Mice aren’t known for their killer instincts as they tend to shy away from other animals. However, a group of researchers at Yale University were able to switch on the specific gene that activates their killer instincts.
The researcher revealed their findings in a study published in the journal Cell on January 12.It reveals how the scientists were able to specifically target the neurons in the amygdala, which is the center of emotion and motivation in the brain. The activated neurons determine the animals to pursue prey while another set of signals are able to make the animals use their jaw and neck muscles in order to bite and kill their prey.
In order to active the killer instincts in mice, the researchers used a method known as optogenetics. It is used to determine specific neurons to activate when they are exposed to light. Using this method, the scientists were able to isolate and selectively activate every set of neurons responsible for the mice’s killer instincts.
The neurons were exposed to light from a laser. When the laser is turned off the mice act normally. However, when the laser is turned on, the mice begin to act more aggressively. They start attacking and biting almost anything they can find, from bottle caps to wood sticks. As soon as the laser was activated their killer instincts activate and grab the object and start biting it continuously as they would do to their prey.
According to Ivan de Araujo, an associate professor of psychiatry at the School of Medicine at Yale University, as well as the leader of the study, predatory instincts usually take the form of very complex behaviors which are present in most vertebrates which jaws and even humans. This instinct played a big part in the evolution of the brain.
The researchers found that the aggressive mice did not attack any of the other mice in its cage. Another interesting behavior is that the mice that were hungry pursued more aggressively what they identified as prey after being stimulated by the laser, than those who were not hungry. The scientists concluded the stimulation of neurons which activates the mice’s killer instincts does not produce just generalized aggression but it relates to its interest in gathering food.
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