These fibers have an important role in motor control, and are known as descending tracts.

I have already mentioned, on page 174, the pyramidal system, which is one of the descending tracts.

The descending tracts are composed of white matter.

There are several descending tracts serving different functions.

Other descending tracts such as the extra-pyramidal system pass through the various levels of the nervous system.

The RAS area of the brain has two tracts, the ascending and descending tract.

In the descending tract of the duodenum two clusters of lizards scales are present and, more below, a fish vertebra.

Red Nucleus: This is a motor nucleus that sends a descending tract to the lower motor neurons.

Descending tracts are upper motor neurons destined to synapse on lower motor neurons in the ventral horn and intermediate horn of the spinal cord.

Those that conduct impulses downward from the brain are the descending tracts and those that conduct them upward to the brain are the ascending tracts.

The descending tract for autonomic inspiration is located laterally, and the tract for autonomic expiration is located ventrally."

These signals then modulate the activity of the cerebellar cortex and nuclei, which in turn regulate descending tract neurons in the vestibulospinal, reticulospinal, and rubrospinal tracts.

It usually appears after a lesion to the ascending or descending tracts that control the transmission of painful stimulus, such as the anterolateral system, but many other causes are also possible.

Descending tracts involve two neurons: the upper motor neuron (UMN) and lower motor neuron (LMN).