Of all the fishes in the sea, the zebrafish has probably yielded the biggest catch for scientists. Being transparent, the zebrafish makes it easy to study various processes in its body while it’s alive and without resorting to expensive imaging.
Scientists from Japan’s National Institute of Genetics managed to genetically introduce a new version of the GCaMP calcium indicator, a green fluorescent protein (GFP) activated monitor of neuron activity, into zebrafish. By having a tasty paramecium swimming in the field of view of the fish, they were able to detect the signals of the thought related to potential dinner. What that thought was and how deep it went remains a mystery.
From the study abstract in Current Biology:
Here we demonstrate visualization of neuronal activity in the optic tectum of larval zebrafish by genetically expressing the new version of GCaMP. First, we demonstrate Ca2+ transients in the tectum evoked by a moving spot on a display and identify direction-selective neurons. Second, we show tectal activity during perception of a natural object, a swimming paramecium, revealing a functional visuotopic map. Finally, we image the tectal responses of a free-swimming larval fish to a paramecium and thereby correlate neuronal activity in the brain with prey capture behavior.
Study abstract in Current Biology: Real-Time Visualization of Neuronal Activity during Perception
(hat tip: Gizmodo)