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Why nerves are bundles of fibres : information theoretic solution by noisy cells for survival| old_uid | 5297 |
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| title | Why nerves are bundles of fibres : information theoretic solution by noisy cells for survival |
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| start_date | 2008/09/25 |
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| schedule | 13h45 |
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| online | no |
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| summary | The rate of information at which a single wind receptor cell of the cricket transmitted in the form of neuronal pulse train was measured as ca. 400 bit/sec at maximum. A single neuronal pulse carried approximately 3 bit of information. Measurement of the mechanical properties of the wind receptor hair revealed that sensory cells elicit a pulse in response to stimulus energy at the order of kBT (ca. 4¥10-21 Joule at 300 ∞K). The entropy cost of measurement (energy cost divided by temperature) in the receptor cell to obtain one bit of information is ca. one kB, which is very close to the thermodynamic limit of 0.7 kB per bit. Based on these two measurements, we conclude that the working principle of the nervous system is signal extraction by summation average against heavy masking noise. This principle also explains the advantages of multi-cellular organization for reliable observation of a weak signal under comparable thermal noise. We further discuss that the sensitivity at the thermodynamic limit is constraint but not acquired by evolutionary improvements. The way of the information theoretic solution by living organisms evolved under the inevitable thermal noise teaches us ways for future technology that will certainly have to confront thermal noise. |
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| responsibles | Fenouil |
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