A Real-Time Visualization of a Zebra Fish's Response to Food

Said to be the first video of its kind, Japanese researchers have videotaped neuronal response to a stimulus -- specifically, the neuronal response of a larval zebrafish in response to food. So, here's it is:

That's actually a short segment. A longer, more descriptive video abstract can be found here (on site select tab for video -- it's not embedable). Here they describe their work (from their written abstract):

To understand how the brain perceives the external world, it is desirable to observe neuronal activity in the brain in real time during perception. The zebrafish is a suitable model animal for fluorescence imaging studies to visualize neuronal activity because its body is transparent through the embryonic and larval stages. ... Here we demonstrate visualization of neuronal activity in the optic tectum of larval zebrafish by genetically expressing the new version of GCaMP [a calcium indicator]. First, we demonstrate [calcium] 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.

Exciting!