The vocabulary word for today is “optogenetics.” It refers to a process that uses light to control living neurons that are light-sensitive. The neurons contain photosensitive proteins, either through selective breeding or through the use of viruses that carry the required DNA proteins. This process is useful because it allows researchers to selectively turn neurons on and off by shining light on the tissue, typically using an implanted LED. This procedure has been used on mice, but it has one major drawback. In order to provide power to the LED, the test mice must be wired to a power source. Tethered by a wire, the mouse’s behavior and movement is limited.
Scientists at Stanford’s NeuroMuscular Biomechanics Lab came up with an ingenious way to transmit power wirelessly to an implanted LED device. A paper describing their research details how they used a radio frequency that matched the resonant frequency of the mouse’s body, which transferred the power to the implants that were completely beneath the skin. The system worked whether the implant was near the surface — as when stimulating a leg nerve — or embedded deep in the body such as in the brain or stimulating the spinal cord. A resonant cavity was placed below the chamber holding the mouse, and the mouse was able to move freely within the chamber.
This is an early experiment, but the potential for this technology is enormous. This wireless power system could be used to stimulate specific nerves in a person’s body. It is conceivable that this could become part of a system that would give patients with paralyzed limbs a way to activate their muscles. We have a long way to go to refine the process, but this new tool will likely help researchers get a much clearer understanding of how the brain and the rest of the nervous system works.