Optogenetic toolkit goes multicolor
Optogenetics is a technique that allows scientists to control neurons’ electrical activity with light by engineering them to express light-sensitive proteins. Within the past decade, it has become a very powerful tool for discovering the functions of different types of cells in the brain.
Most of these light-sensitive proteins, known as opsins, respond to light in the blue-green range. Now, a team led by MIT has discovered an opsin that is sensitive to red light, which allows researchers to independently control the activity of two populations of neurons at once, enabling much more complex studies of brain function.
“If you want to see how two different sets of cells interact, or how two populations of the same cell compete against each other, you need to be able to activate those populations independently,” says Ed Boyden, an associate professor of biological engineering and brain and cognitive sciences at MIT and a senior author of the new study.
The new opsin is one of about 60 light-sensitive proteins found in a screen of 120 species of algae. The study, which appears in the Feb. 9 online edition of Nature Methods, also yielded the fastest opsin, enabling researchers to study neuron activity patterns with millisecond timescale precision.
Boyden and Gane Ka-Shu Wong, a professor of medicine and biological sciences at the University of Alberta, are the paper’s senior authors, and the lead author is MIT postdoc Nathan Klapoetke. Researchers from the Howard Hughes Medical Institute’s Janelia Farm Research Campus, the University of Pennsylvania, the University of Cologne, and the Beijing Genomics Institute also contributed to the study.