Spontaneous activity in septal and hippocampal-lesioned rats.

Abstract

30 rats were assigned in equal numbers to control, hippocampal, and septal groups. Ss were observed in a novel situation for three 15-min. sessions with 24 hr. between sessions and measures taken of their sniffing, walking, and grooming rates. The most important difference occurred in the third session when it was found that the type of lesion exerted control over the habituation of different responses. In walking, there was a tendency for Ss in the hippocampal and control groups to decrease their rate over time, while septal-lesioned Ss tended to increase their rate. Both septal and control groups decreased their sniffing rate, whereas the hippocampal group did not. In grooming, neither the hippocampal nor the septal group showed an increase in rate, whereas the control Ss did. The results of the septal-lesioned Ss were regarded as consistent with a conventional response-inhibition hypothesis while the data of the hippocampal group suggested a deficit in attentional mechanisms.