Javier Gonzalez-Castillo¹, Vinai Roopchansingh², Peter A. Bandettini^1,2, and Jerzy Bodurka^3
1Section on Functional Imaging Methods, National Institute of Mental Health, Bethesda, MD, United States, ²Functional MRI Facility, National Institute of Mental Health, Bethesda, MD, United States, ³Laureate Institute for Brain Research, Tulsa, OK, United States

Flip angles near the Ernst angle are commonly used in fMRI to maximize image SNR. However, lower angles provide significant benefits such as better tissue contrast, less inflow effect, less through-plane motion artifacts, and reduced levels of radio-frequency energy deposition. Recent research has shown that TSNR, a better predictor of sensitivity than SNR, stays fairly constant and close to its maximum value for a wide range of angles when physiological noise dominates. Here we explore the hypothesis that low flip angles have no detrimental effects on our ability to detect BOLD neuronal activations; and might be advised for fMRI experiments

Ilia Makedonov^1,2, David E Crane¹, and Bradley J MacIntosh^1,3
1Heart and Stroke Foundation Centre for Stroke Recovery, Toronto, ON, Canada, ²Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada, ³Medical Biophysics, University of Toronto, Canada

Cardiac noise is usually filtered and otherwise minimized in resting state BOLD fMRI scans. One theory posits that mechanical damage due to cardiac pulsatility is implicated in brain aging and contributes to the formation of pathological small vessel disease. The purpose of this abstract is to characterize cardiac physiological signal in BOLD fMRI and to compare young and elderly groups. Our preliminary results shows that cohort differences exist between the extent of cardiac pulsatility in gray matter in the young and elderly.

Tommaso Gili¹, Ibrahim Eid², Kevin Murphy¹, Ashley Harris¹, Guido Caldarelli³, Bruno Maraviglia², and Richard Geoffrey Wise^1
1Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff, Wales, United Kingdom, ²Dipartimento di Fisica, Università di Roma Sapienza, Roma, Italy, ³CNR-ISC Dipartimento di Fisica, Univeristà di Roma Sapienza, Roma, Italy

Parcellation of the cortex into individual subunits based on correlations in resting-state data opens up the possibility of developing a subunit atlas analogous to the Brodmann areas but based on cortical function rather than cytoarchitecture. Graph theory is a common methodology for studying complex networks. Graph-based clustering approaches have also been applied to the analysis of brain networks using resting-state fMRI. Here we used a random-walk-based algorithm to parcellate visual cortex in healthy subjects in a resting-state condition. Moreover we demonstrate the need for physiological noise removal to obtain consistent results across subjects from this functional segmentation method.

Cécile Madjar¹, Claudine Joëlle Gauthier^1,2, Rasmus M Birn³, and Rick D Hoge^1,2
1CRIUGM/UNF, Montréal, Québec, Canada, ²Physiology/Biomedical Engineering, University of Montréal, Montréal, Québec, Canada, ³University of Wisconsin, Madison, WI, United States

With the ever-increasing number of studies investigating the default-mode network (DMN), there has been a growing interest in trying to take into account the confounding effects from physiological noise, such as respiration, while performing connectivity analysis of fMRI. Variations in respiration cause fluctuations in end-tidal CO2 (ETCO2) which have been shown to exert a significant effect on BOLD fMRI signal. Here we present data comparing resting-state correlations in the DMN, as well as task-related activations, between two conditions: 1) while tightly controlling for ETCO2 concentrations, and 2) while ETCO2 values were allowed to vary spontaneously.

Axel Hartwig¹, Mathias Engström¹, Olof Flodmark¹, Martin Ingvar¹, and Stefan Skare^1
1Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden

In this study, we show the level of interaction between head motion and coil sensitivities for 32-channel fMRI data, in the absence of fMRI stimulus. The magnitude of the coil sensitivity induced signal fluctuations, introduced after image realignment, are similar to common BOLD-response levels, why this can affect the fMRI analysis when motion and the BOLD response are partially correlated. Our method involves a measurement of the coil sensitivity field. By simply normalizing the fMRI data - prior to realignment - with this field, the signal fluctuations - post-realignment - can be largely reduced.

Costin Tanase¹, Jeffrey O'Hara², Denise Davis³, Fernando Boada³, Michael H Buonocore⁴, and Cameron S Carter^1
1Psychiatry and Behavioral Sciences, University of California at Davis, Sacramento, CA, United States, ²Siemens Medical Solutions, ³University of Pittsburgh, United States,⁴Radiology, University of California Davis, United States

It is well accepted that the statistical assessment of fMRI data can be improved by estimating the measurement noise as well as the fMRI series fluctuations due to slow physiological processes. While recent fMRI literature has characterized a larger array of increasingly subtler physiological fluctuations, there is still an overriding assumption that the “leftover� variance in the data can be described by “stationary Gaussian noise�. By analyzing the QA data, the extracted temporal series demonstrate the presence of signal fluctuations that are non-random and consistent across multiple runs.

Chloe Hutton¹, Antoine Lutti¹, and Nikolaus Weiskopf^1
1Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, University College London, London, United Kingdom

Temporal signal-to-noise ratio (SNR) has been characterized as a function of image SNR for fMRI time series allowing physiological noise to be separated from thermal noise. This model is only valid for data acquired with a single-channel receiver coil. Here we propose an extension of this model to allow for state-of-the-art multi-channel acquisition mode, commonly used for fMRI studies. Using Monte Carlo simulations and 7T task-free fMRI, we show improved fit of the extended model for data where noise correlations are present. This extended model allows for characterization of temporal SNR and physiological noise using data acquired with multi-channel receiver coils.

Dan Xu¹, Jian Zhang², Richard Scott Hinks¹, and Kevin F. King^1
1Applied Science Laboratory, GE Healthcare, Waukesha, WI, United States, ²Applied Science Laboratory, GE Healthcare, Bethesda, MD, United States

Conventional 1D, spatially non-selective fat saturation can generate uncrushed fat signals in areas where crusher is weak because of reduced gradient linearity. These fat signals can corrupt in-plane water signal, and in fMRI, they manifest themselves as artifacts such as clouds in image background or localized signal fluctuation over time. We propose a spectral-spatial fat saturation method to remove these artifacts while preserving thin slice capability, pulse duration, and fat suppression performance.

Raquel Phillips¹, Vadim Zotev¹, Jonathan Savitz¹, Ruben Alvarez¹, W Kyle Simmons¹, Patrick Bellgowan¹, Wayne Drevets¹, and Jerzy Bodurka^1
1Laureate Institute for Brain Research, Tulsa, OK, United States

Physiological noise is a major confounding factor in BOLD fMRI. We will show the utility of T2-weighted anatomical fast-spin-echo images for fMRI physiological noise visualization. We propose a method for processing T1- and T2-weighted anatomical high-resolution images that highlights brain compartmentalization at lower fMRI resolution. Such images are formed by computing spatial standard deviation (SD_s) from neighboring voxel intensities within the anatomical volume. Because of the large signal difference with fast-spin-echo between cerebrospinal fluid, grey matter, and/or vasculature, the T2-based SD_s image predicts well the brain areas where the fMRI signal temporal variation will be present.

Tom Ash¹, John Suckling², Martin Walter³, Cinly Ooi², Claus Tempelmann⁴, Adrian Carpenter¹, and Guy Williams^1
1Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom, ²Brain Mapping Unit, University of Cambridge, Cambridge, United Kingdom,³Department of Psychiatry, University of Magdeburg, Magdeburg, Germany, ⁴Department of Neurology, Otto v. Guericke University, Magdeburg, Germany

We present a support vector machine based technique for recreation of partially or fully absent physiological recording data, to allow detrending of physiological noise to occur even in the absence of complete recordings of the physiological cycles. The technique uses a multi-class SVM to predict phase of each physiological cycle from fMRI image data, after training on prior data. Using these predicted phase values as inputs to physiological detrending tool RETROICOR show similar impact on Fourier transforms of the data as using recorded values, showing that they are accurate enough for use as inputs to detrending tools.

Alan Chu^1,2, Jon-Fredrik Nielsen¹, Scott J. Peltier¹, and Douglas C. Noll^1
1Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States, ²University of Michigan Medical School, Ann Arbor, MI, United States

Hadamard-encoded fMRI is a multislice acquisition method that increases SNR. Because the method uses temporal filtering on complex data for subslice extraction, the method is more susceptible to physiological noise and phase fluctuations when compared with conventional fMRI, where only the magnitude is typically used for determination of voxel activation. In this work, we introduce both physiological noise removal and phase correction for Hadamard-encoded fMRI, and compare the resulting functional activation with that of a conventional fMRI scan.

Antoine Lutti¹, Oliver Josephs¹, Dave Thomas², Rebecca Lawson³, Jonathan P Roiser³, Chloe Hutton¹, and Nikolaus Weiskopf^1
1Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, London, United Kingdom, ²Institute of Neurology, Department of Brain Repair and Rehabilitation, University College London, London, United Kingdom, ³Institute of Cognitive Neuroscience, University College London, London, United Kingdom

The use of 3D EPI for the study of brain activity has been limited due to its high sensitivity to physiological noise which counteracts its higher image SNR compared to 2D EPI. In this work, we present an optimized method for physiological noise correction of 3D EPI. The impact of the correction is stronger than for 2D EPI, showing that the higher susceptibility of 3D EPI to physiological noise can be overcome, leading to significantly higher tSNR values.

Evgeniya Kirilina¹, Alexnader Jelzow², Ruediger Bruehl², Angela Heine¹, Michael Niessing¹, Arthur M. Jacobs¹, Bernd Ittermann², Heidrun Wabnitz², Rainer Macdonald², and Ilias Tachtsidis^3
1Free University of Berlin, Berlin, Germany, ²Physikalisch-Technische Bundesanstalt, Berlin, Germany, ³Department Medical Physics and Bioengineering, University College London, London, United Kingdom

Functional near-infrared spectroscopy (fNIRS) is a non-invasive technique for studying the functional organization of the human brain by measuring haemodynamic responses to stimuli in the cerebral cortex. A major challenge of fNIRS is its high sensitivity to haemodynamic fluctuations in the scalp. Here, we combined fNIRS, fMRI and peripheral physiological measurements in order to explore the physiological origin of superficial signals in fNIRS and develop a method to separate them from cortical signals. Using high resolution fMRI data, we show that the main origin of artifacts in fNIRS is task-evoked venous vasoconstriction in the scalp.

Gisela E Hagberg^1,2, David Balla³, Hannes M Wiesner⁴, and Nikos K Logothetis^5
1Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, Tübingen, Germany, Germany, ²Fondazione Santa Lucia, Rome, Italy, ³High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tubingen, Germany, ⁴High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Germany, ⁵Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics

We investigated localized fluctuations during resting state dynamics of 7T phase and magnitude fMRI signals (voxels of 98 and 64nl) at two echo times (13 and 36ms) in rats. We could confirm the presence of TE-dependent signal fluctuations mediated by BOLD susceptibility that was greatest in voxels with strong vascular components and decreased with the distance from such areas. Interestingly, both high phase and magnitude instabilities were observed in the callosal fibers, containing oriented white matter structures. In view of differences in susceptibility between these structures and the surrounding grey matter these fluctuations may result from minute displacements caused for instance by heart pulsations.

Prantik Kundu¹, Souheil J Inati¹, Jennifer W Evans¹, Ziad S Saad², and Peter A. Bandettini^1
1Section on Functional Imaging Methods, National Institute of Mental Health, Bethesda, MD, United States, ²Scientific and Statistical Computing Core, National Institute of Mental Health, Bethesda, MD, United States

A novel configuration of spatial ICA was applied to multi-echo fMRI data. The combination allowed robust, prior-free, and fully automated differentiation of physiological artifact components from BOLD components using an amplitude model for TE-dependence. No anatomical templates, bandpass filtering, physiology regressors, or motion parameters were required. The technique was applied to both task and rest data. Demonstrated is the improvement of including artifact component timecourses as baseline regressors in both activation mapping and seed-voxel functional connectivity.

Mark Chiew^1,2, and Simon James Graham^1,3
1Medical Biophysics, University of Toronto, Toronto, Ontario, Canada, ²Rotman Research Institute, Toronto, Ontario, Canada, ³Imaging Research, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

Multi-echo functional magnetic resonance imaging (fMRI) is a technique capable of providing enhanced contrast-to-noise ratio (CNR) data in blood oxygenation level dependent (BOLD) imaging experiments. Here, data is presented on the relationship between physiological noise correlations and the CNR benefits of densely sampled multi-echo fMRI over traditional fMRI acquisitions, such as echo-planar imaging. Data from Monte Carlo simulations and experiment are presented, and illustrate a decreasing power law dependence of CNR benefit vs. degree of noise correlation measured across echoes.

Xiaoyu Sun¹, Christopher W Weitekamp¹, Jianli Wang¹, Jeffrey Vesek¹, and Qing X Yang^1,2
1Radiology, Penn State College of Medicine, Hershey, PA, United States, ²Neurosurgery, Penn State College of Medicine, Hershey, PA, United States

In recent olfactory fMRI studies, the subjects were trained to follow instructions for respiration or sniffing to synchronize the odor stimulation. Such methods will fail in studying patients that are not able to follow the instructions. Here we present an event-related paradigm design and post-processing tools for olfactory fMRI without requirement to control the subject’s respiration or sniffing. Our data showed that the subject’s respiratory modulation of the olfactory stimulation paradigm significantly confounded the BOLD signal. The presented event-related design and corresponding data processing method are simple and effective for generating olfactory fMRI results with minimal confounding variability.

Prasanna Karunanayaka¹, Christopher W Weitekamp¹, Jianli Wang¹, Megha M Patel¹, Jeffrey Vesek¹, Xiaoyu Sun¹, Paul J Eslinger^2,3, James R Connor⁴, and Qing X Yang^1,4
1Radiology, Center for NMR Research, Penn State University College of Medicine, Hershey, PA, United States, ²Neurology, Penn State University College of Medicine, Hershey, PA, United States, ³Neural & Behavioral Sciences, Penn State University College of Medicine, Hershey, PA, United States, ⁴Neurosurgery, Penn State University College of Medicine, Hershey, PA, United States

The pattern of BOLD response during the time course of a standardized olfactory stimulation paradigm was investigated and characterized using group independent component analysis (ICA). Group ICA is quickly becoming a preferred functional MRI data analysis technique due to its ability to reveal the underlying networks of the human brain subserving cognitive functions. Group ICA does not require a priori knowledge of the hemodynamic response function (HRF), which may vary across subjects and paradigm conditions.

Johnny Ng^1,2, Heather Berlin³, Wayne Goodman³, Emily Eaves¹, David Carpenter¹, and Cheuk Tang^1,3
1Radiology, Mount Sinai School of Medicine, New York, NY, United States, ²Biomedical Engineering Dept., City College of New York, New York, NY, United States,³Psychiatry, Mount Sinai School of Medicine, New York, NY, United States

Orbitofrontal cortex (OFC) is the key structure affected in obsessive-compulsive disorder (OCD). There is a well-established relationship between olfactory identification and the OFC. There are limited studies in this area with functional magnetic resonance imaging (fMRI), which showed activations in the OFC during olfactory stimulation with pleasant and unpleasant odorant stimuli. There are two main issues which limiting studies in this area: the non-availability of olfactometers and it is problematic imaging OFC due to susceptibility artifacts. The aim of this study is to optimized fMRI imaging protocol for the OFC in OCD patients with the in-house built olfactometer.

Johnny Ng^1,2, Emily Evaes¹, David Carpenter¹, and Cheuk Ying Tang^1,3
1Dept. Radiology, Mount Sinai School of Medicine, New York, New York, United States, ²Biomedical Engineering Dept., City College of New York, New York, New York, United States, ³Dept. Psychiatry, Mt. Sinai School of Medicine, New York, New York, United States

Interest in the fMRI of the human olfactory system has increased in recent years. The aim of this study is to build a cost effective MR olfactometer suitable for clinical and laboratory environments. An apparatus was built to determine the temporal resolution and the delay time of the custom-built olfactometer. Six healthy subjects participated in testing the olfactometer with six odorant stimuli. The olfactometer has a very short delay time, less than 1 second. Activations were found in the piriform cortex, insular cortex and DLPFC.

Hengyi Rao^1,2, Dan Luftig², Julian Lim², John A. Detre¹, and Daivid F Dinges^2
1Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, United States, ²Unit for Experimental Psychiatry, University of Pennsylvania, Philadelphia, PA, United States

Little is known about the effects of sleep deprivation on neural correlates of risk-taking. The present study used functional MRI and examined the effects of 24hr of total sleep deprivation (TSD) on risk-taking during a modified balloon analog risk task (BART) in 27 normal subjects. One night TSD did not alter the BART risk-taking behavior, nor the risk-induced brain activation patterns. However, TSD decreased insula activation during the loss events and impaired the negative correlation between risk-taking behavior and neural activation in insula and striatum, suggesting that sleep deprivation may alter neural responses during risk-taking before actual behavioral changes.

Dietmar Cordes¹, Mingwu Jin¹, Tim Curran², Victoria Pelak³, and Rajesh Nandy^4
1C-TRIC and Dept. of Radiology, University of Colorado-Denver, Aurora, CO, United States, ²Dept. of Psychology and Neuroscience, University of Colorado-Boulder, Boulder, CO, United States, ³Dept. of Neurology, University of Colorado-Denver, Aurora, CO, United States, ⁴Depts. of Biostatistic and Psychology, University of California-Los Angeles, Los Angeles, CA, United States

Focusing on activation in subregions of the medial temporal lobe (CA1, CA23DG, SUB, ERC, PRC, FUS, PHC) we used discriminant analysis applied to data from three different memory paradigms to investigate the degree of separation of the aMCI group from the normal control group as a function of the type of paradigm (outdoor pictures, faces-and-occupations, unrelated word pairs) and type of contrast (encoding-control, recognition-control, encoding-recognition, old-control, new-control, old-new). Results indicate optimum separation of groups for the face-and-occupation paradigm for contrast recognition-control. Prediction accuracy using the leave-one-out method is 75% using activations in left CA1, left SUB and left PHC.

John Graner¹, Hai Pan¹, Ping-Hong Yeh¹, Binquan Wang¹, Terrence R Oakes^1,2, Wei Liu^1,2, Louis M French³, Fletcher Munter², and Gerard Riedy^2,4
1TBI Image Analysis Lab, Uniformed Services University of the Health Sciences / HJF, Bethesda, MD, United States, ²National Capital Neuroimaging Consortium, Walter Reed Army Medical Center, Washington, DC, United States, ³Defense and Veterans Brain Injury Center, Walter Reed Army Medical Center, Washington, DC, United States,⁴National Intrepid Center of Excellence, Bethesda, MD, United States

Fourteen (14) USA military TBI victims and 11 control subjects underwent fMRI while performing an N-back working memory task. Significant group differences were seen in the cerebellum in the 3-back vs. 1-back contrast. A preliminary investigation of heterogeneity within the group analysis results also suggests greater activation variability in the TBI population that may need to be accounted for when attempting traditional voxel-based group analysis.

Jeehye Seo¹, Jae-jun Lee¹, Hui-jin Song¹, Seong-Uk Jin¹, Ji-Young Kim², and Yongmin Chang^1,3
1Medical & Biological Engineering, Kyungpook National University, Daegu, Korea, Republic of, ²school of medicine, Kyungpook National University, Daegu, Korea, Republic of,³Diagnostic Radiology, Kyungpook National University, Daegu, Korea, Republic of

Fibromyalgia (FM) is a disorder of uncertain etiology characterized by widespread chronic pain, stiffness, and depression. Patients with FM commonly report cognitive complaints, including memory and attention problems. The aim of this study is to elucidate the differences in neural activation related to working memory between FM patients and healthy subjects. We also investigated differences in deactivation of the default network during performance of working memory between two groups. Nineteen FM patients and 22 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, FM patients showed reduced activation in the dorsolateral and ventrolateral prefrontal cortex, dorsal cingulate cortex, and inferior parietal cortex. There were no differences in neural deactivation between FM patients and healthy subjects during performance of the n-back test. These results suggest that working memory impairment in FM patients may be attributable to differences in neural activation of the frontoparietal network rather than deactivation of the default network.

Toshiki Nakane^1,2, Miyakoshi Makoto², Toshi Nakai², and Shinji Naganawa^1
1Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan, ²NCGG, Ohbu, Aichi, Japan

We performed an fMRI study to separate the effect of attention from self-referential processes. For this purpose, three categories of names, namely one's own, repeated, and unfamiliar, were presented as stimuli, followed by high or low beep sounds. Participant's task was to judge one's own/repeated or unfamiliar (attended task), and to judge beep high or low (unattended task). Results showed fCMS involvement when both self-relevance AND attention were needed. We concluded that fCMS is not always sensitive to self-relevance, but only when self-relevance is task-relevant.

Yang Hu^1,2, Mingxia Fan³, Wenjing Li², Peijia Huang², and Zhaoxin Wang^1,3
1Institute of Cognitive Neuroscience, Shanghai Key Laboratory of Brain Functional Genomics, East China Normal University, Shanghai, China, People's Republic of,²Department of Psychology, School of Psychology and Cognitive Science, East China Normal University, Shanghai, China, People's Republic of, ³Shanghai Key Laboratory of MRI, East China Normal University, Shanghai, China, People's Republic of

The current study aimed to investigate whether simple group categorization can modulate the neural correlates of empathy for other¡¯s pain using a modified minimal paradigm. Participants were randomly assigned to two groups and were instructed to memorize novel faces of in-/out-group members. They were then sent to the MRI scanner to rate the pain intensity felt by their in-/out-group members. We found that increased activation in right anterior insula was detected while participants see their in-group members receiving painful stimulation in relevant to out-group members, indicating that empathic concern for other¡¯s pain could be modulated by simple group categorization.

Xiaolin Liu¹, Kathryn K. Lauer², Stephen M. Rao³, Shijiang Li¹, and Anthony G. Hudetz^2
1Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, ²Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States, ³Schey Center for Cognitive Neuroimaging, Cleveland Clinic, Cleveland, Ohio, United States

In this study, we described our investigation into the integrative mechanisms of general anesthesia using a compelling verbal memory experimental paradigm that allows neuroimaging characterization of consciousness in waking, anesthesia, and emergence. Our neuroimaging methodology was specifically designed to understand the anesthetic-induced changes of temporal coherence in the brain at different hierarchical levels of the cognitive processing, providing a consistent interpretation with the conception of the anesthetic mechanisms as the information disintegration or the cognitive unbinding. The findings reveal a differential effect of propofol anesthesia on sensory and cognitive systems and provide direct imaging evidence for information disintegration as a mechanism of anesthetic-induced unconsciousness.

Vincent Jerome Schmithorst¹, Scott Kerry Holland¹, and Elena Plante^2
1Radiology, Children's Hospital Medical Center, Cincinnati, OH, United States, ²Speech, Language, and Hearing Sciences, University of Arizona, Tucson, AZ, United States

Auditory Processing Disorder (APD) in children is diagnosed on the basis of behavioral tests which can be confounded by attentional or language deficits. We investigate the hypothesis that APD, as currently diagnosed by clinicians, stems from a deficit in cross-modal inhibition (the inhibition of neural processing of other sensory inputs). Performance of behavioral audiology measures was correlated with brain activation during a basic auditory stimulation task using fMRI. Results suggest that performance on tests of auditory processing used to diagnose APD is predicted by cross-modal inhibition of secondary visual areas and the parahippocampal gyrus, associated with repression of irrelevant information.

Ruiliang Wang¹, Gene-Jack Wang², Frank Telang³, Rita Z Goldstein⁴, Nora D Volkow⁵, and Dardo Tomasi^5
1Medical, Brookhaven National Laboratory, Upton, NY, United States, ²Brookhaven Nationa Laboratory, ³medical, Brookhaven National Laboratory, ⁴Brookhaven National Laboratory, ⁵National Institute on Drug Abuse, National Institute on Health

We used magnetic resonance imaging and functional connectivity density mapping (FCDM) to map hubs with high local functional connectivity density (lFCD)in 70 healthy men (age: 18-55). Two resting conditions were tested: 1) when the subjects rested with their eyes open (baseline condition), and 2) while they were listening to classical music (music condition). Our findings suggest that in resting conditions, music can increase the local functional connectivity of the brain. These findings are consistent with the involvement of brain regions in processing rhythm (dorsolateral prefrontal and parietal cortices and cerebellum), tonality (temporal and medial prefrontal cortices) and emotions (limbic cortex).

Kirsteen Davidson-Kelly¹, Sujin Hong¹, Janani Dhinakaran², Joseph Sanders³, Calum Gray⁴, Edwin J.R. van Beek⁴, Neil Roberts⁴, and Katie Overy^1
1Music, University of Edinburgh, Edinburgh, United Kingdom, ²Carl von Ossietzky University of Oldenburgh, Germany, ³Guildhall School of Music & Drama, London, United Kingdom, ⁴Clinical Research Imaging Centre (CRIC), Queen’s Medical Research Institute (QMRI), University of Edinburgh, Edinburgh, United Kingdom

Musical imagery is an expert learning strategy with potential to enhance performance, reduce physical overuse and decrease anxiety. In this fMRI study we scanned a professional pianist with vivid imagery skills during imagined and simulated motor performance of memorised music. The motor system (SMA, pre-motor cortex, cerebellum) was activated during both tasks, while M1 was activated during performance only. Interestingly, the MFG showed differential activation for imagery (bilateral) and performance (left-sided only), possibly indicating a shift/increase in attention. We conclude that the MFG could provide an index of the effectiveness of musical imagery as a learning strategy.

Marko Wilke¹, Kathina Ebner², Till-Karsten Hauser³, and Karen Lidzba^2
1Pediatric Neurology & Developmental Medicine, University Children's Hospital Tübingen, Tübingen, BW, Germany, ²Pediatric Neurology & Developmental Medicine, University Children's Hospital Tübingen, Tübingen, Germany, ³Diagnostic and Interventional Neuroradiology, Radiological Clinic, Tübingen, Germany

Functional MRI in children is still challenging. We here suggest that appropriately-designed fMRI tasks may be analyzed in the active>control as well as the control>active condition, allowing to assess two cognitive domains in one task. Results from a "dual-use" task assessing language and visuospatial functions are compared with a dedicated task designed to assess visuospatial functions. The implications of such an approach are discussed.

Dirk Goldhahn¹, Daniel E Callan², Gabriele Lohmann¹, and Robert Turner^1
1Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, ²ATR Computational Neuroscience Laboratories, Kyoto, Japan

Multi-Voxel Pattern Analysis (MVPA) is a powerful technique for the analysis of fMRI data. It uses the information present in multiple voxels to distinguish between experimental conditions. In this abstract we apply MVPA to examine brain regions differentially involved with listening to and covert production of song relative to speech. We present new findings that univariate analysis failed to discover, and investigate what underlies this discrepancy. As a particular example the superior temporal gyri are discussed, which show highly differential activity for the contrast of covert production of song versus covert production of speech only when using MVPA.

Der-Yow Chen¹, Stephen Dodd¹, Afonso Silva¹, and Alan Koretsky^1
1LFMI, NINDS, NIH, Bethesda, MD, United States

In the present study, we compare the BOLD fMRI of the visual system in awake and alpha-chloralose anesthetized rats. A head post was implanted to minimize the head motion and rats were trained to accustom to a restrainer. Brain activity in response to various frequencies of flashing light was explored. Awake rats showed significant fMRI activation in the lateral geniculate nucleus, superior colliculus, and the visual cortex, especially in response to high frequencies. On the contrary, less activation were found in these regions of anesthetized rats. These findings indicate that fMRI experiments in awake rats may be more appropriate to study the function of visual system.

Naranjargal Dashdorj¹, Mirjam I Schubert¹, Malcolm Prior², Rob Mason³, and Dorothee P Auer^1
1Academic Radiology, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom, ²Brain and Body Centre, University of Nottingham, Nottingham, United Kingdom, ³School of Biomedical Sciences, University of Nottingham, Nottingham, United Kingdom

Pharmacological magnetic resonance imaging (phMRI) is an increasingly popular tool to study drug effects on brain function using the blood oxygen level dependent (BOLD) signal. However, the nature of the drug induced BOLD signal change is still not well understood; in particular its relationship with the underlying neural activity. Additionally, the majority of animal phMRI studies require anaesthesia, which may interact with the investigated drug. The neurophysiological underpinnings of BOLD signal changes were directly studied in few hallmark studies. It remains however unclear whether a similar relation between LFP and BOLD signal change exist for pharmacological fMRI under different anaesthetic protocol. In this study we compared ketamine-induced BOLD changes with electrophysiological recordings in rodent brain under two different anaesthetic protocols.

Naranjargal Dashdorj¹, Mirjam I Schubert¹, Rob Mason², and Dorothee P Auer^1
1Academic Radiology, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom, ²School of Biomedical Sciences, University of Nottingham, Nottingham, United Kingdom

In recent years synchronised low-frequency spontaneous fluctuations detected by fMRI BOLD signal has been widely applied to study functional connectivity networks in human subjects. Although, the nature of functional connectivity detected by spontaneous BOLD fMRI and its underlying neural correlates have not been well understood yet. Animal studies provide wider possibility of invasive and non-invasive methods. Hence, the applications of BOLD fMRI functional connectivity in animal studies are expected to facilitate in-depth understanding of low-frequency BOLD fluctuations. In particular, using psychoactive compound to study changes in functional connectivity would allow us to study changes in a given animal on same background neural activity. This study examined the spatiotemporal dynamics under isoflurane anaesthesia.

Xiao Liu¹, Xiao-Hong Zhu¹, Yi Zhang¹, and Wei Chen^1
1CMRR, Radiology, University of Minnesota, Minneapolis, MN, United States

In this study, we observed strong ~0.1 Hz hemodynamic (CBF and BOLD) oscillations in cats anesthetized with alpha-chloralose. The inter-hemispheric (i.e., left versus right V1, and left versus right LGN) phase coherence of hemodynamic oscillations is alternating between positive and negative values over time. Moreover, the relative proportions of positive and negative correlations changes with anesthesia level with more negative correlations under the deeper anesthesia. The results may suggest that the increased anesthesia level can impair the brain’s capability of synchronizing activity across different regions and result in less phase coherence even at the early thalamic brain regions.

Matthew Man Hin Cheung^1,2, Iris Y Zhou^1,2, Kevin C. Chan^1,2, Frank Y Lee^1,2, Leon C. Ho^1,2, Condon Lau^1,2, and Ed X. Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China, People's Republic of, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China, People's Republic of

In this study, auditory system was investigated in rodents by BOLD fMRI at 7T. Auditory pathway and various components were revealed by BOLD responses in agreement with the known auditory neuroanatomy by other methods. Tonotopic mapping in inferior colliculus was also demonstrated for the first time by fMRI. Such non-invasive study of functional hemodynamic responses in auditory system will provide a valuable tool in hearing research of normal and diseased models. This was by far the first BOLD fMRI study of rodent auditory system.

Jevin W Zhang^1,2, Condon Lau^1,2, Matthew M Cheung^1,2, Kyle Xing^1,2, Iris Y Zhou^1,2, Kevin C Chan^1,2, and Ed X Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, Hong Kong SAR, China, People's Republic of, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, Hong Kong SAR, China, People's Republic of

In rats, the superior colliculus (SC) is the main destination for retinal ganglion cells and is an important subcortical structure for vision. Its light intensity dependence has not been extensively studied with functional imaging. BOLD fMRI is used to measure the SC’s hemodynamic response, in Sprague-Dawley rats, to visual stimulation at five intensity levels (4.2x10^-3 to 0.74W/m²). Significant responses are observed at all intensity levels. Less of the SC responds to 4.2x10^-3W/m² stimulation than to higher intensity stimuli (p<0.05). The response amplitude during 4.2x10^-3W/m² stimulation is also significantly lower than during 7.6x10^-2 and 0.23W/m² stimulation (p<0.05).

Condon Lau^1,2, Jevin W Zhang^1,2, Matthew M Cheung^1,2, Kyle Xing^1,2, Iris Y Zhou^1,2, Kevin C Chan^1,2, and Ed X Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong, Hong Kong SAR, China, People's Republic of, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, Hong Kong SAR, China, People's Republic of

In rats, the superior colliculus (SC) is the main destination for retinal ganglion cells and is an important subcortical structure for vision. Many of its neurons are highly sensitive to moving objects. BOLD fMRI is used to measure the SC’s hemodynamic response, in Sprague-Dawley rats, to a visual stimulus moving at five speeds between 7 and 164°/s. Significant responses are observed at all speeds tested. The maximum response amplitude occurred at 41 and 82°/s and the minimum at 164°/s. The number of responsive voxels was lowest at 164°/s. These findings appear to be in agreement with electrical recording studies.

Daniil Aksenov^1,2, Limin Li^1,2, Michael Miller^1,2, and Alice Wyrwicz^1,2
1NorthShore University Health System, Evanston, IL, United States, ²Pritzker School of Medicine, University of Chicago, Chicago, IL, United States

In order to examine the local differences in BOLD signal, fMRI data were obtained from awake rabbits using either whisker or visual stimulation, and the BOLD responses in cortical and subcortical structures of the pathways were compared within and between each sensory system. Early results reveal striking differences in the shape of BOLD time courses in terms of adaptation (i.e., decrease to a plateau following an initial peak) between in the visual and whisker pathways. These results suggest that visual cerebral cortical versus subcortical and whisker cortical regions are characterized by different hemodynamic properties.

Yi Zhang^1,2, Hsiao-Ying Wey^1,2, Oscar San Emeterio Nateras², Qi Peng^1,2, and Timothy Q. Duong^1,2
1Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States, ²Radiology, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States

In rodent models, layer-specific resolution of anatomical, blood flow and functional MRI has been reported. As a first step toward translation, we investigated the feasibility of multimodal retinal MRI on anesthetized large non-human primate (baboon) using a standard clinical 3-Tesla scanner. Baboon was chosen because it has large eyes and better recapitulates human retinal diseases. Anesthesia and paralysis were used to exclude movement artifacts, such that we could focus on evaluating hardware feasibility and pulse sequence parameters for high-resolution multimodal MRI of the retina on a clinical scanner. These findings offer encouraging data to explore human applications.

Joe Shi Cheng^1,2, Kevin C. Chan^1,2, Iris Y Zhou^1,2, Matthew M Cheung^1,2, Condon Lau^1,2, and Ed X Wu^1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, People's Republic of, ²Department of Electrial and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China, People's Republic of

Environmental inputs play a significant role in visual system development. However, current studies on the effects of visual input deprivation (dark-rearing) mainly use histological, electrophysiological, and optical imaging techniques. The result of this study demonstrated for the first time an in vivo approach for simultaneously assessing the functional developmental changes in rat cortical and subcortical visual system, and found that the visual cortex’s BOLD response is reduced by dark-rearing (p<0.05) while that of the subcortical visual nuclei (superior colliculus and lateral geniculate nucleus ) are less affected.

Wolfgang Weber-Fahr¹, Alexander Sartorius², Natlia Gass¹, Zhijun Li³, and Wolfgang Kelsch^2,3
1Neuroimaging, Central Institute of Mental Health, Mannheim, Germany, ²Psychiatry, Central Institute of Mental Health, Mannheim, Germany, ³Clinical Neurobiology, Ruprecht-Karls-Universität, Heidelberg, Germany

It was shown recently in rats that BOLD activation in a particular region can be caused by optogenetic stimulation. In this study we were interested in the hippocampal network in mice and induced expression of channelrhodopsin-2 in Ca2+/calmodulin-dependent protein kinase II-expressing neurons by viral injection. Laser stimulation was periodically applied through an optical fiber in the left hippocampus with a block design while fMRI data was aquired. We found activation in a large area of the targeted hippocampus. Interestingly, we also we found a corresponding significant activation in areas outside the stimulated region in the primary somatosensory and motor cortices.

Hans F Wehrl¹, Florian C Maier¹, Petros Martirosian², Gerald Reischl³, Fritz Schick², and Bernd J Pichler^1
1Laboratory for Preclinical Imaging and Imaging Technology of the Werner Siemens-Foundation, University of Tuebingen, Tuebingen, Germany, ²Section on Experimental Radiology, University of Tuebingen, Tuebingen, Germany, ³Radiopharmacy and PET-Center, University of Tuebingen, Tuebingen, Germany

Brain activation was studied by small animal [¹⁵O]H₂O PET and BOLD fMRI measurements. Qualitatively PET and MR activation information correlates, however discrepancies are observed concerning the statistical significance, spatial extend as well as spatial location of the activation centers, which arise from methodological as well as physiological differences between the observed PET and MR signal. These studies open the scene for further research of brain metabolism using PET/MR imaging techniques, combining the sensitivity of PET with the the functional imaging capabilities of MR.

Hanbing Lu¹, Qihong Zou¹, William Rea¹, Elliot A Stein¹, and Yihong Yang^1
1National Institute on Drug Abuse, NIH, Baltimore, MD, United States

We have identified coherent, spontaneous activity within a specific brain network in rats that mirrors the default mode network (DMN) previously reported in human and non-human primates, suggesting that operations performed by the DMN may be a fundamental physiological process in the mammalian brain. Our data raise interesting questions about the functions of DMN across species, and open novel opportunity to investigate the physiological basis of DMN using rodent model.

Silke Kreitz¹, Cornelia Heindl-Erdmann¹, Roland Axmann², Jochen Zwerina², Josef Penninger³, Georg Schett², Kay Brune¹, and Andreas Hess^1
1Institute for Pharmacology and Toxicology, FAU Erlangen-Nuremberg, Erlangen, Germany, ²Internal Medicine 3, Rheumatology and Immunology, FAU Erlangen-Nuremberg, Erlangen, Germany, ³Institute of Molecular Biology, Austrian Academy of Sciences, Vienna, Austria

Resting state analysis of brain activity in (transgenic) mice was performed before and after peripheral heat stimulation. “Painless” mice (DREAM -/-), having permanent analgesia due to modification of the dynorphin pain pathway, showed no change in their resting state network connectivity after the painful stimulation compared to wild-type mice. Pharmacological compensation of their genetic modification, reestablished plastic effects of the painful stimulation on the resting state network. These results demonstrate the usefulness of non invasive fMRI in transgenic mice and molecular defined pharmacological intervention to further investigation of functional connectivity in pain research.

Iris Yuwen Zhou^1,2, Y X Liang³, Kevin C. Chan^1,2, Matthew M. Cheung^1,2, Condon Lau^1,2, K F So³, and Ed X Wu^1,2
1Laboratory of Biomedical and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, People's Republic of, ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China, People's Republic of, ³Department of Anatomy, The University of Hong Kong

Resting-state fcMRI has been increasingly used in the diagnosis of a variety of brain diseases. However, the underlying mechanism of the spontaneous fluctuations in fcMRI signals remains largely unexplored. In this study, we employed a well-controlled animal model of corpus callosotomy to evaluate the role of corpus callosum (CC) in the interhemispheric functional connectivity. It was found that a strikingly loss of interhemispheric correlation after the complete transection of CC while the intrahemispheric connections was preserved and seemed to be expanded. The results of this study provide direct evidence of the role of CC in spontaneous neural activity.

Christopher Paul Pawela^1,2, Bharat B Biswal³, Rupeng Li², Anthony G Hudetz⁴, and James S Hyde^2
1Department of Plastic Surgery, Medical College of Wisconsin, Milwaukee, WI, United States, ²Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States, ³Department of Radiology, University of Medicine and Dentistry of New Jersey, Newark, NJ, United States, ⁴Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States

Resting-State Functional Connectivity MRI (fcMRI) is finding application in studying a variety of brain disorders. The underlying physiological basis of the BOLD resting-state fluctuations is still unknown. In this study, manipulation of the peripheral nervous system is performed to modify signal input into the thalamocortical system and disrupt interhemispheric correlation of the sensorimotor system. This study demonstrates the bilateral nature of resting-state correlation and may provide insight into the phenomenon.