Changes in sensory and motor systems during centrally elicited attack.

While emotion can be a subjective experience and emotions are revealed to some extent by facial expressions and changes of respiration, heart rate and other autonomic states, behavior itself is a primary indicator of emotions. The present work deals with a form of emotional behavior, specifically attack, which is one component of fighting. Since the work of Cannon, it has been acknowledged that sympathetically and hormonally mediated changes occur that prepare the organism for fight and flight. It is the thesis of this article that sensory and motor systems are similarly readied to act in specific ways under the influence of electrical stimulation of the brain that induces attack behavior. Specifically electrical stimulation of the hypothalamus that elicits attack influences the visual system. This is shown by the difference between the frequency of lunges directed towards a mouse when it is presented to the eye ipsilateral and to that contralateral to the side of the hypothalamus stimulated. The contralateral eye mediates more lunges. The visual system is also gated by hypothalamic stimulation. A bite ensues in some instances after section of the trigeminal nerve, but not in others. After the successful cats are blindfolded they no longer bite. The tactile system around the mouth and lips is also influenced by hypothalamic stimulation. A more extensive region around the mouth and lip on the contralateral side than on the ipsilateral side responds to touch by eliciting head turning and jaw opening. The motor system for jaw closure and for striking are similarly influenced by hypothalamic stimulation. Reflexes become functional under the influence of stimulation. In the case of attack behavior, the organism's sensory and motor systems are primed to bring about patterned reflexes, which constitute at least in part the overt behavior when suitable stimuli are present in the environment.