The scientists at Yale University had been studying mice living and eating in cages. “They had nothing else to do other than eat the pellets we throw in the cage,” said Professor Ivan de Araujo. “I began to wonder how natural and relevant this behavior is.” The scientists wanted to understand how the mice feed themselves. So they decided to turn them into killing machines.
How Did The Scientists Turn The Mice Into Killing Machines?
Optogenetics is a means of engineering specific neurons to fire upon light stimulation. They found that by using optogenetics they can activate the two sets of neurons in the central nucleus of the amygdala, that prompt them to hunt – one that controls pursuit, and the other to kill.
When one set of neurons was fired it prompted the mouse to pursue its prey, doing the same to another set caused the animal to bite and kill its prey. The effect was so strong that the mouse would savagely attack anything nearby such as bottle caps and wooden sticks. The research found that if the mouse was already hungry it was easier to stimulate aggression. The mice didn’t harm other mice, although a captured cricket would immediately get eaten.
“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 Ivan de Araujo, of Yale University, lead author of the study. “The mice take on qualities of ‘walkers’ from TV series, The Walking Dead, pursuing and biting almost anything in their path.” As said in the study published in the journal Cell.
Hunting is a complex behavior that is common among jawed vertebrates, including humans. “It is a major evolutionarily player in shaping the brain,” said Araujo. “There must be some primordial subcortical pathway that connects sensory input to the movement of the jaw and the biting.”
What Are They Doing Now?
Now the scientists are learning more about what triggers predatory behavior within the amygdala region of the brain. “We now have a grip on their anatomical identities, so we hope we can manipulate them even more precisely in the future,” says de Araujo. Soon the study will be perfected without a flaw, they will have created the ultimate killer-zombie mouse that ever existed.
