Brain communication very much interests me, because it comes down to the essence of how we encode knowledge in biological signals. Like Google Deepdream, understanding how concepts of what a dog looks like and how it is related to other things, encoded as a series of bits, is just absolutely fascinating.

I know we still don't understand beyond a very probabilistic level how the brain encodes this information biologically, but I've heard lots about prosthetics. Can anyone answer me how they control robotic arms using just the brain [1]?

[1] http://www.instructables.com/id/Mind-Controlled-Robotic-Arm/