Physiological Factors in Aggression Flashcards
The _____ is critical in the modulation of aggressive responses, reactions to fear, stress and frustration. Most studies are done with _____.
Limbic system.
Mammals.
Three types of aggression can be identified when investigating the neurophysiology / neuroanatomy of aggression. What are they?
Intrasexual aggression.
Fear-induced or aversion-induced aggression.
Irritable aggression or frustration-induced aggression.
Describe the role of the hypothalamus. Which different areas are involved with specific types of aggression? What happened to low ranking rhesus monkeys who had their hypothalamus electrically stimulated?
Offence, defence, escape.
Ventromedial nucleus: defensive attack (growling, hissing, attacking with claws).
Lateral hypothalamic area: direct attack (biting with no defensive component).
Became dominant in behaviour.
Describe the role of the amygdala. What happens when it is removed from monkeys, cats and rats? How was it formerly used in psychosurgery?
Fear, fear-induced aggression, defensive aggression.
Aggressive reactions to stressful stimuli or fear are dramatically reduced.
To destroy the amygdala in violent criminals, sex offenders, hyperactive kids.
The main outflow from the amygdala is to the hypothalamus. What happens when you lesion the hypothalamaus? When lesioning the amygdala?
Aggressive responses evoked by stimulating the amygdala are blocked.
Responses evoked by the stimulation of the hypothalamus can not be blocked.
Frontal lobe lesions in monkeys will do what?
Impair normal social inhibition.
Describe the roles of serotonin, dopamine, norepinephrine, and nitric oxide in aggression.
Serotonin: levels too low = aggression and depression.
Dopamine: levels too high = aggression; stress sensitizes system.
Norepinephrine: if levels too high or too low = aggression; fighting elevates levels; stress sensitizes.
Nitric oxide: aggression in male mammals.
Describe the roles of testosterone, estrogen, peptide hormones, thyroid hormones, and glucocorticoids in aggression.
Testosterone: high = aggression, aggressiveness.
Estrogen: female aggression; important in birds; anti have anti-aggression effects in rat and mice.
Peptide hormones: more important for affiliative and maternal behaviour.
Thyroid: in fish.
Glucocorticoids: related to stress, anxiety, fear, frustration in mammals.
The main hormonal cause for aggression in mammals: are _____. To a lesser extent, _____.
Androgenic steroid hormones.
Peptide hormones.
Provide three pieces of evidence (from males) implicating androgens.
Seasonal changes: increase in aggression during reproductive season.
Pubertal changes: increase of aggression at puberty.
Sex differences: males more aggressive than females.
Testosterone levels may influence what three things?
Perception of threat.
Inhibitory processes.
Aggressiveness.
