Rat implanted with green LED to restore bladder control

This rat has two green LED lights implanted near its bladder to help the animal regain control of its urination. According to Washington University researcher Robert Gereau, the technology -- which involves a metal ring around the bladder to sense its fullness and a wirelessly rechargeable battery -- could eventually help humans with incontinence. Here's how it works, from New Scientist:

When the device was implanted in rats with bladder dysfunction, the metal ring measured changes in bladder size. When it detected that a rat was urinating more than two times an hour, the LED lights switched on.

These rats had previously received gene therapy, enabling their nerve cells involved in bladder-brain signaling to make a light-sensitive protein. When the LEDs were switched on, their light activated this protein, which in turn blocked urination signals from the bladder from reaching the brain.