Sunday Reading

New Delhi, 22 January 2009

Impulsive Violence

RESEARCH PICKS ON THE BRAIN

By Suraj Saraf

Is the human brain the asli mujrim in today’s wide-spreading violence in the world? Scientists are trying to zero in on mysterious brain process to find answers.

The number of people who have been killed by terrorism around the world were 80,498, an increase of 40 per cent in 2006 alone. This startling revelation comes out in a compilation assessing violence around the world by the National Counter Terrorism Centre of the US State Department. In 2005, the figure stood at 14,618.

While this report pertained only to one aspect i.e terrorism, figures of violence worldwide revealed in the first such comprehensive report “World report on violence and health” by World Health Organisation in 2000, were phenomenal at 1.6 million annually. These included 8,15,6000 suicides, 5,20,000 homicides and 5,10,000 war/civil strife related deaths. Over 90% of these deaths had occasioned in the developing countries. Sadly, there has been no further comprehensive report after this.  

No wonder there is worldwide concern over this blood-splitting. Despite attracting attention of social activists, religious servants, psychologists et al this problem of violence world-over has been on the rise. In the attempts to contain or end this blood and gore, studies being made by scientists for some years need mention here as these highlight brain-violence nexus.

According to a study by researchers at the U.S. Department of Energy’s Brookhaven National Laboratory, it is the level of a brain enzyme termed Monoamine Oxides (MAO) A that determines a person’s violent propensity or otherwise. A healthy person with lower levels of this enzyme exhibited more aggressive personality traits. The Brookhaven National Centre for Translational Neuroimaging held that this study is an example of how scientists are beginning to investigate the complex relationship between an individual’s biology and behaviour.

Study of MAO A levels in relation to violent behaviour and aggressiveness had been a research topic for over two decades. MAO A plays an important role in metabolizing neurotransmitters that affect human behaviour and the gene that regulates MAO A activity has already been associated with aggressive and violent behaviour.

Interestingly, the amount of MAO A activity in the brain of 37 healthy persons (under study) corresponded to the amount of aggression, they reported in a standard personality questionnaire to measure their verbal and non-verbal intelligence, depression and personality traits. Questions such as whether they frequently lost their temper, or enjoyed watching violent movies, measured their aggressiveness.

Accordingly, the less MAO A the persons under study had, the more they answered ‘yes’ to statements about taking advantage of others and causing them discomfort. The findings corroborate the relevance of brain MAO A in an aggressive personality. If this model of understanding is tested on individuals, who engage in violent behaviour (such as domestic violence), it should show promise in the future for pharmacological intervention against abnormal violence.

According to another recent research, strides in understanding human brain chemistry and genetics are giving scientists hope that they may be able to defuse violent behaviour to avoid tragedies such massacre in Virginia University. The incident, the deadliest school shooting case in U.S. history, occurred last April, wherein a 23-year-old man shot dead 38 persons on the campus and committed suicide.

“There is no doubt in my mind that if we could have examined his brain we would have found anomalies, and we would have been able to suggest remedies for him to get therapies,” said neurologist and researcher Dr. Allansiegal at the University of Medicine of New Jersey. “We might have been able to avoid the tragedy….if he had been treated properly in the hospital setting.”

Over some 40 years, clinical research and animal testing, particularly on cats, has shown that there are special zones in the brain linked to aggression and violence. The front region of the brain or the prefrontal cortex, including the limbic system, appears to play an important role in violent behaviour.

The killer Charless Whiteman who gunned down 16 persons in the University of Texas in the 60’s was found to have a tumour in the temporal lobe in the region of the limbic system. Apparently, the link between the prefrontal cortex and violence was first revealed in 1848 in the case of a railroad worker, Phiness Gage, whose skull was impaled by an iron rod in an explosion, damaging the front part of his brain. Gage survived the accident but his behaviour radically changed, with his formerly respectful, sensitive manner replaced by an impulsive and aggressive personality.

Neurologists believe that the frontal region regulates and controls aggression and violent impulses. A brain imaging study of four murderers found evidence that in most cases the prefrontal cortex and some deeper brain areas, including the amygdale, functioned abnormally.

According to Klause Micsek, a neuroscientist at Tufts University, serotonin is a neurotransmitter in the central nervous system, which in low level has been associated with several disorders. A similar study earlier in America had underpinned the interplay between several distinct brain regions, namely orbital frontal cortex, the anterior cingulate cortex and the amygdale. Amygdale, a tiny but highly influential portion of the brain is involved in the production of a fear response and other negative emotions.

This study had underlined that the human brain is wired with natural checks and balances that controls negative emotions, but a breakdown in this regulatory system appears to heighten the risk of violent behaviour.

As part of a special report on violence, UW Madison psychologist, Richard Davidson and his colleagues, analysed brain imagining data from a diverse group of studies on violent subjects and those predisposed to violence. The study focused on people diagnosed with aggressive personality disorder, childhood brain injuries and convicted murderers. They found common neurological disorders among the over 500 subjects, whose brains did not have the ability to properly regulate emotions.

Interestingly, a similar brain process has been implicated in a number of mental health problems, including depression and anxiety disorders. This newfound connection between violence and the brain dysfunction has thus opened a new avenue of studying and possibly treating violence and aggression.

One of the core findings dealt with the interplay between several distinct brain regions, namely the orbital frontal cortex, the anterior singulate cortex and the amygdale. While the first plays a crucial role in constraining impulsive outbursts, the second recruits other brain regions in the response to conflict and the third is involved in production of a fear response and other negative emotions.

The researchers found that normal brain activity in the orbital and anterior regions were blunted or entirely absenting many of the study group, while the amygdale showed normal or heightened activity. The inability of the two brain regions to effectively counteract the response of the amygdale may help explain how threatening situations can become explosive in some people.

A major strength of this research was in the range of people studied and consistency of the results. Researchers found dysfunction in the common brain regions in reviews of brain imaging data from 41 murderers, a study group suffering from aggressive impulsive personality disorder and a group diagnosed with anti-social personality disorders. They also reviewed data from two individuals who had suffered early damage to the two regions of the brain in question. Both had shown history of verbal and physical abusiveness and intermittent explosive bursts of anger.

This research also discerned a large group of subjects who had a genetic deficit that causes a disruption in the brain’s serotonin levels. The serotonin system employs many of the brain regions described above and has been linked to increased aggression. Analysis had shown that these emotion-controlling brain regions showed less activity in the individuals who carried this genetic abnormality.

Undoubtedly, this study could recast the way society looks at impulsive violence, by defining it as a mental health issue. Clearly, “emotion regulation is extremely significant for a whole constellation of problems people encounter.” ---INFA

(Copyright, India News And Feature Alliance)