The "root of all evil" has been discovered by scientists who found that part of the brain fires up before nefarious acts are carried out.

Researchers wanted to find out if bad intentions could be seen forming in the brain before any violence or aggression took place. They found that a distinct part of the hypothalamus - the brain region that controls body temperature, hunger and sleep - is activated shortly before an attack.

The study authors, from New York University, say it may be possible to spot warning signs of premeditated violence, stalking, bullying and even sexual aggression, and prevent it occurring for good.

"Our study pinpoints the brain circuits essential to the aggressive motivations that build up as animals prepare to attack," said Dr Dayu Lin, of the Neuroscience Institute at NYU Langone.


The part of the brain that switches on before aggressive behaviour is known anatomically as the ventro-lateral part of the ventromedial hypothalamus, or VMHvl, because of its central location inside the brain on the underside of the hypothalamus.

Researchers say the finding could lead to drugs that help people control violent behaviour, without the need for restraints or sedation.

It might even be possible to monitor brain activity continually and alert health experts or the security services before an aggressive attack, as in Philip K Dick's dystopian novella The Minority Report.

But the work is likely to prove controversial as drugs to prevent aggression or monitoring might be seen as preventing free will, which would raise ethical concerns.

Lin said targeting this part of the brain remains "only a distant possibility, even if related ethical and legal issues could be resolved".

For the study, male mice were trained to attack weaker males and monitored to see how aggressively they tried to gain access to, and bully, other mice.