By injecting nanoparticles into the brain of mice and exposing them to an external magnetic field, it’s possible to stimulate brain neurons, according to a study published in Science today. This wireless deep brain stimulation technique could help reduce tremors in people who have neurological illnesses like Parkinson’s disease.

Deep brain stimulation isn’t new — but this technique sure is. In the past, researchers have done it using short pulses of electricity, and they’ve had very promising results. People with Parkinson’s disease saw a reduction in the amount of tremors they experienced, for instance. But the treatment isn’t very accessible; it requires brain implants, which usually need to be connected to a power source. This means that the procedure tends to be used as a last resort.

In the study, researchers delivered a genetically modified virus into the brain of mice; the virus causes heat sensitivity in specific neurons. Then, the scientists injected magnetic tiny ion oxide particles into their brain tissue and exposed them to an external magnetic field. This caused the particles to heat up and stimulate the neurons.

Credit: Ritchie Chen and Polina Anikeev

The particles mostly stayed where they were they were injected, the researchers say, which means that humans who suffer from neurological diseases might be able to receive this treatment for up to a month. They also don’t seem to interact with the brain tissue unless they’re heated, the researchers report. Still, this was a preliminary mouse study, which means that the technique needs to be tested a number of times before it can be used on humans.

To make the process easier, the researchers developed nanoparticles with precise sizes and shapes. They also made a device that makes delivering a magnetic field more efficient. They now plan to try to use recordings of neuron activity and mouse behavior to get a better idea of what’s going on in the brain when they activate the magnetic field.