New ways to monitor – and control – neurons are about to become practical. A paper in Neuron by Seo et al describes how researchers at Berkeley created “ultrasonic neural dust” that allowed activity in muscles and nerves to be monitored without traditional electrodes. The technique has not been applied to the brain and has been used only for monitoring, not for control, but the potential is clear, and this short piece in Aeon reviewing the development of comparable techniques concludes that it is time to take these emergent technologies seriously. The diagnostic and therapeutic potential of being able to directly monitor and intervene in the activity of nerves and systems all over the body is really quite mind-boggling; in principle it could replace and enhance all sorts of drug treatments and other interventions in immensely beneficial ways.

From a research point of view the possibility of getting single-neuron level data on an ongoing basis could leap right over the limitations of current scanning technology and tell us, really for the first time, exactly what is going on in the brain. It’s very likely that unexpected and informative discoveries would follow. Some caution is of course in order; for one thing I imagine placement techniques are going to raise big challenges. Throwing a handful of dust into a muscle to pick up its activity is one thing; placing a single mote in a particular neuron is another. If we succeed with that, I wonder whether we will actually be able to cope with the vast new sets of data that could be generated.

Still the way ahead seems clear enough to justify a bit of speculation about mind control.  The ethics are clearly problematic, but let’s start with a broad look at the practicalities. Could we control someone with neural dust?

The crudest techniques are going to be the easiest to pull off. Incapacitating or paralysing someone looks pretty achievable; it could be a technique for confining prisoners (step beyond this line and your leg muscles seize up) or perhaps as a secret fall-back disabling mechanism inserted into suspects and released prisoners.  If they turn up in a theatening role later, you can just switch them off. Killing someone by stopping their heart looks achievable, and the threat of doing so could in theory be used to control hostages or perhaps create ‘human drones’ (I apologise for the repellent nature of some of these ideas; forewarned is forearmed).

Although reading off thoughts is probably too ambitious for the foreseeable future, we might be able to monitor the brain’s states or arousal and perhaps even identify the recognition of key objects or people. I cannot see any obvious reason why remote monitoring of neural dust implants couldn’t pick up a kind of video feed from the optic nerve. People might want that done to themselves as a superior substitute for Google Glass and the like; indeed neural dust seems to offer new scope for the kind of direct brain control of technology that many people seem keen to have. Myself I think the output systems already built into human beings – hands, voice – are hard to beat.

Taking direct and outright control of someone’s muscles and making a kind of puppet of them seems likely to be difficult; making a muscle twitch is a long way from the kind of fluid and co-ordinated control required for effective movement. Devising the torrent of neural signals required looks like a task which is computationally feasible in principle but highly demanding; you would surely look to deep learning techniques, which in a sense were created for exactly this kind of task since they began with the imitation of neural networks.  A basic approach that might be achievable relatively early would be to record stereotyped muscular routines and then play them back like extended reflexes, though that wouldn’t work well for many basic tasks like walking that require a lot of feedback.

Could we venture further and control someone’s own attitudes and thoughts? Again the unambitious and destructive techniques are the easiest; making someone deranged or deluded is probably the most straighforward mental change to bring about. Giving them bad dreams seems likely to be a feasible option.  Perhaps we could simulate drunkenness – or turn it off – I suspect that would need massive but non-specific intervention, so it might be relatively achievable. Simulation of the effects of other drugs might be viable on similar terms, whether to impair performance, enhance it, or purely for pleasure. We might perhaps be able to stimulate paranoia, exhilaration, religiosity or depression, albeit without fully predictable results.

Indirect manipulation is the next easiest option for mind control; we might arrange, for example, to have a flood of good feelings or fear and aversion every time particular political candidates are seen, for example; it wouldn’t force the subject to vote a particular way but it might be heavily influential. I’m not sure it’s a watertight technique as the human mind seems easily able to hold contradictory attitudes and sentiments and widespread empirical evidence suggest many people must be able to go on voting for someone who appears repellent.

Could we, finally, take over the person themselves, feeding in whatever thoughts we chose? I rather doubt that this is ever going to be possible. True, our mental selves must ultimately arise from the firing of neurons, and ex hypothesi we can control all those neurons; but the chances are there is no universal encoding of thoughts; we may not even think the same thought with the same neurons a second time around. The fallback of recording and playing back the activity of a broad swathe of brain tissue might work up to a point if you could be sure that you had included the relevant bits of neural activity, but the results, even if successful, would be more like some kind of  malign mental episode than a smooth take over of the personality. Easier, I suspect, to erase a person than control one in this strong sense. As Hamlet pointed out, knowing where the holes on a flute are doesn’t make you able to play a tune. I can hardly put it better than Shakespeare…

Why, look you now, how unworthy a thing you make of
me! You would play upon me; you would seem to know
my stops; you would pluck out the heart of my
mystery; you would sound me from my lowest note to
the top of my compass: and there is much music,
excellent voice, in this little organ; yet cannot
you make it speak. ‘Sblood, do you think I am
easier to be played on than a pipe? Call me what
instrument you will, though you can fret me, yet you
cannot play upon me.