In conditions of chronic experiment cats reactions were studied to species-specific acoustic signals (SAS) presented separately and against the background of the electric stimulation of the hypothalamus before and after partial bilateral ablation of the sensorimotor area of the cortex (SMC). It was shown that separately presented SAS caused in animals motor reactions, mainly orienting and negative. Ablation of SMC (field 4,6) caused an increase of positive reactions to sound, including also orienting reactions. A selective character of the reaction to SAS of agonistic type was revealed in animals with "true" aggression to combined (acoustic and subthreshold electric) stimulation. In animals with "false" aggression the combined stimulation caused only nonspecific elements of motor reactions and agonistic vocalizations. SMC ablation caused an increase of aggressive reactions to combined stimulation, revealed in the form of tendency for all animals. In this case in animals with "true" aggression after operation the probability increased of the appearance of motor reactions of aggressive type in comparison with agonistic vocalizations.