Connective Fiber Tracts in Default Mode Network Mapped by Diffusion Spectrum Imaging
Date Issued
2009
Date
2009
Author(s)
Huang, Su-Chun
Abstract
Resting-state functional magnetic resonance imaging (fMRI) demonstrated that the low frequency fluctuation of blood oxygen level-dependent (BOLD) showed temporal correlation of widely separated brain regions during rest. The temporal correlations are considered to reflect the inherence functional connectivity of brain network which corresponding to thought, intended speech and emotions. These networks were called resting-state networks (RSNs). One RSN showed highest functional connectivity during rest, the network including brain regions such as posterior cingulum /precuneus cortex (PCC), medial prefrontal lobe (MF), left and right inferior parietal lobes (IPL and IPR) are considered as brain default network work (DMN). n order to find the structural core of MDN, we employ a diffusion acquisition scheme at high angular resolution which capable to reconstruct complex intra-voxel fiber structure. In the present study, we combined diffusion spectrum image (DSI) and resting-state fMRI to reconstruct the whole structural network within DMN. Four right-handed adults were recruited in the study. All images were acquired on a 3T MRI system (Trio, Siemens, Erlangen, Germany). The acquisition protocol including (1) resting-state fMRI with a gradient echo EPI. Patients were asked to stare a cross in the middle of the screen. (2) DSI with a spin-echo diffusion EPI. (3) trans-axial T2-weighted image with spin echo sequence.e found that within DMN, existing known structural white matter connections between almost all DMN nodes. The MFC and PCC were connected by cingulum bundle and one branch of superior longitudinal fasciculus. The PCC and bilateral inferior parietal lobe were connected by cortico-cortical arcuate fibers. The MFC and bilateral inferior parietal lobe were connected by fronto-occipital fasciculus. Bilateral inferior parietal lobes and bilateral PCC regions were connected by splenium of corpus callosum. The bilateral MFC were connected by genu of corpus callosum. n the present we established a standard operation protocol (SOP) to analyze resting-state fMRI and DSI images. Future work is aim to apply the SOP to images of schizophrenia patients, to observe pathological changes on images. We are looking forward to find an image biomarker to diagnose schizophrenia.
Subjects
resting-state fMRI
diffusion spectrum image
DSI,brain imaging technique
magnetic resonance image
Type
thesis
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