Final answer:
The corticonuclear tracts communicate with cranial nerve nuclei in the brainstem and represent a component of the motor pathway for controlling voluntary muscles, especially in the face and neck.
Step-by-step explanation:
The corticobulbar tract is a part of the central nervous system that contains fibers carrying motor commands from the brain to the cranial nerves. These fibers are ipsilateral, which means they project from the cortex to the motor nucleus on the same side of the nervous system. Conversely, the corticospinal tract, another descending tract, is largely contralateral meaning that fibers cross the midline of the brain stem or spinal cord and synapse on the opposite side of the body, a key site of decussation is the pyramidal decussation in the medulla. Therefore, the corticonuclear tracts communicate with cranial nerve nuclei in the brainstem and are crucial for voluntary control of muscles.