Happy little lab mice became bloodthirsty killing machines when scientists beamed lasers into certain parts of their brains, a new study shows.
The lasers flipped an “on-switch” inside the usually docile rodents’ brains, turning them into Mighty Mice — vicious predators who attack nearly everything in their paths, according to an article by Yale University researchers published Thursday in the journal Cell.
“The animals become very efficient in hunting,” Ivan de Araujo, an associate professor of psychiatry at Yale University told NPR. “They pursued the prey [a live cricket] faster and they are more capable of capturing and killing it.”
The animals even attacked inanimate objects, such as toys, bottle caps and sticks.”The animals intensively bite the toy and use their forepaws in an attempt to kill it,” De Araujo said.
But the homicidal furballs drew the line when it came to killing each other, proving the section of the brain is specifically linked to hunting, according to the report.
Scientists first discovered that a cluster of neurons in the amygdala — a brain structure linked to emotion and motivation — lit up when the mice were chasing prey. Nearby neurons also became active when the mice was biting and killing other animals.
Researchers then tapped into a technique called optogenetics, using the laser beam to stimulate specific neurons, prompting them to chase, bite, and kill prey.
“[It’s] an on-off switch for either or both of the circuits,” according to De Araujo, who said the research is meant to shed light on the evolution of hunting.
In the past, scientists have found similar hunting circuits in the brains of rats and humans.