An implant built by Stanford University engineers produces light to stimulate nerves of the brain, spinal cord, or limbs in mice. The technology is powered wirelessly, using the mouse's own body to transfer energy. Scientists will use the new optogenetic nerve stimulation methods to investigate a wider range of scientific questions, including how to relieve tremors in Parkinson's disease.

Traditionally, optogenetics has required a fiber optic cable attached to a mouse's head to deliver light and control nerves. With the somewhat restrictive headgear, mice can move in an open cage but cannot navigate an enclosed space. Such constraints limit what can be learned through optogenetics.

To amplify and store radio frequency energy, a grid is placed over the device's chamber. The holes are smaller than the wavelengths contained within, trapping the energy. The mouse then essentially becomes a conduit, releasing the energy from the chamber into its body, where it is captured by a 2-mm coil in the device.

The device is the first attempt at wireless optogenetics small enough to be implanted under the skin. The technology may even be able to trigger a signal in muscles or some organs, which were previously not accessible to optogenetics.

The novel powering mechanism also enables a range of new experiments to better understand and treat mental health disorders, movement disorders, and diseases of the internal organs.