Hippocampal activity during natural behavior in the guinea pig

Abstract

Macro-electrodes were implanted in the hippocampus of twelve male and twelve female guinea pigs. EEG activity was then correlated with the ongoing behavior of the animal. Voluntary behaviors (e.g. walking, head movements, manipulation) were associated with rhythmical slow activity (RSA) in the hippocampus while automatic behaviors (e.g. chewing, grooming) were associated with irregular hippocampal activity. EEG records were also correlated with sexual behavior and aggressive behavior. Similar results were obtained. Behavior which would readily be regarded as automatic (e.g. pelvic thrusting, anogenital licking) were associated with irregular activity in the hippocampus while more voluntary movements (e.g. walking, mounting) were accompanied by RSA. While these results were consistent with the theory that RSA accompanies voluntary behavior, they do not support the notion that RSA is indicative of a state of arousal.