Rubrospinal tract

The rubrospinal tract is a descending motor pathway that originates in the red nucleus of the midbrain. It primarily facilitates flexor muscle activity while inhibiting extensor (antigravity) muscles. Extending from the midbrain to the anterior gray horn of the spinal cord, this tract plays a role in motor control and posture.

The red nucleus, situated in the midbrain at the level of the superior colliculus, serves as the origin of the rubrospinal tract. After decussating at the same level, the tract descends through the lateral funiculus of the spinal cord and terminates at alpha and gamma motor neuron cell bodies in the anterior horns of the spinal cord.

Since, the red nucleus receives afferents from both cerebral cortex and the cerebellum, therefore the rubrospinal tract serves as an important indirect pathway through which cerebral cortex and cerebellum can modulate the activity of alpha and gamma lower motor neurons.