The projection of the vestibular nerve to the cerebral cortex in the cat.

1. The cerebral cortex in the cat has been examined for responses to contra-lateral vestibular nerve shocks and to natural stimuli.2. Stimulation of the nerve produces short latency (3.5 msec) surface positive responses in very restricted areas. Within these areas, unitary discharges occur during the equivalent negative phase below the surface.3. It has not been possible to evoke unitary activity in these areas by natural stimulation during light anaesthesia with pentobarbitone, chloralose or urethane.4. The distribution and properties of the shock evoked responses have been studied with special attention to the problem of stimulus spread. They are shown to be overlapped by somato-sensory and auditory projections, but to be distinguishable from them. Evidence is presented that previously reported longer latency responses were probably due to stimulus spread.5. Reasons are discussed for the extreme sensitivity of the vestibulocortical pathway to anaesthesia.