Shuttle behavior in rats after lesion of hippocampal pyramidal cells with kainic acid.

Rats with bilateral lesions of hippocampal pyramidal cells in the subfield CA 3 with intracerebroventricular kainic acid (0.1 microgram/2 microliter) made more shuttle responses to a buzzer in Pavlovian paradigm, classical conditioning and two-way active avoidance but did not differ remarkably in pseudoconditioning and avoidance conditioning without stimulus pairing, than sham-operated and intact control rats. Animals with unilateral lesion in the CA 3 hippocampal subfield showed no differences in these shuttle situations. The results suggest that CA 3 hippocampal pyramidal cells are of particular importance to the establishment of the stimulus-stimulus relations in the brain.