Development and optimization of an effective method for evaluating habituation learning behavior in larval zebrafish.

BACKGROUND:Habituation learning is a simple and conserved behavior in all organisms which could be induced by repeated stimuli. However, no standard and universal methods for training and evaluating the habituation learning behavior in larval zebrafish were available. NEW METHOD:This study aims to establish effective training and detection protocols for habituation learning behavior in larval zebrafish by using the ViewPoint system. For this purpose, the detection threshold of velocity-a parameter for distinguishing the escape reaction and the spontaneous motion, the detection sensitivity-a parameter for determining the size of the identified object, the number of stimuli, and the age of larvae were optimized to obtain the best performance. RESULTS:In this study, the optimized parameters were as follows: the detection threshold of velocity at 13, the luminous intensity at 8 %, the detection sensitivity at 32, the number of stimuli at 150, and the age of larvae at 6 dpf. Furthermore, we validated the utility of the established protocol by showing a consistent memory impairment induced by cycloheximide (CHX). COMPARISON WITH EXISTING METHOD:A similar method was reported previously. However, the equipment used in those assays, including the hardware and software, were neither standard nor universal, which might impede the extensive application of the habituation learning assays. Here, we developed an alternative method for studying the habituation learning behavior in larval zebrafish using the ViewPoint system. CONCLUSIONS:Our study provided an alternative method for studying the habituation learning behavior in larval zebrafish.