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− | <pre>
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− | Energy Limits to the Computational Power of the Human Brain
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| by Ralph C. Merkle | | by Ralph C. Merkle |
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| A related article on the memory capacity of the human brain is also | | A related article on the memory capacity of the human brain is also |
| available on the web. | | available on the web. |
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| The Brain as a Computer | | The Brain as a Computer |
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| measure the total distance that all nerve impulses combined can travel per | | measure the total distance that all nerve impulses combined can travel per |
| second, e.g., total nerve-impulse-distance per second. | | second, e.g., total nerve-impulse-distance per second. |
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| Other Estimates | | Other Estimates |
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| estimate of Moravec, who considers this approach in more detail [4, page 57 | | estimate of Moravec, who considers this approach in more detail [4, page 57 |
| and 163]). | | and 163]). |
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| The Brain Uses Energy | | The Brain Uses Energy |
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| a significant fraction of this energy will not be used for useful | | a significant fraction of this energy will not be used for useful |
| computation, we can reasonably round this to 10 watts. | | computation, we can reasonably round this to 10 watts. |
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| Nerve Impulses Use Energy | | Nerve Impulses Use Energy |
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| impulse passes by, the internal voltage briefly rises above 0 volts because | | impulse passes by, the internal voltage briefly rises above 0 volts because |
| of an inrush of Na+ ions. | | of an inrush of Na+ ions. |
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| The Energy of a Nerve Impulse | | The Energy of a Nerve Impulse |
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| in 100 millimeters then it passes one synapse every millimeter--which means | | in 100 millimeters then it passes one synapse every millimeter--which means |
| one synapse operation is about one Ranvier operation. | | one synapse operation is about one Ranvier operation. |
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| Discussion | | Discussion |
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| then that problem can be solved in the future by a personal computer. No | | then that problem can be solved in the future by a personal computer. No |
| field will be left unchanged by this staggering increase in our abilities. | | field will be left unchanged by this staggering increase in our abilities. |
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| Conclusion | | Conclusion |
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| brain has a raw computational power between 1013 and 1016 operations per | | brain has a raw computational power between 1013 and 1016 operations per |
| second. | | second. |
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| | | |
| References | | References |
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− | * 1. Ionic Channels of Excitable Membranes, by Bertil Hille, Sinauer,
| + | 1. Ionic Channels of Excitable Membranes, by Bertil Hille, Sinauer, |
− | 1984.
| + | 1984. |
− | * 2. Principles of Neural Science, by Eric R. Kandel and James H.
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− | Schwartz, 2nd edition, Elsevier, 1985.
| + | 2. Principles of Neural Science, by Eric R. Kandel and James H. |
− | * 3. Tom Binford, private communication.
| + | Schwartz, 2nd edition, Elsevier, 1985. |
− | * 4. Mind Children, by Hans Moravec, Harvard University Press, 1988.
| + | |
− | * 5. From Neuron to Brain, second edition, by Stephen W. Kuffler, John G.
| + | 3. Tom Binford, private communication. |
− | Nichols, and A. Robert Martin, Sinauer, 1984.
| + | |
− | * 6. The switching network of the TF-1 Parallel Supercomputer by Monty M.
| + | 4. Mind Children, by Hans Moravec, Harvard University Press, 1988. |
− | Denneau, Peter H. Hochschild, and Gideon Shichman, Supercomputing,
| + | |
− | winter 1988 pages 7-10.
| + | 5. From Neuron to Brain, second edition, by Stephen W. Kuffler, John G. |
− | * 7. Myelin, by Pierre Morell, Plenum Press, 1977.
| + | Nichols, and A. Robert Martin, Sinauer, 1984. |
− | * 8. The production and absorption of heat associated with electrical
| + | |
− | activity in nerve and electric organ by J. M. Ritchie and R. D. Keynes,
| + | 6. The switching network of the TF-1 Parallel Supercomputer by Monty M. |
− | Quarterly Review of Biophysics 18, 4 (1985), pp. 451-476.
| + | Denneau, Peter H. Hochschild, and Gideon Shichman, Supercomputing, |
| + | winter 1988 pages 7-10. |
| + | |
| + | 7. Myelin, by Pierre Morell, Plenum Press, 1977. |
| + | |
| + | 8. The production and absorption of heat associated with electrical |
| + | activity in nerve and electric organ by J. M. Ritchie and R. D. Keynes, |
| + | Quarterly Review of Biophysics 18, 4 (1985), pp. 451-476. |
| + | |
| | | |
| Acknowledgements | | Acknowledgements |
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| Hans Moravec, and Irwin Sobel for their comments and their patience in | | Hans Moravec, and Irwin Sobel for their comments and their patience in |
| answering questions. | | answering questions. |
− | </pre>
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| [[Category:Body & Health]] | | [[Category:Body & Health]] |