Scientists turned quiet mice into aggressive ones by using optogenetics and activating a set of neurons in the amygdala.
The amygdala is a region in the brain associated with memory and primary emotions such as fear and motivation. A paper published in the journal Cell shows that by stimulating the amygdala with a laser the mice become aggressive immediately.
When the laser if off, the lab mouse acts normally, walking around its cage. However, when the laser is turned on, the mice displays aggressive behavior toward live insects as well as innate objects.
“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,” said lead investigator Ivan de Araujo, coauthor of the paper and associate professor of psychiatry at Yale University.
“The system is not just generalized aggression. It seems to be related to the animal’s interest in obtaining food,” explained the researchers.