Behavioral and neuroanatomical differentiation of response-suppression and response-shift mechanisms in the rat.

Abstract

Trained 4 normal, 4 operated control, and 10 hippocampal lesioned female albino rats in a 2-choice simultaneous visual discrimination task. Results indicate a separation of 2 different learning processes: (a) withholding a response when no reinforcement was present on the preferred side, and (b) shifting a response when reinforcement was present on the nonpreferred side. Normal Ss always exhibited response suppression prior to response shift. Lesioned Ss exhibited only response suppression; no tendency toward response shift was observed during the testing period. The existence of independent response-suppression and response-shift mechanisms is postulated, and the suggestion is made that the hippocampus may participate in the latter rather than in the former, as has been previously suggested. (PsycINFO Database Record (c) 2006 APA, all rights reserved)