Researchers think they've pinpointed the area of the brain that causes us to be violent and aggressive. It's hoped that the discovery could eventually help us develop treatments for severe psychiatric disorders – imagine a drug that removes bullying tendencies – although the team warns that this is still a long way off.
In studies of mice, researchers from New York University found that the ventrolateral part of the ventromedial hypothalamus (VMHvl) within the brain is responsible for urges towards premeditated violence. The hypothalamus has already been associated with the regulation of sleep, hunger, and temperature levels in the body.
"Our study pinpoints the brain circuits essential to the aggressive motivations that build up as animals prepare to attack," said one of the team, Dayu Lin. "Our results argue that the ventrolateral part of the ventromedial hypothalamus should be studied further as part of future efforts seeking to correct behaviours from bullying to sexual predation."
Because the structures of human brains are so alike to those in mice, Lin and her colleagues suggest that the same area is responsible for feelings of aggression in people, and that link could make a huge difference in the analysis of these tendencies in the future.
Previous studies have looked at curbing a desire for violence through the use of electrodes planted in the brain, but a drug would offer a much more convenient and safe way of tackling these types of behavioural problems.
"For us the goal is to find new ways to control violence, especially in patients who suffer from mental disorders," Lin told the Huffington Post. "The idea is to take that component out of the disease."
The team's experiments involved training stronger mice to attack weaker mice in a specially arranged environment. By measuring how aggressively the mice bullies sought out their victims, the researchers were able to track patterns of nerve cells in the brain – and the tests showed that activity in the VMHvl region peaked just before the mice began looking for fellow creatures to attack.
VMHvl nerve cell activity also increased (by as much as 10 times) as the weaker mice came into view.
By blocking VMHvl activity, the team was able to stop the aggressive motivations shown by the mice without inhibiting other normal behaviour (such as seeking out treats). It's the first time that the premeditated, motivational aspect of aggression has been linked to the ventrolateral part of the ventromedial hypothalamus in the brain.
The group's work has been published in the journal Nature Neuroscience.