Bonjour!

Je soutiendrai ma thèse le mercredi 10 décembre à 10h dans l'Amphi 55A, vous êtes tous les bienvenus.

La soutenance sera en anglais.

Title:

Multiscale locomotor dynamics in Danionella cerebrum

Abstract:

Animals rely on movement to survive — to explore their environment, find food and mates and avoid danger. Locomotion reflects a complex interplay between body, brain and environment. It requires flexibility to accommodate morphological changes during growth, and adaptability to meet ever-changing physiological demands. In this work, we explored this phenomenon in Danionella cerebrum, a miniature freshwater fish emerging as an important vertebrate model in systems neuroscience.

We developed a customized freely swimming assay to generate a comprehensive dataset of locomotor behavior across multiple temporal and spatial scales.

At short timescales, we quantified a developmental shift from continuous swimming to an intermittent pattern, in which the animal moves through a series of discrete, high-acceleration swim bouts. We interpret this shift as an energy-saving strategy and show that it arises from an intrinsic instability in the animal’s self-motion regulation system. Our findings indicate that the transition is driven by biomechanical changes associated with body growth, rather than by neural maturation.

At longer timescales, relevant to spatial exploration, we investigated how internal physiological states influence large-scale navigation in open environments.

In particular, we studied how hunger triggers transient local search behavior.

Together, our findings reveal how multiscale locomotor dynamics emerge from the coordinated development of motor systems and behavioral strategies.