A receptor-inactivation model for single-celled habituation in Stentor coeruleus

Area of Science:

• Cell Biology
• Neuroscience
• Biophysics

Background:

• Single-celled organisms, such as the ciliate Stentor coeruleus, exhibit habituation to mechanical stimuli.
• This demonstrates a rudimentary form of learning in single cells, but the underlying mechanism remains unknown.

Purpose of the Study:

• To investigate a biochemistry-based model for Stentor habituation.
• To explain the cellular learning mechanism through receptor dynamics.

Main Methods:

• Developed a bottom-up model based on electrophysiological data and receptor properties.
• Conducted stochastic simulations to test the model's predictions.
• Performed experiments to validate model predictions regarding stimulus magnitude and training protocols.

Main Results:

• The model successfully replicates Stentor habituation, including lack of dishabituation and step-like responses.
• It explains phenomena not covered by previous models, such as stimulus magnitude dependence and potentiation.
• Experimental validation confirmed predictions on receptor number changes and delayed recovery after high-force stimuli.

Conclusions:

• Activity-dependent receptor internalization is a plausible mechanism for single-cell learning (habituation) in Stentor.
• The model provides a framework for understanding cellular memory and decision-making based on past stimuli.
• This work highlights how simple models can guide experimental investigations into single-cell learning.