nerveledning

Nerveledning, or nerve conduction, is the process by which electrical impulses are transmitted along nerve fibers to enable communication within the nervous system. A stimulus initiates an action potential at the axon hillock, triggering sequential opening of voltage-gated sodium and potassium channels that propagate the signal along the axon. In myelinated fibers, myelin sheaths and the nodes of Ranvier facilitate saltatory conduction, allowing faster transmission. Conduction velocity is influenced by axon diameter, degree of myelination, internode length, and temperature; larger, well-myelinated fibers conduct more rapidly. Unmyelinated fibers conduct more slowly, and conduction speed decreases with cooler temperatures or aging.

At the destination, the electrical signal is typically translated into a chemical signal at a synapse, enabling transmission to the next neuron or to an effector organ.

Clinical relevance: Nerve conduction studies measure conduction velocity, latency, and response amplitudes to assess peripheral nerve function. They help diagnose peripheral neuropathies, nerve injuries, and compressive syndromes such as carpal tunnel syndrome. A reduced conduction velocity suggests demyelination, while diminished amplitude indicates axonal loss. These studies complement imaging and clinical examination and are most informative for large-diameter myelinated fibers.

Limitations: They assess peripheral nerves and large fibers and do not directly test small fibers or central pathways. Safety: non-invasive and widely used in neurology and rehabilitation.