Poster abstracts

Poster number 93 submitted by Kaarthik Abhinav Balakrishnan

Characterizing larval zebrafish behavior in thermal environments on longer timescales

Kaarthik Balakrishnan (Biophysics Graduate Program, The Ohio State University), Martin Haesemeyer (Assistant Professor, Department of Neuroscience, The Ohio State University)

Abstract:
Animals execute a variety of behaviors to accomplish different goals. One such goal is to avoid extreme temperatures that can result in their endangerment and eventual death. In ectotherms such as zebrafish, the only means of survival in such thermal environments is through behavioral mechanisms. This makes them an ideal model organism to study the relation between external stimuli and the response of the organism. The larval zebrafish seeks out moderate temperatures by biasing individual movements away from temperature extremes. Their behavioral repertoire is highly tractable since it consists primarily of individual bouts of movement followed by a resting period. The bouts comprise of changing their direction of motion and modulating swim speeds of bouts. In our previous work, we discovered that larval zebrafish avoid hot temperatures by raising their swim speeds in warmer water and performing evasive turns when they experience increasing temperatures. Preliminary data also suggests that they avoid cold temperatures by making targeted movements that quickly removes them from such environments. Together, this indicates a differential response to hot and cold temperatures. In this study, we characterize hot and cold avoidance response as a string of bouts which constitute a trajectory, to describe the behavior as a means to reach a goal. We explore different metrics that could be used to define such a goal and characterize the behavior as an optimization of the metric. The goal of the study is to distinguish cold and hot avoidance behavior, using a metric to explain the differential responses observed at an individual bout level.

References:
1. Haesemeyer M, Robson DN, Li JM, Schier AF, Engert F. A Brain-wide Circuit Model of Heat-Evoked Swimming Behavior in Larval Zebrafish. Neuron. 2018;98(4):817-831.e6. doi:10.1016/j.neuron.2018.04.013
2. Benhamou S. How to reliably estimate the tortuosity of an animal's path: straightness, sinuosity, or fractal dimension? J Theor Biol. 2004 Jul 21;229(2):209-20. doi: 10.1016/j.jtbi.2004.03.016. PMID: 15207476.

Keywords: Thermoregulation, Zebrafish behavior, Computational modeling