Pattern Analysis of Movement Behavior of Medaka (Oryzias latipes): A Decision Tree Approach

摘要

The medaka, Oryzias latipes, is a small, egg-laying, freshwater, bony fish which is native to Asian countries. We were continuously investigated behavioral sequences of the medaka through an automatic image recognition system in increasing temperature from 25℃ to 35℃. The observation of behavior through the movement tracking program showed many patterns of the medaka. Behavioral patterns could be divided into basically 5 patterns: 'active-smooth', 'active-shaking', 'inactive-smooth', 'inactive-shaking', and 'not determined'. These patterns were analyzed by 3 features: 'high-speed Ratio', 'FFT to angle transition', and 'product of projections to x-axis and y-axis'. Each pattern was classified using a devised decision tree after the feature choice. The main focus of this study was to determine whether the decision tree could be useful in interpreting and classifying behavior patterns of the medaka.