Purkinje cell intrinsic activity shapes cerebellar development and function

The emergence of functional cerebellar circuits is heavily influenced by activity-dependent processes. However, the contribution of intrinsic Purkinje cell activity to cerebellar development remains less understood. Here, we demonstrate that before synaptic networks mature, Purkinje cell intrinsic activity is essential for regulating dendritic growth, establishing connections with cerebellar nuclei, and ensuring proper cerebellar function. Disrupting this activity during the postnatal period impairs motor function, with earlier perturbations causing more severe deficits. Importantly, only early developmental disruptions lead to pronounced defects in cellular morphology, highlighting key temporal windows for dendritic growth and maturation. Transcriptomic analyses reveal that early intrinsic activity drives the expression of activity-dependent genes, including Prkcg and Car8, which are essential for dendritic development. Our findings emphasize the importance of temporally regulated intrinsic activity in Purkinje cells in guiding cerebellar circuit development, providing a potential unifying mechanism underlying cerebellum-associated disorders. Overall design: Purkinje cells were collected from either P7 Pcp2+/+;Kir2.1 (control littermates) or P7 Pcp2cre/+;Kir2.1 experimental mice (both in C57Bl6/J background). Sagittal slices of vermal cerebellar tissue were transferred into a recording chamber and maintained at 34?C under continuous perfusion with equilibrated aCSF. For P7 Pcp2cre/+;Kir2.1 mice, Purkinje cells were selected based on their expression of Kir2.1-mCherry. Neurons were extracted into a glass pipette using negative pressure and 50 cells were sampled across the cerebellar cortex. For each genotype, eight biological samples were used for RNA sequencing. Cells were collected in a mild hypotonic lysis buffer composed of 0.2% Triton-X and 2U/µl of RNAse inhibitor. Isolated cells were kept on ice during the collection process or immediately stored at -80°C for RNA extraction. Bulk RNAseq was performed for the eight biological samples.