Amygdalectomized rats can learn the classically conditioned fear response: A preliminary report

Abstract

Amygdalectomized rats can learn the classically conditioned fear response if a discriminative cue is included in the test situation; i.e., if they are run from a white background (shock compartment) to a black background (safe compartment). When the lesioned rats are run from a black shock compartment to a black safe compartment, there is a greater performance deficit. The amount of fear reduction in the test situation is probably a more important variable than the amygdalectomy in contributing to performance of the classically conditioned fear response. The integrity of the amygdaloid complex is probably not essential for the learning processes involved in classical fear conditioning. Other areas of the brain, such as the hippocampus, may be more directly involved in the acquisition and retention of classical fear conditioning and avoidance conditioning.