Advances like these will rely on signals such as are used in household wireless networking as the most convenient means of communication between the thing in your brain and the outside world. Wireless networking is the facilitator — as well as the menace, when viewed from a security perspective. Cardiac defibrillators and pacemakers, for example, have been shown by security experts to be vulnerable to malicious hacking, though the threat has so far been fortunately largely theoretical. Yet neurosecurity has hitherto merited little attention. The worry is that unless security is built in to new technology from the start, you can get insecurity-plagued things like the Internet; and that the consequences of a neurosecurity breach are far worse: “instead of protecting the software on someone’s computer, we are protecting a human’s ability to think.”

And then there’s the old science-fiction question: what’s the line between man and machine? You could argue that thinking itself is just information-processing, in which consciousness is perpetuated through a continuous flow of information. But technological advances will certainly enlarge the realm of that debate.