Trajectory tracking of spasm-oriented zebrafish larvae

As a vertebrate developmental biology model, zebrafish has been widely used in research fields of development, genetics, behavior and molecular biology recently [1]. In the field of drug research, researchers apply various ratios of drugs on zebrafish and determine the proper ratio of drugs by analyzing the behavior of the zebrafish. Trajectory tracking of the zebrafish is the first step of such research. Note that when being applied drugs such as antiepileptic drugs, the larvae will produce spasm [2], in which solution the larvae´s speed is so high that its moving image will appear deformation and the larvae´s color will be light and it is difficult to locate it. In this paper, we propose a method to locate the head and tail of zebrafish in static background by combining background reduction and frame differential method. Experimental results demonstrate that this method can detect the larvae accurately when it produces spasm. Then the larvae´s two-dimensional trajectory is obtained. This method is of high accuracy, high-speed, and easy to implement.