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Related Experiment Video

Updated: Jun 3, 2026

C. elegans Tracking and Behavioral Measurement

C. elegans Tracking and Behavioral Measurement

Published on: November 17, 2012

Mathematical model for contemplative amoeboid locomotion.

Kei-Ichi Ueda¹, Seiji Takagi, Yasumasa Nishiura

¹Research Institute for Mathematical Sciences, Kyoto University, Kyoto 606-8502, Japan.

Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics

|March 17, 2011

Summary

Single-celled organisms like Physarum plasmodium exhibit contemplative behavior when facing obstacles. Mathematical modeling reveals that transitions in chemical reactivity drive this "thinking" process before movement resumes.

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Area of Science:

Cellular dynamics
Mathematical biology
Nonlinear dynamics

Background:

Single-celled organisms, specifically Physarum plasmodium, demonstrate apparent indecisiveness when encountering chemical repellents.
This contemplative behavior involves a temporary halt in migration followed by resumption of movement in various directions (forward, backward, or both).

Purpose of the Study:

To develop a continuum mathematical model simulating the cell dynamics of contemplative amoeboid movement.
To elucidate the underlying mechanisms driving the observed behaviors in Physarum plasmodium.

Main Methods:

Developed a mathematical model incorporating protoplasmic sol mass flow, pressure generation, and autocatalytic kinetics of pseudopod formation/retraction (sol-gel conversion, actin-myosin dynamics).
Validated the model by comparing simulation results with experimentally measured spatiotemporal cell thickness profiles.
Utilized nonlinear dynamics to analyze the model's behavior and clarify the core logic.

Main Results:

The model successfully reproduced the experimentally observed behaviors of Physarum plasmodium, including forward, backward, and simultaneous bidirectional movement.
Simulations demonstrated that an on-off transition in chemical reactivity at the leading edge is crucial for contemplative behavior.
Nonlinear dynamics analysis clarified the mechanisms behind the organism's decision-making process.

Conclusions:

The developed mathematical model provides a robust framework for understanding contemplative amoeboid movement.
The study highlights the critical role of dynamic changes in chemical reactivity in enabling complex cellular behaviors.
This research offers insights into the fundamental principles governing decision-making in simple biological systems.