Corticospinal tract

The cortico-spinal tract is important for conveying sensory information to the brain and relaying output signals from the brain to the motor units

Origin

 * It originates at the pre-central gyrus and at the posterior part of the frontal gyrus (areas 4 to 6)
 * All fibres originate from the 5th layer of the cortex

Course

 * 1) Axons descend from the centrum semiovale to the posterior limb of the internal capsule
 * 2) From the internal capsule, fibres continue to the middle portion of the cerebral crura
 * 3) Fibres continue to the basal part of the pons, where they form connections with pontine nuclei
 * 4) Exiting the pons, two columns form on the external surface of the medulla oblongata
 * 80% fibres decussate (cross-over) at the junction between the spinal cord and medulla oblongata and continue to descend on the lateral aspect of the spinal white matter as the lateral cortico-spinal tract
 * Those that don't decussate, continue in the anterior spinal white matter as the anterior cortico-spinal tract

Termination

 * The tracts terminate in the lateral and dorsal horns of the spinal cord and can synapse with motor neurons

Function

 * Voluntary and discrete movements as well as control of sensory inputs