Vagus nerve stimulation after practice could help new skills stick

Ever spent an evening drilling something new, only to find half of it gone the next morning? Researchers in Japan suspect that a quick jolt to the vagus nerve right after training could help lock in new skills, at least in mice.

The study, out of Tohoku University, was published in iScience at the end of August. It’s since made the rounds on various biohacking forums, where people are already asking whether their own neck stimulators and TENS ear clips might pull off the same trick.

But before anyone goes cranking up the intensity, it’s worth taking a closer look at what the researchers actually did.

Stimulation after practice, not during

The mice were trained on a horizontal optokinetic response task, a fancy way of saying they learned to track moving stripes with their eyes. It’s similar to the reflexive eye movements you make when standing on a platform watching a train go by. This kind of learning relies on the cerebellum.

The team applied vagus nerve stimulation after each training session, not during it. During training itself, it had little effect. The benefit emerged over the following days, with stimulated mice performing better. As Professor Ko Matsui put it, “the key point is that VNS was delivered only after training.”

That suggests the period after practice is a window when the brain is still cementing a skill. According to the researchers, the stimulation makes the brain more open to lasting change during that time.

The blood vessel twist

Most earlier research has focused on how vagus nerve stimulation alters neurotransmitter systems. This study points in a different direction. The team measured blood volume near the cerebellar flocculus, a region involved in this eye task. A single burst of stimulation caused a brief dip in blood volume followed by a rise. Repeated sessions turned that into a rhythmic rise and fall.

Mice with larger oscillations tended to score better on day five. That is a correlation rather than proof, though. The study summary is clear that it does not show the vessel rhythm caused the better learning.

Your neck gadget is a different story

Here’s the catch for anyone hoping for a learning hack. The mice had a small cuff electrode attached directly to the vagus nerve in the neck, which is implanted stimulation. Consumer devices send pulses through the skin. The study did not test those or breathing exercises.

The wider research picture is mixed too. A 2024 study in rats found stimulation paired with training didn’t improve learning across motor, speech sound and memory tasks. That team stimulated during training while the Tohoku group waited until afterwards, so the two results aren’t a straight comparison.

Neck-worn stimulators are sold for stress and sleep, not learning. When I reviewed Pulsetto it helped me fall asleep faster. The newer Pulsetto Fit adds longer battery life and a wave-like stimulation mode. Kineon’s Calm+ also sits around the neck. All of them are pitched at calm rather than mastering a new skill.

If you are more curious about what your brain is doing, the Muse S Athena tracks brain states and sleep. It reads rather than stimulates, which is a very different job.

So the takeaway is about timing more than gadgets. The period right after practice might matter more than we think. Whether any device can make use of that in people is a question for future studies.