I'm not sure that human beings have really gotten to a point that medical ethics is so robust that putting things into people's brains directly is even institutionally feasible outside of a few less invasive obvious use cases; where I have a keen interest is in the potential for taking raw brain data and using it to drive creative applications or record things like dreams and whimsies. I see Steve Mann moving in this direction but I'm not sure where the state of the art is.