Resting-state functional connectivity in post-stroke expressive aphasia：a preliminary study

Objective To analyze the resting-state functional connectivity of the left posterior inferior frontal gyrus in normal subjects with functional MRI and to investigate its preliminary application in post-stroke aphasia.Methods Eleven male patients with post-stroke aphasia and 11 male normal subjects were recruited in this study.Resting-state fMRI data were obtained with GE 1.5 T Twin speed MR Scanner.The fMRI data were processed with SPM2, AFNI and Matlab programs.Based on the results of previous fMRI study with category member generation task , the region of interest ( ROI ) was created in the left posterior inferior frontal gyrus The time course correlations between the ROI and other voxels within whole brain were analyzed.Intra-and inter-group analysis was performed with single sample t-test and two sample t-test.Results Brain regions showed positive resting-state functional connectivity with the ROI in normal subjects including left inferior/middle frontal gyrus , left premotor cortex , left precuneus , left insula , left putamen, right inferior frontal gyrus, right cerebellum and bilateral inferior parietal lobules (voxels 33-809, t=5.80-23.55,P<0.005,uncorrected).Brain regions functionally connected with the ROI in patients with post-stroke aphasia included left inferior/middle frontal gyrus , left premotor cortex , left precuneus , left inferior parietal lobules and right inferior frontal gyrus ( voxels 34-833, t =5.08-20.34, P<0.005, uncorrected ).The left fusiform gyrus was the only region showed significantly decreased functional connectivity with the ROI in the patients group (voxels 84,t=6.25,P<0.005, uncorrected).Conclusions The neural network related to language output exists in normal subjects at the resting-state.Resting-state functional connectivity can be used to investigate the neural mechanism of development and restoration of post-stroke aphasia. Key words: Stroke ;  Aphasia ;  Magnetic resonance imaging ;