neural mechanisms in agression AO1

Question 1

what did papez and maclean link the limbic system to?

Answer 1

emotional behaviours, including aggression.

Question 2

what is the limbic system defined as?

Answer 2

the hypothalamus, amygdala and parts of the hippocampus.

Question 3

what is an important predicator of aggressive behaviour in the limbic system?

Answer 3

the reactivity of the amygdala in humans and other mammals is an important predicator of aggressive behaviour.

Question 4

the ….. responsive the amygdala, the more aggressive a person is.

Answer 4

the more responsive the amygdala, the more aggressive a person is.

Question 5

amygdala activity is illustrated in a study by who?

Answer 5

gospic et al (2011)

Question 6

what happened in gospic et al (2011) study?

Answer 6

some participants were subjected to mild provocation (act of provoking someone - doing something just to get a reaction).

Question 7

what did gospic et al find?

Answer 7

• when participants reacted aggressively, fmri scans showed a fast and heightened response by the amygdala.
• a benzodiazepine drug (which reduces arousal of the autonomic nervous system) taken before the provocation led to 2 effects: it decreased the activity of the amygdala and halved the number of rejections (I.e reduced aggression), illustrating again the role of the amygdala.

Question 8

what is serotonin and what does it do?

Answer 8

serotonin is a neurotransmitter that has widespread inhibitory effects in the brain, I.e it slows down and calms neuronal activity.

Question 9

what are normal levels of serotonin in the orbitofrontal cortex linked with?

Answer 9

normal levels of serotonin in the orbitofrontal cortex are linked with reduced firing of neurons, which in turn is associated with greater behavioural self-control.

Question 10

what is decreased levels of serotonin linked with?

Answer 10

decreased serotonin disrupts this mechanism of reducing firing of neurons therefore reducing self-control and leading to an increase in impulsive behaviour including aggression.

Question 11

what did virkkunen et al (1994) do?

Answer 11

virkkunen et al compared levels of a serotonin break down product (a metabolite called 5-HIAA) in the cerebrospinal fluid of violent impulsive and violent non-impulsive offenders.

Question 12

what did virkkunen et al find?

Answer 12

the levels were significantly lower in the impulsive offenders.