China
Africa
Explore chapters and articles related to this topic
Brain Motor Centers and Pathways
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
The vestibulospinal tract has two components: (i) the lateral vestibulospinal tract, which originates in the lateral vestibular nucleus and descends, ipsilaterally, the length of the spinal cord; and (ii) the medial vestibulospinal tract, which originates in the medial vestibular nucleus and extends bilaterally through mid-thoracic levels of the spinal cord. The APs along the axons of the lateral vestibulospinal tract monosynaptically excite the motoneurons that activate the antigravity muscles, which are extensor muscles of the trunk and legs and flexor muscles of the arms, and they disynaptically inhibit motoneurons that activate the antagonists to the antigravity muscles. This pathway mediates balance, contributes to the maintenance of posture, and is involved in the vestibulospinal reflex (VSR) that stabilizes the body. When the head and trunk are tilted together to one side, for example, this reflexively activates the trunk and leg extensors on the side to which the head is tilted, so as to stabilize the body. The VSR, together with other reflexes, is also involved in the “righting” of the body to prevent a fall when slipping.
Discussions (D)
Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
Most authors of recent textbooks in basic neuroanatomy describe neuronal fibers descending from cell bodies in the medial vestibular nuclei into the anterior funiculi of the spinal cord; and they usually label the collection of these fibers on either side as the “medial vestibulospinal tract” (e.g., B&K, p. 75–76; Brod, p. 201, 204; Heim, p. 160 [Fig. 99B], 192; Nolt, P-150 [including Fig. 9–24]; A&B, p. 149). Several other authors, however, note that the medial vestibulospinal tract may originate in other vestibular nuclei as well—either the medial and inferior (Gar, p. 107 [Fig. 85]); the medial, inferior, and lateral (W&W, p. 875, 940; ch&l, p. 102); or those plus the superior nucleus (i.e., all of the vestibular nuclei: n&f, p. 194).1
ENTRIES A–Z
Published in Philip Winn, Dictionary of Biological Psychology, 2003
The vestibular nucleus is divided into four: (1) the lateral vestibular nucleus (also known as DEITER'S NUCLEUS), important for the control of posture; it has inputs from CEREBELLUM (the VERMIS), SPINAL CORD and VESTIBULAR LABYRINTH; and has output (via lateral vestibulospinal tract) to the VENTRAL HORN. (2 and 3) The medial vestibular nucleus and the superior vestibular nucleus, both important for vestibulo-ocular interactions; there is input from the AMPULLAE of the SEMICIRCULAR CANALS; and output via the medial vestibulospinal tract (to the cervical spinal cord) from where control of the neck muscles can be established. There is also output via the MEDIAL LONGITUDINAL FASCICULUS to sites of control of EYE MOVEMENTS (including the cranial nerve nuclei involved in controlling the musculature of the eye (the third [OCULOMOTOR NERVE], fourth [TROCHLEAR NERVE] and sixth [ABDUCENS NERVE] CRANIAL NERVES). (4) The inferior vestibular nucleus, important for integration of information from the VESTIBULAR SYSTEM and the cerebellum. It has inputs from the semicircular canals, UTRICLE and SACCULE, and from the cerebellum (the vermis); and it has outputs that travels via the VESTIBULOSPINAL and VESTIBULORETICULAR PATHWAYS to influence other sites in the BRAINSTEM and in the THALAMUS.
Different results of vestibular examinations and blood flow in cases with transient vascular vertigo/dizziness with or without central nervous system symptoms
Published in Acta Oto-Laryngologica, 2022
Takaki Inui, Tatsuro Kuriyama, Shin-ichi Haginomori, Kou Moriyama, Takeo Shirai, Yusuke Ayani, Yuko Inaka, Michitoshi Araki, Ryo Kawata
The results may be related to the difference in reflex pathways between the cVEMP and caloric test, descending and ascending from the vestibular nuclei. The presumed pathway for saccular function tested by cVEMP involves the medial vestibulospinal tract, leading to an inhibitory reflex measured from the ipsilateral sternocleidomastoid muscle [20]. This pathway differs from the caloric test, which includes the abducens nucleus, medial longitudinal fasciculus, and oculomotor nucleus. The different cVEMP results may indicate insufficiency in the inferior area of the vertebrobasilar system in TVVo cases. On the other hand, unilateral vestibular dysfunction revealed by cVEMP may suggest peripheral disorder. However, CP of unaffected side of the VA or bilateral CP were seen in many cases in both TVVw and TVVo caess, and the results of caloric test did not show any difference between these groups. It is difficult to explain such results by ipsilateral peripheral impairment. The different result of vestibular examinations and existence or non-existence of central nervous system symptoms between TVVw and TVVo may be attributed to the difference in the extent of insufficiency within the vertebrobasilar system.
Usefulness of masseter vestibular evoked myogenic potentials in identifying brainstem dysfunction among individuals with multiple sclerosis
Published in International Journal of Audiology, 2023
Vignesh Sangu Srinivasan, Bhoopathy Rangappan Munirathinam, Niraj Kumar Singh, Krishna Rajalakshmi
The air conduction mVEMP is reported to share a common vestibular end-organ (saccule and inferior vestibular nerve) with cVEMP (Deriu et al., 2007; Deriu et al., 2005); however, oVEMP is generated predominantly from the utricle and superior vestibular nerve (Rosengren et al., 2010). All three VEMPs receive vestibular input at the level of vestibular nuclei but project to various cranial nerves, oculomotor nerve through medial longitudinal fasciculus (oVEMP), spinal accessory nerve through the medial vestibulospinal tract (cVEMP) and trigeminal nerve through the vestibulomasseteric pathway (mVEMP). The assessment of ascending pathways in the midbrain (oVEMP) and descending pathways (cVEMP) in the medulla of the brainstem (Colebatch, 2012) along with the vestibulomasseteric reflex pathways in the pons (mVEMP) can help us in detecting the white matter lesions along the three regions in the brainstem. Masseter VEMPs have been reported to be abnormal in 62.1% of MS patients (Magnano et al., 2014) and useful in monitoring brainstem dysfunction in MS (Magnano et al., 2016). Although mVEMP has been investigated with cVEMP (Magnano et al., 2016; Magnano et al., 2014), the cVEMP-oVEMP-mVEMP test battery has not been studied in the same set of individuals with MS. This test battery composed of cVEMP, oVEMP and mVEMP has already been found useful in other neurological diseases such as Parkinson’s disease (De Natale, Ginatempo, Paulus, Manca, et al., 2015; De Natale, Ginatempo, Paulus, Pes, et al., 2015) and idiopathic rapid eye movement sleep behaviour disorder (de Natale et al., 2018). Hence, this study investigated the usefulness of cVEMP, oVEMP and mVEMP as a test battery to identify brainstem dysfunction in MS patients.