14 DAY TRIAL // Researchers with the Massachusetts Institute of Technology in the United States claim to have successfully used light to control body movement. In a paper in the journal PLOS ONE, they argue that this achievement is a first.
As detailed in a press release on the matter at hand, the experiments during which these brainiacs managed to use light to toy with muscle contractions were carried out on laboratory mice.
Before anybody goes looking for their pet hamster and a flashlight, and attempts to recreate these experiments, it need be said that the mice the researchers used in their investigation were no ordinary rodents.
Quite the contrary, they were genetically engineered specimens whose bodies accommodated for neurons programmed to express light-sensitive proteins that the scientific community calls opsins.
In their paper in the journal PLOS ONE, the Massachusetts Institute of Technology specialists explain that these light-sensitive proteins have the ability to regulate the electrical activity of neurons, i.e. suppress it or stimulate it.
The spinal cords of the mice that these researchers experimented on packed such neurons programmed to express opsins. In this particular case, the opsins that the rodents' genetically programmed neurons expressed served to suppress electrical activity.
Hence, when the team of scientists shone blue light on the rodents' spinal cords, the mice lost their ability to move their hind limbs. Simply put, they became paralyzed from the waist down. However, this paralysis was temporary.
Shortly after they were no longer exposed to the blue light, the mice were once again able to use their hind legs to walk and get around. Interestingly enough, the rodents' ability to feel was not in any way affected, meaning that the light did not trigger any sensory deficits.
According to the Massachusetts Institute of Technology team behind this research project, the use of light and light-sensitive proteins to control the behavior of neurons in a living organism is known to the scientific community as optogenetics.
The brainiacs say that, unlike electrical stimulation and pharmacological intervention, this approach makes it possible to control specific neurons and establish just what it is that they do in the body. Thus, it delivers a more accurate image of the spinal circuits in charge of movement and sensory processing.
“With optogenetics, you are attacking a system of cells that have certain characteristics similar to each other. It’s a big shift in terms of our ability to understand how the system works,” explains specialist Emilio Bizzi, who is a member of the Massachusetts Institute of Technology's McGovern Institute.