Developed by neuroscientists at the Massachusetts Institute of Technology, a powerful new class of tools could reversibly shut down brain activity by using... different colours of light.
When targeted to specific neurons, these tools could potentially lead to new treatments for abnormal brain activity associated with disorders including chronic pain, epilepsy, brain injury and Parkinson's disease.
The best way to treat such disorders is by silencing, rather than stimulating abnormal brain activity.
The new tools, or 'super silencers,' exert exquisite control over the timing in which overactive neural circuits are shut down-an effect that is not possible with existing drugs or other conventional therapies.
"Silencing different sets of neurons with different colors of light allows us to understand how they work together to implement brain functions. Using these new tools, we can look at two neural pathways and study how they compute together," Nature quoted explained Ed Boyden, senior author of the study.
The tools promise to help researchers understand how to control neural circuits, leading to new understandings and treatments for brain disorders.
Boyden calls brain disorders "some of the biggest unmet medical needs in the world."
Boyden's 'super silencers' derive from two genes found in different natural organisms such as bacteria and fungi.
The genes, referred to as Arch and Mac, are light-activated proteins that help the organisms make energy.
When Arch and Mac are placed within neurons, researchers can inhibit their activity by shining light on them.
Light activates the proteins, which lowers the voltage in the neurons and safely and effectively prevents them from firing. Arch is specifically sensitive to yellow light, while Mac is activated with blue light.
"In this way the brain can be programmed with different colors of light to study and possibly correct the corrupted neural computations that lead to disease," explained co-author Brian Chow.
"Multicolor silencing dramatically increases the complexity with which you can study neural circuits. We will use these tools to parse out the neural mechanisms of cognition," said co-author Xue Han.
Determining whether Arch and Mac are safe and effective in monkeys will be a critical next step towards the potential use of these optical silencing tools in humans.
Boyden plans to use these 'super silencers' to examine the neural circuits of cognition and emotion and to find targets in the brain that, when shut down, could relieve pain and treat epilepsy.
The study will appear in the latest issue of the journal Nature.