Uncovering multiscale structure in the variability of larval zebrafish navigation

TL;DR

This study develops Markov models to analyze larval zebrafish navigation, revealing hierarchical motor strategies and internal states influenced by environmental cues and prior experiences, highlighting exploration-exploitation dynamics.

Contribution

The paper introduces a novel Markov modeling approach to uncover multiscale behavioral structure and internal states in zebrafish navigation, linking variability to internal motivation and experience.

Findings

Identified hierarchical motor strategies distinguishing cruising and wandering.

Environmental cues modulate population-level preferences in navigation modes.

Prior prey exposure influences exploration-exploitation phenotypes.

Abstract

Animals chain movements into long-lived motor strategies, exhibiting variability across scales that reflects the interplay between internal states and environmental cues. To reveal structure in such variability, we build Markov models of movement sequences that bridges across time scales and enables a quantitative comparison of behavioral phenotypes among individuals. Applied to larval zebrafish responding to diverse sensory cues, we uncover a hierarchy of long-lived motor strategies, dominated by changes in orientation distinguishing cruising versus wandering strategies. Environmental cues induce preferences along these modes at the population level: while fish cruise in the light, they wander in response to aversive stimuli, or in search for appetitive prey. As our method encodes the behavioral dynamics of each individual fish in the transitions among coarse-grained motor strategies, we use it to uncover a hierarchical structure in the phenotypic variability that reflects exploration-exploitation trade-offs. Across a wide range of sensory cues, a major source of variation among fish is driven by prior and/or immediate exposure to prey that induces exploitation phenotypes. A large degree of variability that is not explained by environmental cues unravels motivational states that override the sensory context to induce contrasting exploration-exploitation phenotypes. Altogether, by extracting the timescales of motor strategies deployed during navigation, our approach exposes structure among individuals and reveals internal states tuned by prior experience.