Aggressive behavior in cats during different behavioral states following pontine tegmental lesions

Ceile Eileen Hedberg, University of Pennsylvania


This dissertation is a study of the occurrence of spontaneous aggressive behavior in cats in which bilateral pontine tegmental lesions have abolished muscle atonia normally occurring during paradoxical sleep (PS). This behavior is notable in that it occurs in two states of consciousness: PS, or rapid eye movement sleep, and wakefulness (W). Considering the emotional function of the limbic system we also attempted to determine if and to what extent the amygdala contributes to the behavior observed in animals with such lesions. Twenty-eight cats received bilateral, electrolytic lesions; 1 received a bilateral knife-cut lesion. Eleven cats became aggressive during PS without atonia and/or during W. A surprising finding was that the type of aggression displayed was highly dependent on behavioral state. During PS, the behavior approximated feline predation, while during W it closely resembled irritable aggression. These differences in type of attack are probably due to two features of PS. First, during PS there is a reduction in sympathetic activity. Normal predatory attack is also characterized by a lack of autonomic arousal. This suggests that predatory attack during PS is a function of the dampened sympathetic activity. Additionally, the reduced responsiveness to environmental stimuli during PS is likely to alter the expression of aggression. It is highly likely that there is forebrain modulation of the behavior observed in cats with pontine lesions. Contributions of the amygdala were investigated for two reasons. Attack behavior in W in cats with lesions in the central nucleus of the amygdala (Ace) is similar to that observed in cats with pontine lesions in W. Also, Ace projects heavily to the dorsolateral pons. Experiments had shown that unilateral damage to these projections in the pons produced attack in W and PS without atonia. In the present study it was found that lesions placed unilaterally in Ace released aggression in W only. Serial placement of Ace and pontine lesions not only released aggression in PS and W, but also accentuated the effects obtained with pontine lesions alone.

Subject Area

Anatomy & physiology|Physiological psychology

Recommended Citation

Hedberg, Ceile Eileen, "Aggressive behavior in cats during different behavioral states following pontine tegmental lesions" (1992). Dissertations available from ProQuest. AAI9308590.