Found: Brain Area Responsible for Violence
It seems the bad intentions that come just before a violent act occurs originate from a very specific part of our brains -- the hypothalamus.
That’s the finding of a study conducted by researchers at the Neuroscience Institute at the New York University (NYU) Langone Medical Center. Mice were used because they share many brain structures with humans. Previous studies have linked the hypothalamus to violent behavior, but this is the first to link warning signs of premeditated violence, such as stalking, bullying and sexual aggression, to a specific part of the brain.
The study team trained male mice to attack weaker ones. Then they observed how aggressively the male mice tried to get access to and harass other mice. The researchers measured the number of attempts the aggressive mice made to poke their noses through holes leading to another mouse entering their territory so they could attack them.
The team looked specifically at the ventrolateral part of the ventromedial hypothalamus (VMHvl), which is centrally located in the brain underneath the hypothalamus. Probes were used that measured nerve activity in the mouse brains before, during and after they planned to attack.
Nerve cell activity in the VMHvl peaked just before the mice poked their noses through the holes, and this occurred even when the hostile mice could not smell or see the victim mice. The team also found that nerve cell activity in the VMHvl increased by ten times during the first moments after the victim mice appeared.
However, genetically stopping VMHvl activity brought a halt to almost all of the aggressive motivations in the mice (but it didn’t stop other learned behaviors, like nose poking to get a treat).
The researchers believe their work points to a way of "controlling aggressive behaviors" without requiring sedation.