Functional properties of pulvinar-lateral posterior neurons which receive input from the superior colliculus

Focal electrical stimulation of the superior colliculus induced short latency responses and/or a long duration suppression of spontaneous activity in single cells isolated in the pulvinar and lateral posterior (LP) nuclei of the cat. Cells which responded with one or more spikes at short latencies were relatively few in number, and these tended to be encountered in or near the principal tectorecipient zone of LP. In contrast, a suppression response was observed in many more cells which were widely distributed throughout the pulvinar-LP complex. Stimulation of the superficial layers of the colliculus was more effective in driving or suppressing pulvinar-LP cells than that of intermediate and deep layers. There was also an indication of a coarse topography in this projection. On the basis of their sensory response properties the cells responsive to tectal stimulation, at short latency or with a suppression, could not be differentiated from the overall sample of pulvinar-LP neurons.