Sensory and motor axons are different: implications for neurological disease

摘要

Using threshold tracking, differences have been established between large myelinated sensory and α motor axons in humans. Major differences are that sensory axons are relatively depolarised at rest such that they have a greater persistent Na+ current, and have greater activity of hyperpolarisation-activated cyclic nucleotide-gated (HCN) channels. Sensory axons may thereby be protected from hyperpolarising stresses, and are less likely to develop conduction block. However, the corollary is that sensory axons are more excitable and more likely to become ectopically active.