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September 29, 2005
Mechanisms of ageing
Anders Sandberg has together with João Pedro de Magalhães, of Harvard Medical School, written the paper Cognitive aging as an extension of brain development: A model linking learning, brain plasticity, and neurodegeneration in the October issue of Mechanisms of Ageing and Development, number 126.
Magalhães and Sandberg bridge the fields of neuroscience, biogerontology and evolutionary biology to explain a new hypothesis of why mental ageing might be genetically determined. Brain ageing in the adult can be seen as a direct continuation of brain development in the young, continuing in the same direction but now with harmful effects. Very young brains need to adapt to new information rapidly, learning at a high speed. As they mature new information should not overwrite old, so it is favourable to slow down the learning rate. Assuming that evolution would maximise the amount of information learned up to the time of reproduction leads to a declining learning rate throughout life, and there is no reason for evolution to add a mechanism to stop the slowing of learning rate among older people (since they do not have children that would pass on such a beneficial mutation).
If this hypothesis works it would suggest that improving memory and slowing mental ageing would require tinkering with the same genetic core causes or circumventing them.
Posted by Waldemar at September 29, 2005 10:43 AM