood flow (CBF) and cerebral metabolic rate of oxygen consumption (CMRO2). We previously reported that MB (0.5 mg/kg) potentiated evoked BOLD, CBF and CMRO2 changes in rat brain under normoxia. This study further evaluated the effects of MB under stress condition (mild hypoxia: 15% O2). We found that MB further potentiated fMRI responses under mild hypoxia relative to air. These findings have implications in neurological conditions with mitochondrial dysfunction and oxidative stress.

 
2324.   phMRI Effects of the M4 Muscarinic Receptor Acetylcholine Positive Allosteric Modulator VU0152100 on Dopaminergic Activity
Nellie E. Byun1,2, Robert L. Barry2,3, Michael D. Grannan4, Stephen M. Damon5, Nathaniel D. Kelm2,6, Matthew J. Mulder1, Amanda W. Huang1, Thomas M. Bridges1,4, Malcolm J. Avison2,3, Craig W. Lindsley1,7, Jeff Conn1,4, John C. Gore2,3, and Carrie K. Jones1,4
1Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, United States, 2Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States,3Radiology & Radiological Sciences, Vanderbilt University, Nashville, TN, United States, 4Pharmacology, Vanderbilt University, Nashville, TN, United States, 5Neurology, Vanderbilt University, Nashville, TN, United States, 6Biomedical Engineering, Vanderbilt University, Nashville, TN, United States, 7Chemistry, Vanderbilt University, Nashville, TN, United States

 
Pharmacological MRI was used to determine the effects of a selective M4 muscarinic acetylcholine receptor positive allosteric modulator, VU0152100, on amphetamine-evoked dopaminergic neurotransmission and functional connectivity in rats in vivo. VU0152100 blunted amphetamine-evoked activation in striatal regions, consistent with separate microdialysis results, as well as in thalamus and hippocampus. Functional connectivity analysis revealed multiple functional correlations in the amphetamine group and loss of correlations with VU0152100 pretreatment, notably for retrosplenial and accumbal connections. These findings support potentiation of endogenous cholinergic activity at M4 as a novel antipsychotic mechanism through which dopaminergic activity can be modulated without directly targeting dopamine receptors.

 
2325.   Investigation of BOLD Response in Somatosensory Pathway of Awake Marmosets Using High Resolution fMRI
Cecil Chern-Chyi Yen1, Daniel Papoti1, and Afonso C. Silva1
1CMU/LFMI/NINDS, National Institutes of Health, Bethesda, MD, United States

 
To better interpret the result from the BOLD fMRI, a comprehensive understanding of the spatiotemporal characteristic of the BOLD response is critical. In the present study, we have demonstrated the use of the novel RF coil design and refined data processing scheme to study BOLD response in the awake marmoset, a small non-human primate. Robust BOLD responses were detected in the primary and secondary somatosensory areas, as well as in the caudate nucleus. Without the confounds of anaesthesia and concerns of phylogenetic disparity, this novel animal model may shed light on the characteristic of the neural activity evoked hemodynamic response.

 
2326.   Brain Sparing in Fetal Mice: Using BOLD MRI to Study Blood Redistribution During Hypoxia
Lindsay S. Cahill1, Yu-Qing Zhou1, Mike Seed2, Christopher K. Macgowan2,3, and John G. Sled1,3
1Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada, 2Hospital for Sick Children, Toronto, Ontario, Canada, 3Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada

 
Fetal growth restriction is often associated with brain sparing whereby a greater proportion of oxygenated fetal blood is directed to the brain at the expense of other organs. Understanding the physiology of this response may lead to better diagnostic procedures for predicting fetal risk. Here, BOLD MRI contrast is used to characterize the redistribution of fetal blood flow that occurs in mice under hypoxic conditions. As the maternal inspired gas mixture is varied, large BOLD signal changes were observed in the fetal liver but not in the brain. Using Doppler ultrasound, cerebral blood flow was observed to rise under hypoxia.

 

TRADITIONAL POSTER SESSION • FUNCTIONAL MRI
Thursday, 25 April 2013 (10:30-12:30) Exhibition Hall
Human fMRI Studies

2327.   Contribution of Language Processing Areas to Verb Generation and Picture Naming: fMRI Evidence
Lei Zhang1, Min LI1, and Zhen Jin1
1Medical Imaging Center, 306 Hospital Beijing, Beijing, Beijing, China

 
2328.   Different fMRI Representations and Brain Connections for Food Odor Stimuli Depending on the BMI of Infant Volunteers
Benito de Celis Alonso1, Silvia Hidalgo Tobón2, Pilar Dies Suarez2, Samuel Flores Huerta2, Jenny Vilichis2, Manuel Obregon Espejel2, Porfirio Ibañez Fernández2, and Eduardo Castro Sierra2
1Faculty of Medicine, BUAP, Puebla, Puebla, Mexico, 2Hospital Infantil de México, Mexico City, México FD, Mexico

 
Obesity is a precursor of health problems (i.e. in cardiology, neurology, endocrinology, etc.). In Mexico this condition affects more than 70% of the population with a special prevalence in the infant bracket. It is known that odor/smell is one of the principal cues for the appearance and control of appetite. To fight obesity it is crucial to understand the brain mechanisms of this stimulus. Previous fMRI work has shown that adult obese and lean subjects interpret these types of stimuli differently. Nevertheless and surprisingly, no studies have been performed in infants and adolescents who have different metabolism and brain development from adults. Furthermore, there is no information on the changes in connectivity between brain regions for this age group. In this work we studied the different brain fMRI activations and connections between normal weighted and obese adolescents for different types of food odors.

 
2329.   Complex and Widespread Network Modulations During Simple Tasks: Trial-By-Trial Spatio-Temporal Dynamics of Brain Function Revealed by Model-Free Analysis
Stephen D. Mayhew1 and Andrew P. Bagshaw1
1BUIC, School of Psychology, University of Birmingham, Birmingham, United Kingdom

 
We use model-free analysis to characterise the spatio-temporal dynamics activity in multiple brain networks both preceding and during visual and pain stimulation paradigms. We find that stimulus modulations occur at multiple time-points, creating high degree of variability in the shape and polarity of trial-by-trial brain responses. The pre-stimulus BOLD signal amplitude in the DAN and DMN was found to predict the amplitude of the primary visual and pain stimulus-responses. Studying the temporal evolution of responses both in brain regions directly driven by stimulation as well as more subtly recruited networks provides greater insight into the complexity of brain processing.

 
2330.   Evaluation of the Validity of Task Switching Paradigm as a Cognitive Stress Test
Mitsunobu Kunimi1, Sachiko Kiyama1, and Toshiharu Nakai1
1National Center for Geriatrics and Gerontology, Obu, Aichi, Japan

 
We attempted to evaluate the validity of divalent Task Switching Paradigm (TSP) as a cognitive stress test. Fifteen young and 15 elderly volunteers participated. The brain areas with augmented brain activation depending on the difficulty of TSP task were different between the two age groups. In particular, it was observed that the contrast of Elderly against Young of right caudate nucleus and hit rate score was significantly correlated with the activation in the right caudate nucleus in the Elderly. Evaluation of the activation in the caudate nucleus using TSP may be valid to represent the aging effects on reconfiguration function.

 
2331.   Decoding Subjectively Correct "Yes/No" Thoughts in the Human Brain
Zhi Yang1,2, Javier Gonzalez-Castillo2, Zirui Huang1, Rui Dai1, Georg Northoff3, and Peter A. Bandettini2
1Institute of Psychology, Chinese Academy of Sciences, Beijing, China, 2National Institute of Mental Health, Bethesda, MD, United States, 3University of Otawa, Otawa, ON, Canada

 
Multivariate pattern analyses were used to decode the subjectively correct "Yes/No" answers to binary questions. Using a spatiotemporal searchlight approach, a set of brain regions were identified in 10 subjects in a 3T scanner, showing group-level above-chance accuracy in decoding "Yes/No" answers regardless the subjects' intentions that were manipulated in the experimental paradigm. The results from 7T scans further verified that three of these regions can be used to robustly decode the “Yes/No” answers (regardless of intentions) with high accuracy, given sufficiently high TSNR, which can be achieved by means of ultra-high field scanners and trial-averaging. These findings suggest that subjectively correct answers can be accurately decoded with fMRI in the spatial-temporal patterns of prefrontal cortex, providing a basis for fMRI-based brain-computer interface.

 
2332.   Applying MRI for Investigating Brain Plasticity Resulting from Attention Training on Healthy Highly Educated Subjects
Bob Hou1, A Smith2, J. Wiener2, J. Chong2, Julie Brefczynski-Lewis1, D Kerr2, D. G. McLaren3, and Marc W. Haut2
1Radiology, WVU, Morgantown, WV, United States, 2Behavioral Medicine & Psychiatry, WVU, Morgantown, WV, United States, 3MGH, Harvard University, Cambridge, MA, United States

 
Attention training (AT) results in changes in brain structure, grey matter and the connections of the structures (i.e., brain plasticity). Here we present our study on applying resting state functional MRI (rfMRI), DTI, and high resolution structural images to examine the impact of AT on brain plasticity of healthy highly educated subjects. Our hypothesis was that brain plasticity including functional and structural connectivity and grey matter volumes results from AT within 2 weeks. Our results of rfMRI, DTI, and tensor based morphometry (TBM) on the AT of the healthy highly educated subjects demonstrated the brain plasticity indeed happened within 2 weeks.

 
2333.   Age-Related Effects in Brain Activation with Working Memory Tasks: An fMRI Study
Jeehye Seo1, Seong-Uk Jin1, Hee-Kyung Kim1, Jang Woo Park1, Moon Han1, Jong Su Baeck1, Yongmin Chang1,2, and Kyung Jin Suh3
1Medical & Biological Engineering, Kyungpook National University, Daegu, Korea, 2Radiology and Molecular Medicine, Kyungpook National University, Daegu, Korea, 3Radiology, College of Medicine, Dongguk University, Gyeong Ju, Gyeongsangbuk-do, Korea

 
A decline in working memory is well documented with increasing age and age-related differences are seen in working memory tasks using functional neuroimaging techniques . The aim of this study is to elucidate age-related effects on functional activation during working memory task through continuous distribution of age. Sixty-eight healthy subjects aged 18 to 70 years old performed an n-back memory task. We found that with increasing age, working memory activation network showed decreased activation, whereas 2-back deactivation network showed increased brain activation. Decreased brain activity has interpreted as a reflection of cognitive deficits in older adults, and increased activity has interpreted as compensatory.

 
2334.   Detection of Difference in Neural Activity During Visuomotor Finger-Tapping Task by the Elderly: An fMRI Study
Sachiko Kiyama1, Mitsunobu Kunimi1, Tetsuya Iidaka2, and Toshiharu Nakai1
1National Center for Geriatrics and Gerontology, Ohbu, Aichi, Japan, 2Nagoya University, Nagoya, Aichi, Japan

 
This study examined the applicability of a cognitive performance task for the elderly, focusing on visuomotor coordination of bimanual finger movements. In order to detect difference of the elderlyfs neural activity, an fMRI study was conducted during bimanual finger-tapping task on elderly and younger adults. Group analyses revealed that movement frequency of this task influenced on activation in left cuneus and bilateral IFG, whereas the tapping mode (i.e., symmetrical/asymmetrical) did not differentiate their activity. This result suggests that movement velocity of visuomotor finger-tapping task, rather than its mode difference, may work as a detector of difference in the elderlyfs cognitive performance.

 
2335.   Differential fMRI Responses to Visual Food Cues Between Lean and Obese Subjects
Claudia Huerta1, Pooja Sarkar1, and Timothy O. Duong2
1UTHSCSA, San Antonio, TX, United States, 2UT Health Science Center at San Antonio, San Antonio, TX, United States

 
Obesity is at an epidemic proportion. This study used fMRI to probe the neural responses to visual food cues in lean and obese subjects in “fasted” and “satiated” state. We identified stronger activities in structures, such as orbitofrontal cortex and fusiform gyrus, known to engage in reward processing and attention in obese compared with lean. We also found that the orbitofrontal cortex activation did not decrease after eating in obese compared to lean subjects. Our results suggest there are strong neural correlates in eating disorders, which may involve the reward/craving circuitry.

 
2336.   fMRI of Glucose Ingestion
Claudia Huerta1, John Li1, and Timothy O. Duong2
1UTHSCSA, San Antonio, TX, United States, 2UT Health Science Center at San Antonio, San Antonio, TX, United States

 
This study used fMRI to investigate the neural networks responding to ingestion of a standardized glucose solution by correlation with blood glucose levels. In addition to identified hypothalamic activation, we detected a large neural network that regulates satiety. Future studies will examine subjects with eating disorders and correlate with temporal profiles of other blood markers (such as c-peptide) and behavioral data of satiety.

 
2337.   A Combined Study of Functional Magnetic Resonance Imaging and Diffusion Tensor Imaging Revealed Neuronal Tract Associated with Autistic Tendency
Tetsuya Iidaka1, Makoto Miyakoshi2, Tokiko Harada3, and Toshiharu Nakai4
1Department of Psychiatry, Nagoya University, Graduate School of Medicine, Nagoya, Aichi, Japan, 2Swartz Center for Computational Neuroscience, Institute for Neural Computation, UC San Diego, La Jolla, CA, United States, 3NIPS, Okazaki, Aichi, Japan, 4Neuroimaging & Informatics, NCGG, Ohbu, Aichi, Japan

 
We performed fMRI in combination with DTI in 30 healthy young subjects. Face-specific brain activation in the superior temporal sulcus (STS) and amygdala (AMG) was identified. Probabilistic tractography indicated a white matter pathway between the face-specific regions of interest in the STS and AMG. The volume of connectivity between the STS and AMG correlated positively with the total AQ score (p<0.05); however, among the AQ subscales, only imagination was significantly associated with the connectivity volume. Healthy subjects with high autistic traits may show an increase in the white matter pathway that connects key regions involved in face processing.

 
2338.   Brain Activation Study by Passive Intra-Articular Movement of Radiolunate and Sacroiliac Joints Using fMRI.
Chuzo Tanaka1, SETSUO Hakata2, Tomokazu Murase3, Masahiro Umeda4, Yasuharu Watanabe4, Yuko Kawai5, Yoshiaki Someya6, Shoji Naruse7, and Toshihiro Higuchi8
1Meiji University of Integrative Medicine, Kyoto, Kyoto, Japan, 2Japanese Medical Society of Arthrokinematic Approa, Fujiyoshida, Yamanashi, Japan, 3Dept. of Neurosurgery, Meiji University of Integrative Medicine, Nantan-shi, kyoto, Japan, 4Dept. of Medical Informatics, Meiji University of Integrative Medicine, Nantan, Kyoto, Japan, 5Dept. of Medical Informatics, Dept. of Medical Informatics, Nantan, Kyoto, Japan, 6MR center of COE, Keio University, Yokohama, Kanagawa, Japan, 72nd Okamoto General Hospital, Kyoto, Kyoto, Japan, 8Dept. of Neurosurgery, Meiji University of Integrative Medicine, Nantan, Kyoto, Japan

 
We studied to clarify the effect of passive intra-articular movement to the brain using fMRI. Stimulation of joint movement consisted of three kinds of stimulations – passive joint movement of wrist for control, passive intra-articular movement of radiolunate joint, and sacroiliac joint. Main activated areas of radiolunate joint were ipsilateral cerebellum, contaralateral insular cortex and motor cortex. Main activated areas by sacroiliac joint were contaralateral insular cortex and ipsilateral BA 7. Relief of joint pain may be modified by these brain areas to manipulate intra-articular movement. This is a first basic study of manual therapy using fMRI.

 
2339.   Negative BOLD in Somatosensory Cortex During Simple Finger Tapping
Robert Trampel1, Andreas Schäfer1, Laurentius Huber1, Robin Martin Heidemann2, Gabriele Lohmann1, and Robert Turner1
1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, 2Siemens AG Healthcare Sector, Erlangen, Germany

 
The functional properties of the somatosensory system have been intensively studied by functional MRI over the last decades. Somatosensory cortex clearly discriminates touch of self and other objects: one cannot tickle oneself. Using unsmoothed isotropic sub-millimeter fMRI at 7 Tesla, and a paradigm comprising finger tapping and finger movement without fingertip touching, we found an area of robust deactivation in contralateral Brodmann area 3b, consistent with active suppression of somatosensory activity during the anticipation and experience of self-generated touch.

 
2340.   Simultaneous CBF and BOLD Mapping of High Frequency Acupuncture Induced Brain Activity
Yue Zhang1, Christopher B. Glielmi2, Yin Jiang3, Jing Wang1, Xiaoying Wang4, Jing Fang1, Cailian Cui3, Jisheng Han3, Xiaoping P. Hu2, and Jue Zhang1
1College of Engineering, Peking University, BeiJing, BeiJing, China, 2Department of Biomedical Engineering, Georgia Institute of Technology / Emory University, Atlanta, GA, United States, 3Neuroscience Research Institute, Peking University, Beijing, Beijing, China, 4Department of Radiology, Peking University First Hospital, Beijing, Beijing, China

 
This study mapped brain activity elicited by high frequency electroacupuncture by simultaneously using blood oxygenation level dependent (BOLD) and cerebral blood flow (CBF) contrasts. Forty subjects participated in the study, in which twenty ones were imaged during electrical acupoint stimulation (EAS) to the left LI4 acupoint at a maximal intensity without pain, and the others with a minimal-EAS at a just detectible intensity. Both BOLD and CBF data were acquired simultaneously during alternating blocks of rest and stimulation. The results revealed concordant and complementary insights into the neural effects of EAS, including modulation of subcortical structures and limbic system.

 
2341.   Decreased Cerebral Blood Volume and Flow in Areas with Negative BOLD Indicates the Mechanism for Negative BOLD May Be Stimulus- And Area-Specific
Jozien Goense1, Yvette Bohraus1, and Nikos K. Logothetis1,2
1Dept. Physiology of Cognitive Processes, Max-Planck Institute for Biological Cybernetics, Tuebingen, Germany, 2Division of Imaging Science and Biomedical Engineering, University of Manchester, Manchester, United Kingdom

 
In earlier work, we showed increased CBV in regions with negative BOLD responses. This seems to disagree with work in cats where CBV was decreased in areas with negative BOLD. Here, we used a full-field checkerboard stimulus and show decreased CBV and CBF in areas that show negative BOLD responses. However, this type of negative BOLD signals occurred in peripheral V1 and extrastriate visual cortex. Our results suggest that different mechanisms for negative BOLD exist and that these may be area-dependent.

 
2342.   Trial-By-Trial Global Modulation of BOLD Responses to Simple, Sensory Stimuli: Implications for Functional Brain Imaging and Understanding Positive and Negative BOLD Response Coupling
Stephen D. Mayhew1, Karen J. Mullinger2, Camillo Porcaro3,4, Richard W. Bowtell2, Andrew P. Bagshaw1, and Susan T. Francis2
1BUIC, School of Psychology, University of Birmingham, Birmingham, United Kingdom, 2SPMMRC, School of Physics and Astronomy, University of Nottingham, Nottingham, United Kingdom, 3Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom, 4LETs-ISTC-CNR, Fatebenefratelli Hospital-Isola Tiberina, Rome, Italy

 
Conventional GLM analyses of fMRI data localise brain activity from the average stimulus response, ignoring trial-by-trial variability which is most relevant to the dynamics of brain function and behavioural outcomes. We combine data from visual, motor and somatosensory tasks to show that single-trial responses across the whole brain are concurrently modulated with activity in the stimulated primary sensory cortex. These modulations induce a positive correlation between single-trial positive and negative BOLD responses, despite a negative correlation between the average response magnitudes. These findings demonstrate that stimulus modulations extend over a far greater extent of the brain than previously suspected.

 
2343.   Deconvolution Analyses with Tent Functions Reveal Delayed and Long-Sustained Increases of BOLD Signals with Acupuncture Stimulation
Tomokazu Murase1, Masahiro Umeda2, Yuko Kawai2, Yasuharu Watanabe2, Shoji Naruse3, Chuzo Tanaka1, and Toshihiro Highchi1
1Department of Neruosurgery, Meiji University of Integrative Medicine., Nantan, Kyoto, Japan, 2Department of Medical Informatics, Meiji University of Integrative Medicine., Nantan, Kyoto, Japan, 3Daini Okamoto General Hospital, Uji, Kyoto, Japan

 
We focused on the temporal changes in brain activity caused by acupuncture stimulation with deconvolution analysis to analyze brain responses without the expected reference function. 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.

 
2344.   Cortical Activation Induced by Electrical Stimulation in Patients with Multiple Sclerosis and Foot Drop
Bader Aldebasi1, Xia Lin2, Paul M. Glover1, Richard W. Bowtell1, Cris Constantinescu3, and Susan T. Francis1
1SPMMRC, School of Physics & Astronomy, Nottingham, Nottinghamshire, United Kingdom, 2Division of Rehabilitation and ageing, Nottingham, Nottinghamshire, United Kingdom,3Division of clinical Neurology, Nottingham, Nottinghamshire, United Kingdom

 
Functional electrical stimulation (FES) is a technique used to elicit ankle dorsiflexion (ADF) movement by electrically stimulating the common peroneal nerve, and used in gait rehabilitation to correct foot drop. Brain activation patterns associated with Active, Passive, Electrical Stimulated (ES) and combined ES plus Active induced ADF of the affected and non-affected leg are compared in ten MS patients. For Active ADF, a significant increase is seen in secondary motor areas for the affected compared to non-affected leg, whilst for ES ADF, significantly reduced activity in the insula and SII is found for the affected leg.

 
2345.   Working Memory Impairment in Occupational Lead Exposure Subjects Associated with Altered Frontoparietal Memory Network
Jeehye Seo1, Seong-Uk Jin1, Hee-Kyung Kim1, Jang Woo Park1, Moon Han1, Jong Su Baeck1, Yongmin Chang1,2, and Young-Hwan Lee3
1Medical & Biological Engineering, Kyungpook National University, Daegu, Korea, 2Radiology and Molecular Medicine, Kyungpook National University, Daegu, Korea, 3Radiology, Daegu Catholic University Medical Center, Daegu, Korea

 
Occupational lead exposure in adults are associated with decreases in cognitive performance including working memory. The aim of this study is to elucidate the differences in neural activation related to working memory between lead exposure subjects and healthy subjects. Thirty-one lead exposure subjects and 34 healthy subjects performed an n-back memory task. We found that healthy subjects showed better performance in terms of accuracy and reaction times during the task. In between-group analyses, lead exposure subjects showed reduced activation in the dorsolateral, dorsomedial and ventrolateral prefrontal cortex, and inferior parietal cortex. Our findings suggest that functional abnormalities in the frontoparietal working memory network might contribute to impairments in maintenance and manipulation of working memory in lead exposure subjects.

 
2346.   Proximal and Distal Effects of Subconcussive Head Impacts on fMRI Activity in Asymptomatic High School Football Players
Meghan Robinson1,2, Evan Breedlove3, Victoria N. Poole2,4, Larry Leverenz5, Eric Nauman3,4, and Thomas Talavage2,6
1Translational Research Center for TBI and Stress Disorders (TRACTS), VA Boston Healthcare System, Boston, MA, United States, 2Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States, 3Mechanical Engineering, Purdue University, West Lafayette, IN, United States, 4Basic Medical Sciences, Purdue University, West Lafayette, IN, United States, 5Health and Kinesiology, Purdue University, West Lafayette, IN, United States, 6Electrical Engineering, Purdue University, West Lafayette, IN, United States

 
We investigated the effects of subconcussive head trauma in a cohort of asymptomatic high school football players. Head impacts were measured via accelerometers in player’s helmets. Changes from pre-season to in-season in fMRI activations during two working memory tasks were measured. These changes were compared to the hit history (number and location of the hits) of the players through a stepwise regression. We found that hits were likely to produce negative correlations in proximal regions and positive correlations in distal regions. This result was consistent across two task types (visual and verbal) and two contrasts.

 
2347.   Cross-Field Analysis of the Accuracy of Hypercapnia Calibrated BOLD
Nicholas P. Blockley1, Valerie E M Griffeth2, Peter Jezzard1, and Daniel P. Bulte1
1FMRIB, University of Oxford, Oxford, United Kingdom, 2Center for Functional MRI, University of California San Diego, La Jolla, California, United States

 
The calibrated BOLD technique was originally optimised for 1.5T, and was later revised for 3T. However, with the arrival of 7T systems it is unclear what the optimal implementation should be and how this will affect accuracy. In this study we extended an existing detailed model of the BOLD signal to simulate the BOLD response at these field strengths. This model was used to examine the error in oxygen metabolism measurements across fields and provide a guide to the expected BOLD scaling factor M at 7T.

 
2348.   Acetazolamide Improves Tissue Oxygenation During Hypoxia in the Human Brain
Kang Wang1, Zachary M. Smith1, and David J. Dubowitz1
1University of California San Diego, La Jolla, CA, United States

 
Hypoxic hypoxia is accompanied by an increase in cerebral O2 metabolism, and despite increased cerebral blood flow there is reduced cerebral tissue oxygentation. We investigated if Acetazolamide (a carbonic anhydrase inhibitor that increases CO2 in the cerebral tissues) improves tissue oxygentaion during hypoxia. CMRO2 was measured using ASL and TRUST at 3T in human volunteers during normoxia, and following 6-hrs hypoxia with or without acetazolamide treatment. Following acetazolamide, the hypoxia-induced rise in CMRO2 and CBF were reduced. This resulted in improved oxygentation in cerebral tissues despite the continued hypoxia.

 
2349.   Reliable Quantification of Cerebrovascular Reactivity Despite Poorly Performed Breath-Holds
Kevin Murphy1 and Molly G. Bright1
1CUBRIC, School of Psychology, Cardiff University, Cardiff, Wales, United Kingdom

 
Cerebrovascular reactivity, the vascular response to vasodilatory stimuli, can be measured with BOLD fMRI by increasing end-tidal CO2 using a breath-hold task. A long end-expiration breath-hold lasting 20s provides a suitably large BOLD response. However, clinical and elderly populations may find such a long breath-hold difficult and it is likely that the length of breath-hold that each participant can achieve will vary widely across these groups. This study demonstrates that by measuring end-tidal CO2 changes during a breath-hold task, a repeatable measure of cerebrovascular reactivity can be obtained irrespective of whether the participant can perform the task fully or consistently.

 
2350.   A Search for an Optimal Neuronal Marker for Spinal Cord FMRI
Kenneth A. Weber II1,2, Yufen Chen1, Xue Wang1, and Todd B. Parrish1
1Department of Radiology, Northwestern University, Chicago, IL, United States, 2Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL, United States

 
Spinal cord fMRI has lagged behind brain fMRI due to technical difficulties including magnetic susceptibilities at bone-tissue interfaces, the small dimensions of the spinal cord, and physiological noise. Gradient echo EPI (GE EPI) based BOLD fMRI is sensitive to differences in magnetic field susceptibilities at bone-tissue interfaces, which results in signal loss and image distortion. This study investigates steady state free precession, proton density spin-echo EPI, and short TE half-Fourier single-shot turbo spin-echo sequences for functional neuroimaging in the motor cortex to determine their potential for spinal cord fMRI. These data were compared to conventional GE EPI based BOLD fMRI.