scholarly journals Cytochrome P450 26b1-mediated specification of vestibular striola and central zones is required for transient responses in linear acceleration

2019 ◽  
Author(s):  
Kazuya Ono ◽  
James Keller ◽  
Omar López Ramírez ◽  
Antonia González Garrido ◽  
Omid Zobeiri ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Semicircular Canals ◽  
Linear Acceleration ◽  
Conditional Knockout ◽  
Otolith Organs ◽  
Vestibular Input ◽  
Balance Beam ◽  
Sensory Epithelia ◽  
Vestibular Sensory Epithelia ◽  
Vestibular Evoked Potentials

ABSTRACTEach vestibular sensory epithelia of the inner ear is divided into two zones, the striola and extrastriola in maculae of otolith organs and the central and peripheral zones in cristae of semicircular canals, that differ in morphology and physiology. We found that formation of striolar/central zones during embryogenesis requires Cytochrome P450 26b1 (Cyp26b1)-mediated degradation of retinoic acid (RA). In Cyp26b1 conditional knockout mice, the identities of the striolar/central zones were compromised, including abnormal innervating neurons and otoconia in otolith organs. Vestibular evoked potentials (VsEP) in response to jerk stimuli were largely absent. Vestibulo-ocular reflexes and standard motor performances such as forced swimming were unaffected, but mutants had head tremors and deficits in balance beam tests that were consistent with abnormal vestibular input. Thus, degradation of RA during embryogenesis is required for patterning highly specialized regions of the vestibular sensory epithelia that may provide acute feedback about head motion.

scholarly journals Retinoic acid degradation shapes zonal development of vestibular organs and sensitivity to transient linear accelerations

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Kazuya Ono ◽  
James Keller ◽  
Omar López Ramírez ◽  
Antonia González Garrido ◽  
Omid A. Zobeiri ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Sensory Epithelium ◽  
Conditional Knockout ◽  
Otolith Organ ◽  
Multiple Features ◽  
Balance Beam ◽  
Sensory Epithelia ◽  
Head Tremor ◽  
Vestibular Sensory Epithelia ◽  
Vestibular Organs

AbstractEach vestibular sensory epithelium in the inner ear is divided morphologically and physiologically into two zones, called the striola and extrastriola in otolith organ maculae, and the central and peripheral zones in semicircular canal cristae. We found that formation of striolar/central zones during embryogenesis requires Cytochrome P450 26b1 (Cyp26b1)-mediated degradation of retinoic acid (RA). In Cyp26b1 conditional knockout mice, formation of striolar/central zones is compromised, such that they resemble extrastriolar/peripheral zones in multiple features. Mutants have deficient vestibular evoked potential (VsEP) responses to jerk stimuli, head tremor and deficits in balance beam tests that are consistent with abnormal vestibular input, but normal vestibulo-ocular reflexes and apparently normal motor performance during swimming. Thus, degradation of RA during embryogenesis is required for formation of highly specialized regions of the vestibular sensory epithelia with specific functions in detecting head motions.

The Scanning Electron Microscopic Observation of the Vestibular Sensory Epithelia

1969 ◽  
Vol 27 ◽  
pp. 40-41
Author(s):  
D.J. Lim ◽  
W.C. Lane
Keyword(s):  
Semicircular Canals ◽  
Electron Microscopic Observation ◽  
Gravitational Acceleration ◽  
Electron Microscopic ◽  
Sensory Epithelia ◽  
Scanning Electron Microscopic ◽  
Vestibular Sensory Epithelia ◽  
And Function ◽  
Sand Piles ◽  
Active Investigation

The morphology and function of the vestibular sensory organs has been extensively studied during the last decade with the advent of electron microscopy and electrophysiology. The opening of the space age also accelerated active investigation in this area, since this organ is responsible for the sensation of balance and of linear, angular and gravitational acceleration.The vestibular sense organs are formed by the saccule, utricle and three ampullae of the semicircular canals. The maculae (sacculi and utriculi) have otolithic membranes on the top of the sensory epithelia. The otolithic membrane is formed by a layer of thick gelatin and sand-piles of calcium carbonate crystals (Fig.l).

scholarly journals Convergence of linear acceleration and yaw rotation signals on non-eye movement neurons in the vestibular nucleus of macaques

2018 ◽  
Vol 119 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Shawn D. Newlands ◽  
Ben Abbatematteo ◽  
Min Wei ◽  
Laurel H. Carney ◽  
Hongge Luan
Keyword(s):  
Eye Movement ◽  
Multisensory Integration ◽  
Vestibular Nucleus ◽  
Semicircular Canals ◽  
Linear Acceleration ◽  
Vestibular Nuclei ◽  
Otolith Organs ◽  
Angular Rotation ◽  
Sensory Signals ◽  
Nonlinear Integration

Roughly half of all vestibular nucleus neurons without eye movement sensitivity respond to both angular rotation and linear acceleration. Linear acceleration signals arise from otolith organs, and rotation signals arise from semicircular canals. In the vestibular nerve, these signals are carried by different afferents. Vestibular nucleus neurons represent the first point of convergence for these distinct sensory signals. This study systematically evaluated how rotational and translational signals interact in single neurons in the vestibular nuclei: multisensory integration at the first opportunity for convergence between these two independent vestibular sensory signals. Single-unit recordings were made from the vestibular nuclei of awake macaques during yaw rotation, translation in the horizontal plane, and combinations of rotation and translation at different frequencies. The overall response magnitude of the combined translation and rotation was generally less than the sum of the magnitudes in responses to the stimuli applied independently. However, we found that under conditions in which the peaks of the rotational and translational responses were coincident these signals were approximately additive. With presentation of rotation and translation at different frequencies, rotation was attenuated more than translation, regardless of which was at a higher frequency. These data suggest a nonlinear interaction between these two sensory modalities in the vestibular nuclei, in which coincident peak responses are proportionally stronger than other, off-peak interactions. These results are similar to those reported for other forms of multisensory integration, such as audio-visual integration in the superior colliculus. NEW & NOTEWORTHY This is the first study to systematically explore the interaction of rotational and translational signals in the vestibular nuclei through independent manipulation. The results of this study demonstrate nonlinear integration leading to maximum response amplitude when the timing and direction of peak rotational and translational responses are coincident.

Neural Processing of Gravito-Inertial Cues in Humans. I. Influence of the Semicircular Canals Following Post-Rotatory Tilt

2000 ◽  
Vol 84 (4) ◽  
pp. 2001-2015 ◽  
Author(s):  
L. H. Zupan ◽  
R. J. Peterka ◽  
D. M. Merfeld
Keyword(s):  
Eye Movements ◽  
Information Integration ◽  
Constant Velocity ◽  
Gravitational Force ◽  
Inertial Force ◽  
Semicircular Canals ◽  
Linear Acceleration ◽  
Head Orientation ◽  
Otolith Organs ◽  
Sensory Cues

Sensory systems often provide ambiguous information. Integration of various sensory cues is required for the CNS to resolve sensory ambiguity and elicit appropriate responses. The vestibular system includes two types of sensors: the semicircular canals, which measure head rotation, and the otolith organs, which measure gravito-inertial force (GIF), the sum of gravitational force and inertial force due to linear acceleration. According to Einstein's equivalence principle, gravitational force is indistinguishable from inertial force due to linear acceleration. As a consequence, otolith measurements must be supplemented with other sensory information for the CNS to distinguish tilt from translation. The GIF resolution hypothesis states that the CNS estimates gravity and linear acceleration, so that the difference between estimates of gravity and linear acceleration matches the measured GIF. Both otolith and semicircular canal cues influence this estimation of gravity and linear acceleration. The GIF resolution hypothesis predicts that inaccurate estimates of both gravity and linear acceleration can occur due to central interactions of sensory cues. The existence of specific patterns of vestibuloocular reflexes (VOR) related to these inaccurate estimates can be used to test the GIF resolution hypothesis. To investigate this hypothesis, we measured eye movements during two different protocols. In one experiment, eight subjects were rotated at a constant velocity about an earth-vertical axis and then tilted 90° in darkness to one of eight different evenly spaced final orientations, a so-called “dumping” protocol. Three speeds (200, 100, and 50°/s) and two directions, clockwise (CW) and counterclockwise (CCW), of rotation were tested. In another experiment, four subjects were rotated at a constant velocity (200°/s, CW and CCW) about an earth-horizontal axis and stopped in two different final orientations (nose-up and nose-down), a so-called “barbecue” protocol. The GIF resolution hypothesis predicts that post-rotatory horizontal VOR eye movements for both protocols should include an “induced” VOR component, compensatory to an interaural estimate of linear acceleration, even though no true interaural linear acceleration is present. The GIF resolution hypothesis accurately predicted VOR and induced VOR dependence on rotation direction, rotation speed, and head orientation. Alternative hypotheses stating that frequency segregation may discriminate tilt from translation or that the post-rotatory VOR time constant is dependent on head orientation with respect to the GIF direction did not predict the observed VOR for either experimental protocol.

Eyes on Target: What Neurons Must do for the Vestibuloocular Reflex During Linear Motion

2004 ◽  
Vol 92 (1) ◽  
pp. 20-35 ◽  
Author(s):  
Dora E. Angelaki
Keyword(s):  
Sensory Information ◽  
Semicircular Canals ◽  
Linear Acceleration ◽  
Head Rotation ◽  
Oculomotor System ◽  
Eye Position ◽  
Otolith Organs ◽  
Vestibuloocular Reflex ◽  
Linear Motion ◽  
Gaze Stabilization

A gaze-stabilization reflex that has been conserved throughout evolution is the rotational vestibuloocular reflex (RVOR), which keeps images stable on the entire retina during head rotation. An ethological newer reflex, the translational or linear VOR (TVOR), provides fast foveal image stabilization during linear motion. Whereas the sensorimotor processing has been extensively studied in the RVOR, much less is currently known about the neural organization of the TVOR. Here we summarize the computational problems faced by the system and the potential solutions that might be used by brain stem and cerebellar neurons participating in the VORs. First and foremost, recent experimental and theoretical evidence has shown that, contrary to popular beliefs, the sensory signals driving the TVOR arise from both the otolith organs and the semicircular canals. Additional unresolved issues include a scaling by both eye position and vergence angle as well as the temporal transformation of linear acceleration signals into eye-position commands. Behavioral differences between the RVOR and TVOR, as well as distinct differences in neuroanatomical and neurophysiological properties, raise multiple functional questions and computational issues, only some of which are readily understood. In this review, we provide a summary of what is known about the functional properties and neural substrates for this oculomotor system and outline some specific hypotheses about how sensory information is centrally processed to create motor commands for the VORs.

Degeneration of vestibular neurons in late embryogenesis of both heterozygous and homozygous BDNF null mutant mice

Development ◽  
1996 ◽  
Vol 122 (6) ◽  
pp. 1965-1973 ◽  
Author(s):  
L.M. Bianchi ◽  
J.C. Conover ◽  
B. Fritzsch ◽  
T. DeChiara ◽  
R.M. Lindsay ◽  
...  
Keyword(s):  
Time Course ◽  
Semicircular Canals ◽  
Vestibular Neurons ◽  
Neuronal Populations ◽  
Sensory Epithelia ◽  
Inner Ear Development ◽  
Late Embryogenesis ◽  
Vestibular Sensory Epithelia ◽  
Null Mutant Mice ◽  
Afferent Innervation

The generation of mice lacking specific neurotrophins permits evaluation of the trophic requirements of particular neuronal populations throughout development. In the present study, we examined the developing vestibulocochlear system to determine the time course of neurotrophin dependence and to determine whether competition occurred among developing cochlear or vestibular neurons for available amounts of either brain-derived neurotrophic factor (BDNF) or neurotrophin-4/5 (NT-4/5). Both cochlear and vestibular neurons were present in mice lacking NT-4/5. In contrast, vestibular neurons decreased in number beginning at mid-stages of inner ear development, in mice lacking BDNF. Early in development (E12.5-13), the size of the vestibular ganglion was normal in bdnf −/− mice. Decreased innervation to vestibular sensory epithelia was detected at E13.5-15, when progressive loss of all afferent innervation to the semicircular canals and reduced innervation to the utricle and saccule were observed. At E16.5-17, there was a reduction in the number of vestibular neurons in bdnf −/− mice. A further decrease in vestibular neurons was observed at P1 and P15. Compared to bdnf −/− mice, mice heterozygous for the BDNF null mutation (bdnf +/−) showed an intermediate decrease in the number of vestibular neurons from E16.5-P15. These data indicate a late developmental requirement of vestibular neurons for BDNF and suggest competition among these neurons for limited supplies of this factor.

scholarly journals Vestibular Control of Muscular Tone and Posture

1987 ◽  
Vol 14 (S3) ◽  
pp. 493-496 ◽  
Author(s):  
Charles H. Markham
Keyword(s):  
Semicircular Canals ◽  
Linear Acceleration ◽  
Linear Displacement ◽  
Otolith Organs ◽  
Upright Posture ◽  
Muscular Tone ◽  
Neck Motoneurons ◽  
Head Stability ◽  
Lateral Vestibulospinal Tract ◽  
Vestibulospinal Tract

ABSTRACT:The vestibulospinal system helps to maintain upright posture and head stability. The semicircular canals and their short latency connections to the neck motoneurons, largely via the medial vestibulospinal tract, respond to angular accelerations so as to stabilize the head in space. The paired otolith organs, the utricles placed approximately horizontally, and the saccules vertically, respond to linear acceleration including gravity. Their influence leads, via the lateral vestibulospinal tract, to excitation of ipsilateral extensor motoneurons of the limbs and trunk, and to inhibition of reciprocal flexor motoneurons. Linear displacement of the otoliths leads to bracing of the limbs and body so as to maintain upright posture, and to extend the limbs so as to help in landing after sudden falls.

Introductory survey

1960 ◽  
Vol 152 (946) ◽  
pp. 1-2
Keyword(s):  
Sense Organ ◽  
Angular Acceleration ◽  
Organ Of Corti ◽  
Semicircular Canals ◽  
Linear Acceleration ◽  
Otolith Organs ◽  
Gravitational Acceleration ◽  
System A ◽  
History Of ◽  
Food Vacuoles

When we speak of the ear we associate it primarily with hearing. In our symposium today we shall, however, not be exclusively concerned with hearing in aquatic animals; and this has to do with the evolutionary history of the ear. Even in its most highly evolved form the ear is still a dual- or better-to-say a triple-purpose sense organ. In it are combined receptors for angular acceleration (the semicircular canals) for linear, including gravitational, acceleration (the otolith organs) and an organ for the accurate frequency analysis of sound (the organ of Corti in the cochlea). The otolith organs, are by dint of their particular design capable of signalling oscillatory changes in linear acceleration manifesting themselves as vibration or as sound in the widest meaning of the term. The functional association between reception of gravitational and vibrational stimuli, between balance and hearing is, phylogenetically speaking, a very old story. It begins probably with the emergence of the living cell. There exist inhomogeneities in density in the form of various cell inclusions, such as food vacuoles, etc., in an otherwise gravitationally or vibrationally ‘transparent’ cytoplasmic system. A density of two or three times that of water is sufficient to give pivotal importance to such cell inclusions making them capable of acting as internal points of reference for the perception of accelerational changes by the pressure-sensitive surrounding cytoplasm. This, on the multicellular level of organization, is the functional principle of the invertebrate statocyst.

Responses of interneurons in the cat cervical cord to vestibular tilt stimulation

1986 ◽  
Vol 56 (4) ◽  
pp. 1147-1156 ◽  
Author(s):  
R. H. Schor ◽  
I. Suzuki ◽  
S. J. Timerick ◽  
V. J. Wilson
Keyword(s):  
Cervical Spinal Cord ◽  
Semicircular Canals ◽  
Body Tilt ◽  
Whole Body ◽  
Cervical Cord ◽  
Otolith Organs ◽  
Phase Lag ◽  
Response Dynamics ◽  
Decerebrate Cat ◽  
Propriospinal Neurons

The responses of interneurons in the cervical spinal cord of the decerebrate cat to whole-body tilt were studied with a goal of identifying spinal elements in the production of forelimb vestibular postural reflexes. Interneurons both in the cervical enlargement and at higher levels, from which propriospinal neurons have been identified, were examined, both in animals with intact labyrinths and in animals with nonfunctional semicircular canals (canal plugged). Most cervical interneurons responding to tilt respond best to rotations in vertical planes aligned within 30 degrees of the roll plane. Two to three times as many neurons are excited by side-up roll tilt as are excited by side-down roll. In cats with intact labyrinths, most responses have dynamics proportional either to (and in phase with) the position of the animal or to a sum of position and tilt velocity. This is consistent with input from both otolith organs and semicircular canals. In animals without functioning canals, the "velocity" response is absent. In a few cells (8 out of 76), a more complex response, characterized by an increasing gain and progressive phase lag, was observed. These response dynamics characterize the forelimb reflex in canal-plugged cats and have been previously observed in vestibular neurons in such preparations.

Sign in / Sign up

Export Citation Format

Share Document