Characteristics in aggressive behavior induced by midbrain raphe lesions in rats.

Midbrain raphe lesions induced aggressive behavior which was characterized by defensive aggression rather than offensive aggression in nature. Furthermore, raphe-lesioned rats exhibited muricide. This muricide included not only mouse-killing but also mouse-eating behavior. Both dorsal and medial raphe lesioned (dm-R) rats exhibited much greater hyperemotionality than either the dorsal (d-R) or medial raphe lesioned (m-R) rats, though no significant difference was found between d-R and m-R rats. It is concluded that the characteristic of aggression induced by raphe lesions is different in many respects from that induced by p-chlorophenylalanine administration, olfactory bulbectomy and septal lesions.