There have been plenty of horror movies made about mice or rats already, but a new scientific study is about to give moviemakers some new fodder. The study indicates that mice have a sort of kill switch that can be turned on with a laser, turning the disgusting (or cute, depending on who you ask) little rodents into terrifying killing machines.
When mice become terrifying
The study was published on Thursday in the Cell journal. Researchers said that a particular form of light produced by a type of laser activates a pair of neurons in a mouse’s amygdala, the part of the brain responsible for the experiences associated with emotions and fear in humans. Once those specific neurons in the amygdala are activated in the mice, they become aggressive.
In the experiments, scientists shined the light directly on the animals’ amygdalae and found that it caused them to tense the muscles in their neck and jaw. However, the mice didn’t do this when the laser was turned on other parts of their brains. The lead researcher, Ivan de Araujo, said that after they turned the blue laser on, the mice would jump onto an object, grasp it with their paws, and then “intensively bite it as if they were trying to capture and kill it.” The mice would attack live prey like crickets and also inanimate objects like toys or bottle caps.
De Araujo also said the mice would become more efficient in hunting, although they would only attack prey or potential prey and not other mice during the study. Interestingly, the mice wouldn’t attack the researchers either. De Araujo stated that it had to be something that looked like food to them, or they wouldn’t bother attacking it.
Other animal studies associate aggression with amygdala stimulation
Researchers were specifically trying to learn about various animals’ feeding behaviors, the neural functions related to those behaviors, and how the biology of each has evolved over the centuries. As they went about studying these feeding behaviors in mice, they began to learn about the different parts of the animals’ brains and discern the link between each region and a mouse’s hunting instinct.
Throughout the years, researchers have also found that the amygdala is related to fear, as animals that have had their amygdala removed become fearless.
This isn’t the first time such a study has been performed, as scientists have also ran experiments on other types of animals that once depended on their ability to hunt, including humans and various species of animals.