The future of brain interfaces

We're writing a feature to check in on scientists working on bridging the gap between brain and machine. We're planning on asking them, "What's taking so long?" When I think of brain-machine interfaces, a couple of things come to mind: The Borg from Star Trek, whose neural implants give it the ability to communicate telepathically as well as control implanted tazers and pincers. Then there's The Matrix, where a plug in the back of the brain connects the user to an elaborate virtual world. W