A new brain implant doesn't restore sight in blind rats, but it does something a whole lot weirder: give the rat the extra sense of geomagnetism. It could one day be a new way to navigate for blind people -- or heck, even healthy people hankering for a sixth sense.
In the study published in Current Biology, scientists in Japan put a chip that could sense north and south inside the brains of rats. The rats also got two electrodes implanted in the visual cortex of the brains. If its head faced roughly north, the electrodes stimulated the right visual cortex. If south, then the left visual cortex.
Essentially, the rat can "see" which direction it's facing without really, erh, seeing anything through its eyes. It was probably disorientating at first, but after two days and 60 trials, the blind rats could navigate a maze just as well as rats with sight. With the implants removed, they were lost again.
The experiment demonstrates yet again that the brain is remarkably plastic, and neuroscientists have experimented with mixing and matching sensory signals before. For example, a different brain implant let mice "touch" light.
"I'm dreaming that humans can expand their senses through artificial sensors for geomagnetism, ultraviolet, radio waves, ultrasonic waves and so on," Yuji Ikegaya, the senior author study, told New Scientist. And it's not a totally crazy idea, at least for people already convinced they want to explore sensory unknowns. People have implanted magnets in their fingers, and one guy hacked his hearing aids to hear Wi-Fi. Brains implants, though, would be a huge and invasive step up from these small tweaks. [Current Biology, New Scientist]