NEURAL

• NEUROTRANSMITTER?

  chemical messengers found in synapses that either excite or inhibit adjacent neurones
• NEURAL STRUCTURES?

  areas of the nervous system, e.g. neurones or brain regions
• KEY NEURAL INFLUENCES?

  1. Limbic system
  2. Serotonin
• LIMBIC SYSTEM?

  • beneath cortex on top of brainstem
  • coordinates behaviour that satisfy motivational or emotional urges (fear or aggression)
  • amygdala, hypothalamus, hippocampus
• AMYGDALA?

  • attaching emotional significance to sensory information
  • promotes appropriate responses
• EVALUATION OF AMYGDALA?

  + Kluver + Bucy

  + Pardini et al
• KLUVER AND BUCY?

  • destruction of amygdala
  • in dominant monkeys in social group
  • lost dominant position
• PARDINI ET AL?

  • longitudinal study
  • males
  • lower amygdala volumes had higher levels of aggression and violence
• HIPPOCAMPUS?

  • formation of long-term memories
  • compare conditions of current threat with similar past experiences
  • damage produces inappropriate responses to sensory information
• EVALUATION OF HIPPOCAMPUS?

  + Boccardi et al

  + Raine et al
• BOCCARDI ET AL?

  • habitually violent offenders
  • abnormalities in hippocampal functioning
• RAINE ET AL?

  • studied successful and unsuccessful psychopaths
  • different sized hippocampus hemispheres in unsuccessful
  • hippocampus cannot work with amygdala
  • emotional information not processed correctly
  • inappropriate aggressive responses
• HYPOTHALAMUS?

  activating stress response
• PAPEZ MACLEAN LIMBIC THEORY?

  • limbic system involved in reactive aggression
  • response to perceived threat
  • different to proactive aggression
  • more predatory and calculated, usually with anticipation of reward
• SEROTONIN?

  • neurotransmitter
  • normal levels have a calming, inhibitory effect on neuronal firing
  • especially on amygdala leading to reduced fear, anger and other emotional responses
  • low levels lead to serotonin deficiency hypothesis
  • amygdala stimulated more frequently
  • less control over aggressive or impulsive behaviour
  • aggression more likely
• EVALUATION OF SEROTONIN?

  + Mann et al

  -Duke et al
• MANN ET AL?

  • 35 healthy participants
  • given dexfenfluramine
  • reduces serotonin
  • questionnaire to measure hostility and aggression
  • increased scores in males not females
• DUKE ET AL?

  • serotonin more complex
  • meta-analysis
  • small inverse relationship between serotonin and aggression
  • magnitude varied with year of publication, methods to measure, self-reported