Some men more likely to riot because of "impulsive" brains
Some men may be more likely to riot because of their "impulsive" brains, a study suggests.
Certain individuals have lower levels of a brain chemical that helps keep behaviour under control, say scientists.
The University of Cardiff researchers uncovered a link between impulsiveness and levels of the neurotransmitter GABA in a key brain region.
Those with low levels tended to be more aggressive and to respond rashly to "urges".
GABA is one of a family of brain chemicals that allow signals to flow between neurons.
Around 30 male university students had their levels of GABA measured using a specialised type of brain scan.
They were also asked to complete questionnaires that assessed different aspects of impulsiveness, a trait known to influence self-control.
Participants with more GABA in the pre-frontal brain region had lower scores for "urgency" - the tendency to behave rashly in response to distress or strong emotions and urges.
Men with lower GABA levels had higher urgency ratings, making them more likely to act aggressively, drink and take drugs.
The link with GABA was specific to the dorsolateral pre-frontal cortex, a region critical to higher thinking functions.
The research, funded by the Wellcome Trust, is published in the journal Biological Society.
Study leader Dr Frederic Boy said: "What is clear is that the way people behave results from a complex interaction between a number of genetic, social and environmental factors. What we've found is that one of the reasons why some men act impulsively may be related to lower concentration of GABA in a specific part of men's brains."
None of the undergraduates taking part in the study had any history of psychiatric disorders or substance dependence.
The research helps to illustrate the role of basic brain physiology in controlling behaviour, say the scientists.
"The ability to regulate our behaviour in response to a constantly changing physical and social world is key to adapted life," sad Dr Boy.
"Failure in this finely-tuned mechanism is particularly important in most psychiatric disorders, where impulsiveness is the second most common symptom. We hope this research will lead to further studies and help bridge the gap between recent genetic studies and imaging studies of psychiatric disorders."