Ultrasonic Brain Control

The Conversation had an article this week titled “Remote control for brain cells: scientists use ultrasound waves to activate neurons”. It introduced me to the field of sonogenetics, somewhat related to the more widely-known optogenetics except sound is used as the stimuli instead of light. Apparently, there is a protein present in some worm neurons that responds to pressure waves in the ultrasonic range. There’s even a video showing how “ultrasound pulses could make the worms change direction, as if we were using a worm remote control."

According to the article, human neurons do not have the ultrasound-sensitive protein, however it can be introduced via an engineered virus that “delivers genetic material to brain cells.” One advantage of using sonogenetics is its potential ability to target brain cells in specific areas; and this could be very helpful in dealing with movement disorder related brain diseases. If you wanted to get dystopian, you might imagine an evil scientist controlling your physical movements via ultrasound affecting your brain cells! It’s mind control of a sort.

This reminds me of the Imperius Curse in the Harry Potter books. While I have previously speculated on the use of electromagnetic radiation as a vehicle for magic, I suppose this can be extended to ultrasound. Both have wave-like properties, but ultrasonic waves can be transmitted through or into the body more easily than optical waves. However, if used as a scanner (the most common medical use you might be familiar with), there is a tradeoff between how far the waves can penetrate the human body and how good you need the resolution of the scan to be. Presumably if you’re manipulating neurons, you need fine control, so you’d better be close by. That could be a reason why the closer you are to the ‘victim’, the more effective the Imperius curve. Sound wave amplitudes also die with distance, in any case. Another drawback if ultrasound is the carrier wave, is that the Imperius Curse won’t work well in outer space. I suppose a wizard in space could resort to some other curse that is carried by electromagnetic radiation!

In Harry Potter and the Half-Blood Prince, an attempted Imperius curse goes awry, and the victim, junior minister Herbert Chorley, has his brain unfortunately addled – he thinks he’s a duck and he is committed to St. Mungo’s. This perhaps illustrates the challenge of manipulating neurons via ultrasound, certainly true in our science-that-sounds-like-magic world. You might say the same of fMRI, perhaps the equivalent of the Legilimens spell.