For a bunch of mind-controlled mice, walking into a magnetic field has never felt sooo good.

The imperceptible force that the genetically tweaked rodents wandered through fired up the reward-related circuits in their brains, likely conjuring the pure pleasure experienced when, for instance, they ate a yummy treat, researchers report Monday in Nature Neuroscience. Of course, this meant that the mice didn’t want to leave that happy magnetic field.

While getting mice to congregate in specific, magnetized areas may be useful for pest control, the experiment demonstrates a much more powerful point: that researchers can remotely control specific brain circuits in living animals with just magnets. The finding paves the way for magnetic mind control to help study the functions and malfunctions of the brain—plus the use of ‘magneto-genetic’ therapies to treat brain disorders, the authors report.

“This is, to our knowledge, the first demonstration of bona fide magnetic control of the nervous system,” the authors, led by biomedical scientist Ali Güler at the University of Virginia, concluded.

Of course, over the years, scientists have come up with other ways to control specific circuitry in brains, including using light signals (optogenetics) and drugs (chemogenetics). But those methods have some notable drawbacks. Light signals, for instance, have trouble beaming deep into brain tissues, dimming their usefulness in some brain regions. Drugs, on the other hand, can reach deep, but they can take their time seeping in and out. This makes controlling brain processes in real, physiological time tricky.

Magnetic fields, however, can quickly and cleanly infiltrate a noggin, the researchers report.

To pull off the magnetic mental yanking, Güler and colleagues engineered a magnet-responsive ion channel. In brain cells, ion channels are key to building up electrical charges responsible for zapping signals through neural circuitry. The researchers did some genetic surgery on an ion channel known to be responsive to mechanical pressure, called TRPV4. The researchers fused the gene for TRPV4 to a gene for an iron-hoarding protein called ferritin, which is slightly responsive to external magnets (paramagnetic).

With a few more genetic tweaks, the resulting hybrid protein, dubbed Magneto, proved to be viable and responsive to magnetic fields in cells. When the researchers moved a magnet near the cells carrying the hybrid, Magneto jerked, opening the ion channel. This caused an influx of ions into the cells, sparking an electrical change that could fire off brain signals.

When the researchers put the gene for Magneto in zebrafish, a model organism for brain development, they found that the hybrid could alter complex behaviors. Using a genetic switch, the researchers made Magneto active in the zebrafish nerve cells that are involved in sensing touch. And, when they added a magnetic field, the fish upped the amount of time they coiled their tails, a touch-induced escape response.

The researchers next tested Magneto in mice, a mammalian model. By making Magneto active in cells that are responsive to dopamine—a neurotransmitter critical for reward-motivation pathways in the brain—the researchers could charm the mice into preferring an area of a chamber with a magnetic field.

While the results show that the method can work in living animals, Güler and colleagues hope to continue to hone the method, making Magneto even more sensitive to magnetic fields in specific neural circuits. Such improvements “will position the field to better understand neural development, function and pathology,” the authors concluded.

Nature Neuroscience, 2015. DOI: 10.1038/nn.4265 (About DOIs).