Below are mental scaffolds for organizing pathways. I’ve included the descending pathway as well for modulation of pain perception.

Once again, note:

  1. Cross-over (decussation points)
  2. Nuclei
  3. Tracts
One thing to note, Lissauer’s Tract does not ascend into the brainstem… it is part of the first order neuron which may go up or down the spinal cord a bit before terminating onto the substantia gelatinosa.