Neural and Hormonal

• aggression is threatening behaviour with intent to harm or injure
• The Limbic System

  • a network of structures that determines how organisms respond to environmental threats and challenges
• The limbic system

  • hippocampus
  • amygdala
  • hypothalamus
• The hypothalamus regulates the autonomic nervous system

  • triggers the fight or flight response
  • triggers aggressive behaviour
• The amygdala is located in the temporal lobe

  • determines the emotional meaning of an event
  • nerve impulses to the hypothalamus when detecting a threat
• The amygdala is the predictor of aggressive behaviour

  • fMRI scans show heightened activity during aggressive response
• The frontal cortex is not part of the limbic system

  • moderates aggression
  • inhibits the amygdala, stopping nerve impulses to the hypothalamus
• serotonin is a neurotransmitter with inhibitory effects on the brain

  • usually works on the prefrontal areas to inhibit neuron firing in the amygdala - meaning fewer impulses to the hypothalamus
• Hippocampus - gives information to the amygdala to determine the emotional meaning of a situation

  Amygdala - determines emotional meaning of an event

  Hypothalamus - triggers fight or flight response and aggression

  THE FRONTAL CORTEX IS NOT PART OF THE LIMBIC SYSTEM, BUT WORKS WITH IT!
• serotonin is a neurotransmitter that comes from the orbitofrontal cortex

  it works to inhibit the amygdala and prevent neuron firing to trigger the hypothalamus

  decreased serotonin can lead to an increase in impulsive and aggressive behaviour
• Hormonal 

  Testosterone is much higher in males

  Testosterone is an androgen

  And it is a known observation that males tend to display more aggressive behaviours than females

  (a significantly higher proportion of people arrested for violence towards another person in the UK are males)