| [Objective] Using Resting-state functional magnetic resonance imaging(fMRI) and Voxel-based Morphometry(VBM),we explored differences of regional brain spontaneous activity in resting state in depressed vs healthy participants.The purpose was to investigate the baseline character of neural activity in first-episode major depressive disorder(MDD) associated with the brain functional and structural pathological mechanism of physioligical changes or affect disorder.[Methods] Thirty participants diagnosed with first-episode antipsychotic-naive MDD and30healthy controls who were matched in age,gender and education level were recruited.Resting-state functional MRI and three-dimensional brain structure scans were performed on all participants.Regional homogeneity (ReHo) and amplitude of low frequency fluctuation(ALFF) approachs were applied to preprocess the fMRI datasets,and a voxel-based method(VBM) was used to analyse the three-dimensional brain structure datasets.ReHo can evaluate the same time of area between tissue in a sequence of consistency.ALFF can evaluate the whole activity of the synchronicity in local brain regions.VBM can evaluate the whole brain charateristics of morphology change. We analysed the results statistically by SPM8software.For the BOLD data we adopted the method by which was based on voxel single sample t-test within the group,comparison between groups by voxel based double samples t-test,P <0.05,the difference was statistically significant.For VBM data between groups we adopted the method by which was based on voxel two sample t-test,P<0.05,the difference was statistically significant. [Results]1. ReHo analysis:â‘ Two groups of subjects were resting state average common activated brain regions for:left middle temporal gyrus,right superior/middle/inferior frontal gyrus,left middle/inferior frontal gyrus,right medial frontal gyrus, the average activation strength of these regional in MDD group was weaker than healthy control group except for left middle frontal gyrus and left inferior frontal gyrus.â‘¡Different area of the brain in two groups of resting state was:ReHo in the MDD group increased in the left putamen,bilateral cingulate gyrus,left middle occipital gyrus,left precentral gyrus and right precuneus,difference was statistically significant(P<0.05);decreased in the right pons,right inferior frontal gyrus,right transverse/middle temporal gyrus,left orbital gyrus,left gyrus rectus and left superior middle/inferior temporal gyrus,difference was statistically significant(P<0.05).2. ALFF analysis:â‘ Two groups of subjects were resting state average common activated brain regions for:left middle occipital gyrus,left middle frontal gyrus, right superior/middle frontal gyrus,in which the activation strength of left middle frontal gyrus in MDD group(6.75) was weaker than healthy control group(6.93), difference was statistically significant(P<0.05).(2)Different area of the brain in two groups of resting state was:ALFF in the MDD group increased in the left putamen,left clautrum,bilateral cingulate gyrus,left precentral and postcentral gyrus,difference was statistically significant(P<0.05);decreased in the left frontal gyrus rectus and bilateral cerebellum posterior lobe,difference was statistically significant (P<0.05).3. The common actived brain regions of ReHo and ALFF in healthy controls group with resting state were:right precuneus,left superior/middle frontal gyrus,right superior/middle/inferior frontal gyrus,left middle temporal gyrus,bilateral supramarginal gyrus,and the region of the maximum activation strength was right precuneus;The common actived brain regions of ReHo and ALFF in MDD group with resting state were left precuneus,right middle frontal,right postcentral gyrus, left middle/inferior frontal gyrus,bilateral postcentral gyrus,and the region of the maximum activation strength was left precuneus.Their brains of ReHo and ALFF were different in right pons,left superior/inferior temporal gyrus,right transverse/middle temporal gyrus,left clautrum,left cingulate gyrus and bilateral cerebellum posterior lobe.4. VBM analysis:compared to healthy control group,grey matter volume of left superior/middle frontal gyrus,right superior temporal gyrus,left amygdaloid body, left cingulate gyrus,left lentiform nucleus,right head of caudate nucleus and left insular lobe were decreased in the first-episode MDD group,difference was statistically significant(P<0.05).[Conclusion]1. The area of resting-state ReHo with first-episode MDD is increased in the left putamen,bilateral cingulate gyrus,left middle occipital gyrus,right precentral gyrus and left precuneus to normal people;decreased in the right pons,right inferior frontal gyrus,right transverse/middle temporal gyrus,left orbital gyrus.left gyrus rectus and left superior/middle/inferior temporal gyrus to normal people.2. The area of resting-state ALFF with first-episode MDD is increased in the left putamen,left clautrum.bilateral cingulate gyrus,left precentral and postcentral gyrus to normal people;decreased in the left frontal gyrus rectus and bilateral cerebellum posterior lobe to normal people.3. Normal people and first-episode MDD patients have extensive actived areas of multiple brain areas in the resting-state,in which the right precuneus is closely related with normal people in the resting-state.4. First-episode MDD patients in the resting-state have a lot of abnormal brain regions of regional homogeneity and the whole activity of the synchronicity,they may have a wide range of abnormal brain function.Dysfunction in bilateral prefrontal lobe,cingulate,parietal and visual cortex may contribute to the neuropathology of cognitive impairments in MDD.Dysfunction in bilateral prefrontal lobe,limbic system,occipital lobe and bilateral cerebellum posterior lobe may contribute to neuropathology of mood processing bias in MDD.Dysfunction in bilateral temporal lobe and bilateral cingulate may contribute to neuropathology of memory declining in MDD.5. Decreased grey matter volume in left superior/middle frontal gyrus,right superior temporal gyrus,left amygdaloid body,left cingulate gyrus,left lentiform nucleus, right head of caudate nucleus and left insular lobe may be the neuropathological substrate of first-episode MDD rather than a result.6. Brain funcion and morphology change can be reflected effectively through ReHo, ALFF,VBM,and can be widely used in neural cognitive research. |
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