Abstract: | Rabbits received ibotenic acid lesions of the mediodorsal nucleus of the thalamus (MD) or sham lesions. These animals were compared on 4 sessions of Pavlovian eyeblink and heart rate conditioning, in which a tone was the conditioned stimulus/stimuli (CS) and a paraorbital electrical shock was the unconditioned stimulus/stimuli (UCS). Lesions of MD retarded acquisition of the eyeblink conditioned response (CR) and abolished the late-occurring tachycardiac component of the heart rate CR. The data are compatible with previous experiments (H. Groenewegen, 1988), suggesting that MD participated in the sympathetic control associated with somatomotor learning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) |