A genetic tweak makes it easier to see neurons at work in living, breathing animals. The method, described in the Oct. 18 Neuron, capitalizes on a property of a busy neuron: When the cell fires, calcium ions flood in.
Using an altered version of the protein GFP that lights up when calcium is present in a mouse’s brain, neuroscientist Guoping Feng of MIT and colleagues could see smell-sensing neurons respond to an odor, and movement neurons light up during walking.