Scientists zap unruly brain cells with yellow, blue light

WASHINGTON - Opening up new ways of understanding brain disorders, neuroscientists have developed a new class of tools to zap unruly brain activity with blue or yellow light.

These tools, targeting specific neurons (brain cells) could potentially open up new lines of treatment for abnormal brain activity in chronic pain, epilepsy, brain injury and Parkinson’s.

These new ’super silencers’ exert control over the timing in which overactive neural circuits are shut down, an effect that is not possible with existing drugs or conventional therapies.

“Silencing different sets of neurons with different colours of light allows us to understand how they work together to implement brain functions,” explains Ed Boyden, professor and senior study author at the Massachusetts Institute of Technology (MIT).

“Using these new tools, we can look at two neural pathways and study how they compute together,” says Boyden.

Boyden, associate member of the MIT McGovern Institute for Brain Research, 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. These 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 colours of light to study and possibly correct the corrupted neural computations that lead to disease,” explains co-author Brian Chow, postdoctoral associate in Boyden’s lab, according to an MIT release.

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.

The findings appeared in the Thursday issue of Nature.