Geomagnetic Compass Caused Blind Rats to Better Sense Their Surroundings

There may be a new device that could help the blind to see-or at least better sense their surroundings. Scientists have attached a microstimulator and geomagnetic compass to the brains of blind rats and have found that the device can cause the rats to act like they can see.

The new device doesn't restore vision. However, it does restore the blind rats' allocentric sense. This sense allows animals and people to recognize the position of their body within the environment. The researchers also wondered what would happen if animals could "see" a geomagnetic signal and if it would be able to fill in for the animals' lost sight.

The researchers mounted a geomagnetic sensor device on the rats' heads and then connected a digital compass to two tungsten microelectrodes for stimulating the visual cortex of the brain. Once attached the sensor automatically detected the animal's head direction and generated electrical stimulation pulses indicating which direction they were facing.

These blind rats were then trained to seek food pellets in a T-shaped or more complicated maze. Within tens of trials, the animals learned to use the geomagnetic information to solve the mazes. In fact, their performance levels and navigation strategies were similar to those of normally sighted rats.

"We were surprised that rats can comprehend a new sense that had never been experienced or 'explained by anybody' and can learn to use it in behavioral tasks within only two to three days," said Yuji Ikegaya, one of the researchers, in a news release.

The findings suggest that geomagnetic sensors could also be used for the blind; they could potentially be attached to the canes used by the blind to get around.

The findings are published in the journal Current Biology.

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