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Updated: Jan 5, 2026
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Voltage-sensitive Dye Recording from Axons, Dendrites and Dendritic Spines of Individual Neurons in Brain Slices
Published on: November 29, 2012
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Action potential propagation and synchronisation in myelinated axons
Helmut Schmidt1, Thomas R Knösche1,2
1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
Plos Computational Biology
|October 18, 2019
Summary
This study introduces a simplified mathematical model for action potential propagation in white matter, enhancing whole-brain models. It reveals myelin sheath thickness significantly impacts action potential velocity.
Area of Science:
- Neuroscience
- Computational Biology
- Biophysics
Background:
- Advanced MRI techniques enable detailed, non-invasive study of axonal white matter.
- Modeling large-scale neuronal activity requires accurate descriptions of signal transmission across axonal fiber bundles.
Purpose of the Study:
- To develop a biologically plausible yet simple mathematical framework for action potential propagation.
- To investigate the influence of axonal parameters on action potential velocity and fiber coupling.
- To integrate detailed axonal properties into whole-brain models.
Main Methods:
- Developed a spike-diffuse-spike model replacing Hodgkin-Huxley dynamics.
- Incorporated passive sub-threshold dynamics and explicit ion channel currents.
- Analyzed action potential velocity and entrainment without numerical simulations.
Main Results:
- Recovered known influences of axon diameter and Ranvier/internode lengths on action potential velocity.
- Found a stronger dependence of velocity on myelin sheath thickness than previously suggested.
- Explained action potential slowing and synchronization in ephaptically coupled fibers through dynamic interactions.
Conclusions:
- The spike-diffuse-spike model provides a computationally efficient framework for studying axonal signal propagation.
- Detailed axonal parameters, especially myelin thickness, are crucial for accurate whole-brain modeling.
- This approach facilitates the refinement of large-scale neuronal activity models.
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