Influence of the efferent vestibular system on the vestibulo-spinal activity was investigated in the decerebrated, decerebellated guinea pigs. The efferent vestibular system was excited by electrical stimulation of the domain of efferent neurons in the medulla. Electromyographic activity of left and right triceps brachii was used as a test reaction. Muscle activity was initiated by means of the crossed extensor reflex and locomotion evoked by mesencephalic locomotor region stimulation. Adequate vestibular stimulation was performed by static shifts and cyclic tilting of an animal about a longitudinal axis. It has been demonstrated that the efferent system bilaterally inhibits the vestibulo-spinal activity. The stimulation of vestibular efferents decreases the intensity of vestibular influences, but does not change dynamics of vestibulo-spinal reflexes. Mechanisms of the vestibular efferent action on the vestibular control of the spinal motor activity are discussed.
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Front Neurol
December 2024
Institut de Recherche Oto-Neurologique (IRON), Paris, France.
Introduction: While most head movements in daily life are active, most tools used to assess vestibular deficits rely on passive head movements. A single gain value is not sufficient to quantify gaze stabilization efficiency during active movements in vestibular deficit patients. Moreover, during active gaze shifts, anticipatory mechanisms come into play.
View Article and Find Full Text PDFEur J Neurol
January 2025
Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, South Korea.
Background And Purpose: The dorsolateral portion of the caudal pons contains the vestibular nucleus (VN) and inferior cerebellar peduncle (ICP) that play important roles in conveying and processing vestibular and ocular motor signals. This study aimed to characterize ocular motor abnormalities along with their anatomical correlations in dorsolateral pons (DLP) lesions.
Methods: We analyzed clinical features, and results of neuro-otological evaluations and neuroimaging of 18 patients with unilateral DLP lesions (17 with DLP infarction and 1 with cavernous malformation) from among 506 patients with pontine infarction in a stroke registry.
J Vis Exp
November 2024
Department of Otolaryngology - Head & Neck Surgery, Johns Hopkins University School of Medicine.
The living human inner ear is challenging to study because it is encased within dense otic capsule bone that limits access to biological tissue. Traditional temporal bone histopathology methods rely on lengthy, expensive decalcification protocols that take 9-10 months and reduce the types of tissue analysis possible due to RNA degradation. There is a critical need to develop methods to access fresh human inner ear tissue to better understand otologic diseases, such as Ménière's disease, at the cellular and molecular level.
View Article and Find Full Text PDFIntroduction: The Efferent Vestibular System (EVS) originates in brainstem Efferent Vestibular Nuclei (EVN) and modifies afferent vestibular signals at their source, in peripheral vestibular organs. Recent evidence suggests that EVS is also involved in the development of motion sickness symptoms, including vertigo and nausea, but the underlying mechanism is unknown. One possible link between EVN and motion sickness symptoms is through the neuropeptide calcitonin gene-related peptide (CGRP).
View Article and Find Full Text PDFSci Rep
December 2024
Laboratory of Neurophysiology and Movement Biomechanics, UNI - ULB Neuroscience Institute, Université libre de Bruxelles (ULB), Brussels, Belgium.
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