Brain abnormalities in murderers indicated by positron emission tomography left angular gyrus, and the corpus callosum, while abnormal asymmetries of. Raine, A., Buchsbaum, M., & LaCasse, L. (). Brain abnormalities in murderers indicated by positron emission tomography. Biological. A positron emission tomography was used to show brain activity during a cognitive Murderers brain’s had less activity in areas associated with aggression, self.
|Published (Last):||16 May 2005|
|PDF File Size:||12.6 Mb|
|ePub File Size:||2.43 Mb|
|Price:||Free* [*Free Regsitration Required]|
It considers the topic: What makes a criminal biological. Several previous research studies have suggested that damage to the pre-frontal cortex may cause individuals to become increased in impulsivity, immaturity.
Watch this video on Phineas Gage: The part of the limbic system made up of the amygdala, hippocampus and prefrontal cortex governs the expression of emotion. Together with the thalamus, these areas are also important in learning, memory and attention and it has been suggested that abnormal functioning may lead to problems such as not being able to form conditioned emotional responses and the failure to learn from experiences.
In order to gain a deeper understanding of this study, learn how PET Scans work:. One particular group of violent offenders are those who plead not guilty by reason of insanity NGRI to a charge of murder. If significant differences could be found between the patterns of glucose metabolism in the brains of such individuals compared to non-murderers, the correlation may indicate that murderers pleading NGRI are more prone to violence than non-murderers.
Until this study, no previous brain imaging had been conducted to either support or refute this notion. The hypothesis in this study by Raine et al. The dependent variable was whether the participant showed evidence of brain dysfunction in their prefrontal cortex and other areas such as the angular gyrus, amygdala, hippocampus, thalamus and corpus callosum. The experiment is considered quasi abnormzlities the experimenters could not manipulate the independent variable as it was naturally occurring; a person was a murderer, or they were not a murderer.
The study used a matched participants design. They had a mean age of Within in the preceding individuals, 7 were surrounded by unusual circumstances which suggested some mental impairment. Excluding the 6 schizophrenics in the control emisaion, all of the control participants were screen for any history of mental illness. However, six non-murderers were schizophrenics. All of the murderers were abnormaloties in custody and were medication free for two weeks prior to the brain scanning.
All of the non-murderers were not taking any medication. This is a control measure. This is another control. An individually molded, thermosetting plastic head holder was used to hold the emissiin still during the scan. This detail was precise so that the study could be replicated. No significant differences were found for performance on the CPT or handedness except left-handed murderers had significantly less abnormal amygdala asymmetry than right-handed murderers.
This applied to some of the areas identified in the hypothesis as being linked to violence e. No differences in emussion area s, notably those structures that were associated with mental illness but not violence e. Murderers pleading NGRI have significant differences in the metabolism of glucose in a number of brain areas compared to non-murderers.
Reduced activity in the prefrontal, parietal, and callosal regions of the brain, together with asymmetries of activity in the amygdala, thalamus, and medial temporal lobe including the hippocampus, may be one of many predispositions towards violence in murderers pleading not guilty by reason of insanity.
This reduced activity in the prefrontal areas may explain impulsive behaviour, a loss of self-control, evidence of immaturity, altered emotionality and the inability to modify behaviour. All of these may make it easier to carry out different kinds of aggressive acts because the normal constraints on behaviour may be reduced. It seems there are several processes involved and if there are deficits in a number of these processes, the likelihood of violent behaviour occurring is much greater.
The results do NOT show that violent behaviour is determined by biology alone. There are a number of other factors which must be taken into account. Social experiences, situational factors, psychological predispositions and learned responses will all have their part to play and perhaps the physiological elements may only produce predispositions to extreme forms of violent behaviour rather than being a cause in themselves.
One should therefore be cautious about attributing the reason why individuals commit murder simply to the fact that they are found to have mental disorders. It may even be that brain dysfunction is an effect of violence. Results do NOT show that all violent offenders have such brain dysfunctions; the study can only draw conclusions about this kind of violent offender i. This is because it is a highly controlled, nomothetic laboratory study, which has falsifiable measures.
Individuals with sociopathic behavior caused by frontal damage fail to respond autonomically to social stimuli. Behavioural brain research41 2 Brain abnormalities in murderers indicated by positron emission tomography. Biological psychiatry42 6 Selective reductions in prefrontal glucose metabolism in murderers.
Biological psychiatry36 6 An approach to the neurology of aggression. Journal of Psychiatric Research22 2 Cortical Functions Routledge Modular Psychology.
Your email address will not be published. In order to gain a deeper understanding of this study, learn how PET Scans work: Watch this short video on how PET scans work: Two hypotheses were tested: Seriously violent individuals pleading NGRI have relatively localised brain dysfunction in the prefrontal cortex, angular gyrus, amygdala, hippocampus, thalamus and corpus callosum areas of the brain previously linked empirically or conceptually to violence.
Seriously violent individuals pleading NGRI show no dysfunction in other brain areas i. Method and Design Quasi Experiment. The dependent variable was whether the participant showed evidence of brain dysfunction in their prefrontal cortex and other areas such as the angular gyrus, amygdala, hippocampus, thalamus and corpus callosum The experiment is considered quasi because the experimenters tomoraphy not manipulate the independent variable as it was naturally occurring; a person was a murderer, brsin they were not a murderer.
To obtain evidence as to whether they were NGRI.
To find out if they were competent to understand the judicial process. To see if there was any evidence of diminished mental capacity indicater may affect the nature of the sentence they received. PET machine to image brain functioning.
Flourodeoxyglucose FDG tracer injected to trace brain metabolism. A degraded stimulus version of a continuous performance task CPT which required participants to detect target signals for 32 minutes, a task which had been shown to make the frontal lobes work especially hard, together with the right temporal and parietal lobes, so investigators could see how the different areas functioned.
The cantheometal line is a horizontal line drawn from the eye to the ear. Results Brain imaging results. Summary of Murderers results Reduced activity i.
Conclusions Murderers pleading NGRI have significant differences in the metabolism of glucose in a jndicated of brain areas compared to non-murderers. Raine et al – Brain Abnormalities in Murderers. Leave a Reply Cancel reply Your email address will not be published.