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LINKS: ....Bird Flu Info ....Your Memory Enhancer ....Neurotech ....Success Tips ....Free Brain and aggressionHypothalamus Bard & Mountcastle in the 1940s studied rage in cats with lesions that detached 'higher' from 'lower' parts of the brain.. They concluded that the hypothalamus organizes attack behaviour and the cerebral cortex normally inhibits the release of aggression In the 1960s Flynn found that electrical stimulation of lateral hypothalamus elicits predatory aggression in cats, whereas stimulation of the medial hypothalamus elicited vicious attack behaviour. Increased irritability associated with hypothalamic tumours in humans Amygdala Lesioning amygdala has 'taming' effect in animals - The Kluver-Bucy Syndrome 1939 The role of the amygdala is complex. Some studies report that amygdalectomy increases aggression others report that it has a taming effect. The amygdala may modulate output from the hypothalamus. Eggar & Flynn found that (1) attack behaviour produced by stimulating the hypothalamus can be inhibited by stimulating the basomedial nucleus of the amygdala. (2) attack behaviour produced by stimulating the hypothalamus can be facilitated by stimulating the lateral nucleus of the amygdala. Amygdalectomy reduces violent human behaviour - side effect - loss of emotion Temporal lobe epilepsy - which involves the amygdala - can involve violent behaviour Rabies is caused by a virus that damages the temporal lobe. Rabid animals are violently aggressive. Amygdalectomy can disrupt dominance hierarchies in monkeys - Pribram, 1962. Autopsies of Charles Whitman who carried out a sniper attack from the University Tower at Texas in 1966, showed he had a tumor pressing on his amygdala. Fear and the amygdala The central nucleus of the amygdala may be a control centre for fear, receiving fear-related sensory information and transmitting fear-related motor instructions. LeDoux (1994) suggests that the amygdala receives input from three areas:the thalamus, cortex and the hippocampus HOME...... Brain Food LINKS: ....Medical Dictionary ....Stress Management ....Allergy Info |