Pontine neurons which relay projections from the superior colliculus to the posterior vermis of the cerebellum in the cat: distribution and visual properties

Abstract

Extracellular unit recording revealed that the dorsolateral pontine nucleus (DLPN) and nucleus reticularis tegmenti pontis (NRTP) of the cat constituted pontine relays for transmission of visual information from the superior colliculus (SC) to the posterior vermis (lobules VI and VII) of the cerebellum. The relay neurons in DLPN/NRTP responded to moving visual stimuli with large receptive fields (23–75°) which occupied mainly the contralateral hemifield including the fovea. These neurons were usually more responsive to large-sized stimuli than to discrete-spot stimuli, had direction selectivity, and showed preference to visual motion at a relatively high speed. No clear differences in visual properties were observed between DLPN and NRTP. After a local injection of lidocaine into SC, the visual responses in DLPN/NRTP transiently disappeared, indicating that DLPN/NRTP received the visual inputs through SC.