Disrupting cortico-cerebellar communication impairs dexterity

To control reaching, the nervous system must generate large changes in muscle activation to drive limb toward target, and also make smaller adjustments for precise accurate behavior. Motor cortex controls arm through projections diverse targets across central system, but it has been challenging identify roles of cortical specific targets. Here, we selectively disrupt cortico-cerebellar communication mouse by optogenetically stimulating pontine nuclei a cued reaching task. This perturbation did not typically block movement initiation, degraded precision, accuracy, duration, or success rate movement. Correspondingly, cerebellar activity during were largely preserved, differences hand velocity between stimulation conditions predicted from neural correlated with observed differences. These results suggest that while total output motor drives loop makes small contribute successful execution this dexterous