Fluorescent tagging has revolutionized biology, but using it to study large neural networks has been challenging, because neural activity is so short-lived. 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. Now 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.
The so-called CaMPARI label was genetically introduced into transparent zebrafish, going from green to red once neurons fire and there’s a rise in calcium within. The cool thing is that the color stays changed, allowing for a scan of the entire animal to see all the pathways involved during neuronal activity. Here’s a video showing off the fluorescent CaMPARI markers in action:
Here’s Loren Looger from Howard Hughes Medical Institute talking about the CaMPARI sensor:
University of Chicago: A snapshot of neural activity