Fig. 1

Experimental setup for the wireless neurologging system. a Head-mounted neurologger in a waterproof case records multiple neuronal activities from the telencephalon of a free-swimming trout in a water tank. The recording parameters, including start and stop times, and the neuronal signal frequency bands were wirelessly controlled from a personal computer via a radio transceiver. Two-dimensional swimming trajectories were captured using a USB 3.0 camera mounted 1.5 m above the tank. The frame timings were also transmitted to the logger via the radio link (left, blue box) to synchronize the spike timing. Two pipes for water supply (top) and drainage (bottom) are illustrated. b Free-swimming trout with and without loggers. The logger was placed in a case with the base fixed to the skull, while for waterproofing, a rubber seal inserted between the lid and base was screwed into place. The logger recorded neuronal activity from four tetrodes implanted in the brains of the test fish