Hypothalamic and extrahypothalamic substrates of predatory attack. Suppression and the influence of hunger.

Electrical stimulation of medial hypothalamic and ventromedial hypothalamic areas of the cat brain stops the initiation of spontaneous predatory attack in cats, confirming similar evidence of other investigators. Furthermore, a new attack suppressing area, the mammillary bodies, was uncovered. Facilitation of predatory attack by hunger raised the electrical threshold for attack in the mammillary bodies. In addition, baseline levels of neural activity in attack suppressing brain areas prior to any brain stimulation were found to decrease when the cats were hungry and killing was facilitated and neural activity increased when the cats were on ad lib. feeding. These data support the hypothesis that modulation of excitability of neural systems functioning to suppress is involved in facilitation of attack behavior by hunger.