Brain Abnormalities in Murderers Indicated by Positron Emission Tomography.

Adrian Raine, Monte Buchsbaum, and Lori LaCasse

1997

Adrian Raine

Typical Criminals?

Physiological Psychology Physiological Psychology

The central question:

Can we link physiological

process or structure

directly to human behaviour?

Physiological Psychology 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

Physiological PsychologyPhysiological Psychology

Discussion pointsWhat are the advantages to the

physiological explanation of behaviour?What are the disadvantages?Why is this approach described as

determinist?How else can violent behaviour be

explained?

Physiological Psychology - RainePhysiological Psychology - Raine

The Raine hypothesis

That the seriously violent individuals have localised brain damage in

the prefrontal cortex; the amygdala;

the thalamus; the hippocampus;

Physiological Psychology - RainePhysiological Psychology - Raine

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).

Phineas Gage

Frontal Lobes

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, it’s crucial for learning conditioned responses — essential, for example, to a child’s 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) group’s 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."

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.

Parietal Lobe

corpus callosum (cull low' sum)

It is an enormous bundle of axons which interconnects the left and right cerebral hemispheres. Therefore, it is a commissure.

It disseminates information from the cerebral cortex on one side of the brain to the same region on the other side .

Corpus Callosum

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.

Thalamus

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.

Physiological Psychology - RainePhysiological Psychology - Raine

The participants:41 murderers (39 males 2 females)Charged with murder/manslaughter in

California/USAAll pled NGRIAll were referred for physiological

examination

Physiological Psychology - RainePhysiological Psychology - Raine

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

Physiological Psychology - RainePhysiological Psychology - Raine

CONTROL GROUP41 normal individuals (non murderers)matched for sex and ageincluding 6 ‘murdering’ schizophrenics

who were matched with 6 ‘ non murdering’ schizophrenics

Physiological Psychology - RainePhysiological Psychology - Raine

The method

A ‘natural’ experiment

The procedurePET Scans to examine the brain

Physiological Psychology - RainePhysiological Psychology - Raine

What is a PET SCAN?Positron Emission TomographyThis 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.

Physiological Psychology - RainePhysiological 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

A typical PET scan

Physiological Psychology - RainePhysiological Psychology - Raine

THE RESULTSDIFFERENCES in the brains of the

murderers

CORTICAL REGIONSLOWER ACTIVITY

Physiological Psychology - RainePhysiological Psychology - Raine

THE RESULTSDIFFERENCES in the brains of the

murderers

SUBCORTICAL REGIONSLOWER ACTIVITY

Physiological Psychology - RainePhysiological Psychology - Raine

THE RESULTSSUMMARY OF DIFFERENCES in the

brains of the murderersReduced activity in prefrontal cortex,

parietal region & corpus callosumLeft hemisphere less activity than

rightAbnormal asymmetries in amygdala

& thalamus

Physiological Psychology - RainePhysiological Psychology - Raine

THE RESULTSBoth groups performed similarly on

performance taskNOT CONTROLLED6 murderers were left handed14 murderers were non white23 murderers had history of head injury

Physiological Psychology - RainePhysiological Psychology - Raine

DISCUSSION POINTSPre Frontal deficit - associated with

impulsivityHippocampus & amygdala - associated with

aggressive behaviour & with conditioned emotional responses

Amygdala - reduced activity associated with fearlessness

Corpus Callosum - dysfunction associated with predisposition to violence

Physiological Psychology - RainePhysiological Psychology - Raine

CONCLUSIONUnlikely that violence is due to a single

brain mechanismEvidence that - murderers pleading

NGRI may have different brain functions to ‘normal’ people

Evidence that - murderers have different brain functions to psychiatric patients

Physiological Psychology - RainePhysiological Psychology - Raine

Validity & reliability of the research? Large sampleSignificant results (non trivial)Two tailed testsAreas of brain selected based on

previous researchCould IQ differences be a factor?

Physiological Psychology - RainePhysiological 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

Physiological Psychology - RainePhysiological 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

Physiological Psychology - RainePhysiological 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?

Raine’s 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?"

Ethics

Physiological Psychology - RainePhysiological 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?

Physiological Psychology - RainePhysiological 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’?

Physiological Psychology - RainePhysiological Psychology - Raine

Application - how is this study useful?

InterventionsRaine 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.

THE END