Pain transmission

Peripheral Transmission - Noxious stimuli are not transmitted by any particular modality specific nerve fibers but by a variety of fibers that belong to the A delta and C classes of fibers.

A delta fibers are small diameter, slow conducting myelinated axons that respond differently to mechanical or thermal stimuli. C fibers are slow conducting, unmyelinated axons and in humans are all polymodal ; in that they respond to mechanical, thermal and chemical stimuli. A delta and C fibers have in common their small diameter and are referred to collectively as small diameter afferents to distinguish them from large diameter afferents (A beta fibers) that carry the innocuous sensations of touch, vibration and proprioception.

Central Transmission - Upon reaching the spinal cord, small diameter afferents are segregated from large diameter afferents in the dorsal root entry zone. Large diameter afferents pass medial to the dorsal horn with collaterals ramifying in lamina V of the dorsal gray matter and other branches ascending into the dorsal gray column.

Small diameter afferent conveying nociceptive information divide into collateral branches that ascend and descend in the dorsolateral tract with branches entering superficial layers of the dorsal horn at multiple segments above and below their level of entry into the cord.

If you like to know more about Acutouch, browse the site or contact us for free information.