Normal discrimination performance accompanied by priming deficits in monkeys with V4 or TEO lesions.

Primate visual areas V4 and TEO are important for many aspects of visual perception and ablation of these areas leads to a wide range of deficits in visual discrimination, attention to less salient items, recognition of visually transformed objects, visual grouping and in visual memory. All these studies demonstrate that monkeys with V4 or TEO lesions have higher perceptual thresholds or are slower or less accurate than normal monkeys on a particular visual task. Here we show that when monkeys with V4 or TEO lesions perform a simple discrimination task on which they are unimpaired, they perform the task differently from normal monkeys. We examined visual priming in a feature detection task and discovered that it is diminished by lesions of TEO and abolished by lesions of V4. The results support the hypothesis, based on a recent demonstration of visuotopic priming in humans, that areas V4 and TEO are indispensable for normal visual form priming.