Binocular fusion/suppression to spatial frequency differences at the border of areas 17/18 of the cat

• Published in: Neuroscience Vol. 124; no. 1; pp. 121 - 136
• Main Authors: Saint-Amour, D, Lepore, F, Guillemot, J.-P
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2004; Elsevier
• Subjects: Animals; binocular vision; Biological and medical sciences; Cats; Depth Perception - physiology; Dominance, Cerebral - physiology; Electrophysiology; Eye and associated structures. Visual pathways and centers. Vision; Female; Fundamental and applied biological sciences. Psychology; fusion; interocular disparity; Male; primary visual cortex; suppression; Vertebrates: nervous system and sense organs; Vision, Binocular - physiology; Vision, Monocular - physiology; Visual Cortex - physiology; primary visual cortex; AC; S.D; S.E.M; fusion; PSTH; c/deg; SF; suppression; V1; interocular disparity; binocular vision; DC; Fissipedia; Carnivora; Visual cortex; Central nervous system; Encephalon; Spatial frequency; Vertebrata; Mammalia; Visual pathway; Cat; Binocular vision; Disparity
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2003.10.035

As shown by various human psychophysical studies, interocular spatial frequency disparities can yield a variety of percepts. In order to examine how binocular fusion is affected by spatial frequency differences, we have recorded cells in the border region of areas 17/18 of anesthetized cats. The optic axes of the eyes were deviated onto cathode-ray screens, and the optimal spatial frequency of each eye was assessed by monocular stimulations using drifting sinusoidal gratings. The optimal relative phase using identical spatial frequencies in both eyes was first determined. Spatial frequency differences were then introduced by keeping the optimal spatial frequency constant in one eye and varying the spatial frequency in the other. Results indicate that cells (39%) responded with an increased firing rate (facilitation) to similar spatial frequencies in each eye and with a gradual attenuation (occlusion or suppression) when spatial frequency differences were increased. However, binocular facilitation did not always occur to the presentation of identical stimuli. For 16% of the cells, maximal responses were observed when lower spatial frequencies than the optimal one were presented in one eye while higher spatial frequencies produced suppression. The opposite pattern was observed only for two cells. These findings are discussed in terms of binocular fusion and suppression.