Cerebellar Contributions to Hypokinetic Symptoms in an Acute Lesion Parkinsonism Model

Background: Parkinsonism, characterized by motor symptoms, is typically attributed to basal ganglia dysfunction. Recent evidence suggests that the cerebellum may also influence these symptoms. This study investigated Crus II, the dentate nucleus (DN), and the inferior olive (IO) in a rat model of parkinsonism induced by a bilateral ventrolateral striatal (VLS) lesion. Materials and Methods: Twenty-four male Wistar rats were divided into control (n = 12) and experimental (n = 12) groups. Monopolar electrodes were implanted in target structures. The experimental group received a bilateral VLS lesion. Animals underwent four weekly sessions of electrophysiological recordings and blind behavioral assessments (resting, grooming, locomotion, rearing, sniffing) via video tracking. Power spectral density (PSD) in the 300-500 Hz band was computed. Statistical analyses included Mann-Whitney U, Friedman with Wilcoxon post hoc, and Spearman correlation tests. Results: During weeks one and two, there were significant PSD increases in the experimental group compared to the control, particularly in Crus II-grooming (p = 0.005), locomotion (p = 0.007), and rearing (p = 0.026); in IO-sniffing (p = 0.0167); and in DN-grooming (p < 0.001) and locomotion (p = 0.0008). Additionally, intragroup analysis revealed significant PSD elevations relative to baseline in these structures. Significant correlations were observed only for grooming (negative correlations) and sniffing (positive correlations) across all cerebellar regions. Conclusions: These findings suggest compensatory cerebellar hyperactivity induced by VLS lesion, potentially modulating hypokinetic symptoms and highlighting dynamic network interactions. Interpretation warrants caution due to limitations inherent to the acute lesion model and experimental duration.