Responses of cerebellar fastigial nucleus neurons to whole‐body rotations in vertical planes.

Abstract

The rostral portion of the fastigial nucleus (rFN) of the cerebellum has been demonstrated to participate in cardiovascular and respiratory regulation. This deep cerebellar nucleus is also known to receive and process vestibular inputs. Although a number of studies conducted in nonhuman primates have reported the responses of rFN units to body movements, little is known about the vestibular inputs to rFN neurons in conscious cats, a common animal model used in studies of vestibulo‐autonomic regulation. In the present study, activity was recorded from rFN neurons in conscious felines during rotations in vertical planes at frequencies of 0.02–2 Hz and amplitudes up to 15°. None of the units had firing related to eye movements. The response vector orientations for most neurons were closer to the pitch (head‐up or head‐down) plane than the roll (ear‐down) plane. The responses of over 60% of the neurons had gains that were relatively constant (increasing <3‐fold per decade) and phases that were near stimulus position across rotation frequencies. Since vestibulo‐autonomic reflexes are mainly elicited by graviceptive inputs produced by pitch rotations, the response properties of rFN neurons suggest that they could mediate these responses. Supported by NIH grants R01‐DC00693 and R01‐DC03732.