ABSTRACT
This chapter concerns a particular part of the cortex, the prefrontal area, and the manner in which lesions within this area affect performance in situations involving the conditioning of instrumental responses. Two apparently similar tasks are affected in opposite ways by lesions in two areas in dogs: the pregenual areas, situated on the medial aspect of the prefrontal cortex in front of the anterior cingulate gyrus, and the orbital areas, situated on the lateral aspect of the prefrontal cortex in front of the presylvian fissures. The disappearance of an instrumental response to a stimulus in whose presence the response is not reinforced is due to a direct inhibitory connection between the stimulus and the relevant drive center. The inhibitory effect is indirect in that the stimulus becomes connected to the related antidrive center; this follows from Jerzy Konorski's subsequent scheme. The chapter considers prediction concerning reversal learning in operated dogs that arise from the different accounts of inhibitory conditioning.
