Final answer:
C fiber 2nd order neurons are associated with the paleospinothalamic tract, which is responsible for transmitting dull, chronic pain sensations, as opposed to the neospinothalamic tract, which transmits faster pain and temperature sensations.
Step-by-step explanation:
The student asked whether C fiber 2nd order neurons excite the paleospinothalamic tract or the neospinothalamic tract. In the context of the spinothalamic tract, there are two main pathways: the paleospinothalamic tract and the neospinothalamic tract. The paleospinothalamic tract is primarily responsible for the dull, aching sensation of pain, and is involved in emotional and arousal responses to pain. On the other hand, the neospinothalamic tract conducts faster pain and temperature sensations and projects more directly to the somatosensory cortex.
The C fibers are unmyelinated nerve fibers associated with transmitting slower, chronic pain signals. These fibers synapse with second-order neurons that tend to excite the paleospinothalamic tract, which is associated with longer-lasting, poorly localized pain sensations. Hence, C fiber 2nd order neurons are more closely tied to the paleospinothalamic tract than the neospinothalamic tract.