Fig. 8 Four classes of binocular disparity sensitivity in monkey cortex from near (n) through zero (o) to far (f) disparities: A. Binocular facilitation. B. Binocular occlusion. C. Monocular, near. D. Monocular, far sensitivities. (Poggio CF, Fisher B: Binocular interaction and depth sensitivity neurons in stri-ate and prestriate cortex of the behaving Rhesus monkey. J Neurophysiol l40:1392, 1977)