S5 - Key Study

• What was the methodology of raines study

  Research method was ‘Quasi’ meaning the IV was naturally occuring

  IV - NGRI

  DV - brain differences
• Raines study

  • Group of 41 violent murderers (39:2) charged with murder BUT pleaded NGRI
  • Murders had some form of mental disorder

  Six had schizophrenia, etc
• What were participants instructions

  • Medication free for 2 weeks prior to brain scan
  • Control group matching each murder with normal person same sex and age
  • 6 schizophrenics matched
• Whats the procedure

  Sampling method - Opportunity sample

  • PET scan study brain
  • Radioactive tracer FDG - scan done 32 minutes after
  • All asked to do a task CPT
• Results

  • Reduced brain activity of NGRI in places such as hippocampus (Left) - areas previously related to violence
  • Increased activity in NGRI in places such as cerebellum
  • NO differences in Putamen / Midbrain
• Summary of results

  Reduced activity in PCHAT

  Increase in HATCO

  Abnormal symmetries - reduced activity on left side, greater on right
• Conclusion of study

  • Past research - link between areas of brain and aggression (animal/human) (hippocampus + cats)
  • Netural processed underlying violence are complex - reason cant be produced just off brain
  • Confoundibg variables
• What does the study NOT show

  • Does not show is violence is caused by biology alone
  • Do not show pleads NGRI are not responsible for action