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otolith physiology

Ian S Curthoys, Hamish G MacDougall, Pierre-Paul Vidal, Catherine de Waele
Otolithic afferents with regular resting discharge respond to gravity or low-frequency linear accelerations, and we term these the static or sustained otolithic system. However, in the otolithic sense organs, there is anatomical differentiation across the maculae and corresponding physiological differentiation. A specialized band of receptors called the striola consists of mainly type I receptors whose hair bundles are weakly tethered to the overlying otolithic membrane. The afferent neurons, which form calyx synapses on type I striolar receptors, have irregular resting discharge and have low thresholds to high frequency (e...
2017: Frontiers in Neurology
Ian S Curthoys
The classical view of the otoliths-as flat plates of fairly uniform receptors activated by linear acceleration dragging on otoconia and so deflecting the receptor hair bundles-has been replaced by new anatomical and physiological evidence which shows that the maculae are much more complex. There is anatomical spatial differentiation across the macula in terms of receptor types, hair bundle heights, stiffness and attachment to the overlying otolithic membrane. This anatomical spatial differentiation corresponds to the neural spatial differentiation of response dynamics from the receptors and afferents from different regions of the otolithic maculae...
April 2017: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Aasef G Shaikh, Dominik Straumann, Antonella Palla
Contemporary studies speculated that cerebellar network responsible for motion perception projects to the cerebral cortex via vestibulo-thalamus. Here, we sought for the physiological properties of vestibulo-thalamic pathway responsible for the motion perception. Healthy subjects and the patient with focal vestibulo-thalamic lacunar stroke spun a hand-held rheostat to approximate the value of perceived angular velocity during whole-body passive earth-vertical axis rotations in yaw plane. Vestibulo-ocular reflex was simultaneously measured with high-resolution search coils (paradigm 1)...
January 27, 2017: Cerebellum
Oliver R B Thomas, Katherine Ganio, Blaine R Roberts, Stephen E Swearer
Otoliths, the biomineralised hearing "ear stones" from the inner ear of fish, grow throughout the lifespan of an individual, with deposition of alternating calciferous and proteinaceous bands occurring daily. Trace element : calcium ratios within daily increments measured by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) are often used in fisheries science to reconstruct environmental histories. There is, however, considerable uncertainty as to which elements are interacting with either the proteinaceous or calciferous zones of the otolith, and thus their utility as indicators of environmental change...
January 16, 2017: Metallomics: Integrated Biometal Science
Paola C López-Duarte, F Joel Fodrie, Olaf P Jensen, Andrew Whitehead, Fernando Galvez, Benjamin Dubansky, Kenneth W Able
Genomic and physiological responses in Gulf killifish (Fundulus grandis) in the northern Gulf of Mexico have confirmed oil exposure of resident marsh fish following the Macondo blowout in 2010. Using these same fish, we evaluated otolith microchemistry as a method for assessing oil exposure history. Laser-ablation inductively-coupled-plasma mass spectrometry was used to analyze the chemical composition of sagittal otoliths to assess whether a trace metal signature could be detected in the otoliths of F. grandis collected from a Macondo-oil impacted site in 2010, post-spill relative to pre-spill, as well as versus fish from areas not impacted by the spill...
2016: PloS One
H Kingma, R van de Berg
Many medical doctors consider vertigo and dizziness as the major, almost obligatory complaints in patients with vestibular disorders. In this chapter, we will explain that vestibular disorders result in much more diverse and complex complaints. Many of these other complaints are unfortunately often misinterpreted and incorrectly classified as psychogenic. When we really understand the function of the vestibular system, it becomes quite obvious why patients with vestibular disorders complain about a loss of visual acuity, imbalance, fear of falling, cognitive and attentional problems, fatigue that persists even when the vertigo attacks and dizziness decreases or even disappears...
2016: Handbook of Clinical Neurology
Amelia S Wenger, James Whinney, Brett Taylor, Frederieke Kroon
Coral reefs are increasingly subjected to both local and global stressors, however, there is limited information on how reef organisms respond to their combined effects under natural conditions. This field study examined the growth response of the damselfish Neopomacentrus bankieri to the individual and combined effects of multiple abiotic factors. Turbidity, temperature, tidal movement, and wave action were recorded every 10 minutes for four months, after which the daily otolith growth of N. bankieri was aligned with corresponding abiotic conditions...
2016: Scientific Reports
T N Loewen, B Carriere, J D Reist, N M Halden, W G Anderson
Biomineral chemistry is frequently used to infer life history events and habitat use in fishes; however, significant gaps remain in our understanding of the underlying mechanisms. Here we have taken a multidisciplinary approach to review the current understanding of element incorporation into biomineralized structures in fishes. Biominerals are primarily composed of calcium-based derivatives such as calcium carbonate found in otoliths and calcium phosphates found in scales, fins and bones. By focusing on non-essential life elements (strontium and barium) and essential life elements (calcium, zinc and magnesium), we attempt to connect several fields of study to synergise how physiology may influence biomineralization and subsequent inference of life history...
June 17, 2016: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
Dror Tal, Shir Shemy, Gil Kaminski-Graif, Guy Wiener, Dov Hershkovitz
OBJECTIVE: Seasickness is a widespread problem among naval crew, and has a major impact on their performance at sea. The three pharmacological agents most commonly employed in the treatment of seasickness are dimenhydrinate, cinnarizine, and scopolamine. At present, the effectiveness of anti-seasickness drugs is tested by a process of "trial and error", while sailing and exposed to sea conditions. A physiological test to evaluate the action of a drug might save crew members long periods of suffering, as well as simplifying the procedure of selecting the appropriate treatment for each individual...
June 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Hans Straka, Andreas Zwergal, Kathleen E Cullen
Our knowledge of the vestibular sensory system, its functional significance for gaze and posture stabilization, and its capability to ensure accurate spatial orientation perception and spatial navigation has greatly benefitted from experimental approaches using a variety of vertebrate species. This review summarizes the attempts to establish the roles of semicircular canal and otolith endorgans in these functions followed by an overview of the most relevant fields of vestibular research including major findings that have advanced our understanding of how this system exerts its influence on reflexive and cognitive challenges encountered during daily life...
April 2016: Journal of Neurology
Emma Hallgren, Ludmila Kornilova, Erik Fransen, Dmitrii Glukhikh, Steven T Moore, Gilles Clément, Angelique Van Ombergen, Hamish MacDougall, Ivan Naumov, Floris L Wuyts
The information coming from the vestibular otolith organs is important for the brain when reflexively making appropriate visual and spinal corrections to maintain balance. Symptoms related to failed balance control and navigation are commonly observed in astronauts returning from space. To investigate the effect of microgravity exposure on the otoliths, we studied the otolith-mediated responses elicited by centrifugation in a group of 25 astronauts before and after 6 mo of spaceflight. Ocular counterrolling (OCR) is an otolith-driven reflex that is sensitive to head tilt with regard to gravity and tilts of the gravito-inertial acceleration vector during centrifugation...
June 1, 2016: Journal of Neurophysiology
I A Naumov, L N Kornilova, D O Glukhikh, A S Pavlova, E V Khabarova, G A Ekimovsky, A V Vasin
Results of the vestibular function testing of 32 cosmonauts on return from repeated 125- to 215-day space flights (SF) on the International space station are presented. The cosmonauts were tested twice before flight (baseline data collection) and on days 1-2, 4-5 and 8-9 after landing. Electro- and video-oculography were used to register simultaneously eye and head movements. It was found that deadaptation following a repeated stay in long-duration SF takes statistically much shorter time. Most often, atypical vestibular disorders and changed patterns of the otolith-semicircular canal interaction are observed in cosmonauts who have made their maiden flights to microgravity...
2015: Aviakosmicheskaia i Ekologicheskaia Meditsina, Aerospace and Environmental Medicine
Rebecca Lim, Alan M Brichta
We describe the development of the human inner ear with the invagination of the otic vesicle at 4 weeks gestation (WG), the growth of the semicircular canals from 5 WG, and the elongation and coiling of the cochlea at 10 WG. As the membranous labyrinth takes shape, there is a concomitant development of the sensory neuroepithelia and their associated structures within. This review details the growth and differentiation of the vestibular and auditory neuroepithelia, including synaptogenesis, the expression of stereocilia and kinocilia, and innervation of hair cells by afferent and efferent nerve fibres...
August 2016: Hearing Research
Lorenzo Bassi Luciani, Dario Martelli, Vito Monaco, Vincenzo Genovese, Silvestro Micera
This paper describes a novel mechatronic platform, named "Up-Down Chair" (UDC), aimed at investigating otolith function in patients with vestibular disorders. The UDC was designed to provide a wide range of repeatable and controllable vertical oscillations of the head whose kinematic features match those encountered during daily activities. The following parameters were assessed to characterize the performance of the UDC: accordance between expected and measured kinematics in both loaded and unloaded conditions; Dynamic Visual Acuity (DVA) of a group of 15 healthy subjects who were asked to identify a set of Snellen optotypes while being repeatedly moved at different perturbation intensities...
March 2016: Medical Engineering & Physics
Naoki Shimizu, Scott Wood, Keisuke Kushiro, Adrian Perachio, Tomoko Makishima
Systemic administration of a gamma-amino butyric acid type B (GABAB) receptor agonist, baclofen, affects various physiological and psychological processes. To date, the effects on oculomotor system have been well characterized in primates, however those in mice have not been explored. In this study, we investigated the effects of baclofen focusing on vestibular-related eye movements. Two rotational paradigms, i.e. sinusoidal rotation and counter rotation were employed to stimulate semicircular canals and otolith organs in the inner ear...
April 1, 2016: Behavioural Brain Research
Motoki Hojo, Ai Omi, Gen Hamanaka, Kazutoshi Shindo, Atsuko Shimada, Mariko Kondo, Takanori Narita, Masato Kiyomoto, Yohei Katsuyama, Yasuo Ohnishi, Naoki Irie, Hiroyuki Takeda
INTRODUCTION: Calcium carbonate biominerals participate in diverse physiological functions. Despite intensive studies, little is known about how mineralization is initiated in organisms. RESULTS: We analyzed the medaka spontaneous mutant, ha, defective in otolith (calcareous ear stone) formation. ha lacks a trigger for otolith mineralization, and the causative gene was found to encode polyketide synthase (pks), a multifunctional enzyme mainly found in bacteria, fungi, and plant...
2015: Zoological Letters
Peggy L Edds-Walton
Of the three, paired otolithic endorgans in the ear of teleost fishes, the saccule is the one most often demonstrated to have a major role in encoding frequencies of biologically relevant sounds. The toadfish saccule also encodes sound level and sound source direction in the phase-locked activity conveyed via auditory afferents to nuclei of the ipsilateral octaval column in the medulla. Although paired auditory receptors are present in teleost fishes, binaural processes were believed to be unimportant due to the speed of sound in water and the acoustic transparency of the tissues in water...
2016: Advances in Experimental Medicine and Biology
Mousumi Chatterjee, Prosenjit Ghosh, Leena Ramdas, Ramananda Chakrabarti
The otoliths (N = 12) of freshwater invasive species tilapia (Tilapia mossambicus) collected from two water bodies located at Kolkata and Bangalore, India, were analyzed for stable isotopes (δ18O, δ14C) and major and trace elements in order to assess the suitability of using otoliths as a tracer of aquatic environmental changes. The stable isotope analysis was done using the dual inlet system of a Finnigan-MAT 253 isotope ratio mass spectrometer (Thermo-Fisher, Bremen, Germany). Concentrations of major and trace elements were determined using a Thermo X-Series II quadrupole mass spectrometer...
November 2015: Environmental Monitoring and Assessment
Xiangning Cui, Yong Feng, Lingyun Mei, Chufeng He, Xiaojing Lu, Hua Zhang, Hongsheng Chen
OBJECTIVE: To analyze and summarize nystagmus of patients with posterior canal benign paroxysmal positional vertigo (BPPV) in positioning test,and to improve the diagnosis and treatment of posterior canal BPPV (PSC-BPPV). METHOD: The present study was conducted on 175 patients who had unilateral BPPV of the posterior semicircular canal (PSC). Their positional nystagmus recorded by videnonystagmography in Dix-Hallpike test,roll test and roll over test were analyzed to summarize the characteristics of nystagmus on nystagmograph of PSC-BP-PV...
January 2015: Journal of Clinical Otorhinolaryngology, Head, and Neck Surgery
Zeinab A Dastgheib, Brian Lithgow, Brian Blakley, Zahra Moussavi
OBJECTIVE: To describe the development of a new clinically applicable method for assessing vestibular function in humans with particular application in Meniere's disease. STUDY DESIGN: Sophisticated signal-processing techniques were applied to data from human subject undergoing tilts stimulating the otolith organs and semicircular canals. The most sensitive representatives of vestibular function were extracted as "features". METHODS: After careful consideration of expected response features, Electrovestibulography, a modified electrocochleography, recordings were performed on fourteen Meniere's patients and sixteen healthy controls undergoing controlled tilts...
2015: Journal of Otolaryngology—Head & Neck Surgery
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