Representation of the visual field in striate and adjoining cortex of the owl monkey (Aotus trivirgatus)

Abstract

Microelectrode mapping methods were used to determine the representation of the visual field in striate cortex and adjacent cortex in the owl monkey. As in other primates, the center of gaze is represented in dorsolateral striate cortex. Most of the lower quadrant of the visual field is represented on the upper bank of the calcarine sulcusm while more central portions of the lower quadrant are represented on the medial wall and dorsal surface. The representation of the upper quadrant extends from the dorsolateral surface the tentorial surface and across the lower bank of the calcarine sulcus. The representation of the temporal periphery of the upper quadrant was found on the upper bank of the calcarine sulcus. Almost half of striate cortex is devoted to the central 20° of the visual field and 90% of the border corresponds to the zero vertical meridian or lilne of decussation. Recordings from cortex adjoining striate cortex indicate that the second visual area, V II, borders the complete vertical meridian of striate cortex. The small representation of the temporal periphery in striate cortex is bordered by cortez that was nonresponsive to visual stimuli. The responsive and nonresponsive bordering areas were found to relate to two histologically distinct types of cortex, areas 18 and ‘pro-striata’ respectively.