Effect of posterior parietal and frontal neocortical lesions in the squirrel monkey.

2 groups of squirrel monkeys with frontal or parietal cortical lesions and an unoperated control group (N = 12) received the following in the order mentioned: brightness discrimination; 3 forms of a spatial pattern discrimination in which the essential cue and site of reinforcement were separated (SSP); delayed response; form discrimination; and 3 forms of a spatial pattern discrimination in which the essential cue and site of reinforcement were identical. Ss with frontal lesions were impaired on delayed response, and those with parietal lesions were impaired on form and SSP discriminations. Neither group was impaired on brightness discrimination. Results confirm and extend previous findings that the posterior parietal cortex of nonhuman primates is critically involved in visually guided spatial discriminations when the primary cue and the site of reinforcement are separated. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)