Cerebellar Vermis Lesions Increase Impulsive-Like Behaviors in Mice

The cerebellum contributes to motor and non-motor functions, and its interactions with basal ganglia and cortical circuits may influence impulsive and compulsive behaviors. Building on previous studies from our group, we investigated whether specific regions of the cerebellar cortex contribute to impulsive- and compulsive-like behaviors. Excitotoxic lesions were induced with kainic acid at different levels of the cerebellar vermis in male and female mice. Impulsivity was assessed using the plus-maze, cliff, emergence, and Y-maze tests, while compulsive-like behaviors were evaluated using marble-burying, nesting, and hole-board tests. Motor function was assessed by grip strength, balance, gait, and rotarod tests. Vermis lesions increased impulsive-like responses in both sexes in the plus-maze, cliff, and emergence tests, without inducing compulsive-like behaviors. Motor effects were limited to balance deficits. These findings indicate that the cerebellar vermis contributes to the modulation of impulsive-like, but not compulsive-like, behaviors. Although no compulsive phenotype was detected, further studies targeting the cerebellar hemispheres may reveal distinct impulsive and compulsive phenotypes, potentially resembling the behavioral alterations associated with cerebellar dysfunction in humans. This approach may help identify specific cerebellar regions involved in the regulation of complex behaviors.