Lab 9 - Descending Pathways to the Spinal Cord

Rubrospinal Tract

The rubrospinal tract is involved in the control of muscle tone and action of flexor muscle groups. The rubrospinal tract takes origin in the red nucleus. The tract fibers decussate and descend in the lateral funiculus of the spinal cord, medial to and partially intermingled with, the fibers of the lateral corticospinal tracts. Most rubrospinal fibers terminate at cervical and thoracic levels, but some extend to all cord levels. This tract’s fibers have an inhibitory effect on extensor muscles and an excitatory effect on the flexor muscles. The red nucleus receives inputs from the cerebellum and the cerebral cortex. It receives crossed cerebellar efferent fibers via the superior cerebellar peduncles and uncrossed corticorubral fibers that arise from precentral gyrus (motor cortex).

Rubrospinal Tract