Scientists use light to trigger killer instinct in mice

Technique called optogenetics used to pinpoint and take control of brain circuits involved in predatory behaviour

It has all the trappings of a classic horror plot: a group of normally timid individuals are transformed by scientists into instinctive killers, programmed to pursue and sink their jaws into almost anything that crosses their path.

However, this hair-raising scenario was recently played out in a study of laboratory mice, designed to uncover the brain circuits behind the predatory instinct.