Pathway
C fibers synapse to second-order projection neurons in the spinal cord at the upper laminae of the dorsal horn in the substantia gelatinosa. The second-order projection neurons are of the wide dynamic range (WDR) type, which receive input from both nociceptive terminals as well as myelinated A-type fibers. There are three types of second order projection neurons in the spinothalamic tract: wide dynamic range (WDR), high threshold (HT), and low threshold (LT). These classifications are based on their responses to mechanical stimuli. The second-order neurons ascend to the brain stem and thalamus in the ventrolateral, or anterolateral, quadrant of the contralateral half of the spinal cord, forming the spinothalamic tract. The spinothalamic tract is the main pathway associated with pain and temperature perception, which immediately crosses the spinal cord laterally. This crossover feature is clinically important because it allows for identification of the location of injury.
Read more about this topic: Group C Nerve Fiber
Famous quotes containing the word pathway:
“Many are obstinate with regard to the pathway once they have set upon it, few with regard to the goal.”
—Friedrich Nietzsche (1844–1900)
“Socrates drinking the hemlock,
And Jesus on the rood;
And millions who, humble and nameless,
The straight, hard pathway plod—
Some call it Consecration,
And others call it God.”
—William Herbet Carruth (1859–1929)
“To learn from our enemies is the best pathway to loving them: for it makes us grateful to them.”
—Friedrich Nietzsche (1844–1900)