This experiment advances the science of brain-machine interfaces with a test of an implanted computer chip in rat brains, designed to treat chronic pain — which it did admirably well.
The chip reads the rat’s minds: it detects patterns of brain activity in the cingulate gyrus that are consistent with pain, and then stimulates part of the frontal lobe to mute pain: specifically, to “exert top-down nociceptive regulation.” 🤯
Step 1. Detect brain activity in progress that is causing a pain experience.
Step 2. Stimulate the brain in a way that suppresses that activity.
“Nooo, don’t implant a chip in my brain, I’m too cute! Unless it’s the lesser of evils, because I have terrible chronic pain! Squeak!” Photo of Olivia, a dumbo rat, by ArtBrom (used as is, CC BY-SA 2.0), .
Doing this for humans is probably still many years away. But if it works? It’s extremely precise, responding in real-time, only working when there’s pain to treat — completely unlike the continuous, always-zapping approach that has dominated the field so far.
And it really did work amazingly well. The treated rats withdrew from painful stimuli about 40% slower, and greatly preferred spending time in a chamber where the implant was functional to one where it wasn’t. These were strong results, and a very promising demonstration of the principle.
This kind of approach is likely to improve as we continue to improve brain-machine interface technology, and knowledge of brain circuity gets more precise.
What could possibly go wrong?
Science fiction is full of cautionary tales about a brain interface tech that is still decades away (if ever). Yes, you might get used as a battery by our robot overlords. Meanwhile, back in the early to mid 21st Century…
The obvious problem with a technique like this is that it’s about as invasive as invasive can get — it’s a brain implant. There are going to be complications.
Technological glitches aren’t out of the question either. This is not a simple device. “Have you tried rebooting it?” is not what patients want to hear when they call tech support for their brain implant.
The downregulating danger
Here’s a less obvious and more interesting concern: this could cause adaptation and dependence just like opioids. Any time you overstimulate an inhibitory neurological function, there’s a chance that it will get a bit numbed to the input… and no one wants a pain inhibition system that isn’t working at full power. Understatement.
We know this phenomenon extremely well from opioid dependence, but the inexorable logic of “downregulation” applies to anything that tinkers with nerves to kill pain. Pick a pathway that inhibits pain, any pathway, give it a boost with some kind of artificial stimulation, and gosh darn it if it doesn’t start downregulating and become less responsive to natural stimulation… et voila, you become either dependent on the artificial stimulation, or seriously sensitized without it.
But “it’s complicated,” of course. This will just have to be studied over time to find out if that happens.Zhang Q, Hu S, Talay R, et al. A prototype closed-loop brain-machine interface for the study and treatment of pain. Nat Biomed Eng. 2021 Jun. PubMed #34155354 ❐
See also neurologist Dr. Steve Novella’s more detailed explanation of the experiment.