The colored lines show the path of the corticospinal tract from the motor cortex down through the: midbrain, pons, medulla, and spinal cord (EACH REPRESENTED BY ONE CROSS-SECTION ABOVE).

Corticospinal tract:

primary pathway for producing voluntary movement, the corticospinal tract is a large collection of axons that travel from the cerebral cortex down to the spinal cord and synapse on neurons that can influence muscle activity. Many of the axons that enter the corticospinal tract originate in the primary motor cortex, although other motor areas also contribute to the pathway.

Learn more: Know your brain - Corticospinal tract

2-Minute Neuroscience: Corticospinal tract