| Presentation | 2006-03-15 Three-dimensional Analysis of Action-potential Propagation Velocity at Axons based on Nernst-Planck Equation. Masaya WATANABE, Akira HIROSE, |
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| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | In neurons, ions are moved by diffusion or potential gradient. Thus, strictly speaking, spatiotemporal dynamics of action-potential has to be analyzed by this way of thinking. In this paper, spatiotemporal distribution of action-potential and ion concentration is analyzed by finite element method based on Nernst-Planck equation. We analyze how thickness of axons and myelin sheath have influence on action-potential propagation velocity. As a result, we find the following things. First, in small-radius non-myelinated axons, action-potential propagation follows the cable theory because the ions diffuse homogeneously. But in large-radius non-myelinated axons, ions diffuse only to a certain depth beneath the membrane, and action-potential velocity is proportional to radius. Secondly, we analyze propagation velocity at myelinated axons to clarify detailed mechanism. Especially, propagation velocity doesn't increase simply because myelin sheath is wound around an axon, but mainly because a lot of sodium channels gather at node of Ranvier. These results are different from a traditional idea in which the insulation by myelin sheath improves transmission efficiency. Moreover, the sodium channel density quantitatively corresponds with physiological experiment. Thus, the accuracy of this analysis is verified. |
| Keyword(in Japanese) | (See Japanese page) |
| Keyword(in English) | action-potential / Nernst-Planck equation / axon / myelin sheath / node of Ranvier |
| Paper # | NC2005-111 |
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| Committee | NC |
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| Conference Date | 2006/3/8(1days) |
| Place (in Japanese) | (See Japanese page) |
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| Topics (in Japanese) | (See Japanese page) |
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| Registration To | Neurocomputing (NC) |
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| Language | JPN |
| Title (in Japanese) | (See Japanese page) |
| Sub Title (in Japanese) | (See Japanese page) |
| Title (in English) | Three-dimensional Analysis of Action-potential Propagation Velocity at Axons based on Nernst-Planck Equation. |
| Sub Title (in English) | |
| Keyword(1) | action-potential |
| Keyword(2) | Nernst-Planck equation |
| Keyword(3) | axon |
| Keyword(4) | myelin sheath |
| Keyword(5) | node of Ranvier |
| 1st Author's Name | Masaya WATANABE |
| 1st Author's Affiliation | Department of Frontier Informatics, Graduate School of Frontier Sciences, The University of Tokyo() |
| 2nd Author's Name | Akira HIROSE |
| 2nd Author's Affiliation | Department of Frontier Informatics, Graduate School of Frontier Sciences, The University of Tokyo |
| Date | 2006-03-15 |
| Paper # | NC2005-111 |
| Volume (vol) | vol.105 |
| Number (no) | 657 |
| Page | pp.pp.- |
| #Pages | 6 |
| Date of Issue | |