see Corticospinal tract X Y Z

any of the important motor nerves on each side of the central nervous system that run from the sensorimotor areas of the cortex through the brainstem to motor neurons of the cranial nerve nuclei and the ventral horn of the spinal cord

One of the major motor tracts from the brain to the spinal cord. Its fibers form the pyramids of the Medulla. It originates in the cortex of the frontal lobe. - It communicates directly with motor neurons in the of the spinal cord, to activate fine motor control. Ex: tying shoelaces, writing, etc. -It orchestrates the motor response and helps to specify body posture at all levels of the spinal cord. - It adjusts muscle tone to counter the changing centers of gravity. - Plaque here causes the symptoms of spasticity: muscle tightness, ankle clonus, flexor spasms, exhaustion, loss of muscle power, and paralysis.

This is the direct corticospinal tract. It arises in the primary motor cortex, as a bundling together of axons from the upper motor neurons. By the time it reaches the medulla, it contains a million or so fibres, 90% of which decussate (cross over) and travel down the contralateral (or "crossed") lateral corticospinal tract of the spinal cord. The pyramidal tract is conventionally believed to carry voluntary muscle instructions to the alpha motor neurons. (See also corticospinal fibres, and compare corticobulbar fibres.)

a collection of nerve tracts in the brain stem.

Pyramidal tract refers to any of four columns of motor fibers that run in pairs on each side of the spinal cord and that are continuations of the pyramids of the medulla.