Superior colliculus-evoked response in anesthetized cats: space-time characteristics

Publisher Website
Google Scholar
Abstract
The superior colliculus of the cat receives a primary afferent input from the contralateral optic nerve. Electrical stimulation of the optic nerve in anesthetized animals excites cell populations in the colliculus, which in turn generate an evoked potential observable throughout the structure. The spatial and temporal characteristics of the evoked potential were studied, using waveform averaging techniques, and at selected time points, the potential field throughout the colliculus was mapped. These maps show that the evoked potential is generated by an oscillating dipole layer and is primarily a standing wave, the zero potential surface remaining stationary dorsoventrally. The dipole layer has a warped surface which follows the contour of the colliculus and the zero isopotential surface is located in the zonal layer. The poles move from anterior to posterior owing to conduction delays in the optic nerve terminals. Mediolaterally the collicular cell populations are activated nearly synchronously.