What does the mesencephalic nucleus do?

The mesencephalic nucleus is involved with proprioception of the face, that is, the feeling of position of the muscles. Unlike many nuclei within the central nervous system, the mesencephalic nucleus contains no chemical synapses but are electrically coupled.

How is the mesencephalic nucleus unique?

The mesencephalic nucleus is the only structure in the central nervous system to contain the cell bodies of first order sensory neurons. The mesencephalic nucleus can thus be considered functionally as a sensory ganglion embedded within the brainstem, making it neuroanatomically unique.

Where is mesencephalic trigeminal nucleus?

mesopontine junction
The trigeminal mesencephalic nucleus (MesV), located at the mesopontine junction, is a unique sensory structure. It contains cell bodies of primary afferent proprioceptors, Ia afferents, that innervate the jaw-closing muscles (masseter, temporalis and medial pterygoid) and the periodontium.

What does Mesencephalic mean?

Medical Definition of mesencephalic : of or relating to the midbrain the mesencephalic nucleus of the trigeminal nerve.

What is the structure of mesencephalic nucleus of trigeminal nerve?

The mesencephalic nucleus is a paired structure located at the mesopontine junction which projects cephalad through the midbrain. It is situated along the anterolateral aspect of the periaqueductal grey matter and lies ventral to the inferior colliculi at the level of the midbrain.

Does the trigeminal pathway Decussate?

Pathway. The first-order neurons (from the trigeminal ganglion) enter the pons and synapse on second-order neurons in the principal (chief sensory) nucleus. A subset of these fibers do not decussate and travel to the ipsilateral ventral posteromedial nucleus of the thalamus.

What is the trigeminal pathway?

The main sensory trigeminal pathway carries and processes discriminative touch and proprioceptive information from the face (Figure 4.7). Consequently, it is the cranial homologue of the medial lemniscal pathway. form mechanoreceptors in the skin, mucous membranes, muscles and joints of the face.

What is the mesencephalic locomotor region?

The mesencephalic locomotor region (MLR) is a functionally defined area of the midbrain that is associated with the initiation and control of locomotor movements in vertebrate species.

What are the four trigeminal nuclei?

There are four nuclei associated with the trigeminal nerve: Main sensory nucleus. Mesencephalic nucleus. Spinal trigeminal nucleus.

Where is the mesencephalic nucleus located in the trigeminal nerve?

The mesencephalic nucleus of the trigeminal nerve is one of three major nuclei that make up the trigeminal sensory nerve nuclear complex along with the main sensory nucleus and the spinal nucleus 1-2. The mesencephalic nucleus is a paired structure located at the mesopontine junction which projects cephalad through the midbrain.

Are there any synapses in the mesencephalic nucleus?

Unlike many nuclei within the central nervous system (CNS), the mesencephalic nucleus contains no chemical synapses but are electrically coupled. Neurons of this nucleus are unipolar cells that receive proprioceptive information from the mandible and send projections to the trigeminal motor nucleus to mediate monosynaptic jaw jerk reflexes.

How are afferent fibers stimulated in the mesencephalic nucleus?

Likewise, afferent fibers from muscle spindles, the sensory organs of skeletal muscle, are stimulated by the stretch of hard contraction of jaw muscles. The temporomandibular joint receptors and the Golgi tendon organs of the jaw muscles do not project to the mesencephalic nucleus.

How is the mesencephalic nucleus involved in reflex proprioception?

The mesencephalic nucleus is involved with reflex proprioception of the periodontium and of the muscles of mastication in the jaw that functions to prevent biting down hard enough to lose a tooth. To subserve this reflex protective function, mechanoreceptive nerves in the periodontal ligament sense…