Topological aspects of axonal regeneration.
The fibers making up any sensory system in the spinal cord come from the same cells as do the fibers in peripheral nerves yet severed nerve fibers in the adult spinal cord do not regenerate but damaged peripheral nerves - those in the extremities - do heal themselves. Why should spinal cord regeneration even be an issue, why should an inhibiting protein have evolved to prevent it and what causes this protein to be expressed? From a holistic perspective, an answer to this conundrum shows that these questions are intertwined, and suggests that: (1) The model of the neurons as 'wires' is too simplistic. (2) In humans, the 'map' of individual connections is (topologically, at least) locally variable, though the overall global topology and 'functionality' of each normal spinal cord is constant. Both of these issues have to be addressed if functional restoration is to be achieved.
ben-Aaron
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61 South Road, Bedford, MA 01730, USA. xeno3579@cs.com
D000818:Animals; D001369:Axons / Q000473:pathology* / Q000502:physiology*; D001921:Brain / Q000473:pathology; D002490:Central Nervous System / Q000502:physiology; D003491:Cybernetics; D006801:Humans; D008962:Models, Theoretical; D009416:Nerve Regeneration