Effect of bilateral suprasylvian ablation on fear behavior elicited by hippocampal stimulation in cats

Fear responses elicited by electrical stimulation in the dorsal and ventral hippocampus of cats, and the conditioned fear behavior established by pairing this stimulation with a neutral stimulus disappeared after bilateral ablation of the suprasylvian gyrus. The same reactions were not affected when the ectosylvian gyri were removed. The suprasylvian ablation did not impair conditioned classical defence reflexes when a noxious stimulation of the hind limb was used as an unconditioned stimulus. It is suggested that the suprasylvian association area plays an important role in fear produced by hippocampal stimulation but not in pain responses elicited by a noxious peripheral stimulus.