Descending motor pathways of the pyramidal tracts travel from the cerebral cortex to the brainstem or lower spinal cord.
[4][5] Ascending sensory tracts in the dorsal column–medial lemniscus pathway (DCML) carry information from the periphery to the cortex of the brain.
[citation needed] Note that the "old" name was primarily descriptive, evoking the pyramids of antiquity, from the appearance of this neural pathway in the medulla oblongata.
The other main pathway is from the climbing fibers and these project to Purkinje cells and also send collaterals directly to the deep nuclei.
[citation needed] If most or all of the axons lack myelin sheaths (i.e., are unmyelinated), then the pathway will appear a darker beige color, which is generally called grey.
The longest axon in the human body belongs to the Sciatic Nerve and runs from the great toe to the base of the spinal cord.