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otolithic projections

Parthena Soupiadou, Francisco Branoner, Hans Straka
Vestibulo-ocular reflexes (VOR) are mediated by three-neuronal brainstem pathways that transform semicircular canal and otolith sensory signals into motor commands for the contraction of spatially specific sets of eye muscles. The vestibular excitation and inhibition of extraocular motoneurons underlying this reflex is reciprocally organized and allows coordinated activation of particular eye muscles and concurrent relaxation of their antagonistic counterparts. Here, we demonstrate in isolated preparations of Xenopus laevis tadpoles that the discharge modulation of superior oblique motoneurons during cyclic head motion derives from an alternating excitation and inhibition...
March 19, 2018: Journal of Neurology
Richard Boyle, Reza Ehsanian, Alireza Mofrad, Yekaterina Popova, Joseph Varelas
The utricle provides the vestibular reflex pathways with the sensory codes of inertial acceleration of self motion and head orientation with respect to gravity to control balance and equilibrium. Here we present an anatomical description of this structure in the adult oyster toadfish, and establish a morphological basis for interpretation of subsequent functional studies. Light, scanning and transmission electron microscopy techniques were applied to visualize the sensory epithelium at varying levels of detail, its neural innervation and its synaptic organization...
March 10, 2018: Journal of Comparative Neurology
Kun Yang, Shu Li, Xiaoshuai Liu, Weixiong Gan, Longjun Deng, Yezhong Tang, Zhaobin Song
Schizothorax wangchiachii is a key fish species in the stock enhancement program of the Yalong River hydropower project, China. Alizarin red S (ARS) was used to mark large numbers of juvenile S. wangchiachii in the Jinping Hatchery and later used to evaluate stock enhancement in the Jinping area of the Yalong River. In a small-scale pilot study, 7,000 juveniles of the 2014 cohort were successfully marked by immersion in ARS solution, and no mortality was recorded during the marking process. The ARS mark in the fish otoliths remained visible 20 months later...
2017: PeerJ
Omar M Amin, Richard A Heckmann, Atheer H Ali
The acanthocephalan Paratrajectura longcementglandatus n. gen., n. sp. (Transvenidae) is described from specimens of 2 perciform fish species, Nemipterus japonicus Bloch (Nemipteridae) and Otolithes ruber Bloch and Schneider collected in the marine territorial waters of Iraq and Iran in the Arabian Gulf. Metal analysis of hook tip, middle and base is also described using X-ray microanalysis EDAX. The new genus is distinguished from the closely related genus Trajectura Pichelin and Cribb, 2001 described from wrasses (Labridae) (Perciformes) in the Pacific off Australia and Japan by having a proboscis with apical epidermal cone, long rhadinorhynchid-like tubular cement glands, relatively short and lobulated lemnisci, all proboscis hooks with prominent roots, females with subterminal gonopore and a rounded projection on the antero-dorsal end of the trunk, and males with elongate pre-equatorial testes reaching proboscis receptacle...
November 8, 2017: Journal of Parasitology
Anne Le Maître, Philipp Schuetz, Patrick Vignaud, Michel Brunet
The labyrinth has two functional parts: the cochlea for audition and the vestibular system for equilibrioception. In the latter, the semicircular ducts and the otolithic organs are sensitive to rotational and linear accelerations of the head, respectively. The labyrinthine morphology influences perception accuracy, hence the adaptation to a specific locomotor pattern. The aim of this study is to determine the relationship between locomotion and semicircular canal morphology using geometric morphometrics, and to explain these links with existing functional models...
May 19, 2017: Journal of Anatomy
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)...
June 2017: Cerebellum
Catherine A McCormick, Shannon Gallagher, Evan Cantu-Hertzler, Scarlet Woodrick
The nucleus medialis is the main first-order target of the mechanosensory lateral line (LL) system. This report definitively demonstrates that mechanosensory LL inputs also terminate in the ipsilateral dorsal portion of the descending octaval nucleus (dDO) in the goldfish. The dDO, which is the main first-order auditory nucleus in bony fishes, includes neurons that receive direct input from the otolithic end organs of the inner ear and project to the auditory midbrain. There are two groups of such auditory projection neurons: medial and lateral...
2016: Brain, Behavior and Evolution
Derek M Miller, James F Baker, W Zev Rymer
OBJECTIVE: Aberrant vestibular nuclear function is proposed to be a principle driver of limb muscle spasticity after stroke. Although spasticity does not manifest in ocular muscles, we sought to determine whether altered cortical modulation of ascending vestibuloocular pathways post-stroke could impact the excitability of ocular motoneurons. METHODS: Nineteen chronic stroke survivors, aged 49-68 yrs. were enrolled. Vestibular evoked myogenic potentials (VEMPs) were recorded from the inferior oblique muscles of the eye using surface EMG electrodes...
April 2016: Clinical Neurophysiology: Official Journal of the International Federation of Clinical Neurophysiology
Thomas Chartrand, Gin McCollum, Douglas A Hanes, Richard D Boyle
Sensory contribution to perception and action depends on both sensory receptors and the organization of pathways (or projections) reaching the central nervous system. Unlike the semicircular canals that are divided into three discrete sensitivity directions, the utricle has a relatively complicated anatomical structure, including sensitivity directions over essentially 360° of a curved, two-dimensional disk. The utricle is not flat, and we do not assume it to be. Directional sensitivity of individual utricular afferents decreases in a cosine-like fashion from peak excitation for movement in one direction to a null or near null response for a movement in an orthogonal direction...
February 2016: Journal of Mathematical Biology
Michel Toupet, Christian Van Nechel, Alexis Bozorg Grayeli
OBJECTIVE: The aim of this study was to evaluate the effect of initial rod position on the subjective visual vertical (SVV) tilt and to investigate the effect of sex and age on the SVV tilt induced by this initial position. STUDY DESIGN: Prospective cross-sectional study. SETTING: Tertiary referral center. PATIENTS: The study included 6598 consecutive patients with a large range of vestibular disorders and 333 control subjects...
July 2015: Otology & Neurotology
Joanne Rimmer, Mitesh Patel, Kiran Agarwal, Claire Hogg, Qadeer Arshad, Jonny Harcourt
HYPOTHESIS: Patients with primary ciliary dyskinesia (PCD) have absent or reduced otoconial function compared to the normal population. BACKGROUND: Investigations in zebrafish show that ciliation is important for the development of the otolith organs, but this has never been evaluated in humans. PCD is a congenital defect of ciliary structure. We undertook a pilot study to determine whether patients with PCD have absent or reduced otoconial function compared to the normal population...
April 2015: Otology & Neurotology
Rommel H Maneja, R Dineshram, Vengatesen Thiyagarajan, Anne Berit Skiftesvik, Andrea Y Frommel, Catriona Clemmesen, Audrey J Geffen, Howard I Browman
Elevated anthropogenic pCO2 can delay growth and impair otolith structure and function in the larvae of some fishes. These effects may concurrently alter the larva's proteome expression pattern. To test this hypothesis, Atlantic herring larvae were exposed to ambient (370 μatm) and elevated (1800 μatm) pCO2 for one-month. The proteome structure of the larvae was examined using a 2-DE and mass spectrometry. The length of herring larvae was marginally less in the elevated pCO2 treatment compared to the control...
September 15, 2014: Marine Pollution Bulletin
Michel Toupet, Christian Van Nechel, Alexis Bozorg Grayeli
The subjective visual vertical (SVV) is an indicator of vestibular otolithic function and mainly processed by the nondominant parietal cortex. We investigated the hypothesis that recovery from SVV tilt after vestibular neuritis can be influenced by the body's lateral preference. This prospective cohort follow-up study included 254 consecutive adult patients with vestibular neuritis. The recovery from SVV tilt was faster in patients with a left hand or eye dominance than in those with a right dominance. While in left-handers the side of the neuritis did not affect the speed of recovery, in right-handed subjects, the recovery from a right-sided neuritis was significantly slower than from a left-sided affection...
2014: Audiology & Neuro-otology
Fred W Mast, Nora Preuss, Matthias Hartmann, Luzia Grabherr
A growing number of studies in humans demonstrate the involvement of vestibular information in tasks that are seemingly remote from well-known functions such as space constancy or postural control. In this review article we point out three emerging streams of research highlighting the importance of vestibular input: (1) Spatial Cognition: Modulation of vestibular signals can induce specific changes in spatial cognitive tasks like mental imagery and the processing of numbers. This has been shown in studies manipulating body orientation (changing the input from the otoliths), body rotation (changing the input from the semicircular canals), in clinical findings with vestibular patients, and in studies carried out in microgravity...
2014: Frontiers in Integrative Neuroscience
Ian S Curthoys, Vedran Vulovic, Ann M Burgess, Leonardo Manzari, Ljiljana Sokolic, Jacob Pogson, Mike Robins, Laura E Mezey, Samanthi Goonetilleke, Elaine D Cornell, Hamish G MacDougall
Extracellular single neuron recording and labelling studies of primary vestibular afferents in Scarpa's ganglion have shown that guinea-pig otolithic afferents with irregular resting discharge are preferentially activated by 500 Hz bone-conducted vibration (BCV) and many also by 500 Hz air-conducted sound (ACS) at low threshold and high sensitivity. Very few afferent neurons from any semicircular canal are activated by these stimuli and then only at high intensity. Tracing the origin of the activated neurons shows that these sensitive otolithic afferents originate mainly from a specialized region, the striola, of both the utricular and saccular maculae...
May 2014: Clinical and Experimental Pharmacology & Physiology
N P M Todd, A C Paillard, K Kluk, E Whittle, J G Colebatch
Todd et al. (2014) have recently demonstrated the presence of vestibular dependent changes both in the morphology and in the intensity dependence of auditory evoked potentials (AEPs) when passing through the vestibular threshold as determined by vestibular evoked myogenic potentials (VEMPs). In this paper we extend this work by comparing left vs. right ear stimulation and by conducting a source analysis of the resulting evoked potentials of short and long latency. Ten healthy, right-handed subjects were recruited and evoked potentials were recorded to both left- and right-ear sound stimulation, above and below vestibular threshold...
June 2014: Hearing Research
Hans Straka, Robert Baker
Central vestibular neurons form identifiable subgroups within the boundaries of classically outlined octavolateral nuclei in primitive vertebrates that are distinct from those processing lateral line, electrosensory, and auditory signals. Each vestibular subgroup exhibits a particular morpho-physiological property that receives origin-specific sensory inputs from semicircular canal and otolith organs. Behaviorally characterized phenotypes send discrete axonal projections to extraocular, spinal, and cerebellar targets including other ipsi- and contralateral vestibular nuclei...
2013: Frontiers in Neural Circuits
Hui Meng, Pablo M Blázquez, J David Dickman, Dora E Angelaki
A functional role of the cerebellar nodulus and ventral uvula (lobules X and IXc,d of the vermis) for vestibular processing has been strongly suggested by direct reciprocal connections with the vestibular nuclei, as well as direct vestibular afferent inputs as mossy fibres. Here we have explored the types of neurons in the macaque vestibular nuclei targeted by nodulus/ventral uvula inhibition using orthodromic identification from the caudal vermis. We found that all nodulus-target neurons are tuned to vestibular stimuli, and most are insensitive to eye movements...
January 1, 2014: Journal of Physiology
J Kim
Three-dimensional changes in the angular orientation of the head were monitored during galvanic vestibular stimulation (GVS) delivered through electrodes implanted bilaterally in the tensor tympani muscle of the guinea-pig middle ear. Bilateral GVS was delivered by passing current between both ears with the anode situated in one ear and the cathode in the other ear. Unilateral GVS was also delivered between one ear and an indifferent electrode on the skull. Constant-current stimulation caused the head to tilt predominantly within the roll and yaw planes toward an ear stimulated with anodal current and away from an ear stimulated with cathodal current...
December 3, 2013: Neuroscience
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