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.

scholarly journals Age-related reweighting of visual and vestibular cues for vertical perception

2019 ◽  
Vol 121 (4) ◽  
pp. 1279-1288 ◽  
Author(s):  
Bart B. G. T. Alberts ◽  
Luc P. J. Selen ◽  
W. Pieter Medendorp
Keyword(s):  
Spatial Orientation ◽  
Contextual Information ◽  
Sensory Information ◽  
The Body ◽  
Individual Subject ◽  
Noise Characteristics ◽  
Age Related ◽  
Vestibular Cues ◽  
Age Dependent ◽  
Visual Frame

As we age, the acuity of our sensory organs declines, which may affect our lifestyle. Sensory deterioration in the vestibular system is typically bilateral and gradual, and could lead to problems with balance and spatial orientation. To compensate for the sensory deterioration, it has been suggested that the brain reweights the sensory information sources according to their relative noise characteristics. For rehabilitation and training programs, it is important to understand the consequences of this reweighting, preferably at the individual subject level. We psychometrically examined the age-dependent reweighting of visual and vestibular cues used in spatial orientation in a group of 32 subjects (age range: 19–76 yr). We asked subjects to indicate the orientation of a line (clockwise or counterclockwise relative to the gravitational vertical) presented within an oriented square visual frame when seated upright or with their head tilted 30° relative to the body. Results show that subjects’ vertical perception is biased by the orientation of the visual frame. Both the magnitude of this bias and response variability become larger with increasing age. Deducing the underlying sensory noise characteristics, using Bayesian inference, suggests an age-dependent reweighting of sensory information, with an increasing weight of the visual contextual information. Further scrutiny of the model suggests that this shift in sensory weights is the result of an increase in the noise of the vestibular signal. Our approach quantifies how noise properties of visual and vestibular systems change over the life span, which helps to understand the aging process at the neurocomputational level. NEW & NOTEWORTHY Perception of visual vertical involves a weighted fusion of visual and vestibular tilt cues. Using a Bayesian approach and experimental psychophysics, we quantify how this fusion process changes with age. We show that, with age, the vestibular information is down-weighted whereas the visual weight is increased. This shift in sensory reweighting is primarily due to an age-related increase of the noise of vestibular signals.

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.

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.

scholarly journals Oscillatory neural responses evoked by natural vestibular stimuli in humans

2016 ◽  
Vol 115 (3) ◽  
pp. 1228-1242 ◽  
Author(s):  
Steven Gale ◽  
Mario Prsa ◽  
Aaron Schurger ◽  
Annietta Gay ◽  
Aurore Paillard ◽  
...  
Keyword(s):  
Constant Velocity ◽  
Human Subjects ◽  
Whole Body ◽  
Alpha Power ◽  
Alpha Band ◽  
Experimental Conditions ◽  
Healthy Human ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss ◽  
Cortical Oscillations

While there have been numerous studies of the vestibular system in mammals, less is known about the brain mechanisms of vestibular processing in humans. In particular, of the studies that have been carried out in humans over the last 30 years, none has investigated how vestibular stimulation (VS) affects cortical oscillations. Here we recorded high-density electroencephalography (EEG) in healthy human subjects and a group of bilateral vestibular loss patients (BVPs) undergoing transient and constant-velocity passive whole body yaw rotations, focusing our analyses on the modulation of cortical oscillations in response to natural VS. The present approach overcame significant technical challenges associated with combining natural VS with human electrophysiology and reveals that both transient and constant-velocity VS are associated with a prominent suppression of alpha power (8–13 Hz). Alpha band suppression was localized over bilateral temporo-parietal scalp regions, and these alpha modulations were significantly smaller in BVPs. We propose that suppression of oscillations in the alpha band over temporo-parietal scalp regions reflects cortical vestibular processing, potentially comparable with alpha and mu oscillations in the visual and sensorimotor systems, respectively, opening the door to the investigation of human cortical processing under various experimental conditions during natural VS.

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.

Medicine: Experimentation, Politics, Emergent Bodies

2012 ◽  
Vol 18 (3-4) ◽  
pp. 1-17 ◽  
Author(s):  
Mike Michael ◽  
Marsha Rosengarten
Keyword(s):  
Public Health Policy ◽  
Science And Technology Studies ◽  
Controlled Trial ◽  
Judith Butler ◽  
The Body ◽  
The Political ◽  
Medical Evidence ◽  
Special Issue ◽  
Healthy Human ◽  
Randomized Controlled

In this introduction, we address some of the complexities associated with the emergence of medicine’s bodies, not least as a means to ‘working with the body’ rather than simply producing a critique of medicine. We provide a brief review of some of the recent discussions on how to conceive of medicine and its bodies, noting the increasing attention now given to medicine as a technology or series of technologies active in constituting a multiplicity of entities – bodies, diseases, experimental objects, the individualization of responsibility for health and even the precarity of life. We contrast what feminist theorists in the tradition of Judith Butler have referred to as the question of matter, and Science and Technology Studies with its focus on practice and the nature of emergence. As such we address tensions that exist in analyses of the ontological status of ‘the body’ – human and non-human – as it is enacted in the work of the laboratory, the randomized controlled trial, public health policy and, indeed, the market that is so frequently entangled with these spaces. In keeping with the recent turns toward ontology and affect, we suggest that we can regard medicine as concerned with the contraction and reconfiguration of the body’s capacities to affect and be affected, in order to allow for the subsequent proliferation of affects that, according to Bruno Latour, marks corporeal life. Treating both contraction and proliferation circumspectly, we focus on the patterns of affects wrought in particular by the abstractions of medicine that are described in the contributions to this special issue. Drawing on the work of A.N. Whitehead, we note how abstractions such as ‘medical evidence’, the ‘healthy human body’ or the ‘animal model’ are at once realized and undercut, mediated and resisted through the situated practices that eventuate medicine’s bodies. Along the way, we touch on the implications of this sort of perspective for addressing the distribution of agency and formulations of the ethical and the political in the medical eventuations of bodies.

scholarly journals Vibrotactile feedback improves balance and mobility in patients with severe bilateral vestibular loss

2018 ◽  
Vol 266 (S1) ◽  
pp. 19-26 ◽  
Author(s):  
Herman Kingma ◽  
Lilian Felipe ◽  
Marie-Cecile Gerards ◽  
Peter Gerits ◽  
Nils Guinand ◽  
...  
Keyword(s):  
Vibrotactile Feedback ◽  
Vestibular Loss ◽  
Bilateral Vestibular Loss

scholarly journals Exposure to Road, Railway, and Aircraft Noise and Arterial Stiffness in the SAPALDIA Study: Annual Average Noise Levels and Temporal Noise Characteristics

2017 ◽  
Vol 125 (9) ◽  
pp. 097004 ◽  
Author(s):  
Maria Foraster ◽  
Ikenna C. Eze ◽  
Emmanuel Schaffner ◽  
Danielle Vienneau ◽  
Harris Héritier ◽  
...  
Keyword(s):  
Arterial Stiffness ◽  
Aircraft Noise ◽  
Noise Levels ◽  
Annual Average ◽  
Temporal Noise ◽  
Noise Characteristics
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