Neural and hormonal influences on aggression


Neural influences on aggression 

The limbic system - subcorticol structures - involved in regulating emotional behaviour.

  • The amygdala - Resp. for evaluating the emotional importance of sensory info and prompting an appropriate response. If malfunctions (damags, tumor etc.) levels of testosterone raised, increasing aggression levels.
  • Hippocampus - Formation of long-term memories, so comparisons can be made between current threats and past experiences. Impared function prevents the NS from putting things into relevant meaningful context. Cause amygdala to respond inappropriately to sensory stimuli. 

Eval of limbic system:

  • + LeDoux - susteained electric stimulation of the amygdala in animals - results in fear and rage.
  • + Charles Whitman - Sniper, killed 14 innocents and wounded 31, left note for brain examination post mortem. Autopsy showed a temporal lobe tutor, pressing on the amygdala.
  • + Phineas Gage
  • - Amygdala does not operate in isolation in determining aggression. Gospic found that regulation fo aggression is highly complex and involves 3 neural structures - limbic system, orbitofrontal complex and connection between the two.

Serotonin deficiency hypothesis:

  • Normal levels has calming, inhibitory effect on neural firing in brain. Serotinin inhibits the firing of the amygdala (resp. for emotional responses).
  • Low levels of serotinin - aggression and risk taking behaviour - less able to control behaviour.
  • Tyrptophan is an amino acid that produces serotonin. High levels of…


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