Neural and hormonal mechanisms in aggression

  • Created by: EloiseMay
  • Created on: 22-03-18 14:55


The limbic system: Papez and MacLean identified the amygdala, hypothalamus, cingulate gyrus, fornix, septal area and parts of the hippocampus and thalamus. The amygdalas role is to assess and respond to environmental threats. Gospic used the Ultimate Game to assess aggression - the proposer and the responder - if the latter rejects the offer then neither get any money. fMRI scans showed that when they rejected they had heightened activity of the amygdala. And when a benzodiazpine was taken it halved the number of rejections and reduced amygdala activity. Thus, an association between amygdala activity and aggression

Serotonin: Normal levels in the orbitofrontal cortex is linked to reduced firing of neurons and greater self-control. Denson argues that low levels can lead to impulsive behaviour like aggression. Virkkunen studied the levels of metabolite in cerebrospinal fluid of violent impulsive and violent non-impulsive offenders. Levels were lower in first group and they also had sleep irregularities (serotonin regulates sleep); this supports the role of serotonin in aggression.

Testosterone: It has influence on areas of the brain implicated in aggression. Giammanco's animal study shows that experimnetal increases of testosterone caused greater aggression and the reverse was true in castration studies. Dolan found a positive correlation between testosterone levels and aggression in 60 male prison inmates that suffered personality disorders. 


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