Brain Abnormalities in Murderers Indicated by Positron Emission Tomography.

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Brain Abnormalities in Murderers Indicated by
Positron Emission Tomography.

• Adrian Raine, Monte Buchsbaum, and Lori LaCasse
• 1997

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Adrian Raine
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Typical Criminals?
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Physiological Psychology

• The central question is
• Can we link physiological process or structure
  directly to human behaviour?

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Physiological Psychology

• Research suggests that brain dysfunction may
  PREDISPOSE a person to being violent
• The FRONTAL brain region may be associated with
  violent behaviour
• Some violent offenders plead NGRI (not guilty by
  reason of insanity) to murder charges

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Physiological Psychology - Raine

• The Raine hypothesis is that some seriously
  violent individuals have localised brain damage
  in certain areas of the brain including
• the prefrontal cortex the amygdala
• the thalamus the hippocampus and the
  corpuscallosum.
• Top tip take time to get to know the brain see
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Physiological Psychology - Raine

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The frontal lobe

• It is important for voluntary and planned motor
  behaviours - such things as voluntary movement of
  eyes, trunk, limbs and the many muscles used for
  speech
• The motor speech area (Broca's area) is usually
  in the frontal lobe of the left hemisphere
  regardless of which hemisphere is dominant for
  handedness (i.e. the left hemisphere for right
  handers).

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Frontal Lobes
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Frontal Lobes
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• Raine suggests three reasons why prefrontal
  deficits may cause antisocial personality
• First, the region appears to be critical for
  self-restraint and deliberate foresight. "One
  thing we know about antisocials is that they do
  not think ahead," said Raine.
• Second, its crucial for learning conditioned
  responses essential, for example, to a childs
  linking the thought of a misdeed with anxiety
  over punishment. "Unconscious mental-emotional
  associations such as these lie at the core of
  what we call conscience," Raine said.
• Third, if prefrontal deficits underlie the
  Antisocial Personality Disorder (APD) groups low
  levels of autonomic arousal, these people may
  unconsciously be trying to compensate through
  stimulation-seeking. "For some kids," said Raine,
  "one way of getting an arousal-jag is by robbing
  stores or beating people up."

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parietal lobe (pa rye' it ul)

• It is important for aspects of somesthetic
  sensation (i.e. touch, kinesthesia, pain), taste,
  and other sophisticated perceptive abilities.
• An example of the latter would be the receptive
  speech area (Wernicke's area) which is in the
  inferior part of the parietal lobe on the left
  side regardless of which hemisphere is dominant
  for handedness.
• The parietal lobe of the right hemisphere appears
  to be especially important for perceiving spatial
  relationships.

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Parietal Lobe
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corpus callosum (cull low' sum)

• It is an enormous bundle of axons which
  interconnects (joins) the left and right cerebral
  hemispheres.
• It disseminates information from the cerebral
  cortex on one side of the brain to the same
  region on the other side it is a communication
  bridge .

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Corpus Callosum
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• thalamus (thal' uh mus)
• A large mass of grey matter deeply situated in
  the forebrain. There is one on either side of the
  midline.
• It relays to the cerebral cortex information
  received from diverse brain regions. Sort of a
  requisite 'last pit stop' for information going
  to cortex.
• Axons from every sensory system (except
  olfaction) synapse here as the last relay site
  before the information reaches the cerebral
  cortex.
• There are other thalamic nuclei that receive
  input from cerebellar-, basal ganglia- and
  limbic-related brain regions.

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Thalamus
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temporal lobe (temp' or ul)

• Various parts of it are important for the sense
  of hearing, for certain aspects of memory, and
  for emotional/affective behaviour.

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Physiological Psychology - Raine

• The participants
• 41 murderers (39 males 2 females)
• Charged with murder/manslaughter in
  California/USA
• All pled NGRI
• All were referred for physiological examination

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Physiological Psychology - Raine

• The histories
• head injury/brain damage(23)
• drug abuse (3)
• affective disorder (2)
• epilepsy (2)
• hyperactivity learning impairment (3)
• personality disorder (2)

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Physiological Psychology - Raine

• CONTROL GROUP
• 41 normal individuals (non murderers)
• matched for sex and age
• including 6 murdering schizophrenics who were
  matched with 6 non murdering schizophrenics

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Physiological Psychology - Raine

• The method
• A natural experiment (quasi) using independent
  measures design where participants were matched
  on key criteria.
• The procedure
• PET Scans were used to examine the brain

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Physiological Psychology - Raine

• What is a PET SCAN?
• Positron Emission Tomography
• This method assesses the amount of metabolic
  activity in various parts of the brain
• A scanning machine detects positrons emitted
  through the head with high amounts being
  associated with a higher level of metabolic
  activity.

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Physiological Psychology - Raine

• THE PET SCAN process
• Patients are injected with fluorodeoxyglucose
  tracer (radioactive glucose)
• For about 30 minutes before the PET SCAN the
  participants are engaged in a continuous
  activity
• This activity aimed to activate the FRONTAL
  LOBES, and the RIGHT TEMPORAL and PARIETAL LOBES

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Diagrams from Raines research
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A typical PET scan
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Raine found some significant results

• He suggested there was evidence for DIFFERENCES
  in the brains of the murderers
• He found amongst other things LOWER ACTIVITY in
  some
• CORTICAL REGIONS of the brain

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SUMMARY OF DIFFERENCES in the brains of the
murderers

• Reduced activity in prefrontal cortex, parietal
  region corpus callosum
• Left hemisphere less activity than right
• Abnormal asymmetries in amygdala thalamus

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• Both groups performed similarly on performance
  task
• There were certain characteristics that were NOT
  CONTROLLED..i.e
• 6 murderers were left handed
• 14 murderers were non white
• 23 murderers had history of head injury

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Physiological Psychology - Raine

• DISCUSSION POINTS
• Pre Frontal deficit - associated with impulsivity
• Hippocampus amygdala - associated with
  aggressive behaviour with conditioned emotional
  responses
• Amygdala - reduced activity associated with
  fearlessness
• Corpus Callosum - dysfunction associated with
  predisposition to violence

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Physiological Psychology - Raine

• CONCLUSION
• Unlikely that violence is due to a single brain
  mechanism
• Evidence that - murderers pleading NGRI may have
  different brain functions to normal people
• Evidence that - murderers have different brain
  functions to psychiatric patients

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Physiological Psychology - Raine

• Validity reliability of the research?
• Large sample
• Significant results (non trivial)
• Two tailed tests
• Areas of brain selected based on previous
  research
• Could IQ differences be a factor?

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Physiological Psychology - Raine

• WHAT these findings DO NOT demonstrate
• That violent behaviour is caused by biology
• That murderers are NOT RESPONSIBLE for their
  actions
• That brain dysfunction causes violent behaviour

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Physiological Psychology - Raine

• WHAT these findings DO demonstrate
• That there MAY BE a link between brain activity
  and a predisposition towards violence which
  should be investigated further

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Physiological Psychology - Raine

• Ethics - how might you criticise this study?
• Generalisation - can the findings of this study
  be generalised to all murderers?
• Why or why not?

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Ethics
Raines findings raise important ethical
questions about culpability and free will. "To
what extent," he asked, "should we take
disordered brain functioning into account as part
of the reason for certain types of
crime? Assuming these people are not responsible
for their own brain damage, should we hold them
fully responsible for their criminal acts?"
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Physiological Psychology - Raine

• Questions
• Suggest one thing that cannot be concluded from
  this study
• The conclusions suggest that murderers who plead
  NGRI are different to 2 groups - which 2 groups?

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Physiological Psychology - Raine

• Questions
• Describe the strengths weaknesses of the
  NATURAL experimental method?
• What do you think might be the main difficulty in
  drawing conclusions from PET observed brain
  activity?

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Physiological Psychology - Raine

• Application - how is this study useful?

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Interventions

• Raine suggested a number of interventions that
  could be applied.
• Cognitive and behavioural therapy and drug
  therapy have potential.
• Biofeedback training children or adults to
  control their own arousal levels could be a
  useful tool.
• And children could be channelled into safe
  activities that might satisfy their natural
  stimulation-seeking and aggressive proclivities.

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