INTERRELATION OF TUNING CHARACTERISTICS TO BAR, CROSS AND CORNER IN STRIATE NEURONS

Characteristics of responses and background activity, as well as of tu ning to a single bar orientation and to cross or corner shape and orie ntation have been compared in one third (56/174) of neurons in the cat striate cortex. Shortening of the response latency to cross vs bar, t o corner vs bar and to corner vs cross was revealed in most of the uni ts studied. Direct correlation between the response and tuning charact eristics for bar, cross and corner was revealed: units with better tun ing to one type of stimulus were typically better tuned to the other t ypes of stimuli. At the middle cortical depth (700-1200 mu m from the surface) we found a reliable improvement of response magnitude and lat ency, cross/bar response ratio and selectivity of tuning in comparison with more superficial and deeper layers. Although we could not find a direct correlation between characteristics of tuning to figures and t he type of the receptive field (simple, complex or hypercomplex), our data pointed to a lower cross/bar ratio and selectivity of tuning in t he units with small receptive fields. The functional implication of ne uronal sensitivity to cross and corner and possible meaning of correla tion between their functional characteristics are discussed. (C) 1998 IBRO. Published by Elsevier Science Ltd.