Decision Making, Behavioral Development and Fine Motor Control In Larval Zebrafish

Abstract

All organisms need to make decisions after processing sensory inputs. The drift-diffusion model accurately captures average responses observed in the optomotor response of larval zebrafish but fails to capture the structure of individual trial dynamics. We propose a model based on attentional switching that can account for both trial dynamics and average responses. This framework is sensitive to environmental and genetic perturbations, making it useful as a screening tool as well. While larval zebrafish reliably exhibit the optomotor response, there is a degradation in performance with increasing fish age. This contradicts attempts to attribute complex behaviors like schooling in older fish to good alignment performance in the optomotor response. This decrease occurs independent of social or visual cues, and it remains to be seen if stimuli shown to the sides of a tank (representing conspecifics motion) instead of the bottom (representing substrate motion), can recover the performance drop seen in later fish ages. Alignment tasks require motor control to make both fine and coarse adjustments. We show that two strategies facilitating motor control are biased forward swims and upregulation of large angle turns beyond a critical target alignment value. Our work addresses the goal, algorithm and implementation aspects to set a foundation for future studies on decision making, changes with fish age and fine motor control strategies in zebrafish at both behavioral and neural levels.