Scientists at Tel Aviv University have successfully restored lost brain function to rats by implanting them with a prosthetic cerebellum. The prosthetic works by receiving signals from the brainstem, decoding them, and then transmitting a signal to a different part of the brainstem that signals motor neurons to fire which provide information for the desired motion. This was made possible for two main reasons.
First, the cerebellum, among other things, coordinates muscle movement. And secondly, the cerebellum is so well understood that some of the signals that it transmits are able to be replicated in circuitry. The synthetic cerebellum was implemented in a chip that sat on the outside of the skull and then wired into the brain. The whole thing was then tested by anaesthetisizing some rats and disabling their cerebellums (whatever that means). Then when an audible tone was played, they would puff their eyes with air to make them blink until they would blink when only the tone was played.
Without the prosthetic cerebellum connected, the rats were unable to learn this behavior. But with it enabled, they would blink like Pavlov’s dog when just the tone was played. Obviously, this is just a proof of concept and we are far from curing Alzheimer’s but this definitely a step in the right direction.