Visual receptive fields of single striate cortical units projecting to the superior colliculus in the cat

Abstract

Single units in the striate cortex of anesthetized, paralyzed cats were activated antidromically by electrical stimulation of the superior colliculus and their receptive fields were plotted and studied. These corticotectal neurons were found to lie in layer V and, based on standard criteria21,22,30, the majority were complex cells. Most of the corticotectal neurons were driven about equally by the two eyes and none were strictly monocular. All of the corticotectal neurons were orientation selective, a large proportion were direction selective and they tended to have large receptive fields. The corticotectal units differed from most other cortical cells in that they lacked any clear summation with stimulus length and, in general, responded very well to small moving spots. The data reinforces the idea, based on ablation studies4,32,42 that direction selectivity and the effectiveness of the ipsilateral eye in driving collicular units are dependent on binocular, direction selective inputs from the striate cortex. The data were also discussed from the point of view of information sorting within the visual cortex and its efferent projections. © 1974.