Dual Pain Pathways in the Cord and Brain Stem — The Neospinothalamic Tract and the Paleospinothalamic Tract On entering the spinal cord, the pain signals take two pathways to
the brain, through (1) the neospinothalamic tract and (2) the paleospinothalamic tract. Neospinothalamic Tract for Fast Pain.
The fast typeA
pain fibers transmit mainly mechanical and
acute thermal pain. They terminate mainly in lamina I (lamina marginalis) of the dorsal horns, as
shown in Figure 48-2, and there excite second-order neurons of the neospinothalamic tract.
