Recent advances in neuroscience and neurotechnology are propelling man-machine interfacing into a new era in which machines such as computers and prostethic limbs are more directly and tightly coupled to our brain's neural activity. Examples of these advances include: mice whose brains have been altered using optogenetics learn and unlearn on command; a monkey who controls an artificial arm and feeds himself via a brain-machie interface; scientists who can render an image imagined or dreamed of …