By attaching a microstimulator and geomagnetic compass to the brains of blind rats, researchers reporting online on April 2, 2015 in the Cell Press journal Current Biology found that the animals can spontaneously learn to use new information about their location to navigate through a maze nearly as well as normally sighted rats. The article is titled “Visual Cortical Prosthesis with a Geomagnetic Compass Restores Spatial Navigation in Blind Rats" Researchers say the findings suggest that a similar kind of neuroprosthesis might also help blind people walk freely through the world. Most notably, perhaps, the findings show the incredible flexibility of the mammalian brain. "The most remarkable point of this paper is to show the potential, or the latent ability, of the brain," says Dr. Yuji Ikegaya of the University of Tokyo. "That is, we demonstrated that the mammalian brain is flexible even in adulthood--enough to adaptively incorporate a novel, never-experienced, non-inherent modality into the pre-existing information sources." In other words, he says, the brains of the animals they studied were ready and willing to fill in "the 'world' drawn by the five senses" with a new sensory input. What Dr. Ikegaya and his colleague Dr. Hiroaki Norimoto set out to do was to restore not vision per se, but the blind rats' allocentric sense. That sense is what allows animals and people to recognize the position of their body within the environment. What would happen, the researchers asked, if the animals could "see" a geomagnetic signal? Could that signal fill in for the animals' lost sight? Would the animals know what to do with the information?
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