Bilateral Vestibular Loss Leads to Active Destabilization of Balance During Voluntary Head Turns in the Standing Cat

2006 ◽  
Vol 95 (6) ◽  
pp. 3783-3797 ◽  
Author(s):  
Paul J. Stapley ◽  
Lena H. Ting ◽  
Chen Kuifu ◽  
Dirk G. Everaert ◽  
Jane M. Macpherson
Keyword(s):  
Vertical Axis ◽  
The Body ◽  
Head Turn ◽  
Vestibular Input ◽  
Ipsilateral Side ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Postural Responses ◽  
Postural Imbalance ◽  
Lateral Head

The purpose of this study was to determine the source of postural instability in labyrinthectomized cats during lateral head turns. Cats were trained to maintain the head in a forward orientation and then perform a rapid, large-amplitude head turn to left or right in yaw, while standing freely on a force platform. Head turns were biomechanically complex with the primary movement in the yaw plane accompanied by an ipsilateral ear-down roll and nose-down pitch. Cats used a strategy of pushing off by activating extensors of the contralateral forelimb while using all four limbs to produce a rotational moment of force about the vertical axis. After bilateral labyrinthectomy, the initial components of the head turn and accompanying postural responses were hypermetric, but otherwise similar to those produced before the lesion. However, near the time of peak yaw velocity, the lesioned cats produced an unexpected burst in extensors of the contralateral limbs that thrust the body to the ipsilateral side, leading to falls. This postural error was in the frontal (roll) plane, even though the primary movement was a rotation in the horizontal (yaw) plane. The response error decreased in amplitude with compensation but did not disappear. We conclude that lack of vestibular input results in active destabilization of balance during voluntary head movement. We postulate that the postural imbalance arises from the misperception that the trunk was rolling contralaterally, based on signals from neck proprioceptors in the absence of vestibular inputs.

Role of Vestibular Input in Triggering and Modulating Postural Responses in Unilateral and Bilateral Vestibular Loss Patients

2009 ◽  
Vol 14 (2) ◽  
pp. 130-138 ◽  
Author(s):  
F. Mbongo ◽  
C. Qu’hen ◽  
P.P. Vidal ◽  
P. Tran Ba Huy ◽  
C. de Waele
Keyword(s):  
Vestibular Input ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Postural Responses

Vestibular loss disrupts daily rhythm in rats

2015 ◽  
Vol 118 (3) ◽  
pp. 310-318 ◽  
Author(s):  
T. Martin ◽  
B. Mauvieux ◽  
J. Bulla ◽  
G. Quarck ◽  
D. Davenne ◽  
...  
Keyword(s):  
Daily Rhythm ◽  
Control Group ◽  
Vestibular Input ◽  
Daily Rhythms ◽  
Cell Degeneration ◽  
Vestibular Loss ◽  
Anatomical Structures ◽  
Bilateral Vestibular Loss ◽  
Vestibular Lesion ◽  
Vestibular Pathology

Hypergravity disrupts the circadian regulation of temperature (Temp) and locomotor activity (Act) mediated through the vestibular otolithic system in mice. In contrast, we do not know whether the anatomical structures associated with vestibular input are crucial for circadian rhythm regulation at 1 G on Earth. In the present study we observed the effects of bilateral vestibular loss (BVL) on the daily rhythms of Temp and Act in semipigmented rats. Our model of vestibular lesion allowed for selective peripheral hair cell degeneration without any other damage. Rats with BVL exhibited a disruption in their daily rhythms (Temp and Act), which were replaced by a main ultradian period (τ <20 h) for 115.8 ± 68.6 h after vestibular lesion compared with rats in the control group. Daily rhythms of Temp and Act in rats with BVL recovered within 1 wk, probably counterbalanced by photic and other nonphotic time cues. No correlation was found between Temp and Act daily rhythms after vestibular lesion in rats with BVL, suggesting a direct influence of vestibular input on the suprachiasmatic nucleus. Our findings support the hypothesis that the vestibular system has an influence on daily rhythm homeostasis in semipigmented rats on Earth, and raise the question of whether daily rhythms might be altered due to vestibular pathology in humans.

Postural responses to vibration of neck muscles in patients with uni- and bilateral vestibular loss

1998 ◽  
Vol 7 (3) ◽  
pp. 228-236 ◽  
Author(s):  
Hamid Lekhel ◽  
Konstantin Popov ◽  
Adolfo Bronstein ◽  
Michael Gresty
Keyword(s):  
Neck Muscles ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Postural Responses

Bilateral Vestibular Loss in Cats Leads to Active Destabilization of Balance During Pitch and Roll Rotations of the Support Surface

2007 ◽  
Vol 97 (6) ◽  
pp. 4357-4367 ◽  
Author(s):  
Jane M. Macpherson ◽  
Dirk G. Everaert ◽  
Paul J. Stapley ◽  
Lena H. Ting
Keyword(s):  
Center Of Mass ◽  
The Body ◽  
Support Surface ◽  
Postural Response ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Automatic Postural Response ◽  
Vestibular Information ◽  
Body Center ◽  
Proprioceptive Inputs

Although the balance difficulties accompanying vestibular loss are well known, the underlying cause remains unclear. We examined the role of vestibular inputs in the automatic postural response (APR) to pitch and roll rotations of the support surface in freely standing cats before and in the first week after bilateral labyrinthectomy. Support surface rotations accelerate the body center of mass toward the downhill side. The normal APR consists of inhibition in the extensors of the uphill limbs and excitation in the downhill limbs to decelerate the body and maintain the alignment of the limbs with respect to earth-vertical. After vestibular lesion, cats were unstable during rotation perturbations and actively pushed themselves downhill rather than uphill, using a postural response that was opposite to that seen in the control trials. The extensors of the uphill rather than downhill limbs were activated, whereas those of the downhill limbs were inhibited rather than being excited. We propose that vestibular inputs provide an important reference to earth-vertical, which is critical to computing the appropriate postural response during active orientation to the vertical. In the absence of this vestibular information, subjects orient to the support surface using proprioceptive inputs, which drives the body downhill resulting in instability and falling. This is consistent with current models of sensory integration for computation of body posture and orientation.

Postural Control in the Rabbit Maintaining Balance on the Tilting Platform

2003 ◽  
Vol 90 (6) ◽  
pp. 3783-3793 ◽  
Author(s):  
I. N. Beloozerova ◽  
P. V. Zelenin ◽  
L. B. Popova ◽  
G. N. Orlovsky ◽  
S. Grillner ◽  
...  
Keyword(s):  
Frontal Plane ◽  
Threshold Value ◽  
Dorsal Side ◽  
The Body ◽  
Body Posture ◽  
Vestibular Input ◽  
Postural Responses ◽  
Extensor Muscles ◽  
Somatosensory Input ◽  
Emg Patterns

A deviation from the dorsal-side-up body posture in quadrupeds activates the mechanisms for postural corrections. Operation of these mechanisms was studied in the rabbit maintaining balance on a platform periodically tilted in the frontal plane. First, we characterized the kinematics and electromyographic (EMG) patterns of postural responses to tilts. It was found that a reaction to tilt includes an extension of the limbs on the side moving down and flexion on the opposite side. These limb movements are primarily due to a modulation of the activity of extensor muscles. Second, it was found that rabbits can effectively maintain the dorsal-side-up body posture when complex postural stimuli are applied, i.e., asynchronous tilts of the platforms supporting the anterior and posterior parts of the body. These data suggest that the nervous mechanisms controlling positions of these parts of the body can operate independently of each other. Third, we found that normally the somatosensory input plays a predominant role for the generation of postural responses. However, when the postural response appears insufficient to maintain balance, the vestibular input contributes considerably to activation of postural mechanisms. We also found that an asymmetry in the tonic vestibular input, caused by galvanic stimulation of the labyrinths, can affect the stabilized body orientation while the magnitude of postural responses to tilts remains unchanged. Fourth, we found that the mechanisms for postural corrections respond only to tilts that exceed a certain (threshold) value.

scholarly journals Velocity dependence of vestibular information for postural control on tilting surfaces

2016 ◽  
Vol 116 (3) ◽  
pp. 1468-1479 ◽  
Author(s):  
Fay B. Horak ◽  
JoAnn Kluzik ◽  
Frantisek Hlavacka
Keyword(s):  
Visual Information ◽  
Postural Sway ◽  
Somatosensory System ◽  
The Body ◽  
Velocity Range ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Eyes Closed ◽  
Vestibular Information ◽  
Wide Range

Vestibular information is known to be important for postural stability on tilting surfaces, but the relative importance of vestibular information across a wide range of surface tilt velocities is less clear. We compared how tilt velocity influences postural orientation and stability in nine subjects with bilateral vestibular loss and nine age-matched, control subjects. Subjects stood on a force platform that tilted 6 deg, toes-up at eight velocities (0.25 to 32 deg/s), with and without vision. Results showed that visual information effectively compensated for lack of vestibular information at all tilt velocities. However, with eyes closed, subjects with vestibular loss were most unstable within a critical tilt velocity range of 2 to 8 deg/s. Subjects with vestibular deficiency lost their balance in more than 90% of trials during the 4 deg/s condition, but never fell during slower tilts (0.25–1 deg/s) and fell only very rarely during faster tilts (16–32 deg/s). At the critical velocity range in which falls occurred, the body center of mass stayed aligned with respect to the surface, onset of ankle dorsiflexion was delayed, and there was delayed or absent gastrocnemius inhibition, suggesting that subjects were attempting to actively align their upper bodies with respect to the moving surface instead of to gravity. Vestibular information may be critical for stability at velocities of 2 to 8 deg/s because postural sway above 2 deg/s may be too fast to elicit stabilizing responses through the graviceptive somatosensory system, and postural sway below 8 deg/s may be too slow for somatosensory-triggered responses or passive stabilization from trunk inertia.

scholarly journals Dissociating vestibular and somatosensory contributions to spatial orientation

2016 ◽  
Vol 116 (1) ◽  
pp. 30-40 ◽  
Author(s):  
Bart B. G. T. Alberts ◽  
Luc P. J. Selen ◽  
Giovanni Bertolini ◽  
Dominik Straumann ◽  
W. Pieter Medendorp ◽  
...  
Keyword(s):  
Tilt Angle ◽  
Spatial Orientation ◽  
The Body ◽  
Substantial Contribution ◽  
Otolith Organs ◽  
Noise Levels ◽  
Healthy Human ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Noise Characteristics

Inferring object orientation in the surroundings heavily depends on our internal sense of direction of gravity. Previous research showed that this sense is based on the integration of multiple information sources, including visual, vestibular (otolithic), and somatosensory signals. The individual noise characteristics and contributions of these sensors can be studied using spatial orientation tasks, such as the subjective visual vertical (SVV) task. A recent study reported that patients with complete bilateral vestibular loss perform similar as healthy controls on these tasks, from which it was conjectured that the noise levels of both otoliths and body somatosensors are roll-tilt dependent. Here, we tested this hypothesis in 10 healthy human subjects by roll tilting the head relative to the body to dissociate tilt-angle dependencies of otolith and somatosensory noise. Using a psychometric approach, we measured the perceived orientation, and its variability, of a briefly flashed line relative to the gravitational vertical (SVV). Measurements were taken at multiple body-in-space orientations (−90 to 90°, steps of 30°) and head-on-body roll tilts (30° left ear down, aligned, 30° right ear down). Results showed that verticality perception is processed in a head-in-space reference frame, with a systematic SVV error that increased with larger head-in-space orientations. Variability patterns indicated a larger contribution of the otolith organs around upright and a more substantial contribution of the body somatosensors at larger body-in-space roll tilts. Simulations show that these findings are consistent with a statistical model that involves tilt-dependent noise levels of both otolith and somatosensory signals, confirming dynamic shifts in the weights of sensory inputs with tilt angle.

Analysis of the First Order and Slowly Varying Motions of an Axisymmetric Floating Body in Bichromatic Waves

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
João Pessoa ◽  
Nuno Fonseca ◽  
C. Guedes Soares
Keyword(s):  
Vertical Cylinder ◽  
Vertical Axis ◽  
Second Order ◽  
The Body ◽  
Floating Body ◽  
Drift Motion ◽  
First Order ◽  
Motion Responses ◽  
Simple Geometry ◽  
Good Agreement

The paper presents an experimental and numerical investigation on the motions of a floating body of simple geometry subjected to harmonic and biharmonic waves. The experiments were carried out in three different water depths representing shallow and deep water. The body is axisymmetric about the vertical axis, like a vertical cylinder with a rounded bottom, and it is kept in place with a soft mooring system. The experimental results include the first order motion responses, the steady drift motion offset in regular waves and the slowly varying motions due to second order interaction in biharmonic waves. The hydrodynamic problem is solved numerically with a second order boundary element method. The results show a good agreement of the numerical calculations with the experiments.

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