Abstract
Unlike the mammals, fish optic nerve can regenerate after optic nerve transection. The regenerating optic axons reinnervate the tectum and finally the visual function completely restores. It is very important to quantitatively score the functional regeneration of fish visual system. We developed a computer image processing system for quantification of moving zebrafish behavior. The system was consisted of a computer and two CCD cameras with an interface board. The image of moving zebrafish in an aquarium was captured at 30 frames/sec. We applied this system to evaluate the optic nerve regeneration after nerve injury in zebrafish. Two visually guided behaviors, chasing and schooling were followed up for 100 days after axotomy. The ratio of chasing in which one fish chases the other was almost reduced in a pair of two blind fish with optic nerve transection. The recovery of chasing ratio was 80 days after axotomy. In development of zebrafish, the chasing ratio equivalent to adult fish could be seen 60 days after hatching. The schooling behavior in which many fish swim in a group was analyzed in both normal (10 fish) and mixed (9 normal fish and 1 blind fish) groups. We made a quantification to detect a different behavior of both groups. Thus, we can quantify the complex behavior of zebrafish from single to many and from embryo to adult using this system. Our image processing system is a powerful tool in the fields of neurobiology of zebrafish. [Jpn J Physiol 55 Suppl:S167 (2005)]
