By using light to activate certain neurons in the brain the mouse would immediately jump on the nearest object, pin it down and repeatedly bite it.
This rather worrisome effect was manufactured after scientists worked out how to activate the mouse’s ‘predatory instinct’ inside its amygdala.
“When a non-edible item was placed in the cage, laser activation caused the otherwise indifferent mice to immediately assume a ‘capture-like’ body posture and seize the object, which was then held with the forepaws and bitten.”
“Behavior was interrupted immediately upon laser deactivation” explains the paper.
Testing out this ‘switch’, the team found that the mouse would target anything smaller than itself and would attack anything whether it was alive, dead or an inanimate object.
The only thing the mouse wouldn’t attack was one of its own kind.
What’s potentially even more disturbing is the accuracy with which the team were able to control their subjects.
By only activating ‘hunt’ part of the amygdala they found they could command the mouse to chase down its prey but only wound it.
Yet when they activate the ‘biting’ region they discovered the mouse would raise its hands and engage in fictitious eating, almost as though it were imagining food in its grasp.
What’s interesting is that their ability to control the mouse greatly depended on how hungry it was. So when it was very hungry its aggression would be heightened and it’s ability to act as command was increased.
Yet when the mouse was full its reactions would be dulled.
This suggests that for mice and for humans as well, the ability to engage this predatory part of our brains is very closely linked to how hungry we’re feeling.
Thankfully for us humans this predatory instinct usually only stretches as far as grumpily trying to find a McDonalds, not actually jumping on things and biting them.
Coolest Science Photos Of The Decade
A baby weasel took the ride of a lifetime on the back of a green woodpecker in Hornchurch Country Park in East London. Photographer Martin Le-May just happened to be lucky enough to capture the moment on March 2, 2015.
NASA, ESA, H. Teplitz and M. Rafelski (IPAC/Caltech), A. Koekemoer (STScI), R. Windhorst (Arizona State University), and Z. Levay (STScI)
Astronomers using NASA's Hubble Space Telescope assembled a comprehensive picture of the evolving universe -- among the most colorful deep space images ever captured by the 25-year-old telescope. The image was released on June 3, 2014.
NASA astronaut Mike Hopkins snapped a selfie while completing a spacewalk outside of the Earth-orbiting International Space Station on Dec. 24, 2013.
Hadoram Shirihai/Tubenoses project
A rare Mascarene petrel with an egg-shaped bulge in its middle. Photographed in 2012 by researchers near Reunion, an island off the coast of Madagascar, it was said to be the first to show a bird flying with a visible "baby bump."
Wikimedia Commons: Wtop.com
In 2011, a female Celebes crested macaque (Macaca nigra) in North Sulawesi, Indonesia, decided to pick up British wildlife photographer David Slater's camera and take a selfie.
NIAID (National Institute of Allergy and Infectious Diseases)
A stunning scanning electron micrograph of a human T lymphocyte (also called a T cell) from the immune system of a healthy donor, taken on May 24, 2010.
Sung Hoon Kang, Joanna Aizenberg and Boaz Pokroy; Harvard University
An electron microscope photograph shows self-assembling hair-like polymers around a polystyrene sphere, about two micrometers in diameter. It won first place in the National Science Foundation's 2009 International Science & Engineering Visualization Challenge.
Hurricane Ike covers more than half of Cuba. It was taken by the Expedition 17 crew aboard the International Space Station from a vantage point of 220 miles above Earth, on September 9, 2008.
Gloria Kwon/NIKON Small World
A close-up look at a double transgenic mouse embryo, just 18.5 days old. The photo won first place in Nikon's 2007 Small World Photomicrography Competition.