The Induction of Aggressive Behaviour By Electrical Stimulation in the Hypothalamus of Male Rats

Abstract

AbstractElectrical stimulation in the hypothalamus induces male rats to attack another rat in an external stimulus situation where such attacks are unlikely events without stimulation. Among the goal objects which are attacked besides live male rats are live female rats, anaesthetized or dead-and-frozen rats and mice. According to the morphology of the induced attacks, the electrode placements can be classified as attack jump or bite attack electrode placements. Both attack patterns can be observed in "spontaneous" aggression between male rats. These attacks are directed to the fronto-dorsal side of the goal objects. The relation between the current intensity and the induction of the first attack has characteristics of a dose-response relation. The subliminal electrical stimulation in the presence of a partner, which usually precedes the induction of the first attack in an electrode placement, does not facilitate the induction of attack behaviour. Similarly, experience with attacks elicited in one electrode placement in a rat does not facilitate the induction of the first attack in another electrode placement in the same rat. Threshold current intensities of attack behaviour can be determined in about 85% of the attack-inducing electrode placements. Some of the factors probably involved in the initial decrease in such attack thresholds are discussed.