Visual Discrimination with a Single Manipulandum following Temporal Ablations in the Monkey

Abstract

The aim of this investigation was to determine what effect variation in the conditions of cue presentation and response availability has on the visual discrimination performance of monkeys with bilateral inferior temporal ablations. Six animals were trained on one of two versions of a test of successive brightness discrimination. Common to both versions of this test was the availability of a single lever, manipulation of which in the presence of the positive cue constituted the correct response. Performance on this test was compared with performance on a pattern discrimination, for which the customary simultaneous two-choice procedure was used. It was found that the temporal removals were followed by definite impairment on the pattern discrimination (as expected), but no consistent change in efficiency at brightness discrimination could be attributed to the lesions. Alternative interpretations, making reference to the amount of pre-operative training on the brightness discrimination or the lack of differentiation between the correct and alternative responses in this test, are discussed.