Detection of posterior cingulate cortex functional connectivity characteristics in resting-state functional magnetic resonance imaging in relapsing-remitting multiple sclerosis

Abstract

Objective To examine brain regions with a functional connection to posterior cingulate cortex (PCC) in a relapsing-remitting multiple sclerosis (RRMS) group compared with matched control subjects，and to employ resting-state functional MRI (rs-f MRI) to PCC connectivity gathered by investigating synchronic low frequency f MRI signal fluctuations of default mode network with seed-based correlation analysis (SCA). Methods Twenty-seven patients with RRMS (RRMS group) and 27 age-，and sex-matched healthy controls (HC group) were examined by resting-state f MRI，DTI and 3D-T1 on Siemens Trio Tim 3.0T.The f MRI data preprocessing and processing was performed using Data Processing Assistant for Resting-State f MRI Advanced Edition (DPARSFA) based on Matlab 2012a，and PCC (-5，-49，40) was selected as seed.An SCA approach was used to analyze the rs-f MRI data.We examined the differences in SCA-derived connectivity metrics in patients with RRMS and healthy controls，and analyzed correlations between connectivity correlation coefficient of the differences regions and MRI-derived metrics (brain parenchymal fraction，T 2lesion load)，as well as clinical metrics (expanded disability status scale，paced auditory serial addition test，and disease duration) of the disease. Results The SCA via functional connectivity of PCC showed that the temporal correlation between the blood-oxygen-level-dependent signals of the default mode network was reliable spatial patterns of activation in patients with RRMS.The lower connectivity in right superior frontal gyrus within default mode network，and higher connectivity in right posterior lobe of cerebellum，right crus of cerebellum，right medial frontal gyrus，right medial occipital gyrus，left precuneus/cingulate gyrus，right angular gyrus and right cingulate gyrus were found in our study.Significant negative-related was observed between the paced auditory serial addition test and functional connectivity in right middle temporal gyrus (0.387±0.216) of RRMS patients (r=-0.59，P=0.001).Significant negative correlation also was observed between the course of disease and functional connectivity in right superior frontal gyrus (0.039±0.293) in patients (r=-0.39，P=0.041).There was no significant correlations between other regions with different functional connectivity and expanded disability status scale，disease duration，or brain atrophy.The connectivity in right superior frontal gyrus，left medial occipital gyrus，left precentral gyrus was decreased; and connectivity in right cerebellum anterior lobe (dentate)，right frontal lobe white matter was significantly increased.Significant positive correlation was observed between the course of disease and functional connectivity in left precentral gyrus (-0.924±0.253)，right cerebellum anterior lobe (dentate;0.217±0.208) of RRMS patients (r=0.650，P=0.000;r=0.436，P=0.023)，respectively. Conclusion These findings reveal the compensatory mechanism of the brain in response to structural damage，by means of increased activation or synchronization of default mode network，which seems to be finite. Key words: Multiple sclerosis，relapsing-remitting; Magnetic resonance imaging; Nerve net; Gyrus cinguli