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

Topographical representation of the visual field within striate cortex of primates has been demonstrated by a number of methods. In man, visual field deficits have ~ been related to cortical lesions1o,27 and the perceived positions of evoked sensations have been related to sites of electrical stimulation2. In monkeys anterograde or retro~ grade degeneration techniques have been used to determine separately retinogenic~ ulate3 and geniculostriate relations2o.21. While clinical and anatomical procedures are useful in revealing the general organization of striate cortex, electro physiological mapping methods permit a full and detailed exploration of a cortical representation. Early electrophysiological experiments with surface electrodes were restricted to cortex accessible on the dorsolateral surface of the brain26. In later investigations with penetrating electrodes, results were reported for only a few recording sites in the buried cortex of the calcarine sUlcuS4,7.12. Thus, the primary goal of the present investigation was to explore completely the striate cortex. in a primate using eJectro­ physiological mapping techniques. An additional purpose was to compare the visuotopic organization of striate cortex of the owl monkey, as the only nocturnal r--"i j i' -;; monkeyl8, with the organization reported for other monkeys. . ; Another goal of the pres.ent experiments concerns the representation. of the 'Ii visual field in the cortex. that borders striate cortex.. A second representation of the ~ l