Structure of the brain and aggression Flashcards
What is aggression?
Behaviour that is intended to cause injury. In humans, this could be psychological as well as physical injury. In animals, aggression is often is often directed at establishing and maintaining dominance or acquiring resources. Aggression is often expressed in ritualised form to prevent actual physical harm.
What is the key structure in the limbic system that causes aggression?
The amygdala
What is the central role in the amygdala?
In how an organism assesses and respons to environmental threats and challenges. The reactivity of the amygdala in humans is proven to be an important predictor of aggressive behaviour
What type of people did Emil Coccari study?
People with (IED) intermittent explosive disorder.
What did they discover in the fMRI scans after showing the IED pictures of angry photos?
There were high levels of amygdala activity - not in the control IED group
Why are the pictures of angry faces good?
As it is an ecologically valid sign of threat
What does the amygdala function in tandem with?
The prefrontal cortex- more specifically the orbitofrontal cortex (OFX)
What role does the OFC play?
It is involved in self- control, impulse regulation and inhibition of aggressive behaviours. Patients in psychiatric disorders that feature aggression often have lower activity in the OFC.
What is the role of serotonin?
Is a neurotransmitter with widespread inhibitory effects on transmission between neurons in the brain
It slows down and dampens neuronal activity
What is the normal behaviour to decreased serotonin in the PFC?
Reduced self control and lead to more impulsive behaviour inlcuding aggression
What did Virkkunen discover about levels of serotonin in violent impulse offenders?
Significantly lower in impulse offenders who also suffered from more sleep irregularities.
Serotonin helps to regulate sleep 5 disturbance of sleep strongly imlpies some disruption of serotnin functioning.
What is the function of dopamine?
Is a neurotransmitter that has inhibitory effects in some areas of the brain and excitatory effects in others. It is involved in regulating motivated behaviour and our experience of reward.
How does Dongju Seo et al link serotonin and dopamine to aggression?
They say that serotonin underactivity (hypofunction) stimulates dopamine overactivity (hyperfunction) and both are linked with impulsivity and aggression. So serotonin hypofunction is the primary cause of impulsive aggression and dopamine hyperfunction makes n additional contribution.
What is the general role of the PFC?
- Personality
- Decision making
- Self- restraint
- Problem solving and planning
- Control over social inhibitions
How does the PFC link to aggression?
It can change you personality and can cause a lack of self restraint. You could lose rationality and not be able to control impulses if damaged. Acting on par with emotion
What evidence support the idea that the PFC is linked with aggression?
Phineas Gage damaged his PFC and became more rash, reckless and impuslive. Not the calm personality.
What is the role of the amygdala?
- Perception of emotion
- Link emotions to memories
- Fear conditioning
- Fight or flights
How does the amygdala link to aggression?
Could be underactive and overactive
Damage could lead to lack of fear- reduced ability to recognised danger
If damaged not in control of emotions
Blinded emotions
What evidence is there that the amgydala is linked with aggression?
Raine found that the left side was underactive and the right side is overactive in murderes.
How does the hippocampus linke to aggression?
Can influence a persons memories and can likely cant link emotions to memories
What is the general role of hypothalamus?
Linke between NT’s and hormones
Maintains body balance
How does that hypothalamus linke to aggression?
An imbalance of neurotransmitters or hormones which could lead to aggressive bheaviour
What is the role of the hippocampus?
Converts STM to LTM
What evidence is there that the hypothalamus links to aggression?
Wagner et al and his castrated mice
