Final answer:
The red nucleus sends axons to the spinal cord through the rubrospinal tract, which is crucial for modulating motor movements, specifically those related to the limbs.
Step-by-step explanation:
The red nucleus is a structure located in the midbrain which is involved in motor coordination. Specifically, it sends axons to the spinal cord via the rubrospinal tract. The purpose of the rubrospinal tract is to facilitate the modification of ongoing motor programs. This tract particularly influences the muscles responsible for limb movement and is involved in motor coordination.