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bioRxiv · 10.1101/2025.06.13.659371

Behavioral algorithms of ontogenetic switching in larval and juvenile zebrafish phototaxis

Capelle, M. Q.·Slangewal, K.·Bahl, A.
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Abstract

Animals undergo major behavioral adjustments during ontogeny, but how the underlying cognitive algorithms change during this process remains elusive. Here, we describe that zebrafish shift from light-seeking to dark-seeking, as they grow from larval to juvenile stage, within the first few weeks of their life. We apply a combination of complementary phototaxis assays in virtual reality and modeling to dissect the computational basis of this transition. We identify three parallel pathways, one analyzing ambient whole-field luminance levels, one spatially comparing light levels across the eyes, and one computing eye-specific temporal derivatives. Larvae mostly use the latter two spatio-temporal computations for navigation, while juveniles largely employ the first one. We build a library of agent-based models to predict animal behavior across stimulation conditions and in more complex environments. Model-based extraction of latent cognitive variables points towards potential neural correlates of the observed behavioral inversion and illustrates a novel way to explore the processes of vertebrate ontogeny. We suggest that zebrafish phototaxis is regulated via parallel processing streams, which could be a universal implementation to change strategies depending on developmental stage, context, or internal state, making behavior flexible and goal-oriented. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=188 SRC="FIGDIR/small/659371v3_ufig1.gif" ALT="Figure 1"> View larger version (49K): org.highwire.dtl.DTLVardef@40848forg.highwire.dtl.DTLVardef@1bed6c6org.highwire.dtl.DTLVardef@68a10org.highwire.dtl.DTLVardef@1525f06_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTSO_LIWe provide a framework to describe how behavioral strategies evolve during ontogeny. C_LIO_LIZebrafish switch their phototactic behavior within the first weeks of their life. C_LIO_LIBrightness navigation strategies can be described with a three-pathway model. C_LIO_LILarvae use spatial cues, while juveniles use ambient whole-field luminance for phototaxis. C_LI

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Capelle, M. Q., Slangewal, K., Bahl, A.. 2025-06-17. Behavioral algorithms of ontogenetic switching in larval and juvenile zebrafish phototaxis. https://doi.org/10.1101/2025.06.13.659371

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