Characterizing response behavior of medaka (Oryzias latipes) under chemical stress based on self-organizing map and filtering by integration

Abstract

a b s t r a c t a r t i c l e i n f oBehavioral responses (BRs) of medaka (Oryzias latipes) were observed after exposure to low concentrations (0.1 TU (Toxic Unit, TU), 1 TU, 5 TU, and 10 TU) of trichlorfon, parathion and malathion. Overall response patterns of test organisms were reflected from surface shapes of BS (Behavior Strength) values in 3-D: parathion appeared to be most variable in presenting response behaviors whereas trichlorfon showed relatively simple response patterns. The self-organizing map (SOM) addressed the time and toxic effects efficiently. An evident circadian rhythm observed in the control diminished at a low concentration of toxic unit, and variability of toxic effects was accordingly observed according to chemicals and concentrations. Subsequently filtering by integration was conducted to time series BS values. The highly fluctuating nature of original BS values was filtered efficiently to produce linear fitting closely. Slopes of regression decreased monotonically as toxic concentrations increased. Residual curves of integral BS values from linear fitting were further used for determining different BS phases proposed by empirical observations; the positive and negative phases were in accordance with acclimation, adjustment and toxic effects in behavior response modes. According to inclination and declination periods observed in residual curves, new states of test organisms were further defined to present intoxicating and recovering tendencies Profiles based on residual curves of integral BS values were able to show landscape of response patterns across toxic concentrations in different chemicals. Computational methods for defining behavior states provide an objective ground for analyzing complex stress response and could be suitable in referencing toxic behavior modes of test organisms quantitatively.

Integrative Characterization of Toxic Response of Zebra Fish(Danio rerio)to Deltamethrin Based on AChE Activity and Behavior Strength

“…According to integration of the time series BS values [31], integrated BS values were obtained as the time progressed across concentrations (Figure 5). The highly fluctuating nature of the original BS values was filtered efficiently to show linear development of toxic behavior responses (Figure 5(a)).…”

“…Behavior activity was defined as the difference between integrated BS and linear fitting [31] (Figure 6). If behavior activity is in the positive range, the test organisms had greater BS compared with time-averaged BS values obtained from the linear fitting.…”

“…The self-organizing map (SOM) was used to classify movement patterns by training the continuous movement data of BS [31]. The SOM was trained to show patterns of BS and AChE activity in association with experimental conditions using the SOM Toolbox developed by the Laboratory of Information and Computer Science, Helsinki University of Technology in MATLAB environments [32].…”

“…Integration of time series BS values was also used in this study to reveal toxic responses of test organisms as the time progressed [31]. After integration, the data were statistically fitted to linear model regression.…”

Posture tracking of multiple individual fish for behavioral monitoring with visual sensors

“…The movement trajectory can be regenerated easily with these time-series point data and the computational methods could be applied for further behavioral analysis, such as a Self-Organizing Map, HMM (Liu et al, 2011;Wang et al, 2014).…”