What neural mechanisms are important in aggression?
Amygdala, Pre-Frontal Cortex(PFC), Serotonin
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What does the amygdala do?
In both sides of the brain, part of the limbic system+involved in emotion, key role in assessing+ responding to threats and challenges, overactivity=increased aggression
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What does the PFC do?
Involved in planning and moderating, regulates amygdala driven responses, takes impulses and decides if to act on them, damage includes loss of control, impulsiveness, immaturity
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How do they work together to regulate aggression?
Aggression dependent on interacting systems, amygdala=aggression, PFC=maintains control over these impulses
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What is the role of serotonin?
Calming effect on brain, low levels remove inhibitory effect on firing of amygdala responses - serotonin deficiency hypothesis meaning individuals less able to control behaviour
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Psychosurgery support for the role of the amygdala
43 out of 51 patients who had their amygdala destroyed had normal social behaviour afterwards+reduced aggression, shows its role in producing aggression
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Case of Charles Whitman to support role of amygdala
Went on shooting rampage-killed his wife, mother, 14 people and wounded 32 others at Texas Uni, left suicide note saying something was wrong, autopsy found tumour pressing on amygdala
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Moral and social reasoning to support role of PFC
Compared 25 adult-onset patients to 2 adult cases who sustained damage before 16 months, both cases showed aggression, 16m case showed more extreme behaviour+scored poorly in moral social reasoning tests (10yr level)
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Why was there such a difference?
Those with adult onset had an intact PFC during infancy and therefore had much more practice in reasoning skills - early damage leads to greater problems
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fMRIs on murderer's brains as support for the role of the PFC
Reduced glucose uptake+metabolism in PFC in murderers=reduced functioning, neuroimaging studies have showed less brain tissue in people with anti-social tendencies
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Regulating diet to support the role of serotonin
One day=lack of tryptophan, other day=placebo with normal tryptophan, fMRI measured reactions to angry, sad+neutral faces, low serotonin=weak communication in brain
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Issues and Debates involved in this research
Socially sensitive, biological determinism, reductionist including nature v nurture
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Other cards in this set
Card 2
Front
What does the amygdala do?
Back
In both sides of the brain, part of the limbic system+involved in emotion, key role in assessing+ responding to threats and challenges, overactivity=increased aggression
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