The mesencephalic nucleus of the trigeminal nerve is unique among cranial nerve sensory nuclei because it contains:

• A Second-order neurons that decussate in the trigeminal lemniscus
• B Interneurons that modulate the corneal reflex arc
• C Efferent motor neurons for the muscles of mastication
• D Primary afferent cell bodies located within the CNS parenchyma itself ✓

Explanation

The mesencephalic nucleus of CN V houses the cell bodies of primary afferent (proprioceptive) neurons within the brainstem — an exception to the rule that all primary sensory cell bodies reside in peripheral ganglia. These neurons carry proprioceptive information from the muscles of mastication, periodontal ligaments, and extraocular muscles. It is the only location in the CNS where first-order sensory neuron somas are embedded within the CNS itself. This serves the jaw-jerk reflex arc.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.