Role of the amygdala Flashcards
What is the structure of the amygdala?
In the brain.
Made up of “grey matter” - a collection of neuron cell bodies densely packed together into a cluster of 13 nuclei.
Where is the amygdala located?
Medial temporal lobe.
Part of a wider collection of brain structures called the limbic system.
What is the amygdala neurally linked to?
Hypothalamus, Hippocampus.
Prefrontal cortex.
What does the amygdala influence?
Brain functioning and on behaviours associated with emotion, motivation and social interaction in both humans and non-human animals.
Plays a major role in how we assess and respond to environmental threats.
What did Coccaro et al investigate? Who did they study? What did they find?
Effects of amygdala on aggression.
Studied people intermittent explosive disorder (IED).
Common symptom of IED = outbursts of reactive aggression.
Each participant viewed images of faces while having an fMRI scan of their brain.
Participants with IED showed high levels of amygdala activity when they viewed angry faces.
What does Coccaro et al’s findings demonstrate?
An association between amygdala activity and processing of aggressive emotions.
What did Gao et al propose?
We learn as children to inhibit our aggressive and antisocial behaviours through fear conditioning - we learn that aggressive behaviour leads to punishment or other negative outcomes.
Amygdala = involved in processing fear information and fear conditioning.
A dysfunction of the amygdala means the child cannot identify the social cues that indicated threat.
Fear conditioning is disrupted and the outcome is that the individual with amygdala dysfunction seems fearless and overly aggressive.
What did Gospic et al use to measure aggressive behaviour? What did they find?
Used the Ultimatum game, a laboratory-based method.
Involves two players, responder and proposer, and a sum of money.
Proposer = offers to split the money in a fair or unfair way.
If responder accepts, money is split accordingly.
If responder rejects, both get nothing.
Rejection is considered aggressive behaviour.
The study’s participants played the role of responder while undergoing fMRI brain scans.
Found that when responders rejected unfair offers, amygdala activity was heightened.
What does Gospic et al’s findings suggest?
An association between reactive aggression and increased amygdala activity.
What was Pardini et al’s sample? What did they study? What did they find?
503 males who had been part of an earlier study in 1986-87 when they were 6 or 7 years old.
20 years later, researchers identified a subgroup of 56 men who had shown aggressive behaviour since childhood.
fMRI brain scans were used to measure amygdala volume in these men.
Found that high levels of aggression over the 20-year period were associated with lower amygdala volumes.
This association persisted in a follow-up study three years later.
What did Pardini et al’s findings suggest?
Support for the role of the amygdala in aggressive behaviour.
Differences in amygdala volume may predict future aggressive behaviour and involvement in crime.
The amygdala is part of a wider system of connected brain structures and does not operate on its own to determine aggressive criminal behaviour. What does the amygdala function alongside?
The orbitofrontal cortex (OFC).
OFC = located in the prefrontal cortex.
What is the OFC involved in?
Self-control.
Regulation of impulsive behaviour.
Inhibiting aggression.
What did Raine et al (1997) investigate?
Investigated murderers who had used an overwhelming degree of reactive aggression in their crimes.
Those studied had higher glucose metabolism in their amygdala and abnormally low metabolism in the prefrontal cortex (this includes the OFC).
What does Raine et al’s (1997) finding demonstrate?
Just how complex the regulation of aggressive criminal behaviour is.
It involves at least three important brain structures: the amygdala, OFC, and the neural connection between them.
Damage to the amygdala affects the ability to process fear and anxiety-related information. As a result, what does this effect? What does this mean?
Social functioning.
This makes aggressive behaviour more likely but not inevitable.
