Septal lesions increase play fighting in juvenile rats.

Play fighting is a behavior exhibited by juveniles of many mammalian species, but the neurology of this behavior is poorly understood. In the present study lesions of the septal area or control operations were performed in rats at 23 days of age and social play was studied between the ages of 27-41 days of age. Septal lesions increased the frequency of play fighting and play initiation in both sexes; within the lesion and control groups males played more frequently and initiated more play bouts than females. Animals with septal lesions were somewhat lighter in body weight than controls, but since play frequency and body weight were not associated, it is unlikely that changes in body weight caused by the lesions are responsible for the effects of the lesions on play.