NOT many special powers need whiskers. But rats fitted with a prosthesis that allows them to 鈥渢ouch鈥� infrared light are the first animals to acquire a sixth sense.
and colleagues at Duke University in Durham, North Carolina, trained rats to run to a source of visible light. A sensor that can detect infrared, which mammals can鈥檛 see, was connected to electrodes implanted in their somatosensory cortex, which processes touch sensations from their whiskers. When the prosthesis detects infrared, it sends signals to the electrodes, which grow stronger when the light source is close (Nature Communications, ).
When the rats鈥� sensor first picked up signals, the animals would stop and rub their whiskers, but they gradually realised that the sensation was coming from further away. After a month, the rats ran over to the infrared light in the dark, as they had to the visible light; the cortex had adapted to deal with input from both the whiskers and the infrared sensor.
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鈥淚nstead of seeing, the rats learned how to touch the light,鈥� says Nicolelis. The finding could lead to new prostheses for people with damage to their visual cortex, he says.
This article appeared in print under the headline 鈥淣ight-vision rat has sixth sense鈥�