An article in Science Daily's April 2013 edition titled “Tiny Wireless Device Shines Light On Mouse Brain, Generating Reward” describes how implanting a miniature electronic device in the brain, scientists can manipulate the internal reward system of mice by illuminating specific areas and “prodding neurons to release dopamine, a chemical associated with pleasure” (Science Daily, 4/13). The lighting technology described in the article that was small but effective enough to elicit promising results were in fact LEDs. "This strategy should allow us to identify and map brain circuits involved in complex behaviors related to sleep, depression, addiction and anxiety," says co-principal investigator Michael R. Bruchas, PhD, assistant professor of anesthesiology at Washington University (Science Daily, 4/13).
To work in such a sensitive and fragile location such as the brain, engineers needed to devise a way to affect precise areas safely and accurately. “Washington University neuroscientists teamed with engineers at the University of Illinois to design microscale (LED) devices thinner than a human hair. This was the first application such devices in optogenetics, an area of neuroscience that uses light to stimulate targeted pathways in the brain” (Science Daily, 4/13). Now engineers invented a less invasive way to conduct very sensitive experiments where fiber optics and lasers were used in the past. “With the new devices, the mice freely moved about and were able to explore a maze or scamper on a wheel. The electronic LEDs are housed in a tiny fiber implanted deep in the brain. That's important to the device's ability to activate the proper neurons”, according to John A. Rogers, PhD, professor of materials science and engineering at the University of Illinois. "You want to be able to deliver the light down into the depth of the brain," Rogers says. "We think we've come up with some powerful strategies that involve ultra-miniaturized devices that can deliver light signals deep into the brain and into other organs in the future” (Science Daily, 4/13).
You might be asking yourself how exactly did LED light affect the mice’s decision making process. The article describes how “using light from the cellular-scale LEDs to stimulate dopamine-producing cells in the brain, the investigators taught the mice to poke their noses through a specific hole in a maze. Each time a mouse would poke its nose through the hole, that would trigger the system to wirelessly activate the LEDs in the implanted device, which then would emit light, causing neurons to release dopamine, a chemical related to the brain's natural reward system. When the brain cells were activated to release dopamine, the mice quickly learned to poke their noses through the hole even though they didn't receive any food as a reward. They also developed an associated preference for the area near the hole, and they tended to hang around that part of the maze" (Science Daily, 4/13).
So where will this research lead us into the future? “Researchers believe the LED implants may be useful in other types of neuroscience studies or may even be applied to different organs. Related devices already are being used to stimulate peripheral nerves for pain management” (Science Daily, 4/13). Testing of this nature could “help scientists better understand what goes on in the brain in disorders such as depression and anxiety. We believe these devices will allow us to study complex stress and social interaction behaviors," Bruchas explains. "This technology enables us to map neural circuits with respect to things like stress and pain much more effectively” (Science Daily, 4/13).
By mapping brain circuits involved in specific behaviors, we may be on the road to finding ways to alleviate and prevent common ailments in humans. "Understanding which populations of neurons are involved in these complex behaviors may allow us to target specific brain cells that malfunction in depression, pain, addiction and other disorders" (Science Daily, 4/13). LEDs and their specific form and function proved ideal for these experiments which are going a long way to advancing medicine and the understanding of our own brain functionality.
Reference:
Washington University in St. Louis (2013, April 11). Tiny wireless device shines light on mouse brain, generating reward. ScienceDaily. Retrieved June 25, 2013, from http://www.sciencedaily.com/releases/2013/04/130411142708.htm
