Dimensionality and dynamics in the behavior of C. elegans

TL;DR

This study reveals that C. elegans' shape dynamics are low-dimensional and deterministic, enabling real-time steering by synchronizing stimuli with its shape state, advancing understanding of nematode behavior.

Contribution

The paper demonstrates that C. elegans' shape space is low-dimensional and provides a method to steer the worm by aligning stimuli with its shape dynamics.

Findings

Four dimensions account for 95% of shape variance.

Worm behavior is nearly deterministic in response to stimuli.

Real-time steering of the worm is achieved by synchronizing stimuli.

Abstract

A major challenge in analyzing animal behavior is to discover some underlying simplicity in complex motor actions. Here we show that the space of shapes adopted by the nematode C. elegans is surprisingly low dimensional, with just four dimensions accounting for 95% of the shape variance, and we partially reconstruct "equations of motion" for the dynamics in this space. These dynamics have multiple attractors, and we find that the worm visits these in a rapid and almost completely deterministic response to weak thermal stimuli. Stimulus-dependent correlations among the different modes suggest that one can generate more reliable behaviors by synchronizing stimuli to the state of the worm in shape space. We confirm this prediction, effectively "steering" the worm in real time.