3.1.3 - Brain structure

Question 1

draw the brain structure

Answer 1

Question 2

AO1 x 4

Answer 2

1. Prefrontal cortex - it is involved in aggression found by Raine et al and brain scanning. It regulates emotions so aggression comes from a lack of regulation or control rather than actually from the pre-frontal cortex. It has links to the amygdala where messages are inhibited so when damage to the pre-frontal cortex causes messages to not be inhibited, violent behaviour can occur
2. Limbic system - includes the hippocampus, amygdala and hypothalamus and has a role in self preservation by controlling temperature and fight or flight response - Controls behaviour in response to emotion rather than thinking which can lead to impulsive aggression due to an autonomous response
3. Amygdala - it regulates emotions which is why smaller amygdala = less regulation which can be the cause of more aggression
4. Hypothalamus - it has a balancing role, maintaining homeostasis through regulation of hormones which can be linked to aggression in males due to the production of testosterone. It regulates hormones and motivated behaviours such as response to pain, anger and aggression. For example Deville et al showed that the hypothalamus has receptors that interact with serotonin and vasopressin that determine aggression levels.

Question 3

extra AO1

Answer 3

2 halves joined by the corpus callosum (females are more bilateral while males are more brain lateralised)

A series of case studies of people who had suffered brain damage allowed doctors to start a map of the brain:
Eg Phineas Gage:
- A railway worker in the US in 1848 and iron rod set off an explosive which blew the iron rod through gages face and out through the top of his head
- He is survived but his personality changed – he became irresponsible and aggressive due to the damage done to his pre-frontal cortex

Medial temporal lobe (MTL) - includes hippocampus and has role in memory
Limbic system - controls emotions and memory- includes:
- Hippocampus - STM → LTM
- Amygdala - control/regulates emotion
- Hypothalamus - regulates motivated behaviours - maintain homeostasis through regulation of hormones

Question 4

AO3 x 2

strengths

Answer 4

• One strength is that, for example Raine et al found that prisoners in New Mexico supported the structural explanation as brain scans revealed reliable predictors for reoffending as images showed they had a smaller amygdala. Therefore the structural difference means that they would not regulate emotions as affectively due to messages not being inhibited causing them to lose control and present violent behaviour.
• Another strength is that that Bechara and Van der linden reviewed studies at the pre-frontal cortex and confirmed that area regulated behaviour and deferred rewards and so planning. Damage to the pre-frontal cortex mean someone might focus on the present and only want immediate rewards. Therefore this would explain why they may not control aggressive reactions as their brain structure doesn’t allow for a realisation of better future.

Question 5

AO3 x 2

weaknesses

Answer 5

• One weakness is that research into the amygdala shows that animals who had the amygdala stimulated using an electric current, presented aggression showing that aggression response is one role of the amygdala. However animal studies are not generalisable to humans as our brains have different structures and so the pre-frontal cortex is different in humans. Therefore this means consciousness and planning, as well as emotional processing results would not be a representative of a human brain
• Another weakness is that Raine’s research used PET scanning to show that people who had shown emotional impulsive violence differed in their pre-frontal cortex as they had lower functioning compared with controls. However scanning has very weak validity as the scans take place while someone is processing information doing an artificial task. Therefore results may not reflect how the brain responds to angry emotions during every day life functioning.