Differentiating Cerebellar Impact on Thalamic Nuclei

The cerebellum plays a role in coordination of movements and non-motor functions. Cerebellar nuclei (CN) axons connect to various parts of the thalamo-cortical network, but detailed information on the characteristics of cerebello-thalamic connections is lacking. Here, we assessed the cerebellar input to the ventrolateral (VL), ventromedial (VM), and centrolateral (CL) thalamus. Confocal and electron microscopy showed an increased density and size of CN axon terminals in VL compared to VM or CL. Electrophysiological recordings in vitro revealed that optogenetic CN stimulation resulted in enhanced charge transfer and action potential firing in VL neurons compared to VM or CL neurons, despite that the paired-pulse ratio was not significantly different. Together, these findings indicate that the impact of CN input onto neurons of different thalamic nuclei varies substantially, which highlights the possibility that cerebellar output differentially controls various parts of the thalamo-cortical network. [Display omitted] •Cerebello-thalamic axons form terminals of varying size in distinct thalamic nuclei•Cerebello-thalamic responses vary in amplitude in distinct thalamic nuclei•Repetitive stimuli depress cerebello-thalamic responses in all thalamic nuclei In this study, Gornati et al. demonstrate that the impact of cerebellar nuclei axons on thalamic neurons varies per thalamic region. These findings provide insights into how the versatile cerebellum can have a differential effect on the many brain regions that it connects to.