Estimation of Swimming Position of Zebrafish using a Spatial Distribution Model of Ventilatory Signals

Zebrafish is a model organism widely used in behavioral neurology and drug discovery to elucidate the neurobehavioral mechanisms of emotion. Traditionally, its emotional states were assessed from motion patterns, and respiratory information was neglected despite its reported importance. This paper presents a system that enables simultaneous motion and respiration measurement using a bioelectric signal, termed ventilatory signal. The proposed system measures ventilatory signals from an electrode array and applies a spatial distribution model to locate zebrafish and the instantaneous amplitude of the signal. The experimental results confirmed that position estimation was possible with an error of approximately 1/5 of the body length. Simultaneously, the system could detect an increase in respiration frequency caused by a 100 mg/L concentration of caffeine dose.