[Convergence of corticofugal impulse projections onto superior colliculus neurons]

In unanesthetized immobilized cats, 82.75% of tectal neurons responded to direct electrical stimulation of different cortical areas. Stimulation of the associative and visual cortex was the most effective. On simultaneous presentation of light and electrical stimuli, facilitation of responses of the collicular neurons was prevalent. The role of striatal and extrastriatal effects of neocortex as well as the regularities of integration of retinotectal and corticofugal afferents upon the neurons of anterior colliculus, are discussed.