neural and hormonal mechanisms in aggression

Question 1

how many parts of the brain are linked to various behaviours considered to be aggressive

Answer 1

38

Question 2

parts of the brain used in aggression

Answer 2

amygdala and hypothalamus

Question 3

Mark and Ervin

Answer 3

34 year old male suffering from epilepsy, during seizures he would brutally attack his wife.
after part of amygdala removed the attacks stopped so aggression displayed was due to increased activity in amygdala

Question 4

Gloor et al

Answer 4

found people with temporal lobe epilepsy which involves the amygdala, exhibit aggressive behaviour and fear responses

Question 5

Phineas Gage

Answer 5

metal bar went through frontal cortex which altered his personality to aggressive.
the amygdala suppresses and controls aggressive behaviour

Question 6

Charles Whitman

Answer 6

murdered 12 people after a post mortem there was a tumour pressing on his limbic system

Question 7

Gur et al

Answer 7

MRI scans on 57 men and 59 women measuring the volume of amygdala and hypothalamus compared to the volume of the orbital frontal regions.
Hypothalamus and amygdala volumes the same in men and women.
Prefrontal orbital frontal cortex larger volume in women, have greater control over aggression

Question 8

Raine et al

Answer 8

PET scans comparing 41 murderer brains to non murderers.

Murderers have lower activity in amygdala

Question 9

Linnoila and Virkkunem

Answer 9

serotonin levels of alcoholics

reduced levels means lower threshold for aggression

Question 10

Davidson et al

Answer 10

500 violent individuals

those who had genetic deficit had a disruption in serotonin levels

Question 11

Lenard

Answer 11

49 monkeys
low levels of serotonin = more dangerous activities
high levels of serotonin = stayed close to others

Question 12

Wagner et al

Answer 12

testosterone levels in mice
all mice were castrated and aggressive behaviour was observed before
all mice were given testosterone replacement therapy
castration reduced aggression in all mice
mice rated aggressive showed aggressive behaviour after testosterone therapy

Question 13

Wille and Beier

Answer 13

99 surgically castrated sex offenders and 35 non castrated sex offenders were monitored over a decade
castrated = 3% re offended compared to 46% of non castrated individuals
however 54% non castrated didn’t reoffend so testosterone is not the only factor involved in aggressive behaviour

Question 14

Young et al

Answer 14

injected pregnant mice with testosterone

female offspring were more likely to display masculine behaviours (play fighting)

Question 15

Kreuz and Rose

Answer 15

studied a number of criminals with a history of aggression and violent behaviour
many of them had high levels of testosterone when compared to non violent individuals

Question 16

O’connor

Answer 16

meta analysis of experiments where increased testosterone had been administered to men
high doses of testosterone were associated with increased in measures of direct aggression, anger and mood