Regional homogeneity difference between first-episode and recurrent depressed patients: a resting-state fMRI study

Objective To explore the features of the brain function in first-episode and recurrent major depressed patients and their differences. Methods 14 first-episode depressed patients, 14 recurrent depressed patients and 15 healthy subjects experienced the MRI scans. Results Compared with healthy group, the first-episode depressed group showed significantly decreased regional homogeneity ( ReHo) in the right inferior frontal gy-rus,left superior,middle,inferior temporal gyrus, left ventral anterior cingulate gyrus,right posterior cingulate gyms, left hippocampus, left parahippocampal gyrus,left caudate,left lentiform and left claustrum,and increased ReHo in the right fusiform gyrus;the recurrent depressed group showed significantly decreased ReHo in the bilateral superior frontal gyrus, bilateral middle frontal gyrus, left inferior frontal gyrus, left superior, middle, inferior temporal gyrus, bilateral posterior cingulate gyrus, left hippocampus and left parahippocampal gyrus, and increased ReHo in the left supramarginal gyrus. Compared with first-episode depressed group, the recurrent depressed group showed significantly decreased ReHo in the right middle frontal gyrus, right precuneus, right posterior cingulate gyrus and right parahippocampal gyrus, and increased ReHo in the left middle, inferior temporal gyrus and right orbitofrintal cortex. Conclusions This study suggests abnormal brain activity may be distributed extensively in both first-episode and recurrent depressed patients. Their abnormality have some common features, also have each independent features. There are significant differences in brain function between first-episode and recurrent depressed patients. Key words: Depressive Disorder; First-episode and recurrent; Magnetic Resonance Imaging; Resting state; Regional homogeneity