Rats ‘touch’ infrared light
8 Mar 2013 by Evoluted New Media
Neuroscience
Laboratory rats were given the ability to “touch” infrared light by Duke University researchers who have developed a neuroprosthetic device. Their findings are detailed in Nature Communications. Cortical neuroprostheses could be developed in the future to give animals and humans the ability to see in any region of the electromagnetic spectrum, or even magnetic fields.
“We could create devices sensitive to any physical energy,” said lead researcher and neurobiologist Miguel Nicolelis. “We chose infrared initially because it didn’t interfere with our electrophysiological recordings.”
The mammalian retina is blind to infrared light and cannot detect any heat generated from the weak infrared light that was used in the study.
A test chamber was used that contained three light sources that could be switched on at random. The researchers trained the rats to visit ‘reward ports’ of water inside a test chamber whenever visible LED lights were activated.
After training the rats, the team implanted an array of stimulating microelectrodes into the cortical region of the brain – the region that processes touch information from the rats’ facial whiskers.
An infrared detector was then attached to the microelectrodes and affixed to the animals’ foreheads. The system was programmed so that orientation toward an infrared light would trigger an electrical signal to the brain. The signal pulses increased in frequency with the intensity and proximity of the light.
After being reintroduced to the test chamber, the visible LEDs were swapped for infrared ones. After about a month, the animals began responding to the infrared light the way they were trained with the visible LEDs, beginning to actively forage for the signal, sweeping their heads back and forth to guide themselves to the light source.
“This is the first paper in which a neuroprosphetic device was used to augment fuction – literally enabling a normal animal to acquire a sixth sense,” said Eric Thomson, a co-author of the study.
Paper: http://www.nature.com/ncomms/journal/v4/n2/full/ncomms2497.html
