Ascending nociceptive pathway
– Spinothalamic tract (STT)
• Lamina I – mostly high threshold
input, fibers cross to lateral
funiculus – many projections
ascend to the thalamus – carry
pain and temperature info
• Lamina V – some low and high
threshold input, fibers cross to
anterior STT – many projections
as ascends to thalamus -  also
important in pain signaling
– Spinoreticular (SRT) and
– Spinomesencephalic tract (SMT)
– Spinohypothalamic tract (SHT)
Wall and Melzack, Ch 7