Lab 9 - Descending Pathways to the Spinal Cord

The Rubrospinal Pathway - Midbrain

Figure 1 is a transverse section through the midbrain. The red nucleus continues to be surrounded by the crossed superiorcerebellar peduncle fibers that terminate in this nucleus. The corticorubral fibers continue to enter the red nucleus and terminate in it. Fibers arising from the red nucleus decussate completely to form the rubrospinal tract along the anteromedial margin of the red nucleus.

Figure 2 is a transverse section through the midbrain/pons junction. The fibers (crossed) of the rubrospinal tract are being displaced anteriorly by the decussation of the superior cerebellar peduncles. They cannot be distinguished in this section, but are located anterior to the decussation and medial to the medial lemniscus.