The use of fluorescent tagging has revolutionized biology, but since neural activity is short-lived, using it to study large neural networks has been challenging.
The microscope only has a small field of view, so by the time it moves to focus on another region the fluorescence has already gone dark.
Researchers at the Howard Hughes Medical Institute's Janelia Farm Research Campus in Virginia have reported in journal Science on a new fluorescent protein that changes color in response to cellular activity.
When the neurons are fired, the CaMPARI label, genetically introduced into transparent zebra fish, goes from green to red and there's a rise in calcium within.
The color stays changed, allowing for a scan of the entire animal to see all the pathways involved during neuronal activity.