Scientists have created an incredible new implantable device that has the ability to stimulate nerves in mice.

The glowing device is only the size of a peppercorn, and can activate nerves in the brain, spinal cord, and limbs of lab mice. The device also uses the rodent's own body to transfer energy, Stanford University reported. The device is the first to deliver optogenetic nerve stimulation in a "fully implantable format." It combines optogenetics (using light to control brain activity) with a new technique for wirelessly powering implanted devices.

"This is a new way of delivering wireless power for optogenetics," said Ada Poon, an assistant professor of electrical engineering at Stanford. "It's much smaller and the mouse can move around during an experiment."

In the past, optogenetics has required a fiber optic cable to be attached to a subject's head, potentially restricting its movement and altering behavior. This new device could help solve these problems by allowing the rodents to move around untethered.

The researchers noted figuring out a way to get the device to deliver light to prepared nerves was the easy part; what proved to be more challenging was discovering a way to power it over a large area. In these types of experiments, a mouse would move around a relatively large area, and the scientists needed a way of tracking these movements to provide localized power. To solve this, the researchers came up with the "crazy" idea to use the rodent's own body to transfer radio frequency energy into a wavelength that could resonate within the animal.

The researchers created a chamber that could store radio frequency energy that was outfitted with a grid with holes that were smaller than the wavelengths trapped inside, keeping it contained. "Wiggle room" in the grid allowed objects such as a mouse paw to come into contact with the boundary of the stored energy, turning it into a "conduit" that releases energy from the chamber within its body where it is captured in a coil within the device.

"The team says the device and the novel powering mechanism open the door to a range of new experiments to better understand and treat mental health disorders, movement disorders and diseases of the internal organs. They have a Stanford Bio-X grant to explore and possibly develop new treatments for chronic pain," the University concluded.

The findings were published in a recent edition of the journal Nature Methods.