Corticospinal and Spinothalamic Tracts

What type of pathway is the corticospinal tract?

A descending tract.

Is the corticospinal tract an afferent or efferent pathway?

An efferent pathway.

What type of motor control does the corticospinal tract manage?

Voluntary motor control.

What are the two main types of neurons involved in the corticospinal tract?

Upper motor neurons (UMNs) and lower motor neurons (LMNs).

Where does the corticospinal tract originate?

In the primary motor cortex of the frontal lobe.

Where is the cell body of the first neuron in the corticospinal tract located?

In the upper motor neuron (UMN).

Through which part of the brain does the corticospinal tract pass to become the internal capsule?

The lateral diencephalon.

What structures does the corticospinal tract pass through as it descends?

The midbrain and pons.

At which point does the corticospinal tract cross to the contralateral side?

At the lower medulla, in the decussation of the pyramids.

75-90% of corticospinal fibers cross over at the ____?

decussation of the pyramid

After crossing at the medulla, in which part of the spinal cord does the corticospinal tract descend?

The lateral funiculus.

What happens when the corticospinal tract reaches the level of the spinal cord where it exits to the muscles?

It enters the gray matter and activates the second nerve cell body in the anterior horn.

Where is the cell body of the lower motor neuron (LMN) located in the corticospinal tract?

In the anterior horn of gray matter.

How does the axon exit the spinal cord to reach the muscle in the corticospinal tract?

Through the anterior spinal cord (ventral rami), then into the spinal nerve, and down the axon to the muscle.

What type of pathway is the spinothalamic tract?

An ascending tract.

What two sub-tracts make up the spinothalamic tract?

The anterior and lateral tracts.

Is the spinothalamic tract an afferent or efferent pathway?

An afferent pathway.

What type of information does the spinothalamic tract carry?

Sensory information.

What type of sensory information is transmitted by the lateral spinothalamic tract?

Pain and temperature.

What type of sensory information is transmitted by the anterior spinothalamic tract?

Light touch.

Where are the sensory receptors located that feed into the spinothalamic tract?

In the periphery.

Which structure does the sensory information travel through to reach the spinal cord?

The spinal nerve to the dorsal ganglia.

Where does the sensory information enter the spinal cord in the spinothalamic tract?

In the posterior horn of gray matter at the entry level.

Where does the spinothalamic tract cross to the contralateral side?

In the gray matter, either at the level of entry (anterior) or one level higher (lateral).

After crossing to the contralateral side, where does the spinothalamic tract go next?

To the lateral white matter.

Which parts of the central nervous system does the spinothalamic tract ascend through after entering the lateral white matter?

The spinal cord, medulla, and pons.

Where does the spinothalamic tract project after passing through the brainstem?

Into the thalamus in the diencephalon.

After reaching the thalamus, where is the sensory information projected in the spinothalamic tract?

To the postcentral gyrus of the cerebral cortex in the parietal lobe.

Where does the corticospinal tract cross vs spinothalamic

Motor Medulla vs Sensory Spinal Cord