Neural and hormonal mechanisms

• Neural mechanisms refer to the processes by which the brain and nervous system contribute towards behaviour, thoughts and emotions. This involves interactions between brain structures and neurotransmitters.
• The Limbic System is a group of brain structures that are involved in emotion, long-term memory and physiological arousal.

  • including the amygdala and hypothalamus
• Serotonin is an inhibitory neurotransmitter

  • normal levels reduce neural firing in the pre-frontal cortex and amygdala
  • 'serotonin deficiency hypothesis' - low levels of serotonin are linked with implusivity and aggression
  • amygdala - low levels = more neural firing = increased impulsivity = increased aggression
  • pre-frontal cortex - low levels = reduced self-control = increased aggression
• The amygdala is responsible for attaching emotional significance to sensory information.
• Dysfunction in the amygdala means someone might percieve things as threats when they are not.
• The hypothalamus is responsible for the regulation of the autonomic nervous system, which regulates responses to emotional situations. As it is also part of the endocrine system, it controls the release of hormones (and fight or flight).
• Dysfunction in the hypothalamus (or amygdala) could mean inappropriate activation of the fight or flight response, therefore aggression.
• Testosterone

  • is an androgen hormone responsible for masculinising the male body
  • plays a role in regulating social behaviour, including aggression
  • highest levels are seen in young men
  • levels influence activity in the amygdala, higher levels = enhanced amygdala reactivity, increasing aggression