Why does motor neuron axon demyelination cause muscle weakness?

💡 Explanation

Demyelination reduces the axon's insulation, thus saltatory conduction, where action potentials jump between Nodes of Ranvier, becomes less efficient. Because the signal degrades more rapidly, it may not reach the axon terminal at a high enough frequency to trigger muscle contraction; therefore, muscle weakness results, rather than hyper-excitability.

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