A double-transgenic larva was embedded in agarose, and a spot was presented on an LCD display placed on the right-eye side. Ca2+ signals were detected on the left tectum upon appearance (ON) and disappearance (OFF) of the spot. The spot was shown for the first 3 s in this 6 s movie. The video is shown at 3x real time.
Credit: Current Biology, Muto et al