Scientists Find the Kill Switch in Mice's Brains That Turns Them Into Zombie-Like Predators

Kill switches in the brain? It's true. In a new study, scientists discover that one could actually turn mice's predatory kill instinct on and off, turning them into predatory creatures not unlike zombies from The Walking Dead.

According to a report from Phys Org, researchers from Yale University were able to identify two sets of neurons in the brains that triggers predatory hunting: one in the amygdala that spurs on the animal to chase after prey and another that gets them to use their jaw and neck muscles to bite and kill.

Furthermore, the team found a way to control the mice's urges. Using optogenetics, which is a method of tweaking the neurons so they respond to laser light, they were able to activate the sets of neurons that gets the mice into "kill mode". The researchers discovered that when the laser is turned off, the creatures exhibited regular behavior.

It's when the laser is turned on that things get interesting and the mice begin behaving like the walkers from The Walking Dead. The animals chase and bite practically anything around them, even inanimate objects that are of no threat to them like bottle caps and wooden sticks, according to lead investigator Ivan de Araujo who is also an Associate Professor of Psychiatry at the Yale University School of Medicine and an Associate Fellow at the John B. Pierce Laboratory.

"We'd turn the laser on and they'd jump on an object, hold it with their paws and intensively bite it as if they were trying to capture and kill it," Araujo explained. Predatory hunting, he added, is a "major evolutionary player in shaping the brain. There must be some primordial subcortical pathway that connects sensory input to the movement of the jaw and the biting."

The team also experimented by blocking the different sets of neurons one at a time, a report from New Scientist revealed. In blocking the set of neurons assigned to pursue, the animals were found to slow down in chasing the prey although they are still able to go in for the kill. On the other hand, when they blocked the neurons responsible for the jaw and neck, the strength of their bite decreased by 50 percent.

This new study was published in the January 12 issue of Cell.