Cost-effective electrophysiological recording of wild-type zebrafish larvae. The experiments were conducted at three developmental stages (5, 9, and 16 days post-fertilization). All zebrafish larvae were pre-anesthetized with 0.02% tricaine, paralyzed with 10 µM d-tubocurarine, and immobilized in 1.2% low-melting agarose. The electrode was carefully placed in the optic tectum of the zebrafish larvae using a micromanipulator and a binocular stereoscope. We used an in-house 316L stainless steel electrode with a diameter of 125 μm for the analysis. The electrophysiographic data were filtered within the range of 1 to 1000 Hz. The signal was pre-amplified by a factor of 10 and further amplified using the RhD2000 Evaluation System, with an initial amplification of 100 and a final amplification of 1000 Hz. The data were recorded in a single channel at 10K samples per second frame rate.