Unit activity in cingulate cortex and anteroventral thalamus of the rabbit during differential conditioning and reversal.

Abstract

Multiple-unit activity was recorded from the rabbit anterior cingulate cortical area (AC) and from the anteroventral nucleus of the thalamus (AV) during differential avoidance conditioning and reversal. The positive and negative conditioned stimuli were tones of different frequency, and the unconditioned stimulus (UCS) was shock delivered through the grid floor of a rotating-wheel conditioning apparatus. Conditioning was preceded by pretraining with tones and noncontingent presentations of the shock UCS. The results showed associative (differential) neuronal activity in both AC and AV during differential conditioning. The effect in AC occurred in the intermediate and final sessions of conditioning. A very large differential effect appropriate to original conditioning occurred in AC in the first two sessions of reversal training. The differential effect in AV occurred in the final session of conditioning when the behavioral response was well learned. There was no clear neuronal reversal in AC or AV.