Emerging evidence positions that cerebellar lesions cause impulsivity and compulsivity. However, whether these lesions alone trigger these behaviors or their connections with other brain areas are responsible remains unclear. Our study dives into these compelling questions to uncover the cerebellum and it's cerebello-cerebral connectivity related impulsive and compulsive symptoms.

The cerebellum functions as a critical hub within brain networks governing motor, cognitive-affective, and reward processes. The evolutionarily expanded posterior cerebellum supports cognitive operations. Recent evidence reveals that impulsivity and compulsivity are clinical features in cerebellar ataxia patients. These findings establish the cerebellum's previously underrecognized role in regulating impulsive and compulsive behaviors.

We showed that lesions associated with higher CIA scores were predominantly localized to the right cerebellar hemisphere, with significant involvement of lobule VI, Crus I-II. LNM results demonstrated that patients with elevated CIA scores displayed enhanced connectivity between the right cerebellar hemisphere and left frontal cortical regions, including the inferior/medial frontal gyrus, caudate nucleus, and angular gyrus. Conversely, these patients exhibited reduced connectivity between the right and left cerebellar hemispheres, specifically involving lobules III–V, Crus I–II, and lobules VII–IX.

The observed cerebello-cerebral connectivity patterns delineate critical neural circuits implicated in the manifestation of impulsive and compulsive behaviors following focal cerebellar injury. Our findings suggest that targeting fronto-cerebellar connectivity through neuromodulation strategies could represent a therapeutic approach for mitigating impulsivity and compulsivity.