Cerebellar Functional Connectivity Reorganization in a Split-Brain Patient

The Functional Connectivity (FC) assesses the functional relationships between different brain regions. Interhemispheric FC is assumed to be specifically supported by the corpus callosum (CC). This study aims to investigate FC between cerebellum and resting state networks (RSNs), as well as intra-cerebellar FC, in a patient who underwent surgical resection of CC and in a healthy control. The investigation contributes to verify the hypothesis of a compensatory cerebellar role in maintaining a certain degree of interhemispheric FC after callosal resection. Anatomical and functional magnetic resonance images were analyzed using CONN. After standard preprocessing, the brain was parcellated into 30 cortical RSN regions of interest (ROIs) based on the Human Connectome Project (HCP) networks, and the cerebellum was parcellated into 18 ROIs according to the Automated Anatomical Labeling (AAL) atlas. FC was evaluated by computing the Fisher z-transformed bivariate correlation coefficients, and statistical differences were assessed by Wilcoxon signed rank test. Distinct patterns of FC were observed between patient and healthy control, both within the cerebellum and between cerebellar and cortical RSN ROIs. The patient's cerebellar FC with RSN ROIs was statistically different from that of the control (in most instances higher) in 11 cerebellar ROIs, 7 of which in the right of the cerebellum and 4 in the left. The patient intra-cerebellar FC was also statistically different from that of the control (in most instances higher). These results suggest that the cerebellum may have a role in the maintenance of interhemispheric FC after surgical resection of the CC.