| fMRI Connectivity |
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Thursday 23 April 2009 |
| Room 323ABC |
16:00-18:00 |
Moderators: |
Scott J. Peltier and Silvina G. Horovitz |
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16:00 |
689. |
Genetic Influences on
Economical Properties of Human Functional Cortical
Networks |
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Alex Fornito1,2,
Andrew Zalesky2, Danielle Bassett1,
David Meunier1, Murat Yücel2,
Stephen J. Wood2, Deborah Nertney3,
Bryan Mowry3, Christos Pantelis2,
Ed Bullmore1
1Brain Mapping Unit, Department of Psychiatry,
University of Cambridge, Cambridge, Cambridgeshire,
UK; 2Melbourne Neuropsychiatry Centre,
Department of Psychiatry, University of Melbourne,
Parkville, Victoria, Australia; 3Queensland
Centre for Mental Health Research, University of
Queensland, Brisbane, Queensland, Australia |
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The connectivity network
of the human brain evolved to balance the competing
priorities of maximizing efficiency of information
transfer while minimizing wiring cost. In this
study, we quantified the degree to which individual
differences in the cost-efficiency of cortical
functional networks are attributable to genetic
factors using graph analytic techniques applied to
resting fMRI data acquired in twins. Genetic factors
accounted for approximately 91% of the variance in
global network cost-efficiency, with some cortical
regions under more genetic influence than others.
These findings indicate that economical properties
of cortical networks are highly heritable. |
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16:12 |
690. |
Resting-State Functional
Connectivity, Probabilistic Diffusion Tensor
Tractography, and Histological Delineation in the
Human Thalamus |
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Dongyang Zhang1,
Joshua S. Shimony1, Abraham Z. Snyder1,
Michael D. Fox1, Mark W. Sansbury1,
Marcus E. Raichle1
1Radiology, Washington University School of
Medicine, Saint Louis, MO, USA |
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Resting-state functional
connectivity MRI (fcMRI) and diffusion weighted
imaging and tractography (DTI/DTT) were performed as
measures of functional and structural connectivity
of the human thalamocortical system. Five ROIs were
drawn in cortex corresponding to prefrontal,
parietal/occipital, motor/premotor, somatosensory,
and temporal cortices. Connectivity was measured
between cortical ROIs and voxels in the thalamus
using spontaneous neuronal activity correlations
from fcMRI and probabilistic tractography from DTI.
Results from these two dissimilar approaches showed
remarkably similar thalamic localization. fcMRI and
DTT results were compared to gold standard
histological atlas reconstructed in 3D volume and
registered to the same space as our MR results. |
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16:24 |
691. |
Deafferentation Induced
Cross-Hemispheric Brain Plasticity Detected by
Resting-State Functional Connectivity Magnetic
Resonance Imaging |
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Christopher Paul
Pawela1,2, Bharat B. Biswal3,
Rupeng Li2, Anthony G. Hudetz4,
James S. Hyde2
1Department of Plastic Surgery, Medical
College of Wisconsin, Milwaukee, WI, USA; 2Department
of Biophysics, Medical College of Wisconsin,
Milwaukee, WI, USA; 3Department of
Radiology, University of Medicine and Dentistry of
New Jersey, Newark, NJ, USA; 4Department
of Anesthesiology, Medical College of Wisconsin,
Milwaukee, WI, USA |
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Functional connectivity
magnetic resonance imaging (fcMRI) studies in rat
brain show neuroplasticity following peripheral
nerve injury. Sub-acute brain plasticity was
observed two weeks following transection of the four
major nerves of the brachial plexus. Direct
functional magnetic resonance imaging (fMRI)
stimulation of the intact radial nerve reveals an
activation pattern in the forelimb regions of the
sensory and motor cortices that is significantly
different from that observed in normal rats. The
combination of fMRI and fcMRI provides a general
marker for brain plasticity and may provide insight
into phantom limb epiphenomena. |
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16:36 |
692. |
Functional MRI of
Somatosensory Cortical Reorganization in the Rat
Brain |
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Xin Yu1,
Shumin Wang1, Stephen Dodd1,
Der-yow Chen1, Alan Koretsky1
1National Institutue of Neurological Disorders
and Stroke, National Institutes of Health, Bethesda,
MD, USA |
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A 3D somatotopic map in
the rat primary somatosensory cortex (S1) was
characterized with BOLD-fMRI, including forepaw,
hindpaw, whisker pad, and nose S1 regions. These
maps enabled analysis of the topographic cortical
reorganization following sensory deprivation of the
whisker barrel cortex. It is well known that
functional MRI maps vary largely depending on the
t-threshold used. Here we show that the location of
center of mass in S1 subdivisions is highly
consistent regardless of t statistics. Utilizing
mass-center as anchor points to model BOLD response
enabled a quantitative analysis of cortical
reorganization in the rat brain with BOLD-fMRI. |
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16:48 |
693. |
Intrinsically Organized Low
Frequency Network for Face Perception |
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Zhang hui1,
Tian Jie*1
1Institute of automation Chinese Academy of
Sciences , Beijing, China |
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For the first time, we
investigated the low-frequency fluctuations of
distributed face perception network in resting
states and the modulation of this network from
resting to face viewing task. By using 0.01-0.08HZ
low-frequency spontaneous fluctuations of BOLD-fMRI
signals, Our result suggested an intrinsically
organized low-frequency face perception network
involving right lateral posterior fusiform gyrus
(lateral pFg), inferior occipital gyrus (IOG),
bilateral superior temporal sulcus (STS) and an
altered extended network for face perception from
resting states to face viewing task. |
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17:00 |
694. |
Spectral Clustering of
Low-Frequency Fluctuations in FMRI Data Reveal a
Distinct Separation Between the Superior Temporal
Sulcus and the Superior Temporal Gyrus |
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Gabriele Lohmann1,
Jonas Obleser1, Angela Friederici1,
Robert Turner1
1Max Planck Institute for Human Cognitive and
Brain Sciences, Leipzig, Germany |
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Low Frequency
Fluctuations (LFFs) are known to represent a large
portion of the variance of the BOLD signal.
Furthermore, such fluctuations generally have
significant spatial coherence. Task-dependent
condition-locked fMRI data has confirmed an
important role of the superior temporal cortex in
many language and hearing related processes. Within
this area, many studies have claimed to identify
activation distinct to superior temporal gyrus (STG)
and superior temporal sulcus (STS). Using a
data-driven clustering technique applied to LFFs, we
found a clear separation between STS and STG that
showed a high inter-subject consistency. |
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17:12 |
695. |
Integration and Comparison of
Brain Functional and Structural Connectivity Maps |
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David C. Zhu1,
Shantanu Majumdar2
1Psychology and Radiology, Michigan State
University, East Lansing, MI, USA; 2Electrical
and Computer Engineering, Michigan State University,
East Lansing, MI, USA |
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Resting-state fMRI
allows the testing of brain functional connectivity.
Diffusion tensor imaging fiber tracking allows the
evaluation of structural connection between cortical
regions. Often there is a need to integrate them
together to understand the networks of brain
activity, to compare their advantages and
disadvantages, and to evaluate potential
applications. In this work, we combined the
functional and structural connectivity maps based on
common seed regions. The integration demonstrates
potential interpretation issues and also shows that
functional connectivity might be a more sensitive
and robust technique in understanding the
connectivity between cortical regions. |
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17:24 |
696. |
An FMRI Study of Induced
Plasticity in S1 in the Human Brain |
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rishma vidyasagar1,
Laura Parkes2
1MARIARC, University of Liverpool, Liverpool,
Merseyside, UK; 2School of Cancer and
Imaging Sciences, manchester, UK |
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This study measured
induced connectivity in the human brain on S1
between Digit 2 and Digit 4 of the right hand using
fMRI. Cortical reorganisation was induced by
training subjects on vibrotactile tactors for 3
hours. Subjects were scanned before and after
training and cortical representations of the digits
were successfully imaged. Significant shifts and
overlap of these areas were observed following the
training period. This is in accordance with previous
animal and human studies. It is postulated that what
is observed are changes linked to synchronised
synaptic input and can be related to Hebbian
mechanisms. |
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17:36 |
697. |
Analysis of Changes in
Functional Connectivity Patterns with Serial Resting
State FMRI After Transient Ischemic Stroke in Rat
Brain |
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Kajo van der Marel1,
Maurits P. A. van Meer1,2, Kun Wang3,
Willem Maarten Otte1, Jan Willem
Berkelbach van der Sprenkel2, Rick M.
Dijkhuizen1
1Image Sciences Institute, University Medical
Center Utrecht, Utrecht, Netherlands; 2Rudolf
Magnus Institute of Neuroscience, University Medical
Center Utrecht, Utrecht, Netherlands; 3Institute
of Automation, Chinese Academy of Sciences, Beijing,
China |
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Resting state fMRI
analysis provides a method to measure changes in
functional connectivity within various neural
networks without the need of stimulating a specific
functional system. These functional networks may be
altered during recovery from stroke. In this study
we found differences in functional connectivity
pattern dependent on time and lesion size after
transient stroke in rats. Loss and recovery of
functional connectivity within bilateral
sensorimotor network areas were indicative of
functional brain reorganization after stroke. |
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17:48 |
698. |
Connectivity Alterations in
Motor-Related Areas Suggest Neuroplasticity in
Chronic Stroke |
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Dionyssios
Mintzopoulos1,2, Loukas G. Astrakas1,3,
Azadeh Khanicheh4, Angelos A. Konstas5,
Michael A. Moskowitz2,6, Bruce R. Rosen5,
A. Aria Tzika1,2
1NMR Surgical Laboratory, MGH & Shriners
Hospitals, Harvard Medical School, Boston, MA, USA;
2Radiology, Athinoula A. Martinos Center
for Biomedical Imaging, Boston, MA, USA; 3Medical
Physics, University of Ioannina, Ioannina, Greece,
USA; 4Mechanical and Industrial
Engineering, Northeastern University, Boston, MA,
USA; 5Radiology, MGH, Harvard Medical
School, Boston, MA, USA; 6Neuroscience
Center, Neurology and Neurosurgery, Massachusetts
General Hospital, Harvard Medical School, Boston,
MA, USA |
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Using a hand motor task,
we investigated functional reorganization of motor
systems by probing connectivity between motor
related areas in chronic stroke patients undergoing
training with functional magnetic resonance imaging
(fMRI) at 3T combined with a novel MR-compatible
hand-induced robotic device (MR_CHIROD). The results
demonstrate that rehabilitation training enhances
the connectivity between motor areas in chronic
stroke patients that may help counterbalance a
functionally abnormal M1 motor area in stroke
patients thus suggesting neuroplasticity in chronic
stroke. |
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