Mechanisms underlying vestibulo-cerebellar motor learning in mice depend on movement direction

Compensatory eye movements elicited by head rotation, also known as vestibulo-ocular reflex (VOR), can be adapted with the use of visual feedback. The cerebellum is essential for this type of movement adaptation, but its neuronal correlates remain to be elucidated. Here we show that the direction of vestibular input determines the magnitude of eye movement adaptation induced by mismatched visual input in mice, with larger changes during contraversive head rotation. Moreover, the location of the neural correlate of this changed behaviour depends on the type of paradigm. Gain-increase paradigms induce increased simple spike (SS) activity in ipsilateral cerebellar Purkinje cells (PC), which is in line with eye movements triggered by optogenetic PC activation. In contrast, gain-decrease paradigms do not induce changes in SS activity, highlighting that the murine vestibulo-cerebellar cortical circuitry is optimally designed to enhance ipsiversive eye movements. This article is protected by copyright. All rights reserved.