Unmyelinated fibers (C fibers)

Unmyelinated fibers, also known as C fibers, are slow-conducting nerve fibers that transmit dull, aching and burning pain sensations.

Unlike faster myelinated A-delta fibers, which carry sharp and well-localized pain, C fibers produce diffuse, lingering pain that is harder to pinpoint.

These fibers are central to chronic pain mechanisms. Persistent activation of C fibers can sensitize the spinal cord and brain, contributing to central sensitization. They are also heavily involved in neuropathic and inflammatory pain. Understanding C fiber physiology has shaped the development of treatments that aim to reduce their hyperexcitability, including pharmacological agents and neuromodulation techniques.