Altered intra- and interregional synchronization in the absence of the corpus callosum: a resting-state fMRI study

Agenesis of the corpus callosum (AgCC) can result in subtle to severe cognitive deficits. Individuals with impaired cognition often show abnormalities on resting-state functional magnetic resonance imaging (rs-fMRI). This study used rs-fMRI to investigate changes in regional homogeneity (ReHo) and functional connectivity (FC) among individuals with AgCC. AgCC individuals (n = 10) and age-, sex-, and education-matched healthy control subjects (n = 19) were included in this study. The ReHo values were calculated to represent spontaneous brain activity. The regions which showed altered ReHo were selected as seeds to compare FC with the whole brain between the AgCC group and the healthy control group. Compared with healthy control subjects, the AgCC individuals had increased ReHo in the left anterior cingulate gyrus, left rolandic operculum, and right precuneus and decreased ReHo in the right calcarine, right cingual gyrus and right cuneus gyrus. The right calcarine and the right lingual gyrus in the AgCC exhibited decreased FC with bilateral cuneus, superior occipital gyrus, Rolandic operculum, superior temporal gyrus, posterior central gyrus, and midcingulate gyrus.The right cuneus gyrus in the AgCC individuals exhibited decreased FC with the bilateral calcarine gyrus, left cuneus, and left superior occipital gyrus. Our study revealed several subareas within the visual cortex exhibited remarkable abnormalities of spontaneous brain activity and decreased FC with the higher-order cognitive cortex.The abnormalities of ReHo and FC in AgCC individuals may provide new insights into the neurological pathophysiology.