Scientists have made a startling discovery in laboratory mice that someday could be used to turn humans into killing machines.
As reported by National Public Radio (NPR), researchers discovered how to make mice kill at the flip of a switch, essentially, adding that may reveal how hunting behaviors evolved hundreds of millions of years ago.
Mice in the lab became very aggressive predators when two sets of neurons in the amygdala were activated using laser light, according to a research team which published its findings recently in the journal Cell. (RELATED: Discover more scientific news and discoveries at Scientific.news)
Ivan de Araujo, an associate professor of psychiatry at Yale University, as well as an associate fellow at The John B. Pierce Laboratory in New Haven, Conn., said that the use of the laser light stimulant transformed the rodents into very efficient hunters.
“They pursue the prey [a live cricket] faster and they are more capable of capturing and killing it,” he said—all without undergoing any special conditioning or previous training to hone their hunting skills.
NPR noted further:
Activating the neurons even caused the mice to attack inanimate objects, including sticks, bottle caps and an insectlike toy. “The animals intensively bite the toy and use their forepaws in an attempt to kill it,” De Araujo says.
But the aggressive behavior is reserved for prey. Mice didn’t attack each other, even when both sets of neurons were activated.
The results of the stimulation research may provide insight into how the brain has changed over the course of hundreds of millions of years, when the first animals with jaws began to appear on earth. De Araujo said that the new ability to aggressively hunt down and kill prey very likely “influenced the way the brain is wired up in a major way.”
“Superior predatory skills led to the evolutionary triumph of jawed vertebrates. However, the mechanisms by which the vertebrate brain controls predation remain largely unknown,” says a summary of the research.
De Araujo said that, specifically, the brain had to develop so-called ‘hunting circuits’ that enabled precise, coordinated movements of a predator’s jaw and neck, adding that is a “very demanding task.”
The research team believed from the outset of their study that mice had these hunting circuits wired already in their brains because many kill and eat insects. Also, one species that is known as the killer mouse “basically feeds on live prey, including sometimes even other mice,” said de Araujo.
As expected, the research team indeed discovered a set of neurons in the amygdala, which is a structure that spurs both emotion and motivation, became active when a mouse began to pursue prey. In addition, they were able to isolate a second set of neurons that were activated when the rodent was biting and killing.
Using a technique called optogenetics, the researchers managed to create mice in which both sets of neurons were controllable through the use of light emitted from a laser. That essentially created “an on-off switch” the team could use to activate either set of neurons or both, the associate professor said.
“When we stimulate [both sets of] neurons it is as if there is a prey in front of the animal,” he said. At that point, the mice assume a body posture and take actions that are generally associated with real hunting.
The research team also unearthed evidence of similar hunting circuits in rats and other species—including human beings—whose survival at one point during evolution depended on our ability to hunt and kill large animals.
You can imagine that this kind of discovery would interest, say, the Defense Department, which could utilize it as a means of turning soldiers “on and off” on the battlefield. [RELATED: Stay current with the evil side of science at Evil.news]
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