Anatomy of the Cochlea and Vestibular System: Relating Ultrastructure to Function
John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed in Paediatrics, The Ear, Skull Base, 2018
The vestibular system can be generally divided into two parts: the saccule is anatomically a separate chamber from the utricle and the three semicircular canals which arise from and terminate in the utricle and run in orthogonal planes – horizontal (lateral), posterior and superior (anterior) (Figures 47.1a and 47.2a). Not only is there anatomical separation; the utricle and semicircular canals are evolutionarily and developmentally separate from the saccule. In the evolutionarily most primitive extant vertebrates (e.g. hag fish), the inner ear is composed of only two semicircular canals that are continuous with a single utricle-like chamber with a macula.50,51 During ontogenetic development, the utricle and semicircular canals arise on one side of the embryonic otic vesicle, opposite to that of the saccule which develops close to the site at which the cochlea is defined.52 There is thus an anatomical and developmental relationship between the saccule and the cochlea, and in fish and some amphibia, the saccule does have an auditory function.53,54 This biological relationship may be an underlying factor in the sound-induced vertigo and dizziness characteristic of Tullio syndrome.
Stroke mimics
Christos Tziotzios, Jesse Dawson, Matthew Walters, Kennedy R Lees in Stroke in Practice, 2017
Motion is sensed by the vestibular system, which comprises the semicircular canals and the otolith organs. Signals are relayed from each of the right and left vestibular labyrinths to the central nervous system via the vestibular portion of CN VIII, to the vestibular nuclei in the brainstem, and subsequently to the cerebellum, ocular motor nuclei, and spinal cord, with more complex projections to the cerebrum. The cerebellum coordinates this orchestra of signals and interconnections, with a role in modulating vestibulo-ocular and vestibule-spinal pathways. These play a role in coordinating motion with eye movement and posture coordination, respectively. The relayed signals are compared centrally. Any differences are perceived as motion and a unilateral vestibulopathy, which would naturally impair signal transmission on the affected side, will be misinterpreted by the central nervous system as motion (hallucination of motion or vertigo).38
Perceptual-cognitive development and cognition of movement
Michael Horvat, Ronald V. Croce, Caterina Pesce, Ashley Fallaize in Developmental and Adapted Physical Education, 2019
Finally, the vestibular system is involved in kinesthesis by detecting acceleration movements of the head and using this information to orient the head and eyes during movement and to control posture. Receptor cells found within the inner ear detect linear and angular acceleration movements of the head and through an intricate and complex network influence eye and body movements. The primary receptors for the vestibular system are tiny hair cells that are found within the semicircular canals (detecting angular acceleration of the head) and the saccule and utricle (detecting linear acceleration of the head). In total, vestibular receptors are sensitive to (1) head position in space (i.e., whether the head is upright, upside down, or in some other position) and (2) sudden changes in direction of the body.
Effect of vestibular stimulation using a rotatory chair in human rest/activity rhythm
Published in Chronobiology International, 2020
Florane Pasquier, Nicolas Bessot, Tristan Martin, Antoine Gauthier, Jan Bulla, Pierre Denise, Gaëlle Quarck
The recent literature raises the hypothesis that vestibular afferents could influence the circadian timing system. The vestibular system, located in the inner ear, is composed of three semi-circular canals and two otolithic organs, respectively responsible for angular and linear head acceleration detection. The system is principally involved in postural control and gaze stabilization during locomotion (Grossman et al. 1989; Peterson and Richmond 1988). A continuous change in canalicular and otolithic information is integrated by the central nervous system, during the day, when head accelerations in space occur. This information is largely reduced to an uncommon change in otolithic organ activity during the night. Thus, the vestibular system works in parallel with human activity, particularly with motor activity. This functioning raises the question of the potential implication of the vestibular system as a synchronizer of biological rhythms.
Effect of vibration on the vestibular system in noisy and noise-free environments in heavy industry
Published in Acta Oto-Laryngologica, 2019
Nihat Yilmaz, Kadri Ila
The vestibular system consists of the central system, which includes the vestibular nuclei, cerebellum autonomic nervous system, thalamus, and cerebral cortex, and the peripheral system, which includes the semicircular canals (SCCs), otoliths, and the vestibular nerve [9]. Because the vestibular system is a complex structure, no single test can evaluate the entire vestibular system. The caloric test can only evaluate the horizontal SCC, whereas cervical vestibular evoked myogenic potential (cVEMP) testing evaluates the saccule, and ocular vestibular evoked myogenic potential (oVEMP) testing evaluates the utricle [10]. The video head impulse test (vHIT) can evaluate all six semicircular canals separately. This test is fast, harmless, and may be conducted repeatedly [11]. In addition, vHIT is useful in cases of bilateral vestibular damage [2]. The aim of this study was to evaluate the effects of vibration on the vestibular system in noisy and noise-free environments using vHIT.
Neurorehabilitation for an individual with bilateral thalamic stroke and preexisting visual impairment presenting with impaired use of sensory cues: a case report
Published in Physiotherapy Theory and Practice, 2021
Christina Kelly, Jen Meyer, Valery Hanks, Christy Barefield
The vestibular system detects the motion of the head in space by encoding self-motion information. Some of the vestibular nuclei neurons are designated as vestibular only; rather than projecting to oculomotor structures, these specific neurons project to the spinal cord and mediate the vestibular spinal reflexes. They are interconnected with the nodulus of the cerebellum, which then project to the thalamus and cortex. Therefore, with intact vestibular neurons, the patient is theoretically able to use vestibular cues in the absence of visual cues to maintain postural equilibrium and spatial orientation through higher order vestibular processing (Cullen, 2012). While a substantial amount of research has been completed regarding visuo-vestibular interactions, little is known regarding the training of vestibular cues in visually impaired individuals. However, it has been determined that the vestibular system is the predominant contributor to self-motion perception in individuals lacking visual input (Moser, Grabherr, Hartmann, and Mast, 2015) and compensation includes increased vestibular sensitivity or upregulation and integration of signals that stimulate the remaining sensory organs.
Related Knowledge Centers
- Auditory System
- Cochlea
- Eye Movement
- Inner Ear
- Motor Coordination
- Otolith
- Semicircular Canals
- Sensory Nervous System
- Sense of Balance
- Vestibulo–Ocular Reflex