c fibers carry sensory information to the brain.
c fibers carry what type of information to the brain?
sensory information
the posterior column has a prominent role in the pain system, it is the first central relay in the nociceptive pathway. the first order afferent neuron carries sensory information to the second order neuron in the dorsal horn. the axon of the second order neuron, if it is a projection neuron and not an interneuron, then goes to the third order neuron in the thalamus. the thalamus is known as the "gateway to the cortex". the third order neuron then goes to the cerebral cortex. the afferent neurons are either a fibers or c fibers. a fibers are myelinated allowing for faster signal conduction. among these there are a beta fibers which are faster and carry information about non-painful touch and a delta fibers which are slower and thinner than the a beta fibers. the c fibers are not myelinated and therefore slower. c fibers that carry nociceptive signals can be divided into two types: fibers that contain neuropeptides, like substance p, and fibers that do not contain neuropeptides. the two types terminate in very different areas. non-peptidergic c fibers are linked to the skin, where they innervate the epidermis while peptidergic c fibers innervate other tissues and deeper parts of the skin.
grey column
type aδ fibers are the afferent fibers of nociceptors. aδ fibers carry information from peripheral mechanoreceptors and thermoreceptors to the dorsal horn of the spinal cord. this pathway describes the first-order neuron. aδ fibers serve to receive and transmit information primarily relating to acute pain (sharp, immediate, and relatively short lasting). this type of pain can result from several classifications of stimulants: temperature-induced, mechanical, and chemical. this can be part of a withdrawal reflex - initiated by the aδ fibers in the reflex arc of activating withdrawal responses. these are the "type iii" group. aδ fibers carry cold, pressure, and acute pain signals, and because they are thin (2 to 5 μm in diameter) and myelinated, they send impulses faster than unmyelinated c fibers, but more slowly than other, more thickly myelinated group a nerve fibers. their conduction velocities are moderate.
group a nerve fiber