Hormones, Neurotransmitters, limbic system

• Testosterone?


  aggression more evident in male than females. male hormones implicated in aggression. Testosterone peaks in young male teenagers.
• serotonin?


  works on the frontal areas and inhibits firing of the amygdala, part that controls fear and anger.
• levels of serotonin?


  low levels affect our response to external stimuli. cannot control impulsive or aggressive behaviour. serotonin regulates our pre-frontal cortex
• Papez- Maclean?


  reactive aggression is a response to a perceived threat. proactive: response to anticipation of a reward.
• Hypothalamus?


  regulation of autonomic nervous system- regulates responses to emotional circumstances. damage to area can cause inappropriate aggressive response
• Amygdala?


  attaching emotional significance to sensory information
• Pre-frontal cortex?


  crucial for regulating social behaviour and aggressive responses. damaged to the pre-frontal cortex would reduce inhibition
• Kluver and Bucy (1939)?

  Rhesus monkeys removed main areas of the limbic system. demonstrated: absence of emotional, motor & vocal skills associated with stimuli or situations eliciting fear.
• Wong et al (1997)?

  MRI scans of 19 violent male criminals and compared amygdala to 20 normal control subjects.
• Wong et al - Findings?

  volume of the amygdala significantly smaller in violent criminals. lacks population validity, gender bias
• Ferrari et al?


  allowed male rats to fight other rats. found dopamine levels raised by 65% and serotonin lowered by 35%
• Mann et al (1990?

  administered a drug that depleted dopamine in 35 adults. questionnaire to asses hostility and aggression levels, which rose following administration of drugs
• Wagner 1979?


  castrated mice and aggression went down