But the implanted electrodes used in such trials eventually become useless, as scar tissue forms that degrades their electrical connection to brain cells 

Next month, tests will begin in monkeys of a new implant for piping data into the brain that is designed to avoid that problem. The project is intended to lead to devices that can restore vision to blind people long-term.

Researchers at Harvard Medical School will use a new kind of implant that will go beneath the skull but can rest on the surface of an animal's brain, instead of penetrating inside the organ. An array of microscopic coils inside the hair-like device can generate powerful, highly targeted magnetic fields to induce electrical activity at particular locations in the brain tissue underneath. The implant will also be tested when placed inside brain tissue.