Optic projections to nonvisual cortex of the cat.

Publisher Website
Google Scholar
Abstract
The dorsal and lateral surface of the cerebral cortex of the cat was explored for evoked responses to brief flashes, before and after removal by suction of thalamus and other subcortical structures except the primary optic afferent system. Photically evoked responses appeared in visual cortex, in "association" areas of suprasylvian and anterior marginal gyri, "motor" cortex (primarily in the anterior sig-moid part), orbital gyrus (insular cortex), and in the dorsal part of auditory cortex. Evoked responses in these areas persisted after the extensive subcortical ablation, hence are not dependent on structures medial to lateral the geniculate body. However, changes in waveform and latency of responses outside primary visual cortex following the ablation suggests loss of some components of the potentials which are normally mediated by medial thalamus. Except for the anterior lateral and posterior suprasylvian areas, photically evoked responses in non-visual cortex were not abolished by removal of visual cortex. Visual cortex did, however, exert an influence on evoked activity in most non-visual areas. Similar influence of orbital gyrus on motor cortex potentials was demonstrated.