To understand how the brain works scientists have been using two broad categories of experiments: ones that record and ones that manipulate brain activity. Early neuroscience studies used electricity to change the activity of neurons. Then, just two decades ago, scientists developed new technologies that used light. Now, they are using magnets. 

Does it sound like mind control? Yes, it does. Brain stimulation technologies, magnetogenetics included, have allowed scientists to influence the behavior of animals. But no, you are not at risk of being unwittingly influenced. The technology relies on magnetic nanoparticles in the brain and close-range magnetic fields.

How this new technology works is actually really cool. It combines a mechanosensitive protein called Piezo with a magnetic nanoparticle (it’s 200 nanometers in size! That’s 0.0002 millimeters). Piezo (meaning pressure in Greek) is a well-known channel protein that, when mechanically stimulated, can activate a cell. It’s what gives you the sense of light touch. 

A rotating magnetic field moves the magnetic nanoparticles. This generates torque (rotational force) that can mechanically stimulate the Piezo channels. The nanoparticles only activate the Piezo variant that scientists have delivered to a cell, not native Piezo proteins.

Seo-Hyun Choi and colleagues were able to deliver the protein and nanoparticle to specific subgroups of cells in the brains of mice. When the mice were surrounded by a magnetic field, those cells would be activated. Depending on the targeted cells, this could make the mice eat more, or be more attentive parents.

It sounds a bit Frankenstein-y, but this technology will allow scientists to manipulate with high temporal precision the brain activity in animals without the presence of any head-mounted devices. 

Previous technologies using light or electricity always required a cable or device to be attached to the skull of the animal to deliver the stimulus. With magnetogenetics the animals’ behavior will be completely unimpeded, improving their welfare. This will also facilitate the study of the behavior of multiple animals together in social experiments as they will be freer to interact together. 

Could this technology be used in humans? Not anytime soon. However, stimulation of brain circuits in humans is already being done. Deep brain stimulation (DBS) is a powerful therapy for Parkinson’s disease that uses electrical stimulation of dopaminergic neurons. In the future, magnetogenetics could provide an alternative method for targeted stimulation of neurons to alleviate the symptoms of such disorders.

As senior author Cheon Jinwoo said in a statement, “We expect it to be widely used in research to understand brain functions, sophisticated artificial neural networks, two-way BCI [brain-computer interface] technologies, and new treatments for neurological disorders.”

This study is published in Nature Nanotechnology.