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1

Improving balance function using vestibular stochastic resonance: optimizing stimulus characteristics  

Microsoft Academic Search

Stochastic resonance (SR) is a phenomenon whereby the response of a non-linear system to a weak periodic input signal is optimized\\u000a by the presence of a particular non-zero level of noise. Stochastic resonance using imperceptible stochastic vestibular electrical\\u000a stimulation, when applied to normal young and elderly subjects, has been shown to significantly improve ocular stabilization\\u000a reflexes in response to whole-body

Ajitkumar P. Mulavara; Matthew J. Fiedler; Igor S. Kofman; Scott J. Wood; Jorge M. Serrador; Brian Peters; Helen S. Cohen; Millard F. Reschke; Jacob J. Bloomberg

2011-01-01

2

Optimization of Stimulus Characteristics for Vestibular Stochastic Resonance to Improve Balance Function  

NASA Technical Reports Server (NTRS)

Stochastic resonance (SR) is a mechanism by which noise can assist and enhance the response of neural systems to relevant sensory signals. Recent studies have shown that applying imperceptible stochastic noise electrical stimulation to the vestibular system significantly improved balance and ocular motor responses. The goal of this study was to optimize the amplitude of the stochastic vestibular signals for balance performance during standing on an unstable surface. Subjects performed a standardized balance task of standing on a block of 10-cm-thick medium-density foam with their eyes closed. Balance performance was measured using a force plate under the foam block and using inertial motion sensors placed on the torso and head segments. Stochastic electrical stimulation was applied to the vestibular system through electrodes placed over the mastoid process. Subjects were tested at seven amplitudes in the 0.01-30Hz frequency range. The root mean square of the signal increased by 30 microamperes for each +/-100 microampere increment in the current range of 0 - +/-700 microampere. Six balance parameters were calculated to characterize the performance of subjects during the baseline and the stimulus periods for all seven amplitudes. Optimal stimulus amplitude was determined as the one at which the ratio of parameters from the stimulus period to the baseline period for any amplitude range was less than that for the no stimulus condition on a minimum of four of six parameters. Results from this study showed that balance performance at the optimal stimulus amplitude showed significant improvement with the application of the vestibular SR stimulation. The amplitude of optimal stimulus for improving balance performance in normal subjects was in the range of +/-100 - +/-300 microamps.

Mulavara, Ajitkumar; Fiedler, Matthew; Kofman, Igor; Acock, Keena; DeDios, Yiri E.; Heap, Erin; Peters, Brian; Wood, Scott; Serrador, Jorge; Cohen, Helen; Reschke, Millard; Bloomberg, Jacob

2010-01-01

3

Vestibular Stochastic Resonance as a Method to Improve Balance Function: Optimization of Stimulus Characteristics  

NASA Technical Reports Server (NTRS)

Stochastic resonance (SR) is a mechanism by which noise can assist and enhance the response of neural systems to relevant sensory signals. Application of imperceptible SR noise coupled with sensory input through the proprioceptive, visual, or vestibular sensory systems has been shown to improve motor function. Specifically, studies have shown that that vestibular electrical stimulation by imperceptible stochastic noise, when applied to normal young and elderly subjects, significantly improved their ocular stabilization reflexes in response to whole-body tilt as well as balance performance during postural disturbances. The goal of this study was to optimize the characteristics of the stochastic vestibular signals for balance performance during standing on an unstable surface. Subjects performed a standardized balance task of standing on a block of 10 cm thick medium density foam with their eyes closed for a total of 40 seconds. Stochastic electrical stimulation was applied to the vestibular system through electrodes placed over the mastoid process behind the ears during the last 20 seconds of the test period. A custom built constant current stimulator with subject isolation delivered the stimulus. Stimulation signals were generated with frequencies in the bandwidth of 1-2 Hz and 0.01-30 Hz. Amplitude of the signals were varied in the range of 0- +/-700 micro amperes with the RMS of the signal increased by 30 micro amperes for each 100 micro amperes increase in the current range. Balance performance was measured using a force plate under the foam block and inertial motion sensors placed on the torso and head segments. Preliminary results indicate that balance performance is improved in the range of 10-25% compared to no stimulation conditions. Subjects improved their performance consistently across the blocks of stimulation. Further the signal amplitude at which the performance was maximized was different in the two frequency ranges. Optimization of the frequency and amplitude of the signal characteristics of the stochastic noise signals on maximizing balance performance will have a significant impact in its development as a unique system to aid recovery of function in astronauts after long duration space flight or for people with balance disorders.

Mulavara, Ajitkumar; Fiedler, Matthew; Kofman, Igor; Peters, Brian; Wood, Scott; Serrador, Jorge; Cohen, Helen; Reschke, Millard; Bloomberg, Jacob

2010-01-01

4

Stochastic resonance  

Microsoft Academic Search

Over the last two decades, stochastic resonance has continuously attracted considerable attention. The term is given to a phenomenon that is manifest in nonlinear systems whereby generally feeble input information (such as a weak signal) can be be amplified and optimized by the assistance of noise. The effect requires three basic ingredients: (i) an energetic activation barrier or, more generally,

Luca Gammaitoni; Peter Hänggi; Peter Jung; Fabio Marchesoni

1998-01-01

5

Stochastic Resonance  

E-print Network

Stochastic resonance (SR) - a counter-intuitive phenomenon in which the signal due to a weak periodic force in a nonlinear system can be {\\it enhanced} by the addition of external noise - is reviewed. A theoretical approach based on linear response theory (LRT) is described. It is pointed out that, although the LRT theory of SR is by definition restricted to the small signal limit, it possesses substantial advantages in terms of simplicity, generality and predictive power. The application of LRT to overdamped motion in a bistable potential, the most commonly studied form of SR, is outlined. Two new forms of SR, predicted on the basis of LRT and subsequently observed in analogue electronic experiments, are described.

M. I. Dykman; D. G. Luchinsky; R. Mannella; P. V. E. McClintock; S. M. Soskin; N. D. Stein; N. G. Stocks

1993-07-17

6

Stochastic resonance  

NASA Astrophysics Data System (ADS)

We are taught by conventional wisdom that the transmission and detection of signals is hindered by noise. However, during the last two decades, the paradigm of stochastic resonance (SR) proved this assertion wrong: indeed, addition of the appropriate amount of noise can boost a signal and hence facilitate its detection in a noisy environment. Due to its simplicity and robustness, SR has been implemented by mother nature on almost every scale, thus attracting interdisciplinary interest from physicists, geologists, engineers, biologists and medical doctors, who nowadays use it as an instrument for their specific purposes. At the present time, there exist a lot of diversified models of SR. Taking into account the progress achieved in both theoretical understanding and practical application of this phenomenon, we put the focus of the present review not on discussing in depth technical details of different models and approaches but rather on presenting a general and clear physical picture of SR on a pedagogical level. Particular emphasis will be given to the implementation of SR in generic quantum systems—an issue that has received limited attention in earlier review papers on the topic. The major part of our presentation relies on the two-state model of SR (or on simple variants thereof), which is general enough to exhibit the main features of SR and, in fact, covers many (if not most) of the examples of SR published so far. In order to highlight the diversity of the two-state model, we shall discuss several examples from such different fields as condensed matter, nonlinear and quantum optics and biophysics. Finally, we also discuss some situations that go beyond the generic SR scenario but are still characterized by a constructive role of noise.

Wellens, Thomas; Shatokhin, Vyacheslav; Buchleitner, Andreas

2004-01-01

7

Mechanical Stochastic Resonance  

NASA Astrophysics Data System (ADS)

Noise and nonlinearity can produce a stochastic resonance that maximizes a system's output signal-to-noise ratio. Stochastic resonance has been observed in electronic, chemical, optical, magnetic, and biological systems. Here, we report stochastic resonance in a simple mechanical system consisting of a bistable pendulum driven by a harmonic oscillator and the broad-band noise of a flapping flag.

Wainwright, Elliot; Lindner, John

2013-03-01

8

Stochastic resonance in the mechanoelectrical transduction of hair cells  

NASA Astrophysics Data System (ADS)

In transducing mechanical stimuli into electrical signals, at least some hair cells in vertebrate auditory and vestibular systems respond optimally to weak periodic signals at natural, nonzero noise intensities. We understand this stochastic resonance by constructing a faithful mechanical model reflecting the hair cell geometry and described by a nonlinear stochastic differential equation. This Langevin description elucidates the mechanism of hair cell stochastic resonance while supporting the hypothesis that noise plays a functional role in hearing.

Lindner, John F.; Bennett, Matthew; Wiesenfeld, Kurt

2005-11-01

9

Stochastic resonance of quantum discord  

E-print Network

We study the stochastic resonance of quantum discord (“discord resonance”) in coupled quantum systems and make a comparison with the stochastic resonance of entanglement (“entanglement resonance”). It is found that the ...

Lee, Chee Kong

10

Stochastic resonance without tuning  

Microsoft Academic Search

STOCHASTIC resonance1á¤-4 (SR) is a phenomenon wherein the response of a nonlinear system to a weak periodic input signal is optimized by the presence of a particular, non-zero level of noise5 á¤-7. SR has been proposed as a means for improving signal detection in a wide variety of systems, including superconducting quantum interference devices8, and may be used in some

J. J. Collins; Carson C. Chow; Thomas T. Imhoff

1995-01-01

11

Stochastic Resonance: from climate to biology  

E-print Network

In this paper I will review some basic aspects of the mechanism of stochastic resonance. Stochastic resonance was first introduced as a possible mechanism to explain long term climatic variation. Since then, there have been many applications of stochastic resonance in physical and biological systems. I will show that in complex system, stochastic resonance can substantially change as a function of the ``system complexity''. Also, I will briefly mention how to apply stochastic resonance for the case of Brownian motors.

Roberto Benzi

2007-02-05

12

Stochastic resonance with matched filtering  

E-print Network

Along with the development of interferometric gravitational wave detector, we enter into an epoch of gravitational wave astronomy, which will open a brand new window for astrophysics to observe our universe. Almost all of the data analysis methods in gravitational wave detection are based on matched filtering. Gravitational wave detection is a typical example of weak signal detection, and this weak signal is buried in strong instrument noise. So it seems attractable if we can take advantage of stochastic resonance. But unfortunately, almost all of the stochastic resonance theory is based on Fourier transformation and has no relation to matched filtering. In this paper we try to relate stochastic resonance to matched filtering. Our results show that stochastic resonance can indeed be combined with matched filtering for both periodic and non-periodic input signal. This encouraging result will be the first step to apply stochastic resonance to matched filtering in gravitational wave detection. In addition, based on matched filtering, we firstly proposed a novel measurement method for stochastic resonance which is valid for both periodic and non-periodic driven signal.

Li-Fang Li; Jian-Yang Zhu

2010-06-28

13

Stochastic resonance effects in quantum channels  

E-print Network

We provide some examples of quantum channels where the addition of noise is able to enhance the information transmission rate. This may happen for both quantum and classical uses and realizes stochastic resonance effects.

Garry Bowen; Stefano Mancini

2005-12-13

14

Stochastic resonance in the Bénard system  

NASA Astrophysics Data System (ADS)

In this paper the effect of small stochastic perturbations on a dynamical system describing the Bénard thermal convection is studied. In particular, the two-dimensional Oberbeck-Boussinesq equations governing the dynamics of three interacting Rayleigh rolls with increasing horizontal wave numbers ( i.e., three horizontal modes in the Fourier transform) are reduced to a system of gradient type. The aim is to study the transition paths between the stable steady states, when a stochastic perturbation is taken into account, and the occurrence of stochastic resonance, when the system is perturbed by white noise and the first (gravest) mode is forced by an external periodic component. Results show that i) random transitions between stable steady states representing a clockwise and a counter-clockwise circulation occur through the two saddle points associated with the second mode and not through the (unstable) conductive state nor the saddle points related to the third mode; ii) the introduction of the third mode, as well as of others of smaller spatial scales, does not affect transitions that remain confined along the trajectories linking stable convective states through the saddle points associated with the second mode; iii) the system exhibits a stochastic resonance behavior leading to large amplification of the small amplitude periodic component compared to the one leading to the classical (one-dimensional) stochastic resonance.

Barbini, Leonardo; Bordi, Isabella; Fraedrich, Klaus

2014-09-01

15

The mechanism of stochastic resonance  

Microsoft Academic Search

It is shown that a dynamical system subject to both periodic forcing and random perturbation may show a resonance (peak in the power spectrum) which is absent when either the forcing or the perturbation is absent.

R. Benzi; A. Sutera; A. Vulpiani

1981-01-01

16

Stochastic resonance in an intracellular genetic perceptron  

NASA Astrophysics Data System (ADS)

Intracellular genetic networks are more intelligent than was first assumed due to their ability to learn. One of the manifestations of this intelligence is the ability to learn associations of two stimuli within gene-regulating circuitry: Hebbian-type learning within the cellular life. However, gene expression is an intrinsically noisy process; hence, we investigate the effect of intrinsic and extrinsic noise on this kind of intracellular intelligence. We report a stochastic resonance in an intracellular associative genetic perceptron, a noise-induced phenomenon, which manifests itself in noise-induced increase of response in efficiency after the learning event under the conditions of optimal stochasticity.

Bates, Russell; Blyuss, Oleg; Zaikin, Alexey

2014-03-01

17

Stochastic resonance of electrochemical aperiodic spike trains  

NASA Astrophysics Data System (ADS)

Aperiodic stochastic resonance in an electrochemical system with excitable dynamics is characterized in experiments and simulations. Two different spike trains, one with stochastic and the other with chaotic interspike intervals, are imposed on the system as subthreshold aperiodic signals. Information transmission is quantified by the cross correlation between the subthreshold input signal and the noise induced system response. A maximum is exhibited in the input-output correlation as a function of the noise amplitude. Numerical simulations with an electrochemical model are in excellent agreement with the experimental observations.

Parmananda, P.; Escalera Santos, Gerardo J.; Rivera, M.; Showalter, Kenneth

2005-03-01

18

Reverse resonance and stochastic resonance in intracellular calcium oscillations  

NASA Astrophysics Data System (ADS)

The roles of time delay on the coherence resonance are investigated in the intracellular calcium oscillation system described by the processes of active and passive transport of intracellular Ca2+ driven by colored noises. From the numerical simulation of the reciprocal coefficient of variance of interspike intervals of calcium spikes by the method of second-order algorithm, the results indicate that: (i) The stochastic or reverse synchronization is induced by a certain value of time delay or correlation time; (ii) A phenomenon of reverse resonance can be obtained in the function of reciprocal coefficient of variance vs. time delay or vs. strength of noises as time delay increases; (iii) Both stochastic and reverse resonance are observed in the function of reciprocal coefficient of variance vs. correlation time with varying strength of noises.

Duan, Wei-Long; Long, Fei; Li, Chun

2014-05-01

19

Frequency (Stochastic) Resonance and Stochastic Resonance for a Superconducting Junctions' Device  

NASA Astrophysics Data System (ADS)

In this paper, we investigate a Josephson-junction device with dichotomous resistance or a special SQUID (superconducting quantum interference device). It is shown that frequency (stochastic) resonance and stochastic resonance can appear for some suitably selected parameters' values of the device respectively. Our results can provide some insights for the investigation of the SQUID response to the signal (including the input alternating current, the added alternating voltage, the vertically added alternating magnetic field, and the detected (electric-magnetic) temporal-periodic signal).

Li, Jing-Hui

2014-06-01

20

Crossing resonance of stochastically interacting wave fields  

SciTech Connect

The dynamic susceptibilities (Green's functions) of the system of two interacting wave fields of different physical natures with a stochastically inhomogeneous coupling parameter between them with zero mean value have been examined. The well-known self-consistent approximation taking into account all diagrams with noncrossing correlation/interaction lines has been generalized to the case of stochastically interacting wave fields. The analysis has been performed for spin and elastic waves. The results obtained taking into account the processes of multiple scattering of waves from inhomogeneities are significantly different from those obtained for this situation earlier in the Bourret approximation [R.C. Bourret, Nuovo Cimento 26, 1 (1962)]. Instead of frequencies degeneracy removal in the wave spectrum and the splitting of resonance peaks of dynamic susceptibilities, a wide single-mode resonance peak should be observed at the crossing point of the unperturbed dispersion curves. The fine structure appears at vertices of these wide peaks in the form of a narrow resonance on the Green's-function curve of one field and a narrow antiresonance on the vertex of the Green's-function curve of the other field.

Ignatchenko, V. A., E-mail: vignatch@iph.krasn.ru; Polukhin, D. S. [Russian Academy of Sciences, L.V. Kirensky Institute of Physics, Siberian Branch (Russian Federation)] [Russian Academy of Sciences, L.V. Kirensky Institute of Physics, Siberian Branch (Russian Federation)

2013-02-15

21

Fractional Brownian motors and stochastic resonance  

NASA Astrophysics Data System (ADS)

We study fluctuating tilt Brownian ratchets based on fractional subdiffusion in sticky viscoelastic media characterized by a power law memory kernel. Unlike the normal diffusion case, the rectification effect vanishes in the adiabatically slow modulation limit and optimizes in a driving frequency range. It is shown also that the anomalous rectification effect is maximal (stochastic resonance effect) at optimal temperature and can be of surprisingly good quality. Moreover, subdiffusive current can flow in the counterintuitive direction upon a change of temperature or driving frequency. The dependence of anomalous transport on load exhibits a remarkably simple universality.

Goychuk, Igor; Kharchenko, Vasyl

2012-05-01

22

Stochastic resonance in mammalian neuronal networks  

SciTech Connect

We present stochastic resonance observed in the dynamics of neuronal networks from mammalian brain. Both sinusoidal signals and random noise were superimposed into an applied electric field. As the amplitude of the noise component was increased, an optimization (increase then decrease) in the signal-to-noise ratio of the network response to the sinusoidal signal was observed. The relationship between the measures used to characterize the dynamics is discussed. Finally, a computational model of these neuronal networks that includes the neuronal interactions with the electric field is presented to illustrate the physics behind the essential features of the experiment. {copyright} {ital 1998 American Institute of Physics.}

Gluckman, B.J.; So, P. [Department of Physics and Astronomy and The Krasnow Institute for Advanced Studies, George Mason University, Fairfax, Virginia 22030 (United States)] [Department of Physics and Astronomy and The Krasnow Institute for Advanced Studies, George Mason University, Fairfax, Virginia 22030 (United States); Netoff, T.I. [Program in Neuroscience, The George Washington University, Washington, DC 20052 (United States)] [Program in Neuroscience, The George Washington University, Washington, DC 20052 (United States); Spano, M.L. [Naval Surface Warfare Center, Carterock Division, West Bethesda, Maryland 20817 (United States)] [Naval Surface Warfare Center, Carterock Division, West Bethesda, Maryland 20817 (United States); Schiff, S.J. [The Krasnow Institute for Advanced Studies and the Department of Psychology, George Mason University, Fairfax, Virginia 22030 (United States)] [The Krasnow Institute for Advanced Studies and the Department of Psychology, George Mason University, Fairfax, Virginia 22030 (United States); [Program in Neuroscience, The George Washington University, Washington, DC 20052 (United States)

1998-09-01

23

Spatiotemporal Stochastic Resonance and its consequences in a neural system  

Microsoft Academic Search

Biological neurons are good examples of a threshold device—this is why neural systems are in the focus when looking for realization of Stochastic Resonance (SR) and Spatiotemporal Stochastic Resonance (STSR) phenomena. There are two different ways to simulate neural systems—one based on differential equations, the other based on a simple threshold model. In this talk the effect of noise on

Ga´bor Bala´zsi; La´szlo´ B. Kiss; Frank E. Moss

2000-01-01

24

Cortical and subcortical vestibular response to caloric stimulation detected by functional magnetic resonance imaging.  

PubMed

The posterior insula, central sulcus, and inferior parietal lobule including the intraparietal sulcus have been considered the vestibular cortex based on functional brain mapping in humans as well as experiments in lower primates. The same regions receive optokinetic, visual, and proprioceptive projections. We examined the cortical and subcortical projection of vestibular activity with visual and proprioceptive input eliminated during caloric stimulation (CS), using functional magnetic resonance imaging (fMRI). Single-shot gradient-echo echoplanar image (EPI) volumes were sensitive to BOLD contrast in oblique orientation. We adopted a pharmacokinetic model for analysis of imaging data from 10 subjects as a group. The insular gyrus, intraparietal sulcus, superior temporal gyrus, hippocampus, cingulate gyrus, and thalamus showed activation by CS. Cortical and subcortical activation during CS in the present study was observed within regions less precisely delineated by other methods. As intraparietal sulcus activation showed right hemispheric dominance, this region may have an oculomotor projection as well as the vestibular input. PMID:11689304

Suzuki, M; Kitano, H; Ito, R; Kitanishi, T; Yazawa, Y; Ogawa, T; Shiino, A; Kitajima, K

2001-12-01

25

Linear Response Theory in Stochastic Resonance  

E-print Network

The susceptibility of an overdamped Markov system fluctuating in a bistable potential of general form is obtained by analytic solution of the Fokker-Planck equation (FPE) for low noise intensities. The results are discussed in the context of the LRT theory of stochastic resonance. They go over into recent results (Gang Hu et al {\\em Phys. Lett. A} {\\bf 172}, 21, 1992) obtained from the FPE for the case of a symmetrical potential, and they coincide with the LRT results (Dykman et al, {\\em Phys. Rev. Lett.} {\\bf 65}, 2606, 1990; {\\em JETP Lett} {\\bf 52}, 144, 1990; {\\em Phys. Rev. Lett.} {\\bf 68}, 2985, 1992) obtained for the general case of bistable systems.

MI Dykman; H Haken; Gang Hu; DG Luchinsky; R Mannella; PVE McClintock; CZ Ning; ND Stein; NG Stocks

1993-08-09

26

City traffic jam relief by stochastic resonance  

NASA Astrophysics Data System (ADS)

We simulate traffic in a city by means of the evolution of a row of interacting cars, using a cellular automaton model, in a sequence of traffic lights synchronized by a "green wave". When our initial condition is a small density jammed state, its evolution shows the expected scaling laws close to the synchronization resonance, with a uniform car density along the street. However, for an initial large density jammed state, we observe density variations along the streets, which results in the breakdown of the scaling laws. This spatial disorder corresponds to a different attractor of the system. As we include velocity perturbations in the dynamics of the cars, all these attractors converge to a statistically equivalent system for all initial jammed densities. However, this emergent state shows a stochastic resonance-like behavior in which the average traffic velocity increases with respect to that of the system without noise, for several initial jammed densities. This result may help in the understanding of dynamics of traffic jams in cities.

Castillo, F.; Toledo, B. A.; Muñoz, V.; Rogan, J.; Zarama, R.; Kiwi, M.; Valdivia, J. A.

2014-06-01

27

Analog-to-digital conversion using suprathreshold stochastic resonance  

NASA Astrophysics Data System (ADS)

We present an analysis of the use of suprathreshold stochastic resonance for analog to digital conversion. Suprathreshold stochastic resonance is a phenomenon where the presence of internal or input noise provides the optimal response from a system of identical parallel threshold devices such as comparators or neurons. Under the conditions where this occurs, such a system is effectively a non-deterministic analog to digital converter. In this paper we compare the suprathreshold stochastic resonance effect to conventional analog to digital conversion by analysing the rate-distortion trade-off of each.

McDonnell, Mark D.; Stocks, Nigel G.; Pearce, Charles E. M.; Abbott, Derek

2005-02-01

28

Stochastic Resonance in a simple model of magnetic reversals  

E-print Network

We discuss the effect of stochastic resonance in a simple model of magnetic reversals. The model exhibits statistically stationary solutions and bimodal distribution of the large scale magnetic field. We observe a non trivial amplification of stochastic resonance induced by turbulent fluctuations, i.e. the amplitude of the external periodic perturbation needed for stochastic resonance to occur is much smaller than the one estimated by the equilibrium probability distribution of the unperturbed system. We argue that similar amplifications can be observed in many physical systems where turbulent fluctuations are needed to maintain large scale equilibria.

Roberto Benzi; Jean-Francois Pinton

2011-04-22

29

Spatiotemporal stochastic resonance and its consequences in neural model systems  

Microsoft Academic Search

The realization of spatiotemporal stochastic resonance is studied in a two-dimensional FitzHugh–Nagumo system, and in a one-dimensional system of integrate-and-fire neurons. We show that spatiotemporal stochastic resonance occurs in these neural model systems, independent of the method of modeling. Moreover, the ways of realization are analogous in the two model systems. The biological implications and open questions are discussed.

Ga´bor Bala´zsi; La´szlo´ B. Kish; Frank E. Moss

2001-01-01

30

Stochastic resonance in human vision and audition  

NASA Astrophysics Data System (ADS)

Stochastic resonance (SR) has been demonstrated in numerous dynamical systems, both model and real, including peripheral sensory neurons and whole animal behavior. We present the first direct evidence that SR is demonstrable also, at a level relevant to behavior in the natural environment, in human visual and auditory signal detection. Human subjects detected either square or sine wave gratings presented mixed with different amounts of pixel noise in the dark on a high-resolution computer monitor, or 3 Hz beats in a 70-Hz base tone, again mixed with different amounts of auditory noise and presented in a sound attenuation chamber while wearing industrial-quality sound-attenuating headphones. In both cases an unbiased index of performance was maximal for intermediate amounts of added noise, indicating that SR enhanced detection of subthreshold signals in both modalities. We present simple and approximate theories of performance in these experiments based on a nondynamical, or threshold, version of SR. We also discuss the possibility that SR is a general property of biological information processing that has been utilized by evolutionary processes.

Ward, Lawrence M.; Desai, Simren; Rootman, Daniel; Tata, Matthew; Moss, Frank

2001-03-01

31

Optimal quantization and suprathreshold stochastic resonance  

NASA Astrophysics Data System (ADS)

It is shown that Suprathreshold Stochastic Resonance (SSR) is effectively a way of using noise to perform quantization or lossy signal compression with a population of identical threshold-based devices. Quantization of an analog signal is a fundamental requirement for its efficient storage or compression in a digital system. This process will always result in a loss of quality, known as distortion, in a reproduction of the original signal. The distortion can be decreased by increasing the number of states available for encoding the signal (measured by the rate, or mutual information). Hence, designing a quantizer requires a tradeoff between distortion and rate. Quantization theory has recently been applied to the analysis of neural coding and here we examine the possibility that SSR is a possible mechanism used by populations of sensory neurons to quantize signals. In particular, we analyze the rate-distortion performance of SSR for a range of input SNR's and show that both the optimal distortion and optimal rate occurs for an input SNR of about 0 dB, which is a biologically plausible situation. Furthermore, we relax the constraint that all thresholds are identical, and find the optimal threshold values for a range of input SNRs. We find that for sufficiently small input SNRs, the optimal quantizer is one in which all thresholds are identical, that is, the SSR situation is optimal in this case.

McDonnell, Mark D.; Stocks, Nigel G.; Pearce, Charles E. M.; Abbott, Derek

2005-05-01

32

Use of behavioural stochastic resonance by paddle fish for feeding  

NASA Astrophysics Data System (ADS)

Stochastic resonance is the phenomenon whereby the addition of an optimal level of noise to a weak information-carrying input to certain nonlinear systems can enhance the information content at their outputs. Computer analysis of spike trains has been needed to reveal stochastic resonance in the responses of sensory receptors except for one study on human psychophysics. But is an animal aware of, and can it make use of, the enhanced sensory information from stochastic resonance? Here, we show that stochastic resonance enhances the normal feeding behaviour of paddlefish (Polyodon spathula), which use passive electroreceptors to detect electrical signals from planktonic prey. We demonstrate significant broadening of the spatial range for the detection of plankton when a noisy electric field of optimal amplitude is applied in the water. We also show that swarms of Daphnia plankton are a natural source of electrical noise. Our demonstration of stochastic resonance at the level of a vital animal behaviour, feeding, which has probably evolved for functional success, provides evidence that stochastic resonance in sensory nervous systems is an evolutionary adaptation.

Russell, David F.; Wilkens, Lon A.; Moss, Frank

1999-11-01

33

Use of behavioural stochastic resonance by paddle fish for feeding.  

PubMed

Stochastic resonance is the phenomenon whereby the addition of an optimal level of noise to a weak information-carrying input to certain nonlinear systems can enhance the information content at their outputs. Computer analysis of spike trains has been needed to reveal stochastic resonance in the responses of sensory receptors except for one study on human psychophysics. But is an animal aware of, and can it make use of, the enhanced sensory information from stochastic resonance? Here, we show that stochastic resonance enhances the normal feeding behaviour of paddlefish (Polyodon spathula), which use passive electroreceptors to detect electrical signals from planktonic prey. We demonstrate significant broadening of the spatial range for the detection of plankton when a noisy electric field of optimal amplitude is applied in the water. We also show that swarms of Daphnia plankton are a natural source of electrical noise. Our demonstration of stochastic resonance at the level of a vital animal behaviour, feeding, which has probably evolved for functional success, provides evidence that stochastic resonance in sensory nervous systems is an evolutionary adaptation. PMID:10580499

Russell, D F; Wilkens, L A; Moss, F

1999-11-18

34

1International Journal of Bifurcation and Chaos 6 (1996) 2069{2076. STOCHASTIC RESONANCE  

E-print Network

1International Journal of Bifurcation and Chaos 6 (1996) 2069{2076. STOCHASTIC RESONANCE resonance is studied. First, an exact model is presented which describes stochastic resonance white noise. Second, a simulation demonstrates a novel possibility of stochastic resonance in the neuron

Chapeau-Blondeau, François

35

Quantum Forbidden-Interval Theorems for Stochastic Resonance  

E-print Network

We extend the classical forbidden-interval theorems for a stochastic-resonance noise benefit in a nonlinear system to a quantum-optical communication model and a continuous-variable quantum key distribution model. Each quantum forbidden-interval theorem gives a necessary and sufficient condition that determines whether stochastic resonance occurs in quantum communication of classical messages. The quantum theorems apply to any quantum noise source that has finite variance or that comes from the family of infinite-variance alpha-stable probability densities. Simulations show the noise benefits for the basic quantum communication model and the continuous-variable quantum key distribution model.

Mark M. Wilde; Bart Kosko

2008-01-21

36

Stochastic resonance in a linear system: An exact solution.  

PubMed

Multistable systems can exhibit stochastic resonance which is characterized by the amplification of small periodic signals by additive noise. Here we consider a nonmultistable linear system with a multiplicative noise forced by an external periodic signal. The noise is the sum of a colored noise of mean value zero and a noise with a definite sign. We show that the system exhibits stochastic resonance through the numerical study of an exact analytical expression for the mean value obtained by functional integral techniques. This is proof of the effect for a very general kind of noise which can even have a definite sign. PMID:17025489

Calisto, Héctor; Mora, Fernando; Tirapegui, Enrique

2006-08-01

37

Stochastic Resonance Modulates Neural Synchronization within and between Cortical Sources  

Microsoft Academic Search

Neural synchronization is a mechanism whereby functionally specific brain regions establish transient networks for perception, cognition, and action. Direct addition of weak noise (fast random fluctuations) to various neural systems enhances synchronization through the mechanism of stochastic resonance (SR). Moreover, SR also occurs in human perception, cognition, and action. Perception, cognition, and action are closely correlated with, and may depend

Lawrence M. Ward; Shannon E. Maclean; Aaron Kirschner; Pedro Antonio Valdes-Sosa

2010-01-01

38

Stochastic resonance: non-robust and robust tuning notions  

E-print Network

energy balance models designed for a qualitative explanation of global glacial cycles. Large de- viations and warm ages. It was no surprise that the phenomenon of stochastic resonance appearing in numer- ous systems by Ganopolski and Rahmstorf [14]. In the analysis of the Greenland ice core record

39

High Frequency Stochastic Resonance in Periodically Driven Systems  

E-print Network

High frequency stochastic resonance (SR) phenomena, associated with fluctuational transitions between coexisting periodic attractors, have been investigated experimentally in an electronic model of a single-well Duffing oscillator bistable in a nearly resonant field of frequency $\\omega_F$. It is shown that, with increasing noise intensity, the signal/noise ratio (SNR) for a signal due to a weak trial force of frequency $\\Omega \\sim \\omega_F$ at first decreases, then {\\it increases}, and finally decreases again at higher noise intensities: behaviour similar to that observed previously for conventional (low frequency) SR in systems with static bistable potentials. The stochastic enhancement of the SNR of an additional signal at the mirror-reflected frequency $\\vert \\Omega - 2 \\omega_F \\vert$ is also observed, in accordance with theoretical predictions. Relationships with phenomena in nonlinear optics are discussed.

M. I. Dykman; D. G. Luchinsky; R. Mannella; P. V. E. McClintock; S. M. Soskin; N. D. Stein; N. G. Stocks

1993-08-09

40

Stochastic resonance in a biological motor under complex fluctuations  

NASA Astrophysics Data System (ADS)

The dynamics division approach proposed in this work enables us to handle dynamical equations with complex fluctuations. A Brownian motor with cyclic conformational changes is analyzed to understand effects of noise on its signal transduction, and on condition in which stochastic resonance may take place. The result reproduces several features of the experimental data on the electric activation of ion pumping by Na, K-ATPase.

Chang, Cheng-Hung; Tsong, Tian Yow

2004-02-01

41

Stochastic resonance in feedforward acupuncture networks  

NASA Astrophysics Data System (ADS)

Effects of noises and some other network properties on the weak signal propagation are studied systematically in feedforward acupuncture networks (FFN) based on FitzHugh-Nagumo neuron model. It is found that noises with medium intensity can enhance signal propagation and this effect can be further increased by the feedforward network structure. Resonant properties in the noisy network can also be altered by several network parameters, such as heterogeneity, synapse features, and feedback connections. These results may also provide a novel potential explanation for the propagation of acupuncture signal.

Qin, Ying-Mei; Wang, Jiang; Men, Cong; Deng, Bin; Wei, Xi-Le; Yu, Hai-Tao; Chan, Wai-Lok

2014-10-01

42

Thermal enhancement and stochastic resonance of polaron ratchets.  

PubMed

We study the ratchet drift of large polarons (solitons) in molecular diatomic chains induced by unbiased time periodic electric fields at nonzero temperature below its critical value. We show that, at a nonzero temperature, the critical value of the intensity of the electric field above which the ratchet phenomenon takes place is lower than at zero temperature for the same frequency of the field. We show that there is a range of temperatures for which the polaron drift is larger than that at zero temperature. We also show that temperature decreases the value of the lowest critical period of the field. And, finally, we demonstrate that there is a stochastic resonance in a polaron ratchet, namely that there is an optimal temperature at which the polaron drift is a maximum. The values of the stochastic resonance temperature, the lowest critical values of the field intensity, and its period depend on various parameters of the system and, in particular, on the anisotropy of the chain parameters. This temperature induced decrease of the critical value of the field intensity and its period, as well as the stochastic resonance itself, may be important for practical applications of the ratchet phenomenon in systems involving conducting polymers and other low-dimensional materials. They may also be important in some biological macromolecules where the ratchet phenomenon could take place in biomotors and energy and/or charge transport. PMID:25019849

Brizhik, L S; Eremko, A A; Piette, B M A G; Zakrzewski, W J

2014-06-01

43

Neural mechanism for binaural pitch perception via ghost stochastic resonance.  

PubMed

We present a physiologically plausible binaural mechanism for the perception of the pitch of complex sounds via ghost stochastic resonance. In this scheme, two neurons are driven by noise and a different periodic signal each (with frequencies f(1)=kf(0) and f(2)=(k+1)f(0), where k>1), and their outputs (plus noise) are applied synaptically to a third neuron. Our numerical results, using the Morris-Lecar neuron model with chemical synapses explicitly considered, show that intermediate noise levels enhance the response of the third neuron at frequencies close to f(0), as in the cases previously described of ghost resonance. For the case of an inharmonic combination of inputs (f(1)=kf(0)+Deltaf and f(2)=(k+1)f(0)+Deltaf) noise is also seen to enhance the rates of most probable spiking for the third neuron at a frequency f(r)=f(0)+[Deltaf(k+12)]. In addition, we show that similar resonances can be observed as a function of the synaptic time constant. The suggested ghost-resonance-based stochastic mechanism can thus arise either at the peripheral level or at a higher level of neural processing in the perception of pitch. PMID:16035898

Balenzuela, Pablo; García-Ojalvo, Jordi

2005-06-01

44

Noise color and asymmetry in stochastic resonance with silicon nanomechanical resonators  

NASA Astrophysics Data System (ADS)

Stochastic resonance with white noise has been well established as a potential signal amplification mechanism in nanomechanical two-state systems. While white noise represents the archetypal stimulus for stochastic resonance, typical operating environments for nanomechanical devices often contain different classes of noise, particularly colored noise with a 1/f spectrum. As a result, improved understanding of the effects of noise color will be helpful in maximizing device performance. Here we report measurements of stochastic resonance in a silicon nanomechanical resonator using 1/f noise and Ornstein-Uhlenbeck noise types. Power spectral densities and residence time distributions provide insight into asymmetry of the bistable amplitude states, and the data sets suggest that 1/f? noise spectra with increasing noise color (i.e. ?) may lead to increasing asymmetry in the system, reducing the achievable amplification. Furthermore, we explore the effects of correlation time ? on stochastic resonance with the use of exponentially correlated noise. We find monotonic suppression of the spectral amplification as the correlation time increases.

Dunn, T.; Guerra, D. N.; Mohanty, P.

2009-05-01

45

PHYSICAL REVIEW A 84, 062113 (2011) Stochastic resonance of quantum discord  

E-print Network

PHYSICAL REVIEW A 84, 062113 (2011) Stochastic resonance of quantum discord Chee Kong Lee,1,* Leong Chuan Kwek,1,2 and Jianshu Cao3 1 Centre for Quantum Technologies, National University of Singapore the stochastic resonance of quantum discord ("discord resonance") in coupled quantum systems and make

Cao, Jianshu

46

Stochastic resonance in an over-damped linear oscillator  

NASA Astrophysics Data System (ADS)

For an over-damped linear system subjected to both parametric excitation of colored noise and external excitation of periodically modulated noise, and in the case that the cross-correlation intensity between noises is a time-periodic function, we study the stochastic resonance (SR) in this paper. Using the Shapiro—Loginov formula, we acquire the exact expressions of the first-order and the second-order moments. By the stochastic averaging method, we obtain the analytical expression of the output signal-to-noise ratio (SNR). Meanwhile, we discuss the evolutions of the SNR with the signal frequency, noise intensity, correlation rate of noise, time period, and modulation frequency. We find a new bona fide SR. The evolution of the SNR with the signal frequency presents periodic oscillation, which is not observed in a conventional linear system. We obtain the conventional SR of the SNR with the noise intensity and the correlation rate of noise. We also obtain the SR in a wide sense, in which the evolution of the SNR with time period modulation frequency presents periodic oscillation. We find that the time-periodic modulation of the cross-correlation intensity between noises diversifies the stochastic resonance phenomena and makes this system possess richer dynamic behaviors.

Lin, Li-Feng; Tian, Yan; Ma, Hong

2014-08-01

47

Study of stochastic resonance in a quantum dot network  

NASA Astrophysics Data System (ADS)

This paper reports a study of stochastic resonance in a huge quantum dot network for single-electron (SE) circuits. Such circuits, which are controlled by the Coulomb blockade, are one type of next-generation information-processing device. However, they are very sensitive to noises such as thermal noise and device mismatch noise. Thus, we introduce the stochastic resonance phenomenon into the circuit to improve its noise tolerance. Stochastic resonance is a phenomenon that was discovered in the brains of living things in noisy environments and was modeled for neural networks. When the phenomenon occurs, its harnessing of noise energy makes weak signals become clear. In current research, SE devices that operate with stochastic resonance have been reported. However, signals were attenuated in particularly noisy environments. In contrast, it was reported that a huge molecular network amplified weak signals by harnessing noise energy. The report said the current-voltage characteristics of the molecular network described the Coulomb blockade under a noisy environment. Thus, a huge quantum dot network that is partly similar to a molecular network is expected to amplify the weak signal harnessing noise, when the current-voltage characteristics of the network show the Coulomb blockade. To confirm this, in this study we use the Monte Carlo method to simulate the noisy-environment operation of a quantum dot network comprising quantum dots and tunneling junctions. We observe the current-voltage characteristics of the network, when changing the network size (5×5, 10×10, and 100×100) and the noise intensity (0 K, 2 K, 5 K, and 10 K for operating temperature, and 0%, 5%, 10%, and 30% for device mismatch). As a result, we are able to observe the Coulomb blockade under the appropriate noise strength, which in this study is 5 K or less with thermal noise, and 30% with device mismatch. From the results, we conclude the network operates correctly under appropriate noise strength. Moreover, the noise energy amplifies the network current, indicating that SE circuits can function as signal-amplifying devices.

Fujino, Hiroki; Oya, Takahide

2012-10-01

48

Planetary gearbox fault diagnosis using an adaptive stochastic resonance method  

NASA Astrophysics Data System (ADS)

Planetary gearboxes are widely used in aerospace, automotive and heavy industry applications due to their large transmission ratio, strong load-bearing capacity and high transmission efficiency. The tough operation conditions of heavy duty and intensive impact load may cause gear tooth damage such as fatigue crack and teeth missed etc. The challenging issues in fault diagnosis of planetary gearboxes include selection of sensitive measurement locations, investigation of vibration transmission paths and weak feature extraction. One of them is how to effectively discover the weak characteristics from noisy signals of faulty components in planetary gearboxes. To address the issue in fault diagnosis of planetary gearboxes, an adaptive stochastic resonance (ASR) method is proposed in this paper. The ASR method utilizes the optimization ability of ant colony algorithms and adaptively realizes the optimal stochastic resonance system matching input signals. Using the ASR method, the noise may be weakened and weak characteristics highlighted, and therefore the faults can be diagnosed accurately. A planetary gearbox test rig is established and experiments with sun gear faults including a chipped tooth and a missing tooth are conducted. And the vibration signals are collected under the loaded condition and various motor speeds. The proposed method is used to process the collected signals and the results of feature extraction and fault diagnosis demonstrate its effectiveness.

Lei, Yaguo; Han, Dong; Lin, Jing; He, Zhengjia

2013-07-01

49

Pulsar State Switching from Markov Transitions and Stochastic Resonance  

NASA Astrophysics Data System (ADS)

Markov processes are shown to be consistent with metastable states seen in pulsar phenomena, including intensity nulling, pulse-shape mode changes, subpulse drift rates, spin-down rates, and X-ray emission, based on the typically broad and monotonic distributions of state lifetimes. Markovianity implies a nonlinear magnetospheric system in which state changes occur stochastically, corresponding to transitions between local minima in an effective potential. State durations (though not transition times) are thus largely decoupled from the characteristic timescales of various magnetospheric processes. Dyadic states are common but some objects show at least four states with some transitions forbidden. Another case is the long-term intermittent pulsar B1931+24 that has binary radio-emission and torque states with wide, but non-monotonic duration distributions. It also shows a quasi-period of 38 ± 5 days in a 13 yr time sequence, suggesting stochastic resonance in a Markov system with a forcing function that could be strictly periodic or quasi-periodic. Nonlinear phenomena are associated with time-dependent activity in the acceleration region near each magnetic polar cap. The polar-cap diode is altered by feedback from the outer magnetosphere and by return currents from the equatorial region outside the light cylinder that may also cause the neutron star to episodically charge and discharge. Orbital perturbations of a disk or current sheet provide a natural periodicity for the forcing function in the stochastic-resonance interpretation of B1931+24. Disk dynamics may introduce additional timescales in observed phenomena. Future work can test the Markov interpretation, identify which pulsar types have a propensity for state changes, and clarify the role of selection effects.

Cordes, J. M.

2013-09-01

50

PULSAR STATE SWITCHING FROM MARKOV TRANSITIONS AND STOCHASTIC RESONANCE  

SciTech Connect

Markov processes are shown to be consistent with metastable states seen in pulsar phenomena, including intensity nulling, pulse-shape mode changes, subpulse drift rates, spin-down rates, and X-ray emission, based on the typically broad and monotonic distributions of state lifetimes. Markovianity implies a nonlinear magnetospheric system in which state changes occur stochastically, corresponding to transitions between local minima in an effective potential. State durations (though not transition times) are thus largely decoupled from the characteristic timescales of various magnetospheric processes. Dyadic states are common but some objects show at least four states with some transitions forbidden. Another case is the long-term intermittent pulsar B1931+24 that has binary radio-emission and torque states with wide, but non-monotonic duration distributions. It also shows a quasi-period of 38 ± 5 days in a 13 yr time sequence, suggesting stochastic resonance in a Markov system with a forcing function that could be strictly periodic or quasi-periodic. Nonlinear phenomena are associated with time-dependent activity in the acceleration region near each magnetic polar cap. The polar-cap diode is altered by feedback from the outer magnetosphere and by return currents from the equatorial region outside the light cylinder that may also cause the neutron star to episodically charge and discharge. Orbital perturbations of a disk or current sheet provide a natural periodicity for the forcing function in the stochastic-resonance interpretation of B1931+24. Disk dynamics may introduce additional timescales in observed phenomena. Future work can test the Markov interpretation, identify which pulsar types have a propensity for state changes, and clarify the role of selection effects.

Cordes, J. M., E-mail: cordes@astro.cornell.edu [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States)

2013-09-20

51

Barrier fluctuations and stochastic resonance in membrane transport  

NASA Astrophysics Data System (ADS)

The role of barrier fluctuations in membrane enzymatic processes, in particular in the active transport of ions through cell membranes, is examined. For enzymes embedded in the cell membrane the role of the barrier height (activation energy) is played by the membrane electric potential. This barrier height can be modulated either by internal fluctuations or by external electrical fields, either random or periodic. Existing experimental data on active transport of Na+ and Rb+ in human erythrocytes (catalyzed by Na+-K+-ATPase) can be interpreted as evidence of stochastic resonance between the external ac field and the fluctuations of the membrane potential. The obtained results suggest that the significant part of these fluctuations is supplied by the stimulated action of neighbor voltage-gated ionic channels. This supports the idea that intrinsic noise plays a constructive role in one of most important and most frequent biophysical processs, viz. ion transmission through cell membranes. Means of further experimental verification of this conjecture are proposed.

Fuli?ski, A.

1998-09-01

52

Comparison of stochastic resonance in static and dynamical nonlinearities  

NASA Astrophysics Data System (ADS)

We compare the stochastic resonance (SR) effects in parallel arrays of static and dynamical nonlinearities via the measure of output signal-to-noise ratio (SNR). For a received noisy periodic signal, parallel arrays of both static and dynamical nonlinearities can enhance the output SNR by optimizing the internal noise level. The static nonlinearity is easily implementable, while the dynamical nonlinearity has more parameters to be tuned, at the risk of not exploiting the beneficial role of internal noise components. It is of interest to note that, for an input signal buried in the external Laplacian noise, we show that the dynamical nonlinearity is superior to the static nonlinearity in obtaining a better output SNR. This characteristic is assumed to be closely associated with the kurtosis of noise distribution.

Ma, Yumei; Duan, Fabing

2014-07-01

53

Stochastic resonance for information flows on hierarchical networks  

NASA Astrophysics Data System (ADS)

A simple model of information flows represented by package delivery on networks with hierarchical structures is considered. The packages should be transferred from one network node to another and the delivery process is influenced by two types of noise. The first type of noise is related to a partially false knowledge of network topology (topological noise), i.e. membership of nodes in communities in a shipping algorithm include a number of errors corresponding to a random rewiring of a fraction of network links. The second type of noise (dynamical noise) is related to a diffusive part in packet dynamics, i.e. package paths do not follow from completely deterministic rules. In the case of a pure topological noise and in the case of combination of both types of noises, we observe a resonance-like phenomenon for communication efficiency. The system performance measured as a fraction of packages that are delivered in a certain time period or as an inverse of time of a package delivery is maximal for intermediate levels of noise. This effect resembles the phenomenon of stochastic resonance that exists in many complex systems where a noise can enhance the information transfer.

Czaplicka, Agnieszka; Ho?yst, Janusz A.; Sloot, Peter M. A.

2013-09-01

54

Temperature-driven coherence resonance and stochastic resonance in a thermochemical system  

NASA Astrophysics Data System (ADS)

We perform the stochastic analysis of a thermochemical system using a master equation which describes a chemical reaction and includes discrete and continuous temperature jumps. We study the time evolution of the system selecting the temperature of the thermostat as an easily tunable control parameter. Depending on the thermostat temperature, the system can be in an excitable, oscillatory, or stationary regime. Stochastic time series for the system temperature are generated and the distributions of interspike intervals are analyzed in the three dynamical regimes separated by a homoclinic bifurcation and a Hopf bifurcation. Different constructive roles of internal fluctuations are exhibited. A noise-induced transition is observed in the vicinity of the Hopf bifurcation. Coherence resonance and stochastic resonance are found in the oscillatory regime. In a range of thermostat temperatures, a nontrivial behavior of the highly nonlinear system is revealed by the existence of both a minimum and a maximum in the scaled standard deviation of interspike intervals as a function of particle number. This high sensitivity to system size illustrates that controlling dynamics in nanoreactors may remain a difficult task.

Lemarchand, A.; Gorecki, J.; Gorecki, A.; Nowakowski, B.

2014-02-01

55

Stochastic resonance in a discrete neuron with time delay and two different modulation signals  

NASA Astrophysics Data System (ADS)

Stochastic resonance in an excitable neuron based on the Rulkov map with noise, delay feedback, low-frequency signal and high-frequency signal is investigated numerically. The results show that there exist an optimal noise intensity, optimal time delay and optimal amplitude of the high-frequency signal at which the phase synchronisation between the low-frequency input signal and the output signal is the best. The Fourier coefficient is calculated to measure the stochastic resonance. It is found that the existence of a maximum in the Q-\\tau , Q-B and Q-D plots is the identifying characteristic of the stochastic resonance phenomenon.

Wang, Can Jun; Li Yang, Ke; Xian Qu, Shi

2014-10-01

56

Stochastic resonance induced by Lévy noise in a tumor growth model with periodic treatment  

NASA Astrophysics Data System (ADS)

In this paper, the stochastic resonance phenomenon in a tumor growth model under subthreshold periodic therapy and Lévy noise excitation is investigated. The possible reoccurrence of tumor due to stochastic resonance is discussed. The signal-to-noise ratio (SNR) is calculated numerically to measure the stochastic resonance. It is found that smaller stability index is better for avoiding tumor reappearance. Besides, the effect of the skewness parameter on the tumor regrowth is related to the stability index. Furthermore, increasing the intensity of periodic treatment does not always facilitate tumor therapy. These results are beneficial to the optimization of periodic tumor therapy.

Xu, Wei; Hao, Mengli; Gu, Xudong; Yang, Guidong

2014-05-01

57

Stochastic resonance as a filter for signal detection from multisignal inputs  

E-print Network

We undertake a detailed numerical study of the phenomenon of stochastic resonance with multisignal inputs. A bistable cubic map is used as the model and we show that it combines the features of a bistable system and a threshold system. A study of stochastic resonance in these two setups reveal some fundamental differences between the two mechanisms with respect to amplification of a composite input signal. As a practically relevant result, we show that the phenomenon of stochastic resonance can be used as a filter for the detection/transmission of the component frequencies in a composite signal.

K P Harikrishnan; G Ambika

2006-06-01

58

Stochastic resonance in temporal processing by cochlear implant listeners?  

NASA Astrophysics Data System (ADS)

Cochlear implants (CI) provide speech information to the hearing-impaired by transmitting temporal information from specific frequency bands to corresponding regions of the tonotopically organized auditory system via electrical stimulation. We are interested in the role of applied noise in temporal coding by CI listeners. We measured sensitivity to sinusoidal amplitude modulation in adult users of the Nucleus-22 cochlear implant. The carrier was a train of current pulses presented at various amplitudes within the subject's dynamic range, driving a single electrode pair in the middle of the implanted electrode array. Consistent with previous findings, modulation sensitivity in CI listeners was positively related to carrier level. Introducing uniformly distributed, pseudorandom noise into the carrier envelope produced level-dependent effects. At high levels, modulation sensitivity decreased with increasing noise. At less sensitive low carrier levels, modulation sensitivity showed a stochastic resonance (SR) signature with increasing noise, displaying maximum sensitivity at an optimal noise level. This finding was also consistent with previous work. In a new experiment, we tested two new ways of degrading modulation sensitivity without changing carrier level: (1) by increasing modulation frequency and (2) by introducing a concurrent, fluctuating masker on another channel. Under each of these two conditions, our results show that increasing noise in the signal carrier envelope improved sensitivity in a manner consistent with SR. These results suggest that conditions that weaken modulation sensitivity strengthen the potential for SR. We speculate that the effect arises at a relatively central stage of temporal processing in the auditory system.

Chatterjee, Monita; Robert, Mark E.

2003-05-01

59

Stochastic Resonance in crayfish hydrodynamic receptors stimulated with external noise  

NASA Astrophysics Data System (ADS)

Stochastic Resonance (SR) is a statistical process occurring only in nonlinear dynamical systems whereby a subthreshold coherent stimulus or signal can be enhanced by noise. The signal alone is too weak to cause a state change of the system. State changes are the carriers of information through the system. In the presence of random noise, however, the system can change state, more-or-less randomly, but with some degree of coherence with the signal. A measure of this coherence at the output shows a maximum at an optimal value of the noise intensity as the signature of SR. SR is the object of recent and continued experimental and theoretical research in statistical physics. While SR has been demonstrated in a variety of physical systems, it has not yet been discovered in any naturally occurring system. This paper was stimulated by the idea that the sensory nervous system might be an appropriate setting for a search for naturally occurring SR. The detection of weak stimuli, often in the presence of noise, is, after all, the first business of the sensory system. Moreover, the system is evolved, which admits the possibility that the process of natural selection might have resulted in an optimization with respect to the (inevitable) noise. This paper describes an experiment designed to observe SR in the mechanoreceptor cells of the crayfish Procambarus clarkii, shown on the left in Fig. 1, using external noise plus a weak coherent signal as the stimulus.

Douglass, J. K.; Wilkens, L. A.; Pantazelou, E.; Moss, F.

1993-08-01

60

The Ghost of Stochastic Resonance: An Introductory Review  

E-print Network

Nonlinear systems driven by noise and periodic forces with more than one frequency exhibit the phenomenon of Ghost Stochastic Resonance (GSR) found in a wide and disparate variety of fields ranging from biology to geophysics. The common novel feature is the emergence of a "ghost" frequency in the system's output which it is absent in the input. As reviewed here, the uncovering of this phenomenon helped to understand a range of problems, from the perception of pitch in complex sounds or visual stimuli, to the explanation of climate cycles. Recent theoretical efforts show that a simple mechanism with two ingredients are at work in all these observations. The first one is the linear interference between the periodic inputs and the second a nonlinear detection of the largest constructive interferences, involving a noisy threshold. These notes are dedicated to review the main aspects of this phenomenon, as well as its different manifestations described on a bewildering variety of systems ranging from neurons, semiconductor lasers, electronic circuits to models of glacial climate cycles.

Pablo Balenzuela; Holger Braun; Dante R. Chialvo

2011-10-01

61

Topologically determined optimal stochastic resonance responses of spatially embedded networks  

NASA Astrophysics Data System (ADS)

We have analyzed the stochastic resonance phenomenon on spatial networks of bistable and excitable oscillators, which are connected according to their location and the amplitude of external forcing. By smoothly altering the network topology from a scale-free (SF) network with dominating long-range connections to a network where principally only adjacent oscillators are connected, we reveal that besides an optimal noise intensity, there is also a most favorable interaction topology at which the best correlation between the response of the network and the imposed weak external forcing is achieved. For various distributions of the amplitudes of external forcing, the optimal topology is always found in the intermediate regime between the highly heterogeneous SF network and the strong geometric regime. Our findings thus indicate that a suitable number of hubs and with that an optimal ratio between short- and long-range connections is necessary in order to obtain the best global response of a spatial network. Furthermore, we link the existence of the optimal interaction topology to a critical point indicating the transition from a long-range interactions-dominated network to a more lattice-like network structure.

Gosak, Marko; Korošak, Dean; Marhl, Marko

2011-01-01

62

Logical stochastic resonance in bistable system under ?-stable noise  

NASA Astrophysics Data System (ADS)

In the presence of ?-stable noise, the logical stochastic resonance (LSR) phenomenon in a class of double well nonlinear system is investigated in this paper. LSR effect is obtained under ?-stable noise. The probability of getting correct logic outputs is used to evaluate LSR behavior. Four main results are presented. Firstly, in the optimal band of noise intensity, Gaussian white noise is considered a better choice than heavy tailed noise to obtain clean logic operation. But at weak noise background, the success probability of getting the right logic outputs is higher when the system is subjected to heavy tailed noise. Secondly, it is shown that over the entire range of noise variance, the asymmetric noise induced LSR performs better than that induced by the symmetric noise. Furthermore, we find which side the tail skews also affects the correct probability of LSR. At last, the fractional Fokker-Planck equation is presented to show when the characteristic exponent of ?-stable noise is less than 1, LSR behavior will not be obtained irrespective of the setting for other parameters.

Wang, Nan; Song, Aiguo

2014-05-01

63

Application of stochastic resonance in gravitational-wave interferometer  

E-print Network

We investigate novel approach, which improves the sensitivity of gravitational wave (GW) interferometer due to stochastic resonance (SR) phenomenon, performing in additional nonlinear cavity (NC). The NC is installed in the output of interferometer before photodetector, so that optical signal emerging interferometer incidents on the NC and passes through it. Under appropriate circumstances a specific transformation of noisy signal inside the NC takes place, which results in the increase of output signal-to-noise ratio (SNR). As a result optical noisy signal of interferometer becomes less noisy after passing through the NC. The improvement of SNR is especially effective in bistable NC for wideband (several hundreds Hz) detection, when chirp GW signal is detected. Then SNR gain reaches amount ~ 10. When detection bandwidth is narrowed, the influence of SR mechanism gradually disappears, and SNR gain tends to 1. SNR gain also tends to 1 when the NC is gradually transformed to linear cavity. Proposed enhancement of SNR due to the SR is not dependent of noise type, which is prevalent in interferometer. Particularly proposed approach is capable to increase signal-to-displacement noise ratio.

G. G. Karapetyan

2006-01-30

64

Anti-coherence and coherence resonance induced by nonlinear time delay in autonomous stochastic system  

NASA Astrophysics Data System (ADS)

An autonomous stochastic system with nonlinear time-delayed feedback is investigated employing the stochastic simulation method. In the autonomous stochastic system with quadratic time-delayed feedback or under positive feedback, the nonlinear delay time fails to possess the role improving the noisy state of the system. In the autonomous stochastic system with cubic time-delayed feedback and under negative feedback, the nonlinear delay time can improve the noisy state, tuning the signal output, and generating incoherence and coherence maximization. We reveal a new kind of anti-coherence and coherence resonance phenomena induced by the nonlinear time delay in the autonomous stochastic system without external periodic force, discussing further the effects of the noise strength, the control parameter, and the feedback strength on anti-coherence and coherence resonance.

Zhu, Ping; Mei, Dong Cheng

2014-05-01

65

Stochastic resonance on a global atmospheric circulation model  

NASA Astrophysics Data System (ADS)

Seeking for alternative sources of the observed climatic variability, and in the spirit of both classic (Nicolis, 1982; Benzi et al., 1982) and recent work (Ganopolski and Rahmstorg, 2002; Vélez-Belch&{acute;i} et al., 2001), we have added a space-independent, Gaussian and uncorrelated stochastic perturbation with amplitude eta, to the temperature equation of a simplified atmospheric global circulation model, the so-called PUMA (Portable University Model of the Atmosphere) (Frisius et al., 1998; Pérez-Muñuzuri et al., 2003). In the latter model, diabatic processes are parameterized by a Newtonian cooling term with typical timescale ?_c, whose reference temperature profile T_R(?,?,?;t) (representing the ``equilibrium'' profile induced by solar heating) is given by T_R=overline{T}_R(?,?,?)+ hat{T}_R \\cos[(2pi/Tac)t+Pac]. We show that the time averages of several forecasting magnitudes (like temperature and horizontal vorticity) at a point on the 300 hPa surface, undergo a non-monotonic behavior with regard to eta. Moreover, the normalized variance R=sqrt{-^2}/ of the interval t_p between the passage at the point of cyclonic and anticyclonic circulation regions exhibits an ``anticoherence resonance'' effect, thus maximizing climatic variability for some intermediate value of eta. A theoretical explanation is advanced in terms of activated processes with competing time scales. begin{itemize} C. Nicolis, Tellus 34, 1 (1982); Benzi et al., Tellus 34, 10 (1982). A. Ganopolski and S. Rahmstorg, Phys. Rev. Lett. 88, 038501 (2002); P. Vélez-Belch&{acute;i} et al., Geophys. Res. Lett. 28, 2053 (2001). T. Frisius, F. Lunkeit, K. Fraedrich and I.N. James. Q.J.R. Meteorol. Soc. 124, 1019 (1998); V. Pérez-Muñuzuri et al. Nonlin. Proc. Geophys. (submitted) (2003).

Perez-Munuzuri, V.; Deza, R.; Fraedrich, K.; Kirk, E.; Lunkeit, F.

2003-04-01

66

Vestibular experiments  

NASA Technical Reports Server (NTRS)

Spacelab experiments designed to investigate space motion sickness, any associated changes in otolith-mediated responses occurring during weightlessness, and the carryover of any such changes to postflight conditions are described. The experiments aimed at assessing otolithic responses in space are intended to clarify presumed alterations in vestibular function during weightlessness. Vestibular function will be investigated at several levels: vestibulo-ocular reflexes, vestibulo-spinal pathways, cortical functions involving perception of motion and spatial orientation, visual vestibular interaction, and motion sickness susceptibility. A second major objective relates to space motion sickness and man's well-being and productivity in space.

Young, L. R.

1981-01-01

67

Stochastic Resonance Improves Broadband Encoding in the Cricket Cercal System.  

NASA Astrophysics Data System (ADS)

In any physical or biological system a certain amount of environmental noise is unavoidable, and the information therein irrelevant to the organism. Traditionally in signal analysis noise is considered detrimental to the process of signal encoding, and merely a necessary evil to be avoided. It has been observed recently, however, that in some nonlinear systems power from random input noise actually improves the output signal-to-noise ratio (SNR) over a limited operating range, particularly near threshold. This effect is known as stochastic resonance (SR). By taking advantage of SR during the neural encoding process, a cell can optimize its information flow properties. Previous experimental work in SR has investigated only the coding of sinusoidal signals embedded in a broadband white noise background. In this work we demonstrate SR for not only the sine wave case, but also for extended bandwidth stimuli in the presence of white noise, and for cases in which the signal and white noise background frequency spectra are completely non-overlapping. We have investigated the effects of noise on information transfer in the cricket cercal system, a mechanosensory system sensitive to small near-field air particle disturbances, by presenting known wind stimuli to the cricket through audio speakers in a controlled environment along with varying levels of uncorrelated white noise background air current. Spike trains from the second layer of neuronal processing, the primary sensory interneurons, were recorded with intracellular electrodes with the signal and noise presented along the cell's preferred direction. Through the statistical techniques of Shannon's information theory we quantified the amount of information contained in the elicited spike trains about the signal in the various noise environments, as well as the SNR and other measures of the encoding process. An enhancement of output SNR was observed over the entire frequency operating range of the neurons, for almost an entire order of magnitude of near-threshold signal amplitudes. Additionally, we found that the amount of information about the signal carried, on average, by each spike was INCREASED for small signals when presented with noise - implying that added input noise can, in certain situations, actually improve the accuracy of the encoding process itself.

Levin, Jacob

1996-03-01

68

Enhanced diffusion in conic channels by means of geometric stochastic resonance.  

PubMed

Geometric stochastic resonance of Brownian particles diffusing across a converging conic channel subject to oscillating forces is studied in this paper. Conic channel geometries have been previously considered as a model for transport of particles in biological membranes, zeolites, and nanostructures. For this system, a broad excess peak of the effective diffusion above the free diffusion limit is exhibited over a wide range of frequencies, suggesting a synchronization effect in the confining geometry as particles respond to the periodic modulation of the external force. This indicates that the geometric stochastic resonance effect with unbiased ac forces can be exploited for improving the transport of particles in complex geometries. PMID:22070287

Vazquez, M V; Valdes-Parada, F J; Dagdug, L; Alvarez-Ramirez, J

2011-11-01

69

Stochastic resonance of a damped oscillator with frequency fluctuation driven by a periodic external force  

NASA Astrophysics Data System (ADS)

Considering a damped linear oscillator model subjected to a white noise with an inherent angular frequency and a periodic external driving force, we derive the analytic expression of the first moment of output response, and study the stochastic resonance phenomenon in a system. The results show that the output response of this system behaves as a simple harmonic vibration, of which the frequency is the same as the external driving frequency, and the variations of amplitude with the driving frequency and the inherent frequency present a bona fide stochastic resonance.

Zhang, Ling-Ying; Jin, Guo-Xiang; Cao, Li; Wang, Zhi-Yun

2012-12-01

70

Stochastic resonance in a model of opinion formation on small-world networks  

NASA Astrophysics Data System (ADS)

We analyze the phenomenon of stochastic resonance in an Ising-like system on a small-world network. The system, which is subject to the combined action of noise and an external modulation, can be interpreted as a stylized model of opinion formation by imitation under the effects of a ``fashion wave''. Both the amplitude threshold for the detection of the external modulation and the width of the stochastic-resonance peak show considerable variation as the randomness of the underlying small-world network is changed.

Kuperman, M.; Zanette, D.

2002-04-01

71

Coherence Resonance-Induced Stochastic Neural Firing at a Saddle-Node Bifurcation  

NASA Astrophysics Data System (ADS)

Coherence resonance at a saddle-node bifurcation point and the corresponding stochastic firing patterns are simulated in a theoretical neuronal model. The characteristics of noise-induced neural firing pattern, such as exponential decay in histogram of interspike interval (ISI) series, independence and stochasticity within ISI series are identified. Firing pattern similar to the simulated results was discovered in biological experiment on a neural pacemaker. The difference between this firing and integer multiple firing generated at a Hopf bifurcation point is also given. The results not only revealed the stochastic dynamics near a saddle-node bifurcation, but also gave practical approaches to identify the saddle-node bifurcation and to distinguish it from the Hopf bifurcation in neuronal system. In addition, many previously observed firing patterns can be attribute to stochastic firing pattern near such a saddle-node bifurcation.

Gu, Huaguang; Zhang, Huimin; Wei, Chunling; Yang, Minghao; Liu, Zhiqiang; Ren, Wei

72

Stochastic resonance in the two-dimensional q-state clock models.  

PubMed

We numerically study stochastic resonance in the two-dimensional q-state clock models from q=2 to 7 under a weak oscillating magnetic field. As in the mean-field case, we observe double resonance peaks, but the detailed response strongly depends on the direction of the field modulation for q?5 where the quasiliquid phase emerges. We explain this behavior in terms of free-energy landscapes on the two-dimensional magnetization plane. PMID:24730819

Park, Hye Jin; Baek, Seung Ki; Kim, Beom Jun

2014-03-01

73

Broadband neural encoding in the cricket cereal sensory system enhanced by stochastic resonance  

NASA Astrophysics Data System (ADS)

SENSORY systems are often required to detect a small amplitude signal embedded in broadband background noise. Traditionally, ambient noise is regarded as detrimental to encoding accuracy. Recently, however, a phenomenon known as stochastic resonance has been described in which, for systems with a nonlinear threshold, increasing the input noise level can actually improve the output signal-to-noise ratio over a limited range of signal and noise strengths. Previous theoretical and experimental studies of stochastic resonance in physical1-7and biological6-10 systems have dealt exclusively with single-frequency sine stimuli embedded in a broadband noise background. In the past year it has been shown in a theoretical and modelling study that stochastic resonance can be observed with broadband signals11,12. Here we demonstrate that broadband stochastic resonance is manifest in the peripheral layers of neural processing in a simple sensory system, and that it plays a role over a wide range of biologically relevant stimulus parameters. Further, we quantify the functional significance of the phenomenon within the context of signal processing, using information theory.

Levin, Jacob E.; Miller, John P.

1996-03-01

74

Universality of residence-time distributions in non-adiabatic stochastic resonance  

E-print Network

Universality of residence-time distributions in non-adiabatic stochastic resonance Nils Berglund 1 forcing as well as white noise. Despite of the amplitude of the forcing being too small to enable description of the phenomenon of SR, many of its aspects are not yet fully understood. Mathematically rigorous

75

Stochastic resonance in the absence and presence of external signals for a chemical reaction  

E-print Network

Stochastic resonance in the absence and presence of external signals for a chemical reaction Lingfa Yang, Zhonghuai Hou, and Houwen Xina) Department of Chemical Physics, University of Science random perturbation. Noise-induced oscillations and noise-induced frequency shifts have been observed

Yang, Lingfa

76

Stochastic resonance and the benefits of noise: from ice ages to crayfish and SQUIDs  

Microsoft Academic Search

Noise in dynamical systems is usually considered a nuisance. But in certain nonlinear systems, including electronic circuits and biological sensory apparatus, the presence of noise can in fact enhance the detection of weak signals. This phenomenon, called stochastic resonance, may find useful application in physical, technological and biomedical contexts.

Kurt Wiesenfeld; Frank Moss

1995-01-01

77

The effects of nonlinear series resonance on Ohmic and stochastic heating in capacitive discharges  

SciTech Connect

The flow of electron and ion conduction currents across a nonlinear capacitive sheath to the electrode surface self-consistently sets the dc bias voltage across the sheath. We incorporate these currents into a model of a homogeneous capacitive sheath in order to determine the enhancement of the Ohmic and stochastic heating due to self-excitation of the nonlinear series resonance in an asymmetric capacitive discharge. At lower pressures, the series resonance can enhance both the Ohmic and stochastic heating by factors of 2-4, with the Ohmic heating tending to zero as the pressure decreases. The model was checked, for a particular set of parameters, by a particle-in-cell (PIC) simulation using the homogeneous sheath approximation, giving good agreement. With a self-consistent Child-law sheath, the PIC simulation showed increased heating, as expected, whether the series resonance is important or not.

Lieberman, M. A.; Lichtenberg, A. J.; Kawamura, E. [Department of Electrical Engineering and Computer Science-1770, University of California, Berkeley, California 94720 (United States); Mussenbrock, Thomas; Brinkmann, Ralf Peter [Lehrstuhl fuer Theoretische Elektrotechnik, Ruhr-Universitaet Bochum, D44801 Bochum (Germany)

2008-06-15

78

Vestibular Hyperacusis  

MedlinePLUS

... the abnormal system is markedly different: for example, the sounds in a quiet library may seem like a loud parade to a person with hyperacusis. Cochlear vs. vestibular hyperacusis With ... ears or leaving the room. Severe emotional reactions may also occur; crying ...

79

A digital accelerometer array utilizing suprathreshold stochastic resonance for detection of sub-Brownian noise floor accelerations.  

SciTech Connect

The goal of this LDRD project was to evaluate the possibilities of utilizing Stochastic resonance in micromechanical sensor systems as a means for increasing signal to noise for physical sensors. A careful study of this field reveals that in the case of a single sensing element, stochastic resonance offers no real advantage. We have, however, identified a system that can utilize very similar concepts to stochastic resonance in order to achieve an arrayed sensor system that could be superior to existing technologies in the field of inertial sensors, and could offer a very low power technique for achieving navigation grade inertial measurement units.

Carr, Dustin Wade; Olsson, Roy H.

2004-12-01

80

A Modified Adaptive Stochastic Resonance for Detecting Faint Signal in Sensors  

PubMed Central

In this paper, an approach is presented to detect faint signals with strong noises in sensors by stochastic resonance (SR). We adopt the power spectrum as the evaluation tool of SR, which can be obtained by the fast Fourier transform (FFT). Furthermore, we introduce the adaptive filtering scheme to realize signal processing automatically. The key of the scheme is how to adjust the barrier height to satisfy the optimal condition of SR in the presence of any input. For the given input signal, we present an operable procedure to execute the adjustment scheme. An example utilizing one audio sensor to detect the fault information from the power supply is given. Simulation results show that the modified stochastic resonance scheme can effectively detect fault signal with strong noise.

Huang, Qi; Liu, Jun; Li, Hengwei

2007-01-01

81

Stochastic Transport Modeling of Resonant Magnetic Perturbations in DIII-D  

SciTech Connect

Three-dimensional two-fluid simulations of heat transport due to resonant magnetic perturbations of tokamaks have been computed by coupling the TRIP3D field line tracing code to the E3D edge transport code. The predicted electron temperature contours follow the new separatrix represented by the perturbed invariant manifold structure of the X-point in qualitative agreement with X-point TV observations. However, preliminary modeling predicts that the resulting stochastic heat transport is greater than that measured in low-collisionality ELM suppression experiments in DIII-D H-mode plasmas. While improved determination of transport coefficients is definitely required, possible explanations include plasma screening of resonant perturbations, invalid treatment of the edge as a fluid, or insufficient understanding of stochastic heat transport.

Joseph, I; Moyer, R A; Evans, T E; Schaffer, M J; Runov, A M; Schneider, R; Kasilov, S V; Groth, M; Fenstermacher, M E

2006-06-01

82

Study of frequency-shifted and re-scaling stochastic resonance and its application to fault diagnosis  

Microsoft Academic Search

When detecting a weak and high-frequency signal submerged in strong noise, the existing large parameter stochastic resonance (LPSR) models need either a high sampling frequency or a large number of sample points. To breach the above limits and raise the usability of LPSR, a novel method named frequency-shifted and re-scaling stochastic resonance (FRSR) is proposed in this paper. By shifting

Jiyong Tan; Xuefeng Chen; Junying Wang; Huaxin Chen; Hongrui Cao; Yanyang Zi; Zhengjia He

2009-01-01

83

Selective effects of noise by stochastic multi-resonance in coupled cells system  

NASA Astrophysics Data System (ADS)

By investigating a stochastic model for intracellular calcium oscillations proposed by Höfer, we have analyzed the transmission behavior of calcium signaling in a one-dimensional two-way coupled hepatocytes system. It is shown that when the first cell is subjected to the external noise, the output signal-to-noise ratio (SNR) in the cell exhibits two maxima as a function of external noise intensity, indicating the occurrence of stochastic bi-resonance (SBR). It is more important that when cells are coupled together, the resonant behavior in the 1st cell propagates along the chain with different features through the coupling effect. The cells whose locations are comparatively close to or far from the 1st cell can show SBR, while the cells located in the middle position can display stochastic multi-resonance (SMR). Furthermore, the number of cells that can show SMR increases with coupling strength enhancing. These results indicate that the cells system may make an effective choice in response to external signaling induced by noise, through the mechanism of SMR by adjusting coupling strength.

Zhang, Jiqian; Liu, Jianqing; Chen, Hanshuang

2008-05-01

84

Far from Equilibrium Percolation, Stochastic and Shape Resonances in the Physics of Life  

PubMed Central

Key physical concepts, relevant for the cross-fertilization between condensed matter physics and the physics of life seen as a collective phenomenon in a system out-of-equilibrium, are discussed. The onset of life can be driven by: (a) the critical fluctuations at the protonic percolation threshold in membrane transport; (b) the stochastic resonance in biological systems, a mechanism that can exploit external and self-generated noise in order to gain efficiency in signal processing; and (c) the shape resonance (or Fano resonance or Feshbach resonance) in the association and dissociation processes of bio-molecules (a quantum mechanism that could play a key role to establish a macroscopic quantum coherence in the cell). PMID:22072921

Poccia, Nicola; Ansuini, Alessio; Bianconi, Antonio

2011-01-01

85

Improving Sensorimotor Adaptation Following Long Duration Space Flight by Enhancing Vestibular Information Transfer  

NASA Technical Reports Server (NTRS)

Crewmember adapted to the microgravity state may need to egress the vehicle within a few minutes for safety and operational reasons after gravitational transitions. The transition from one sensorimotor state to another consists of two main mechanisms: strategic and plastic-adaptive and have been demonstrated in astronauts returning after long duration space flight. Strategic modifications represent "early adaptation" - immediate and transitory changes in control that are employed to deal with short-term changes in the environment. If these modifications are prolonged then plastic-adaptive changes are evoked that modify central nervous system function, automating new behavioral responses. More importantly, this longer term adaptive recovery mechanism was significantly associated with their strategic ability to recover on the first day after return to Earth G. We are developing a method based on stochastic resonance to enhance information transfer by improving the brain's ability to detect vestibular signals (Vestibular Stochastic Resonance, VSR) especially when combined with balance training exercises such as sensorimotor adaptability (SA) training for rapid improvement in functional skill, for standing and mobility. This countermeasure to improve detection of vestibular signals is a stimulus delivery system that is wearable/portable providing low imperceptible levels of white noise based binaural bipolar electrical stimulation of the vestibular system (stochastic vestibular stimulation). To determine efficacy of vestibular stimulation on physiological and perceptual responses during otolith-canal conflicts and dynamic perturbations we have conducted a series of studies: We have shown that imperceptible binaural bipolar electrical stimulation of the vestibular system across the mastoids enhances balance performance in the mediolateral (ML) plane while standing on an unstable surface. We have followed up on the previous study showing VSR stimulation improved balance performance in both ML and anteroposterior planes while stimulating in the ML axis only. We have shown the efficacy of VSR stimulations on enhancing physiological and perceptual responses of whole-body orientation during low frequency perturbations (0.1 Hz) on the ocular motor system using a variable radius centrifuge on both physiological (using eye movements) and perceptual responses (using a joystick) to track imposed oscillations. The variable radius centrifuge provides a selective tilting sensation that is detectable only by the otolith organs providing conflicting information from the canal organs of the vestibular system (intra-vestibular conflict). These results indicate that VSR can improve performance in sensory conflict scenarios like that experienced during space flight. We have showed the efficacy of VSR stimulation to improve balance and locomotor control on subjects exposed to continuous, sinusoidal lateral motion of the support surface while walking on a treadmill while viewing perceptually matched linear optic flow. We have shown the safety of short term continuous use of up to 4 hours of VSR stimulation and its efficacy in improving balance and locomotor function in Parkinson's Disease patients. This technique for improving vestibular signal detection may thus provide additional information to improve strategic abilities. We hypothesize that VSR stimulation will act synergistically with SA training to improve adaptability by increased utilization of vestibular information and therefore serve to optimize and personalize the SA countermeasure prescription. This forms the basis of its usefulness both as a training modality and further help in significantly reducing the number of days required to recover functional performance to preflight levels after long duration space flight.

Mulavara, A. P.; Kofman, I. S.; De Dios, Y. E; Galvan, R.; Goel, R.; Miller, C.; Peters, B.; Cohen, H. S.; Jeevarajan, J.; Reschke, M.; Wood, S.; Bergquist, F.; Seidler, R. D.; Bloomberg, J. J.

2014-01-01

86

Components of vestibular cortical function.  

PubMed

It is known that the functional response (e.g., nystagmus) to caloric vestibular stimulation is delayed and prolonged compared with the stimulus-response timing of other sensory systems. Imaging studies have used different models to predict cortical responses and to determine the areas of the brain that are involved. These studies have revealed a widespread network of vestibular brain regions. However, there is some disagreement regarding the brain areas involved, which may partly be caused by differences in the models used. This disagreement indicates the possible existence of multiple cortical components with different temporal characteristics that underlie cortical vestibular processing. However, data-driven methods have yet to be used to analyze the underlying hemodynamic components during and after vestibular stimulation. We performed functional magnetic resonance imaging (fMRI) on 12 healthy subjects during caloric stimulation and analyzed these data using a model-free analysis method (ICA). We found seven independent stimulus-induced components that outline a robust pattern of cortical activation and deactivation. These independent components demonstrated significant differences in their time courses. No single-modeled response function was able to cover the entire range of these independent components. The response functions determined in the present study should improve model-based studies investigating vestibular cortical processing. PMID:22960258

Klingner, Carsten M; Volk, Gerd F; Flatz, Claudia; Brodoehl, Stefan; Dieterich, Marianne; Witte, Otto W; Guntinas-Lichius, Orlando

2013-01-01

87

Effects of spike-time-dependent plasticity on the stochastic resonance of small-world neuronal networks  

NASA Astrophysics Data System (ADS)

The phenomenon of stochastic resonance in Newman-Watts small-world neuronal networks is investigated when the strength of synaptic connections between neurons is adaptively adjusted by spike-time-dependent plasticity (STDP). It is shown that irrespective of the synaptic connectivity is fixed or adaptive, the phenomenon of stochastic resonance occurs. The efficiency of network stochastic resonance can be largely enhanced by STDP in the coupling process. Particularly, the resonance for adaptive coupling can reach a much larger value than that for fixed one when the noise intensity is small or intermediate. STDP with dominant depression and small temporal window ratio is more efficient for the transmission of weak external signal in small-world neuronal networks. In addition, we demonstrate that the effect of stochastic resonance can be further improved via fine-tuning of the average coupling strength of the adaptive network. Furthermore, the small-world topology can significantly affect stochastic resonance of excitable neuronal networks. It is found that there exists an optimal probability of adding links by which the noise-induced transmission of weak periodic signal peaks.

Yu, Haitao; Guo, Xinmeng; Wang, Jiang; Deng, Bin; Wei, Xile

2014-09-01

88

Effects of spike-time-dependent plasticity on the stochastic resonance of small-world neuronal networks.  

PubMed

The phenomenon of stochastic resonance in Newman-Watts small-world neuronal networks is investigated when the strength of synaptic connections between neurons is adaptively adjusted by spike-time-dependent plasticity (STDP). It is shown that irrespective of the synaptic connectivity is fixed or adaptive, the phenomenon of stochastic resonance occurs. The efficiency of network stochastic resonance can be largely enhanced by STDP in the coupling process. Particularly, the resonance for adaptive coupling can reach a much larger value than that for fixed one when the noise intensity is small or intermediate. STDP with dominant depression and small temporal window ratio is more efficient for the transmission of weak external signal in small-world neuronal networks. In addition, we demonstrate that the effect of stochastic resonance can be further improved via fine-tuning of the average coupling strength of the adaptive network. Furthermore, the small-world topology can significantly affect stochastic resonance of excitable neuronal networks. It is found that there exists an optimal probability of adding links by which the noise-induced transmission of weak periodic signal peaks. PMID:25273205

Yu, Haitao; Guo, Xinmeng; Wang, Jiang; Deng, Bin; Wei, Xile

2014-09-01

89

Coexisting stochastic and coherence resonance in a mean-field dynamo model for Earth's magnetic field reversals  

E-print Network

Using a spherical symmetric mean field alpha^2-dynamo model for Earth's magnetic field reversals, we show the coexistence of the noise-induced phenomena coherence resonance and stochastic resonance. Stochastic resonance has been recently invoked to explain the 100 kyr periodicity in the distribution of the residence time between reversals. The comparison of the resulting residence time distribution with the paleomagnetic one allows for some estimate of the effective diffusion time of the Earth's core which may be 100 kyr or slightly below rather than 200 kyr as it would result from the molecular resistivity.

M. Fischer; F. Stefani; G. Gerbeth

2007-09-25

90

Three dimensional nuclear magnetic resonance spectroscopic imaging of sodium ions using stochastic excitation and oscillating gradients  

SciTech Connect

Nuclear magnetic resonance (NMR) spectroscopic imaging of {sup 23}Na holds promise as a non-invasive method of mapping Na{sup +} distributions, and for differentiating pools of Na{sup +} ions in biological tissues. However, due to NMR relaxation properties of {sup 23}Na in vivo, a large fraction of Na{sup +} is not visible with conventional NMR imaging methods. An alternate imaging method, based on stochastic excitation and oscillating gradients, has been developed which is well adapted to measuring nuclei with short T{sub 2}. Contemporary NMR imaging techniques have dead times of up to several hundred microseconds between excitation and sampling, comparable to the shortest in vivo {sup 23}Na T{sub 2} values, causing significant signal loss. An imaging strategy based on stochastic excitation has been developed which greatly reduces experiment dead time by reducing peak radiofrequency (RF) excitation power and using a novel RF circuit to speed probe recovery. Continuously oscillating gradients are used to eliminate transient eddy currents. Stochastic {sup 1}H and {sup 23}Na spectroscopic imaging experiments have been performed on a small animal system with dead times as low as 25{mu}s, permitting spectroscopic imaging with 100% visibility in vivo. As an additional benefit, the encoding time for a 32x32x32 spectroscopic image is under 30 seconds. The development and analysis of stochastic NMR imaging has been hampered by limitations of the existing phase demodulation reconstruction technique. Three dimensional imaging was impractical due to reconstruction time, and design and analysis of proposed experiments was limited by the mathematical intractability of the reconstruction method. A new reconstruction method for stochastic NMR based on Fourier interpolation has been formulated combining the advantage of a several hundredfold reduction in reconstruction time with a straightforward mathematical form.

Frederick, B.deB. [California Univ., Berkeley, CA (United States)]|[Lawrence Berkeley Lab., CA (United States)

1994-12-01

91

Novel Class of Neural Stochastic Resonance and Error-Free Information Transfer  

NASA Astrophysics Data System (ADS)

We investigate a novel class of neural stochastic resonance (SR) exhibiting error-free information transfer. Unlike conventional neural SR, where the decrease of a system’s response with too much noise is associated with an increase in the baseline firing rate, here the bell-shaped SR behavior of the input-output cross correlation emerges versus increasing input noise in spite of no significant increase of the baseline firing rate. The neuron thus acts as an error-free detector for weak signals. An integrate-and-fire model with short-term synaptic depression convincingly validates our experimental findings for SR in the human tactile blink reflex.

Yasuda, Hideaki; Miyaoka, Tsuyoshi; Horiguchi, Jun; Yasuda, Akira; Hänggi, Peter; Yamamoto, Yoshiharu

2008-03-01

92

Optimal range of a nonlocal kernel for stochastic resonance in extended systems  

NASA Astrophysics Data System (ADS)

Here we study stochastic resonance (SR) in a spatially extended system described by a reaction-diffusion equation for a scalar (activator-like) field including a nonlocal contribution. We assume that such a contribution arises from an effective adiabatic elimination of an auxiliary (inhibitor-like) field. Our aim is to study the role played by the range of the nonlocal kernel on the SR phenomena. We have found that increasing the nonlocal coupling reduces the system's response and that, similar to the so-called system size SR, there is an “optimal” value of the kernel's range, yielding a maximum in the system's response.

von Haeften, B.; Wio, H. S.

2007-03-01

93

Stochastic Resonance in a Spatially Symmetric and Flashing Periodic Potential Subjected to Correlated Noises  

NASA Astrophysics Data System (ADS)

A Brownian particle in a spatially symmetric and Bashing periodic potential subjected to correlated noises is investigated. The exact expression of its current is analytically derived. The numerical results indicate that its current as a function of noise intensity exhibits two peaks in the case of positive correlations, and two vales in the case of negative correlations, i.e., a novel stochastic resonance (SR) phenomenon. The SR is attributed to the harmonic cooperation between the noises and the Bashing periodic potential. The conditions under which the SR occurs are also presented.

Nie, Lin-Ru; Gong, Yu-Lan; Mei, Dong-Cheng

2009-10-01

94

Note: On-line weak signal detection via adaptive stochastic resonance  

NASA Astrophysics Data System (ADS)

We design an instrument with a novel embedded adaptive stochastic resonance (SR) algorithm that consists of a SR module and a digital zero crossing detection module for on-line weak signal detection in digital signal processing applications. The two modules are responsible for noise filtering and adaptive parameter configuration, respectively. The on-line weak signal detection can be stably achieved in seconds. The prototype instrument exhibits an advance of 20 dB averaged signal-to-noise ratio and 5 times averaged adjust R-square as compared to the input noisy signal, in considering different driving frequencies and noise levels.

Lu, Siliang; He, Qingbo; Kong, Fanrang

2014-06-01

95

Stochastic resonance in an underdamped fractional oscillator with signal-modulated noise  

NASA Astrophysics Data System (ADS)

With increasingly deep studies into physics and technology, the behavior of fractional oscillators has become a focus of scientific research. In this paper, the fractional Langevin equation is derived from the generalized Langevin equation. Stochastic resonance (SR) in underdamped fractional oscillators driven by multiplicative noise and periodically modulated noise is extensively investigated. Using the Shapiro-Loginov formula, the moment equation and the Laplace transformation technique, the exact expression for complex susceptibility is obtained. Numerical results indicate that the influence of fractional order of the fractional oscillator, the inherent frequency of the system and the frequency of the modulated periodic signal can induce multiresonance.

He, Guitian; Tian, Yan; Luo, Maokang

2014-05-01

96

Stochastic resonant response in the transient boiling regime with periodic heat release  

NASA Astrophysics Data System (ADS)

Results of experimental investigation into thermal pulsations with a transition from the bubble to the film boiling regime of water in a wire heater with periodic Joule release are presented. The intermittency of the bubble and film regimes was observed with the frequencies of the periodic current component lower than 0.1 Hz. The amplitude of thermal pulsations increased by a factor of approximately 4 in this case. These results are interpreted as the stochastic resonant response of the system when the periodic component of pulsations increases in the presence of noise.

Vinogradov, A. V.; Skokov, V. N.; Koverda, V. P.

2014-10-01

97

Supernarrow Spectral Peaks and High Frequency Stochastic Resonance in Systems with Coexisting Periodic Attractors  

E-print Network

The kinetics of a periodically driven nonlinear oscillator, bistable in a nearly resonant field, has been investigated theoretically and through analogue experiments. An activation dependence of the probabilities of fluctuational transitions between the coexisting attractors has been observed, and the activation energies of the transitions have been calculated and measured for a wide range of parameters. The position of the kinetic phase transition (KPT), at which the populations of the attractors are equal, has been established. A range of critical phenomena is shown to arise in the vicinity of the KPT including, in particular, the appearance of a supernarrow peak in the spectral density of the fluctuations, and the occurrence of high-frequency stochastic resonance (HFSR). The experimental measurements of the transition probabilities, the KPT line, the multipeaked spectral densities, the strength of the supernarrow spectral peak, and of the HFSR effect are shown to be in good agreement with the theoretical predictions.

MI Dykman; DG Luchinsky; R Mannella; PVE McClintock; ND Stein; NG Stocks

1993-08-09

98

Signal detection for frequency-shift keying via short-time stochastic resonance  

NASA Astrophysics Data System (ADS)

A series of short-time stochastic resonance (SR) phenomena, realized in a bistable receiver, can be utilized to detect a train of information represented by signals that adopt frequency-shift keying (FSK). It is demonstrated that the values of noise intensity at resonance regions are close for adjacent periodic signals with an appropriate frequency separation. This establishes the possibility of decoding subthreshold or slightly suprathreshold M-ary FSK signals in bistable receivers. Furthermore, the mechanism of FSK signal detection via short-time SR effects is elucidated in terms of the receiver response speed. This phenomenon provides a possible mechanism for information processing in a bistable device operating in nonstationary noisy environments, where even the inputs appear over a short timescale or have a frequency shift.

Duan, Fabing; Abbott, Derek

2005-09-01

99

Electrical Vestibular Stimulation after Vestibular Deafferentation and in Vestibular Schwannoma  

PubMed Central

Background Vestibular reflexes, evoked by human electrical (galvanic) vestibular stimulation (EVS), are utilized to assess vestibular function and investigate its pathways. Our study aimed to investigate the electrically-evoked vestibulo-ocular reflex (eVOR) output after bilateral and unilateral vestibular deafferentations to determine the characteristics for interpreting unilateral lesions such as vestibular schwannomas. Methods EVOR was recorded with dual-search coils as binocular three-dimensional eye movements evoked by bipolar 100 ms-step at EVS intensities of [0.9, 2.5, 5.0, 7.5, 10.0]mA and unipolar 100 ms-step at 5 mA EVS intensity. Five bilateral vestibular deafferented (BVD), 12 unilateral vestibular deafferented (UVD), four unilateral vestibular schwannoma (UVS) patients and 17 healthy subjects were tested with bipolar EVS, and five UVDs with unipolar EVS. Results After BVD, bipolar EVS elicited no eVOR. After UVD, bipolar EVS of one functioning ear elicited bidirectional, excitatory eVOR to cathodal EVS with 9 ms latency and inhibitory eVOR to anodal EVS, opposite in direction, at half the amplitude with 12 ms latency, exhibiting an excitatory-inhibitory asymmetry. The eVOR patterns from UVS were consistent with responses from UVD confirming the vestibular loss on the lesion side. Unexpectedly, unipolar EVS of the UVD ear, instead of absent response, evoked one-third the bipolar eVOR while unipolar EVS of the functioning ear evoked half the bipolar response. Conclusions The bidirectional eVOR evoked by bipolar EVS from UVD with an excitatory-inhibitory asymmetry and the 3 ms latency difference between normal and lesion side may be useful for detecting vestibular lesions such as UVS. We suggest that current spread could account for the small eVOR to 5 mA unipolar EVS of the UVD ear. PMID:24349188

Aw, Swee Tin; Todd, Michael John; Lehnen, Nadine; Aw, Grace Elizabeth; Weber, Konrad Peter; Eggert, Thomas; Halmagyi, Gabor Michael

2013-01-01

100

Resonant pedestal pressure reduction induced by a thermal transport enhancement due to stochastic magnetic boundary layers in high temperature plasmas.  

PubMed

Good alignment of the magnetic field line pitch angle with the mode structure of an external resonant magnetic perturbation (RMP) field is shown to induce modulation of the pedestal electron pressure p(e) in high confinement high rotation plasmas at the DIII-D tokamak with a shape similar to ITER, the next step tokamak experiment. This is caused by an edge safety factor q95 resonant enhancement of the thermal transport, while in contrast, the RMP induced particle pump out does not show a significant resonance. The measured p(e) reduction correlates to an increase in the modeled stochastic layer width during pitch angle variations matching results from resistive low rotation plasmas at the TEXTOR tokamak. These findings suggest a field line pitch angle resonant formation of a stochastic magnetic edge layer as an explanation for the q95 resonant character of type-I edge localized mode suppression by RMPs. PMID:19905705

Schmitz, O; Evans, T E; Fenstermacher, M E; Unterberg, E A; Austin, M E; Bray, B D; Brooks, N H; Frerichs, H; Groth, M; Jakubowski, M W; Lasnier, C J; Lehnen, M; Leonard, A W; Mordijck, S; Moyer, R A; Osborne, T H; Reiter, D; Samm, U; Schaffer, M J; Unterberg, B; West, W P

2009-10-16

101

Resonant Pedestal Pressure Reduction Induced by a Thermal Transport Enhancement due to Stochastic Magnetic Boundary Layers in High Temperature Plasmas  

SciTech Connect

Good alignment of the magnetic field line pitch angle with the mode structure of an external resonant magnetic perturbation (RMP) field is shown to induce modulation of the pedestal electron pressure p{sub e} in high confinement high rotation plasmas at the DIII-D tokamak with a shape similar to ITER, the next step tokamak experiment. This is caused by an edge safety factor q{sub 95} resonant enhancement of the thermal transport, while in contrast, the RMP induced particle pump out does not show a significant resonance. The measured p{sub e} reduction correlates to an increase in the modeled stochastic layer width during pitch angle variations matching results from resistive low rotation plasmas at the TEXTOR tokamak. These findings suggest a field line pitch angle resonant formation of a stochastic magnetic edge layer as an explanation for the q{sub 95} resonant character of type-I edge localized mode suppression by RMPs.

Schmitz, O.; Frerichs, H.; Lehnen, M.; Reiter, D.; Samm, U.; Unterberg, B. [Forschungszentrum Juelich GmbH, IEF4-Plasma Physics, 52428 Juelich (Germany); Evans, T. E.; Austin, M. E.; Bray, B. D.; Brooks, N. H.; Leonard, A. W.; Osborne, T. H.; Schaffer, M. J.; West, W. P. [General Atomics, San Diego, California 92186-5608 (United States); Fenstermacher, M. E.; Groth, M.; Lasnier, C. J. [Lawrence Livermore National Laboratory, Livermore, California (United States); Unterberg, E. A. [Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee (United States); Jakubowski, M. W. [Max Planck Institut fuer Plasmaphysik, Greifswald (Germany); Mordijck, S. [University of California, San Diego, La Jolla, California 92093 (United States)

2009-10-16

102

Resonant Pedestal Pressure Reduction Induced by a Thermal Transport Enhancement due to Stochastic Magnetic Boundary Layers in High Temperature Plasmas  

SciTech Connect

Good alignment of the magnetic field line pitch angle with the mode structure of an external resonant magnetic perturbation (RMP) field is shown to induce modulation of the pedestal electron pressure p(e) in high confinement high rotation plasmas at the DIII-D tokamak with a shape similar to ITER, the next step tokamak experiment. This is caused by an edge safety factor q(95) resonant enhancement of the thermal transport, while in contrast, the RMP induced particle pump out does not show a significant resonance. The measured p(e) reduction correlates to an increase in the modeled stochastic layer width during pitch angle variations matching results from resistive low rotation plasmas at the TEXTOR tokamak. These findings suggest a field line pitch angle resonant formation of a stochastic magnetic edge layer as an explanation for the q(95) resonant character of type-I edge localized mode suppression by RMPs.

Schmitz, O. [Forschungszentrum Julich, Julich, Germany; Evans, T.E. [General Atomics, San Diego; Fenstermacher, M. E. [Lawrence Livermore National Laboratory (LLNL); Unterberg, E. A. [Oak Ridge Institute for Science and Education (ORISE); Austin, M. E. [General Atomics, San Diego; Bray, B. D. [General Atomics, San Diego; Brooks, N. H. [General Atomics, San Diego; Frerichs, H. [Forschungszentrum Julich, Julich, Germany; Groth, M. [Lawrence Livermore National Laboratory (LLNL); Jakubowski, M. W. [Max-Planck-Institute for Plasmaphysik, EURATOM-Association, Greifswald, Germany; Lasnier, C. J. [Lawrence Livermore National Laboratory (LLNL); Lehnen, M. [Forschungszentrum Julich, Julich, Germany; Leonard, A. W. [General Atomics; Mordijck, S. [University of California, San Diego; Moyer, R.A. [University of California, San Diego; Osborne, T. H. [General Atomics; Reiter, D. [Forschungszentrum Julich, Julich, Germany; Samm, U. [Forschungszentrum Julich, Julich, Germany; Schaffer, M. J. [General Atomics, San Diego; Unterberg, B. [Forschungszentrum Julich, Julich, Germany; West, W. P. [General Atomics, San Diego

2009-01-01

103

Weak-Periodic Stochastic Resonance in a Parallel Array of Static Nonlinearities  

PubMed Central

This paper studies the output-input signal-to-noise ratio (SNR) gain of an uncoupled parallel array of static, yet arbitrary, nonlinear elements for transmitting a weak periodic signal in additive white noise. In the small-signal limit, an explicit expression for the SNR gain is derived. It serves to prove that the SNR gain is always a monotonically increasing function of the array size for any given nonlinearity and noisy environment. It also determines the SNR gain maximized by the locally optimal nonlinearity as the upper bound of the SNR gain achieved by an array of static nonlinear elements. With locally optimal nonlinearity, it is demonstrated that stochastic resonance cannot occur, i.e. adding internal noise into the array never improves the SNR gain. However, in an array of suboptimal but easily implemented threshold nonlinearities, we show the feasibility of situations where stochastic resonance occurs, and also the possibility of the SNR gain exceeding unity for a wide range of input noise distributions. PMID:23505523

Ma, Yumei; Duan, Fabing; Chapeau-Blondeau, Francois; Abbott, Derek

2013-01-01

104

Large vestibular aqueduct syndrome.  

PubMed

Large Vestibular Aqueduct Syndrome is a congenital malformation of the temporal bone characterised by early onset of sensorineural hearing loss and vestibular disturbance. Familial large vestibular aqueduct syndrome suggests autosomal recessive or X-linked inheritance and accounts for non-syndromic sensorineural hearing loss in these patients. PMID:16570713

Dipak, S; Prepageran, N; Sazila, A S; Rahmat, O; Raman, R

2005-10-01

105

Vestibular Evoked Myogenic Potentials in Patients With Acoustic Neuromas  

Microsoft Academic Search

Background: To diagnose acoustic neuromas (ANs), the auditory brainstem response test and the caloric test have been used in addition to magnetic resonance imaging. The auditory brainstem response and the caloric tests mainly reflect functions of the auditory pathway, ie, the cochlear nerve and the superior vestibular nerve, respec- tively. Because the vestibular evoked myogenic poten- tial (VEMP) has been

Toshihisa Murofushi; Masaki Matsuzaki; Masahiro Mizuno

1998-01-01

106

Vestibular Neuronitis  

MedlinePLUS

... Manuals available in print, online, and as mobile applications. See more at MerckManuals.com Sections in Patients & ... for nystagmus (see see What the doctor does ). Magnetic resonance imaging (MRI) of the head may be performed to ...

107

Compton harmonic resonances, stochastic instabilities, quasilinear diffusion, and collisionless damping with ultra-high intensity laser waves  

SciTech Connect

The dynamics of electrons in two-dimensional, linearly or circularly polarized, ultra-high intensity (above 10{sup 18}W/cm{sup 2}) laser waves, is investigated. The Compton harmonic resonances are identified as the source of various stochastic instabilities. Both Arnold diffusion and resonance overlap are considered. The quasilinear kinetic equation, describing the evolution of the electron distribution function, is derived, and the associated collisionless damping coefficient is calculated. The implications of these new processes are considered and discussed.

Rax, J.M.

1992-04-01

108

Stochastic resonance in the thermohaline circulation P. V'elez , A. Alvarez 1 , P. Colet, J. Tintor'e  

E-print Network

1 Stochastic resonance in the thermohaline circulation P. V'elez , A. Alvarez 1 , P. Colet, J might be related to transitions between stable equilibrium states of the ocean thermohaline circulation of the thermohaline circulation seems well established, the mechanism and magnitude of the forcings that could

Colet, Pere

109

Stochastic resonance in a tumor-immune system subject to bounded noises and time delay  

NASA Astrophysics Data System (ADS)

Immunotherapy is one of the most recent approaches in cancer therapy. A mathematical model of tumor-immune interaction, subject to a periodic immunotherapy treatment (imitated by a periodic signal), correlative and bounded stochastic fluctuations and time delays, is investigated by numerical simulations for its signal power amplification (SPA). Within the tailored parameter regime, the synchronous response of tumor growth to the immunotherapy, stochastic resonance (SR), versus both the noises and delays is obtained. The details are as follows (i) the peak values of SPA versus the noise intensity (A) in the proliferation term of tumor cells decrease as the frequency of periodic signal increases, i.e. an increase of the frequency restrains the SR; (ii) an increase of the amplitude of periodic signal restrains the SR versus A, but boosts up the SR versus the noise intensity B in the immune term; (iii) there is an optimum cross-correlated degree between the two bounded noises, at which the system exhibits the strongest SR versus the delay time ??(the reaction time of tumor cell population to their surrounding environment constraints); (iv) upon increasing the delay time ??, double SR versus the delay time ?? (the time taken by both the tumor antigen identification and tumor-stimulated proliferation of effectors) emerges. These results may be helpful for an immunotherapy treatment for the sufferer.

Guo, Wei; Mei, Dong-Cheng

2014-12-01

110

GENERAL: A Study on Stochastic Resonance in Biased Subdiffusive Smoluchowski Systems within Linear Response Range  

NASA Astrophysics Data System (ADS)

The method of matrix continued fraction is used to investigate stochastic resonance (SR) in the biased subdiffusive Smoluchowski system within linear response range. Numerical results of linear dynamic susceptibility and spectral amplification factor are presented and discussed in two-well potential and mono-well potential with different subdiffusion exponents. Following our observation, the introduction of a bias in the potential weakens the SR effect in the subdiffusive system just as in the normal diffusive case. Our observation also discloses that the subdiffusion inhibits the low-frequency SR, but it enhances the high-frequency SR in the biased Smoluchowski system, which should reflect a “flattening" influence of the subdiffusion on the linear susceptibility.

Li, Yi-Juan; Kang, Yan-Mei

2010-08-01

111

Improved Detection of Magnetic Signals by a MEMS Sensor Using Stochastic Resonance  

PubMed Central

We introduce the behavior of the electrical output response of a magnetic field sensor based on microelectromechanical systems (MEMS) technology under different levels of controlled magnetic noise. We explored whether a particular level of magnetic noise applied on the vicinity of the MEMS sensor can improve the detection of subthreshold magnetic fields. We examined the increase in the signal-to-noise ratio (SNR) of such detected magnetic fields as a function of the magnetic noise intensity. The data disclosed an inverted U-like graph between the SNR and the applied magnetic noise. This finding shows that the application of an intermediate level of noise in the environment of a MEMS magnetic field sensor improves its detection capability of subthreshold signals via the stochastic resonance phenomenon. PMID:25329563

Herrera-May, Agustin L.; Tapia, Jesus A.; Dominguez-Nicolas, Saul M.; Juarez-Aguirre, Raul; Gutierrez-D, Edmundo A.; Flores, Amira; Figueras, Eduard; Manjarrez, Elias

2014-01-01

112

The Recovery of Weak Impulsive Signals Based on Stochastic Resonance and Moving Least Squares Fitting  

PubMed Central

In this paper a stochastic resonance (SR)-based method for recovering weak impulsive signals is developed for quantitative diagnosis of faults in rotating machinery. It was shown in theory that weak impulsive signals follow the mechanism of SR, but the SR produces a nonlinear distortion of the shape of the impulsive signal. To eliminate the distortion a moving least squares fitting method is introduced to reconstruct the signal from the output of the SR process. This proposed method is verified by comparing its detection results with that of a morphological filter based on both simulated and experimental signals. The experimental results show that the background noise is suppressed effectively and the key features of impulsive signals are reconstructed with a good degree of accuracy, which leads to an accurate diagnosis of faults in roller bearings in a run-to failure test. PMID:25076220

Jiang, Kuosheng.; Xu, Guanghua.; Liang, Lin.; Tao, Tangfei.; Gu, Fengshou.

2014-01-01

113

Logical stochastic resonance with correlated internal and external noises in a synthetic biological logic block  

NASA Astrophysics Data System (ADS)

Following the advent of synthetic biology, several gene networks have been engineered to emulate digital devices, with the ability to program cells for different applications. In this work, we adapt the concept of logical stochastic resonance to a synthetic gene network derived from a bacteriophage ?. The intriguing results of this study show that it is possible to build a biological logic block that can emulate or switch from the AND to the OR gate functionalities through externally tuning the system parameters. Moreover, this behavior and the robustness of the logic gate are underpinned by the presence of an optimal amount of random fluctuations. We extend our earlier work in this field, by taking into account the effects of correlated external (additive) and internal (multiplicative or state-dependent) noise. Results obtained through analytical calculations as well as numerical simulations are presented.

Dari, Anna; Kia, Behnam; Bulsara, Adi R.; Ditto, William L.

2011-12-01

114

The recovery of weak impulsive signals based on stochastic resonance and moving least squares fitting.  

PubMed

In this paper a stochastic resonance (SR)-based method for recovering weak impulsive signals is developed for quantitative diagnosis of faults in rotating machinery. It was shown in theory that weak impulsive signals follow the mechanism of SR, but the SR produces a nonlinear distortion of the shape of the impulsive signal. To eliminate the distortion a moving least squares fitting method is introduced to reconstruct the signal from the output of the SR process. This proposed method is verified by comparing its detection results with that of a morphological filter based on both simulated and experimental signals. The experimental results show that the background noise is suppressed effectively and the key features of impulsive signals are reconstructed with a good degree of accuracy, which leads to an accurate diagnosis of faults in roller bearings in a run-to failure test. PMID:25076220

Jiang, Kuosheng; Xu, Guanghua; Liang, Lin; Tao, Tangfei; Gu, Fengshou

2014-01-01

115

Review of book vestibular crises  

NASA Technical Reports Server (NTRS)

The etiology, pathogenesis, clinical practice, treatment and rehabilitation of patients with vestibular crises is discussed. Classifications for vestibular disorders are given. Information on the frequency of vestibular crises is given.

Blagoveshchenskaya, N. S.

1980-01-01

116

[Vestibular compensation studies]. [Vestibular Compensation and Morphological Studies  

NASA Technical Reports Server (NTRS)

The following topics are reported: neurophysiological studies on MVN neurons during vestibular compensation; effects of spinal cord lesions on VNC neurons during compensation; a closed-loop vestibular compensation model for horizontally canal-related MVN neurons; spatiotemporal convergence in VNC neurons; contributions of irregularly firing vestibular afferents to linear and angular VOR's; application to flight studies; metabolic measures in vestibular neurons; immediate early gene expression following vestibular stimulation; morphological studies on primary afferents, central vestibular pathways, vestibular efferent projection to the vestibular end organs, and three-dimensional morphometry and imaging.

Perachio, Adrian A. (Principal Investigator)

1996-01-01

117

Vestibular humanoid postural control.  

PubMed

Many of our motor activities require stabilization against external disturbances. This especially applies to biped stance since it is inherently unstable. Disturbance compensation is mainly reactive, depending on sensory inputs and real-time sensor fusion. In humans, the vestibular system plays a major role. When there is no visual space reference, vestibular-loss clearly impairs stance stability. Most humanoid robots do not use a vestibular system, but stabilize upright body posture by means of center of pressure (COP) control. We here suggest using in addition a vestibular sensor and present a biologically inspired vestibular sensor along with a human-inspired stance control mechanism. We proceed in two steps. First, in an introductory review part, we report on relevant human sensors and their role in stance control, focusing on own models of transmitter fusion in the vestibular sensor and sensor fusion in stance control. In a second, experimental part, the models are used to construct an artificial vestibular system and to embed it into the stance control of a humanoid. The robot's performance is investigated using tilts of the support surface. The results are compared to those of humans. Functional significance of the vestibular sensor is highlighted by comparing vestibular-able with vestibular-loss states in robot and humans. We show that a kinematic body-space sensory feedback (vestibular) is advantageous over a kinetic one (force cues) for dynamic body-space balancing. Our embodiment of human sensorimotor control principles into a robot is more than just bionics. It inspired our biological work (neurorobotics: 'learning by building', proof of principle, and more). We envisage a future clinical use in the form of hardware-in-the-loop simulations of neurological symptoms for improving diagnosis and therapy and designing medical assistive devices. PMID:19665555

Mergner, Thomas; Schweigart, Georg; Fennell, Luminous

2009-01-01

118

Logical stochastic resonance in triple-well potential systems driven by colored noise.  

PubMed

In this work, the logic stochastic resonance (LSR) phenomenon in a class of stochastic triple-well potential systems is investigated. Approximate Fokker-Planck equation is first obtained by using decoupling approximation. Then, we show that LSR can be successfully induced by additive or multiplicative Gaussian colored noise in some cases. In the absence of internal noise, LSR implementation seems impossible for a?=?0 (The parameter a characterizes the depth of the potential well) since the two side wells are so deep that the particle cannot hop over the barrier into the middle well when the input signal is 0. With the increasing of a, the optimal noise band to yield flexible logic gates appears and moves to higher level of noise as the correlation time of noise increases. Compared with the Gaussian white noise, the reliable region in the parameter plane of potential depth parameter a and additive noise strength D first expands and then shrinks with increasing noise color. Furthermore, the effects of multiplicative Gaussian colored noise on LSR are investigated. It was found that the flexible and reliable logic behavior can be yielded for a?=?0 due to the fact that the multiplicative Gaussian colored noise strongly affects the shape of the potential function. With the increasing of a, i.e., a?=?0.25, multiplicative Gaussian white noise cannot yield desired logic behavior. Fortunately, LSR can also be expected by adjusting the correlation time of Gaussian colored noise. It can also be observed that the reliable region in the parameter plane of potential depth parameter a and multiplicative noise strength Q is small for the case of Gaussian white noise and it becomes larger with the increasing of noise color. PMID:23278065

Zhang, Huiqing; Xu, Yong; Xu, Wei; Li, Xiuchun

2012-12-01

119

On stochastic stabilization of the Kelvin-Helmholtz instability by three-wave resonant interaction.  

PubMed

An analytical investigation of the effect of three-wave resonant interactions with the linearly unstable wave is proposed. We consider the waves in the Kelvin-Helmholtz model, consisting of two fluid layers with different densities and velocities. We suppose that the velocity shear is weakly supercritical, the instability is of the algebraic type, i.e., the amplitude of the unstable wave grows linearly, and the instability occurs within the framework of a single mode. The amplitudes of two other waves taking part in the nonlinear interaction are assumed to be stable. The initial amplitudes of these waves are supposed to be small in comparison with the initial amplitude of the unstable wave. We present an analysis of the system of amplitude equations derived for this case using JWKB-method. As a result, we obtain equations that couple solutions pre- and post-passing the singular point, i.e., the point where the amplitude of the unstable wave has a local minimum. These equations give us the transformation rule of a parameter that characterizes the phase shift between fast and slow waves and defines the behavior of the system. This parameter is constant between two singular points and varies by chance at a singular point. As long as it stays positive, the amplitude of the wave remains limited and performs stochastic oscillations. If this parameter passes over zero, then we leave the region of stabilization and turn out in the region, where the amplitude grows infinitely. Accordingly, the transition to the region of instability happens stochastically. However, if the time interval, when the amplitude remains bounded, is large enough, the proposed scenario can be treated as a partial stabilization of instability. PMID:22225354

Kostrykin, S V; Romanova, N N; Yakushkin, I G

2011-12-01

120

Vestibular perception following acute unilateral vestibular lesions.  

PubMed

Little is known about the vestibulo-perceptual (VP) system, particularly after a unilateral vestibular lesion. We investigated vestibulo-ocular (VO) and VP function in 25 patients with vestibular neuritis (VN) acutely (2 days after onset) and after compensation (recovery phase, 10 weeks). Since the effect of VN on reflex and perceptual function may differ at threshold and supra-threshold acceleration levels, we used two stimulus intensities, acceleration steps of 0.5°/s(2) and velocity steps of 90°/s (acceleration 180°/s(2)). We hypothesised that the vestibular lesion or the compensatory processes could dissociate VO and VP function, particularly if the acute vertiginous sensation interferes with the perceptual tasks. Both in acute and recovery phases, VO and VP thresholds increased, particularly during ipsilesional rotations. In signal detection theory this indicates that signals from the healthy and affected side are still fused, but result in asymmetric thresholds due to a lesion-induced bias. The normal pattern whereby VP thresholds are higher than VO thresholds was preserved, indicating that any 'perceptual noise' added by the vertigo does not disrupt the cognitive decision-making processes inherent to the perceptual task. Overall, the parallel findings in VO and VP thresholds imply little or no additional cortical processing and suggest that vestibular thresholds essentially reflect the sensitivity of the fused peripheral receptors. In contrast, a significant VO-VP dissociation for supra-threshold stimuli was found. Acutely, time constants and duration of the VO and VP responses were reduced - asymmetrically for VO, as expected, but surprisingly symmetrical for perception. At recovery, VP responses normalised but VO responses remained shortened and asymmetric. Thus, unlike threshold data, supra-threshold responses show considerable VO-VP dissociation indicative of additional, higher-order processing of vestibular signals. We provide evidence of perceptual processes (ultimately cortical) participating in vestibular compensation, suppressing asymmetry acutely in unilateral vestibular lesions. PMID:23671577

Cousins, Sian; Kaski, Diego; Cutfield, Nicholas; Seemungal, Barry; Golding, John F; Gresty, Michael; Glasauer, Stefan; Bronstein, Adolfo M

2013-01-01

121

The effects of stochastic resonance electrical stimulation and neoprene sleeve on knee proprioception  

PubMed Central

Background A variety of knee injuries and pathologies may cause a deficit in knee proprioception which may increase the risk of reinjury or the progression of disease. Stochastic resonance stimulation is a new therapy which has potential benefits for improving proprioceptive function. The objective of this study was to determine if stochastic resonance (SR) stimulation applied with a neoprene sleeve could improve knee proprioception relative to a no-stimulation/no-sleeve condition (control) or a sleeve alone condition in the normal, healthy knee. We hypothesized that SR stimulation when applied with a sleeve would enhance proprioception relative to the control and sleeve alone conditions. Methods Using a cross-over within subject design, twenty-four healthy subjects were tested under four combinations of conditions: electrical stimulation/sleeve, no stimulation/sleeve, no stimulation/no sleeve, and stimulation/no sleeve. Joint position sense (proprioception) was measured as the absolute mean difference between a target knee joint angle and the knee angle reproduced by the subject. Testing was conducted during both partial-weight bearing (PWB) and non-weight bearing (NWB) tasks. Differences in joint position sense between the conditions were evaluated by repeated-measures analysis of variance testing. Results Joint position sense error during the stimulation/sleeve condition (2.48° ± 1.32°) was found to be more accurate (P < 0.05) relative to the control condition (3.35° ± 1.63°) in the PWB task. No difference in joint position sense error was found between stimulation/sleeve and sleeve alone conditions for the PWB task. Joint position sense error was not found to differ between any of the conditions for the NWB task. Conclusion These results suggest that SR electrical stimulation when combined with a neoprene sleeve is an effective modality for enhancement of joint proprioception in the PWB knee. We believe these results suggest the need for further study of the potential of SR stimulation to correct proprioceptive deficits in a clinical population with knee injury/pathology or in subjects at risk of injury because of a proprioceptive deficit. PMID:19187538

Collins, Amber T; Blackburn, J Troy; Olcott, Chris W; Dirschl, Douglas R; Weinhold, Paul S

2009-01-01

122

Enhancement of ohmic and stochastic heating by resonance effects in capacitive radio frequency discharges: a theoretical approach.  

PubMed

In low-pressure capacitive radio frequency discharges, two mechanisms of electron heating are dominant: (i) Ohmic heating due to collisions of electrons with neutrals of the background gas and (ii) stochastic heating due to momentum transfer from the oscillating boundary sheath. In this work we show by means of a nonlinear global model that the self-excitation of the plasma series resonance which arises in asymmetric capacitive discharges due to nonlinear interaction of plasma bulk and sheath significantly affects both Ohmic heating and stochastic heating. We observe that the series resonance effect increases the dissipation by factors of 2-5. We conclude that the nonlinear plasma dynamics should be taken into account in order to describe quantitatively correct electron heating in asymmetric capacitive radio frequency discharges. PMID:18764627

Mussenbrock, T; Brinkmann, R P; Lieberman, M A; Lichtenberg, A J; Kawamura, E

2008-08-22

123

Stochastic resonance in the presence or absence of external signal in the continuous stirred tank reactor system  

NASA Astrophysics Data System (ADS)

A two variable model, which has been proposed to describe a first-order, exothermic, irreversible reaction A?B carried out in a continuous stirred tank reactor (CSTR), is investigated when the control parameter is modulated by random and/or periodic forces. Within the bistable region where a limit cycle and a stable node coexist, stochastic resonance (SR) is observed when both random and periodic modulations are present. In the absence of periodic external signal noise induced coherent oscillations (NICO) appear when the control parameter is randomly modulated near the supercritical Hopf bifurcation point. In addition, the NICO-strength goes through a maximum with the increment of the noise intensity, characteristic for the occurrence of internal signal stochastic resonance (ISSR).

Hou, Zhonghuai; Xin, Houwen

1999-07-01

124

Stochastic Resonance In The Rikitake Dynamo: An Implication For The Relationship Between Geomagnetic Reversal And Glacial Events  

NASA Astrophysics Data System (ADS)

Not yet a theoretical analysis can explain the coincident temporal correlation between the geomagnetic reversal and glacial events, which both have a quasi-period of about 100 kyr, although there exists dozens of observational evidences for such correlation. In this work, by simulating the behavior of a simple Rikitake dynamo subject to an external periodic force, we show a series of quasi-periodic polarity reversals can be embedded in the geomagnetic filed via the mechanism of stochastic resonance. The term of "stochastic resonance" describes the group of effects in nonlinear system, whereby the response of the system to the weak external, periodic signal is remarkably amplified by the increase of noise intensity. We consequently suggest a common triggering mechanism for the geomagnetic reversal and glacial events, neither the glacial epoch controls the geomagnetic epoch nor vice versa. Instead, both kinds of catastrophes may result from the cyclic variation of the Earth's orbital eccentricity. Our demonstration of stochastic resonance in the Rikitake dynamo thus provides the first theoretical evidence for the relationship between two kinds of catastrophes, the geomagnetic reversal and glacial events, in the Earth's history.

Chen, C.; Tseng, C.

2004-12-01

125

Enhanced Fault Detection of Rolling Element Bearing Based on Cepstrum Editing and Stochastic Resonance  

NASA Astrophysics Data System (ADS)

By signal pre-whitening based on cepstrum editing,the envelope analysis can be done over the full bandwidth of the pre-whitened signal, and this enhances the bearing characteristic frequencies. The bearing faults detection could be enhanced without knowledge of the optimum frequency bands to demodulate, however, envelope analysis over full bandwidth brings more noise interference. Stochastic resonance (SR), which is now often used in weak signal detection, is an important nonlinear effect. By normalized scale transform, SR can be applied in weak signal detection of machinery system. In this paper, signal pre-whitening based on cepstrum editing and SR theory are combined to enhance the detection of bearing fault. The envelope spectrum kurtosis of bearing fault characteristic components is used as indicators of bearing faults. Detection results of planted bearing inner race faults on a test rig show the enhanced detecting effects of the proposed method. And the indicators of bearing inner race faults enhanced by SR are compared to the ones without enhancement to validate the proposed method.

Zhang, Xiaofei; Hu, Niaoqing; Hu, Lei; Fan, Bin; Cheng, Zhe

2012-05-01

126

Electrical noise modulates perception of electrical pulses in humans: sensation enhancement via stochastic resonance.  

PubMed

Although noise is usually considered to be harmful for signal detection and information transmission, stochastic resonance (SR) describes the counterintuitive phenomenon of noise enhancing the detection and transmission of weak input signals. In mammalian sensory systems, SR-related phenomena may arise both in the peripheral and the central nervous system. Here, we investigate behavioral SR effects of subliminal electrical noise stimulation on the perception of somatosensory stimuli in humans. We compare the likelihood to detect near-threshold pulses of different intensities applied on the left index finger during presence vs. absence of subliminal noise on the same or an adjacent finger. We show that (low-pass) noise can enhance signal detection when applied on the same finger. This enhancement is strong for near-threshold pulses below the 50% detection threshold and becomes stronger when near-threshold pulses are applied as brief trains. The effect reverses at pulse intensities above threshold, especially when noise is replaced by subliminal sinusoidal stimulation, arguing for a peripheral direct current addition. Unfiltered noise applied on longer pulses enhances detection of all pulse intensities. Noise applied to an adjacent finger has two opposing effects: an inhibiting effect (presumably due to lateral inhibition) and an enhancing effect (most likely due to SR in the central nervous system). In summary, we demonstrate that subliminal noise can significantly modulate detection performance of near-threshold stimuli. Our results indicate SR effects in the peripheral and central nervous system. PMID:24353303

Iliopoulos, Fivos; Nierhaus, Till; Villringer, Arno

2014-03-01

127

Stochastic resonance of charge carriers diffusing in a nonhomogeneous medium with nonhomogeneous temperature  

NASA Astrophysics Data System (ADS)

We investigate the dynamics of charge carriers hopping from one trap to the other trap along an n-type semiconductor layer consisting of a spatially nonhomogeneous trap distribution of depth ? assisted by thermal noise. The trap profile is denser at the center and decays as one moves outward. In presence of a uniform background temperature, the charge carriers tend to accumulate around the center. Moreover, applying a nonhomogeneous temperature which is hot at the location of the maximum of trap density, results in a new redistribution of charge carriers which pile up around two points symmetrically positioned with respect to the center of the semiconductor layer making the system to behave like a bistable potential. The thermally activated rate of hopping of charge carriers as a function of the model parameters is studied in the high barrier limit. Using the two-state approximation, the stochastic resonance (SR) of the charge carriers dynamics in the presence of time varying external signal is also investigated.

Aragie, Berhanu; Tatek, Yergou B.; Bekele, Mulugeta

2014-05-01

128

Vestibular and visual responses in human posterior insular cortex.  

PubMed

The central hub of the cortical vestibular network in humans is likely localized in the region of posterior lateral sulcus. An area characterized by responsiveness to visual motion has previously been described at a similar location and named posterior insular cortex (PIC). Currently it is not known whether PIC processes vestibular information as well. We localized PIC using visual motion stimulation in functional magnetic resonance imaging (fMRI) and investigated whether PIC also responds to vestibular stimuli. To this end, we designed an MRI-compatible caloric stimulation device that allowed us to stimulate bithermally with hot temperature in one ear and simultaneously cold temperature in the other or with warm temperatures in both ears for baseline. During each trial, participants indicated the presence or absence of self-motion sensations. We found activation in PIC during periods of self motion when vestibular stimulation was carried out with minimal visual input. In combined visual-vestibular stimulation area PIC was activated in a similar fashion during congruent and incongruent stimulation conditions. Our results show that PIC not only responds to visual motion but also to vestibular stimuli related to the sensation of self motion. We suggest that PIC is part of the cortical vestibular network and plays a role in the integration of visual and vestibular stimuli for the perception of self motion. PMID:25185806

Frank, Sebastian M; Baumann, Oliver; Mattingley, Jason B; Greenlee, Mark W

2014-11-15

129

Vestibular Schwannoma (Acoustic Neuroma) and Neurofibromatosis  

MedlinePLUS

... Vestibular Schwannoma (Acoustic Neuroma) and Neurofibromatosis Vestibular Schwannoma (Acoustic Neuroma) and Neurofibromatosis On this page: What is ... get additional information? What is a vestibular schwannoma (acoustic neuroma)? A vestibular schwannoma (also known as acoustic ...

130

Inferior vestibular neuritis.  

PubMed

Vestibular neuritis (VN) mostly involves the superior portion of the vestibular nerve and labyrinth. This study aimed to describe the clinical features of VN involving the inferior vestibular labyrinth and its afferents only. Of the 703 patients with a diagnosis of VN or labyrinthitis at Seoul National University Bundang Hospital from 2004 to 2010, we retrospectively recruited 9 patients (6 women, age range 15-75) with a diagnosis of isolated inferior VN. Diagnosis of isolated inferior VN was based on torsional downbeating spontaneous nystagmus, abnormal head-impulse test (HIT) for the posterior semicircular canal (PC), and abnormal cervical vestibular-evoked myogenic potentials (VEMP) in the presence of normally functioning horizontal and anterior semicircular canals, as determined by normal HIT and bithermal caloric tests. All patients presented with acute vertigo with nausea, vomiting, and imbalance. Three patients also had tinnitus and hearing loss in the involved side. The rotation axis of torsional downbeating spontaneous nystagmus was best aligned with that of the involved PC. HIT was also positive only for the involved PC. Cervical VEMP was abnormal in seven patients, and ocular VEMP was normal in all four patients tested. Ocular torsion and subjective visual vertical tests were mostly within the normal range. Since isolated inferior VN lacks the typical findings of much more prevalent superior VN, it may be mistaken for a central vestibular disorder. Recognition of this rare disorder may help avoid unnecessary workups in patients with acute vestibulopathy. PMID:22215238

Kim, Ji-Soo; Kim, Hyo Jung

2012-08-01

131

Static equilibrium and vestibular function  

Microsoft Academic Search

Possible relations between vestibular function and body sway were investigated (a) by measuring body sway and by other observations on a male subject showing complete loss of vestibular function and (b) by observation of vestibular function, Bárány chair tests, and body sway in 45 subjects with intact labyrinth. While the biologically defective subject showed marked body sway on the first

J. E. Birren

1945-01-01

132

Is there a vestibular cortex?  

Microsoft Academic Search

Very different areas of the primate cortex have been labelled as `vestibular'. However, no clear concept has emerged as to where and how the vestibular information is processed in the cerebral cortex. On the basis of data from single-unit recordings and tracer studies, the present article gives statistical evidence of the existence of a well-defined vestibular cortical system. Because the

W. O. Guldin; O. J. Grüsser

1998-01-01

133

Spike-interval triggered averaging reveals a quasi-periodic spiking alternative for stochastic resonance in catfish electroreceptors.  

PubMed

Catfish detect and identify invisible prey by sensing their ultra-weak electric fields with electroreceptors. Any neuron that deals with small-amplitude input has to overcome sensitivity limitations arising from inherent threshold non-linearities in spike-generation mechanisms. Many sensory cells solve this issue with stochastic resonance, in which a moderate amount of intrinsic noise causes irregular spontaneous spiking activity with a probability that is modulated by the input signal. Here we show that catfish electroreceptors have adopted a fundamentally different strategy. Using a reverse correlation technique in which we take spike interval durations into account, we show that the electroreceptors generate a supra-threshold bias current that results in quasi-periodically produced spikes. In this regime stimuli modulate the interval between successive spikes rather than the instantaneous probability for a spike. This alternative for stochastic resonance combines threshold-free sensitivity for weak stimuli with similar sensitivity for excitations and inhibitions based on single interspike intervals. PMID:22403709

Lankheet, Martin J M; Klink, P Christiaan; Borghuis, Bart G; Noest, André J

2012-01-01

134

Recovery from vestibular ototoxicity  

NASA Technical Reports Server (NTRS)

OBJECTIVE: Determine whether subjects with documented vestibular ototoxicity recover vestibular function and, if so, investigate the recovery dynamics. STUDY DESIGN: Prospective and retrospective reviews and repeated measures. SETTING: Clinical research and technology center. SUBJECTS: Twenty-eight subjects who received vestibulotoxic medications were followed for at least 12 months after initial treatment. CONTROLS: Our subject sample was compared with a published database of normal individuals. INTERVENTIONS: All 28 subjects received systemically administered medications known to be ototoxic. The subjects' treating physicians controlled medication, dosage, and administration schedules. MAIN OUTCOME MEASURES: Tests of horizontal canal vestibulo-ocular function were performed. Subjects' auditory and vestibular symptoms were recorded. RESULTS: Eleven subjects (39%) showed changes in horizontal canal vestibulo-ocular gain constant (GC) and/or time constant (TC) consistent with vestibular ototoxicity. When tested 1 year after ototoxic drug administration, eight of the nine subjects who experienced ototoxic decrease in GC showed a recovery of GC to normal limits. Only one of the eight subjects who experienced ototoxic decrease in TC showed recovery of TC to within normal limits. Ototoxicity onset and recovery were independent of baseline vestibular function, and ototoxicity onset did not correlate with cumulative dose of ototoxic medication. There was no relationship between subjective symptoms and ototoxicity onset. CONCLUSIONS: Recovery of GC after vestibular ototoxicity is more commonly observed than recovery of TC. Because ototoxic changes developed and continued in an unpredictable time and manner in relation to ototoxic drug administration, we propose that once ototoxic changes in vestibulo-ocular reflex are detected, ototoxic medications should be discontinued as soon as possible.

Black, F. O.; Gianna-Poulin, C.; Pesznecker, S. C.

2001-01-01

135

Vestibular Stimulation Attenuates Unrealistic Optimism RUNNING HEAD: Vestibular Stimulation and Optimism  

E-print Network

1 Vestibular Stimulation Attenuates Unrealistic Optimism RUNNING HEAD: Vestibular Stimulation. Moreover, anosognosia is temporarily abolished by vestibular stimulation, particularly by irrigation vestibular stimulation of both ears in succession. During each stimulation episode, and at baseline

Royal Holloway, University of London

136

Can Electrical Vestibular Noise Be Used for the Treatment of Brain Diseases?  

NASA Astrophysics Data System (ADS)

The therapy currently available for the treatment of degenerative neurological diseases is far from satisfactory, and a novel therapeutic strategy, especially for pharmacologically unresponsive patients, would be welcomed. The vestibular nerves are known to influence neuronal circuits in the medullary cardiovascular areas and, through the cerebellar vermis, the basal ganglia and the limbic system. By means of noisy galvanic vestibular stimulation (GVS), it may now be possible to ameliorate blunted responsiveness of degenerated neuronal circuits in the brains of multiple system atrophy (MSA) and/or Parkinson's disease (PD) patients, through a mechanism known as stochastic resonance. We evaluate the effect of 24-hour noisy GVS on long-term heart rate dynamics in seven MSA patients, and on daytime locomotor activity dynamics in twelve patients with either PD or levodopa unresponsive parkinsonism. Short-range heart rate variability and long-range anti-correlation of trunk activity are significantly increased by the noisy GVS compared with sham stimulation, suggestive of improved autonomic and motor responsiveness. The noisy GVS is effective in boosting the neuro-degenerative brains of MSA and/or PD patients, including those unresponsive to standard levodopa therapy.

Yamamoto, Yoshiharu; Soma, Rika; Struzik, Zbigniew R.; Kwak, Shin

2005-11-01

137

Vestibular postural control model  

Microsoft Academic Search

Current models for physiological components and a posture control experiment conducted with three normal subjects form the basis for a model which seeks to describe quantitatively the control of body sway when only vestibular motion cues are used. Emphasis is placed on delineating the relative functional roles of the linear and the angular acceleration sensors and on modeling the functional

Lewis M. Nashner

1972-01-01

138

Management of vestibular migraine  

PubMed Central

Vestibular migraine is considered to be the second most common cause of vertigo and the most common cause of spontaneous episodic vertigo. The duration of attacks varies from seconds to days, usually lasting minutes to hours, and they mostly occur independently of headaches. Long-lasting individual attacks are treated with generic antivertiginous and antiemetic drugs. Specific antimigraine drugs are unlikely to be very effective for rescue. The mainstay of the management of vestibular migraine is prophylactic medication. To date, there are no controlled trials available; the body of knowledge builds on case series and retrospective or observational studies. Most drugs are also used for the prevention of migraine headaches. The choice of medication should be guided by its side effect profile and the comorbidities of patients. Betablockers such as propanolol or metoprolol are preferred in patients with hypertension but in the absence of asthma. Anticonvulsants include topiramate when patients are obese, valproic acid and lamotrigine. Lamotrigine is preferred if vertigo is more frequent than headaches. Calcium antagonists include verapamil and flunarizine. If patients have anxiety, tricyclic antidepressants such as amitryptiline or nortryptiline or SSRIs and benzodiazepines such as clonazepam are recommended. Acetazolamide is effective in rare genetic disorders related to migraine-like episodic ataxia; however, its place in vestibular migraine is still to be established. Nonpharmacological measures such as diet, sleep, hygiene and avoidance of triggers are recommended as they are for migraine. Vestibular rehabilitation might be useful when there are complications such as loss of confidence in balance or visual dependence. PMID:21694818

Bisdorff, Alexandre R.

2011-01-01

139

Theoretical evidence for the link between geomagnetic reversal and glacial events: stochastic resonance in the geodynamo model  

NASA Astrophysics Data System (ADS)

Not yet a theoretical analysis can explain the coincident temporal correlation between the geomagnetic reversal and glacial events, which both have a quasi-period of about 100 kyr, although there exists dozens of observational evidences for such correlation. The geodynamo has widely been thought to be an intuitive and self-sustained model of the Earth's magnetic field^10. In this letter we report how possible a signal with 100 kyr quasi-period can be embedded in the geomagnetic filed via the mechanism of stochastic resonance in a forced Rikitake dynamo. We thus suggest one common triggering for the geomagnetic reversal and glacial events, neither the glaciation controls the geomagnetic reversal nor vice versa. Instead, both kinds of catastrophes may result from the cyclic variation of the Earth's orbital eccentricity.

Tseng, Chih-Yuan; Chen, Chien-Chih

2005-03-01

140

ON DEVELOPMENT OF TOTALLY IMPLANTABLE VESTIBULAR PROSTHESIS  

E-print Network

ON DEVELOPMENT OF TOTALLY IMPLANTABLE VESTIBULAR PROSTHESIS Andrei M. Shkel 1 Department vestibular prosthesis. The sensing element of the prosthesis is a custom designed one-axis MEMS gyroscope to stimulate the corresponding vestibular nerve branch. Our preliminary experimental evaluations

Tang, William C

141

Temporal Adaptation to delayed vestibular feedback  

E-print Network

Temporal Adaptation to delayed vestibular feedback Douglas W. Cunningham, Björn Kreher, Markus von stimulus are perceived as occurring simultaneously. Conclusions Results The vestibular feedback, proprioceptive, and vestibular systems are integrated, we examined the sensitivity and flexibility

142

Is Vestibular Neuritis an Immune Related Vestibular Neuropathy Inducing Vertigo?  

PubMed Central

Objectives. To review the current knowledge of the aetiology of vestibular neuritis including viral infections, vascular occlusion, and immunomediated mechanisms and to discuss the pathogenesis with relevance to pharmacotherapy. Systematic Review Methodology. Relevant publications on the aetiology and treatment of vestibular neuritis from 1909 to 2013 were analysed. Results and Conclusions. Vestibular neuritis is the second most common cause of peripheral vestibular vertigo and is due to a sudden unilateral loss of vestibular function. Vestibular neuronitis is a disorder thought to represent the vestibular-nerve equivalent of sudden sensorineural hearing loss. Histopathological studies of patients who died from unrelated clinical problems have demonstrated degeneration of the superior vestibular nerve. The characteristic signs and symptoms include sudden and prolonged vertigo, the absence of auditory symptoms, and the absence of other neurological symptoms. The aetiology and pathogenesis of the condition remain unknown. Proposed theories of causation include viral infections, vascular occlusion, and immunomediated mechanisms. The management of vestibular neuritis involves symptomatic treatment with antivertiginous drugs, causal treatment with corticosteroids, and physical therapy. Antiviral agents did not improve the outcomes. PMID:24741601

Greco, A.; Macri, G. F.; Gallo, A.; Fusconi, M.; De Virgilio, A.; Pagliuca, G.; Marinelli, C.; de Vincentiis, M.

2014-01-01

143

Improving Early Adaptation Following Long Duration Spaceflight by Enhancing Vestibular Information  

NASA Technical Reports Server (NTRS)

Crewmember adapted to the microgravity state may need to egress the vehicle within a few minutes for safety and operational reasons after g-transitions. The transition from one sensorimotor state to another consists of two main mechanisms: strategic and plastic-adaptive and have been demonstrated in astronauts returning after long duration space flight. Strategic modifications represent "early adaptation" -immediate and transitory changes in control that are employed to deal with short-term changes in the environment. If these modifications are prolonged then plastic-adaptive changes are evoked that modify central nervous system function, automating new behavioral responses. More importantly, this longer term adaptive recovery mechanism was significantly associated with their strategic ability to recover on the first day after return to Earth G. We are developing a method based on stochastic resonance (SR) to enhance information transfer by improving the brain's ability to detect vestibular signals especially when combined with balance training exercises for rapid improvement in functional skill, for standing and mobility. The countermeasure to improve post-flight balance and locomotor disturbances is a stimulus delivery system that is wearable/portable providing low imperceptible levels of white noise based binaural bipolar electrical stimulation of the vestibular system (stochastic vestibular stimulation, SVS). The techniques for improving signal detection using SVS may thus provide additional information to improve such strategic abilities and thus help in significantly reducing the number of days required to recover functional performance to preflight levels after long duration space flight. We have conducted a series of studies to document the efficacy of SVS stimulation on balance/locomotion tasks on unstable surfaces and motion tracking tasks during intra-vestibular system conflicts. In an initial study, we showed that SVS improved overall balance performance while standing on an unstable surface indicating that SVS may be sufficient to provide a comprehensive countermeasure approach for improving postural stability. In a second study, we showed that SVS improved locomotor performance on a treadmill mounted on an oscillating platform indicating that SVS may also be used to maximize locomotor performance during walking in unstable environments. In a third study, SVS was evaluated during an otolith-canal conflict scenario in a variable radius centrifuge at low frequency of oscillation (0.1 Hz) on both eye movements and perceptual responses (using a joystick) to track imposed oscillations. The variable radius centrifuge provides a selective tilting sensation that is detectable only by the otolith organs providing conflicting information from the canal organs of the vestibular system (intra-vestibular conflict). Results show that SVS significantly reduced the timing difference between both the eye movement responses as well as the perceptual tracking responses with respect to the imposed tilt sensations. These results indicate that SVS can improve performance in sensory conflict scenarios like that experienced during space flight. Such a SR countermeasure will act synergistically along with the pre-and in-flight adaptability training protocols providing an integrated, multi-disciplinary countermeasure capable of fulfilling multiple requirements making it a comprehensive and cost effective countermeasure approach to enhance sensorimotor capabilities following long-duration space flight.

Mulavara, Ajitkumar; Kofman, Igor; DeDios, Yiri E.; Galvan, Raquel; Miller, Chris; Peters, Brian; Cohen, Helen; Jeevarajan, Jerome; Reschke, Millard; Wood, Scott; Bloomberg, Jacob

2014-01-01

144

Apollo flight crew vestibular assessment  

NASA Technical Reports Server (NTRS)

Vestibular function in the weightless state of space flight is examined. Due to the lack of a systematic program to assess quantitatively the effects of space flight on crew vestibular function the analysis is based on qualitative information derived from motion sickness histories and subjective reporting by individual astronauts on the type and magnitude of vestibular disturbances experienced during and following their missions. It is concluded that the increased mobility afforded by the larger volume of the Apollo CM/LM resulted in a higher incidence of vestibular disturbances in the Apollo Program and that it is difficult to predict the likelihood of inflight vestibular problems. Quantitative examination of the effects of weightlessness on the vestibular function is recommended.

Homick, J. L.; Miller, E. F., II

1975-01-01

145

Conflicting visual-vestibular stimulation and vestibular nucleus activity in alert monkeys  

Microsoft Academic Search

In alert Rhesus monkeys (Macaca mulatta) neuronal activity of vestibular nuclei was recorded during pure vestibular and conflicting visual-vestibular stimulation. Pure vestibular stimulation consisted of rotating the monkey about the vertical axis in complete darkness. During conflicting visual-vestibular stimulation the monkeys were rotated in the light within a vertically striped cylinder mechanically coupled to the turntable. The conflict is that

W. Waespe; V. Henn

1978-01-01

146

Vestibular blueprint in early vertebrates  

PubMed Central

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. The anatomical locations of vestibuloocular and vestibulospinal neurons correlate with genetically defined hindbrain compartments that are well conserved throughout vertebrate evolution though some variability exists in fossil and extant vertebrate species. The different vestibular subgroups exhibit a robust sensorimotor signal processing complemented with a high degree of vestibular and visual adaptive plasticity. PMID:24312016

Straka, Hans; Baker, Robert

2013-01-01

147

The Application of Multiobjective Genetic Algorithm to the Parameter Optimization of Single-Well Potential Stochastic Resonance Algorithm Aimed at Simultaneous Determination of Multiple Weak Chromatographic Peaks  

PubMed Central

Simultaneous determination of multiple weak chromatographic peaks via stochastic resonance algorithm attracts much attention in recent years. However, the optimization of the parameters is complicated and time consuming, although the single-well potential stochastic resonance algorithm (SSRA) has already reduced the number of parameters to only one and simplified the process significantly. Even worse, it is often difficult to keep amplified peaks with beautiful peak shape. Therefore, multiobjective genetic algorithm was employed to optimize the parameter of SSRA for multiple optimization objectives (i.e., S/N and peak shape) and multiple chromatographic peaks. The applicability of the proposed method was evaluated with an experimental data set of Sudan dyes, and the results showed an excellent quantitative relationship between different concentrations and responses. PMID:24526920

Xiang, Bingren; Wu, Xiaohong; Liu, Dan

2014-01-01

148

Constructing the Davies process of Resonance Fluorescence with Quantum Stochastic Calculus  

E-print Network

Starting point is a given semigroup of completely positive maps on the 2 times 2 matrices. This semigroup describes the irreversible evolution of a decaying 2-level atom. Using the integral-sum kernel approach to quantum stochastic calculus we couple the 2-level atom to an environment, which in our case will be interpreted as the electromagnetic field. The irreversible time evolution of the 2-level atom then stems from the reversible time evolution of atom and field together. Mathematically speaking, we have constructed a Markov dilation of the semigroup. The next step is to drive the atom by a laser and to count the photons emitted into the field by the decaying 2-level atom. For every possible sequence of photon counts we construct a map that gives the time evolution of the 2-level atom inferred by that sequence. The family of maps that we obtain in this way forms a so-called Davies process. In his book Davies describes the structure of these processes, which brings us into the field of quantum trajectories. Within our model we calculate the jump operators and we briefly describe the resulting counting process.

Luc Bouten; Hans Maassen; Burkhard Kuemmerer

2002-07-29

149

Stochastic approach to diffusion inside the chaotic layer of a resonance.  

PubMed

We model chaotic diffusion in a symplectic four-dimensional (4D) map by using the result of a theorem that was developed for stochastically perturbed integrable Hamiltonian systems. We explicitly consider a map defined by a free rotator (FR) coupled to a standard map (SM). We focus on the diffusion process in the action I of the FR, obtaining a seminumerical method to compute the diffusion coefficient. We study two cases corresponding to a thick and a thin chaotic layer in the SM phase space and we discuss a related conjecture stated in the past. In the first case, the numerically computed probability density function for the action I is well interpolated by the solution of a Fokker-Planck (FP) equation, whereas it presents a nonconstant time shift with respect to the concomitant FP solution in the second case suggesting the presence of an anomalous diffusion time scale. The explicit calculation of a diffusion coefficient for a 4D symplectic map can be useful to understand the slow diffusion observed in celestial mechanics and accelerator physics. PMID:24580301

Mestre, Martín F; Bazzani, Armando; Cincotta, Pablo M; Giordano, Claudia M

2014-01-01

150

Stochastic approach to diffusion inside the chaotic layer of a resonance  

E-print Network

We model chaotic diffusion, in a symplectic 4D map by using the result of a theorem that was developed for stochastically perturbed integrable Hamiltonian systems. We explicitly consider a map defined by a free rotator (FR) coupled to a standard map (SM). We focus in the diffusion process in the action, $I$, of the FR, obtaining a semi--numerical method to compute the diffusion coefficient. We study two cases corresponding to a thick and a thin chaotic layer in the SM phase space and we discuss a related conjecture stated in the past. In the first case the numerically computed probability density function for the action $I$ is well interpolated by the solution of a Fokker-Planck (F-P) equation, whereas it presents a non--constant time delay respect to the concomitant F-P solution in the second case suggesting the presence of an anomalous diffusion time scale. The explicit calculation of a diffusion coefficient for a 4D symplectic map can be useful to understand the slow diffusion observed in Celestial Mechanics and Accelerator Physics.

Martín F. Mestre; Armando Bazzani; Pablo M. Cincotta; Claudia M. Giordano

2013-11-11

151

Visuo-Vestibular Interactions  

NASA Technical Reports Server (NTRS)

Session TA3 includes short reports covering: (1) Vestibulo-Oculomotor Interaction in Long-Term Microgravity; (2) Effects of Weightlessness on the Spatial Orientation of Visually Induced Eye Movements; (3) Adaptive Modification of the Three-Dimensional Vestibulo-Ocular Reflex during Prolonged Microgravity; (4) The Dynamic Change of Brain Potential Related to Selective Attention to Visual Signals from Left and Right Visual Fields; (5) Locomotor Errors Caused by Vestibular Suppression; and (6) A Novel, Image-Based Technique for Three-Dimensional Eye Measurement.

1997-01-01

152

Stochastic resonance and dynamic first-order pseudo-phase-transitions in the irreversible growth of thin films under spatially periodic magnetic fields.  

PubMed

We study the irreversible growth of magnetic thin films under the influence of spatially periodic fields by means of extensive Monte Carlo simulations. We find first-order pseudo-phase-transitions that separate a dynamically disordered phase from a dynamically ordered phase. By analogy with time-dependent oscillating fields applied to Ising-type models, we qualitatively associate this dynamic transition with the localization-delocalization transition of spatial hysteresis loops. Depending on the relative width of the magnetic film L compared to the wavelength of the external field ?, different transition regimes are observed. For small systems (L < ?), the transition is associated with the standard stochastic resonance regime, while for large systems (L > ?), the transition is driven by anomalous stochastic resonance. The origin of the latter is identified as due to the emergence of an additional relevant length scale, namely, the roughness of the spin domain switching interface. The distinction between different stochastic resonance regimes is discussed at length both qualitatively by means of snapshot configurations and quantitatively via residence-length and order-parameter probability distributions. PMID:24229194

Loscar, Ernesto S; Candia, Julián

2013-10-01

153

Disrupted functional connectivity of the default mode network due to acute vestibular deficit  

PubMed Central

Vestibular neuritis is defined as a sudden unilateral partial failure of the vestibular nerve that impairs the forwarding of vestibular information from the labyrinth. The patient suffers from vertigo, horizontal nystagmus and postural instability with a tendency toward ipsilesional falls. Although vestibular neuritis is a common disease, the central mechanisms to compensate for the loss of precise vestibular information remain poorly understood. It was hypothesized that symptoms following acute vestibular neuritis originate from difficulties in the processing of diverging sensory information between the responsible brain networks. Accordingly an altered resting activity was shown in multiple brain areas of the task-positive network. Because of the known balance between the task-positive and task-negative networks (default mode network; DMN) we hypothesize that also the DMN is involved. Here, we employ functional magnetic resonance imaging (fMRI) in the resting state to investigate changes in the functional connectivity between the DMN and task-positive networks, in a longitudinal design combined with measurements of caloric function. We demonstrate an initially disturbed connectedness of the DMN after vestibular neuritis. We hypothesize that the disturbed connectivity between the default mode network and particular parts of the task-positive network might be related to a sustained utilization of processing capacity by diverging sensory information. The current results provide some insights into mechanisms of central compensation following an acute vestibular deficit and the importance of the DMN in this disease. PMID:25379422

Klingner, Carsten M.; Volk, Gerd F.; Brodoehl, Stefan; Witte, Otto W.; Guntinas-Lichius, Orlando

2014-01-01

154

First Cross-Correlation Analysis of Interferometric and Resonant-Bar Gravitational-Wave Data for Stochastic Backgrounds  

E-print Network

Data from the LIGO Livingston interferometer and the ALLEGRO resonant bar detector, taken during LIGO's fourth science run, were examined for cross-correlations indicative of a stochastic gravitational-wave background in the frequency range 850-950 Hz, with most of the sensitivity arising between 905 Hz and 925 Hz. ALLEGRO was operated in three different orientations during the experiment to modulate the relative sign of gravitational-wave and environmental correlations. No statistically significant correlations were seen in any of the orientations, and the results were used to set a Bayesian 90% confidence level upper limit of Omega_gw(f) <= 1.02, which corresponds to a gravitational wave strain at 915 Hz of 1.5e-23/rHz. In the traditional units of h_100^2 Omega_gw(f), this is a limit of 0.53, two orders of magnitude better than the previous direct limit at these frequencies. The method was also validated with successful extraction of simulated signals injected in hardware and software.

LIGO Scientific Collaboration; ALLEGRO Collaboration; B. Abbott

2007-03-12

155

An improved multiscale noise tuning of stochastic resonance for identifying multiple transient faults in rolling element bearings  

NASA Astrophysics Data System (ADS)

Stochastic resonance (SR), a noise-assisted tool, has been proved to be very powerful in weak signal detection. The multiscale noise tuning SR (MSTSR), which breaks the restriction of the requirement of small parameters and white noise in classical SR, has been applied to identify the characteristic frequency of a bearing. However, the multiscale noise tuning (MST), which is originally based on discrete wavelet transform (DWT), limits the signal-to-noise ratio (SNR) improvement of SR and the performance in identifying multiple bearing faults. In this paper, the wavelet packet transform (WPT) is developed and incorporated into the MSTSR method to overcome its shortcomings and to further enhance its capability in multiple faults detection of bearings. The WPT-based MST can achieve a finer tuning of multiscale noise and aims at detecting multiple target frequencies separately. By introducing WPT into the MST of SR, this paper proposes an improved SR method particularly suited for the identification of multiple transient faults in rolling element bearings. Simulated and practical bearing signals carrying multiple characteristic frequencies are employed to validate the performance improvement of the proposed method as compared to the original DWT-based MSTSR method. The results confirm the good capability of the proposed method in multi-fault diagnosis of rolling element bearings.

Wang, Jun; He, Qingbo; Kong, Fanrang

2014-12-01

156

First Cross-Correlation Analysis of Interferometric and Resonant-Bar Gravitational-Wave Data for Stochastic Backgrounds  

E-print Network

Data from the LIGO Livingston interferometer and the ALLEGRO resonant bar detector, taken during LIGO's fourth science run, were examined for cross-correlations indicative of a stochastic gravitational-wave background in the frequency range 850-950 Hz, with most of the sensitivity arising between 905 Hz and 925 Hz. ALLEGRO was operated in three different orientations during the experiment to modulate the relative sign of gravitational-wave and environmental correlations. No statistically significant correlations were seen in any of the orientations, and the results were used to set a Bayesian 90% confidence level upper limit of Omega_gw(f) <= 1.02, which corresponds to a gravitational wave strain at 915 Hz of 1.5e-23/rHz. In the traditional units of h_100^2 Omega_gw(f), this is a limit of 0.53, two orders of magnitude better than the previous direct limit at these frequencies. The method was also validated with successful extraction of simulated signals injected in hardware and software.

Abbott, B; Adhikari, R; Agresti, J; Ajith, P; Allen, B; Amin, R; Anderson, S B; Anderson, W G; Arain, M; Araya, M; Armandula, H; Ashley, M; Aston, S; Aufmuth, P; Aulbert, C; Babak, S; Ballmer, S; Bantilan, H; Barish, B C; Barker, C; Barker, D; Barr, B; Barriga, P; Barton, M A; Bayer, K; Belczynski, K; Betzwieser, J; Beyersdorf, P T; Bhawal, B; Bilenko, I A; Billingsley, G; Biswas, R; Black, E; Blackburn, K; Blackburn, L; Blair, D; Bland, B; Bogenstahl, J; Bogue, L; Bork, R; Boschi, V; Bose, S; Brady, P R; Braginsky, V B; Brau, J E; Brinkmann, M; Brooks, A; Brown, D A; Bullington, A; Bunkowski, A; Buonanno, A; Burgamy, M; Burmeister, O; Busby, D; Byer, R L; Cadonati, L; Cagnoli, G; Camp, J B; Cannizzo, J; Cannon, K; Cantley, C A; Cao, J; Cardenas, L; Casey, M M; Castaldi, G; Cepeda, C; Chalkey, E; Charlton, P; Chatterji, S; Chelkowski, S; Chen, Y; Chiadini, F; Chin, D; Chin, E; Chow, J; Christensen, N; Clark, J; Cochrane, P; Cokelaer, T; Colacino, C N; Coldwell, R; Conte, R; Cook, D; Corbitt, T; Coward, D; Coyne, D; Creighton, J D E; Creighton, T D; Croce, R P; Crooks, D R M; Cruise, A M; Cumming, A; Dalrymple, J; D'Ambrosio, E; Danzmann, K; Davies, G; De Bra, D; Degallaix, J; Degree, M; Demma, T; Dergachev, V; Desai, S; DeSalvo, R; Dhurandhar, S V; Díaz, M; Dickson, J; Di Credico, A; Diederichs, G; Dietz, A; Doomes, E E; Drever, R W P; Dumas, J C; Dupuis, R J; Dwyer, J G; Ehrens, P; Espinoza, E; Etzel, T; Evans, M; Evans, T; Fairhurst, S; Fan, Y; Fazi, D; Fejer, M M; Finn, L S; Fiumara, V; Fotopoulos, N; Franzen, A; Franzen, K Y; Freise, A; Frey, R; Fricke, T; Fritschel, P; Frolov, V V; Fyffe, M; Galdi, V; Garofoli, J; Gholami, I; Giaime, J A; Giampanis, S; Giardina, K D; Goda, K; Goetz, E; Goggin, L; González, G; Gossler, S; Grant, A; Gras, S; Gray, C; Gray, M; Greenhalgh, J; Gretarsson, A M; Grosso, R; Grote, H; Grünewald, S; Günther, M; Gustafson, R; Hage, B; Hamilton, W O; Hammer, D; Hanna, C; Hanson, J; Harms, J; Harry, G; Harstad, E; Hayler, T; Heefner, J; Heng, I S; Heptonstall, A; Heurs, M; Hewitson, M; Hild, S; Hirose, E; Hoak, D; Hosken, D; Hough, J; Howell, E; Hoyland, D; Huttner, S H; Ingram, D; Innerhofer, E; Ito, M; Itoh, Y; Ivanov, A; Jackrel, D; Johnson, B; Johnson, W W; Jones, D I; Jones, G; Jones, R; Ju, L; Kalmus, Peter Ignaz Paul; Kalogera, V; Kasprzyk, D; Katsavounidis, E; Kawabe, K; Kawamura, S; Kawazoe, F; Kells, W; Keppel, D G; Khalili, F Ya; Kim, C; King, P; Kissel, J S; Klimenko, S; Kokeyama, K; Kondrashov, V; Kopparapu, R K; Kozak, D; Krishnan, B; Kwee, P; Lam, P K; Landry, M; Lantz, B; Lazzarini, A; Lee, B; Lei, M; Leiner, J; Leonhardt, V; Leonor, I; Libbrecht, K; Lindquist, P; Lockerbie, N A; Longo, M; Lormand, M; Lubinski, M; Luck, H; Machenschalk, B; MacInnis, M; Mageswaran, M; Mailand, K; Malec, M; Mandic, V; Marano, S; Marka, S; Markowitz, J; Maros, E; Martin, I; Marx, J N; Mason, K; Matone, L; Matta, V; Mavalvala, N; McCarthy, R; McClelland, D E; McGuire, S C; McHugh, M; McKenzie, K; McNabb, J W C; McWilliams, S; Meier, T; Melissinos, A C; Mendell, G; Mercer, R A; Meshkov, S; Messaritaki, E; Messenger, C J; Meyers, D; Mikhailov, E; Miller, P; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Miyakawa, O; Mohanty, S; Moody, V; Moreno, G; Mossavi, K; Mow Lowry, C; Moylan, A; Mudge, D; Müller, G; Mukherjee, S; Muller-Ebhardt, H; Munch, J; Murray, P; Myers, E; Myers, J; Nettles, D; Newton, G; Nishizawa, A; Numata, K; O'Reilly, B; O'Shaughnessy, R; Ottaway, D J; Overmier, H; Owen, B J; Paik, H J; Pan, Y; Papa, M A; Parameshwaraiah, V; Patel, P; Pedraza, M; Penn, S; Pierro, V; Pinto, I M; Pitkin, M; Pletsch, H; Plissi, M V; Postiglione, F; Prix, R; Quetschke, V; Raab, F; Rabeling, D; Radkins, H; Rahkola, R; Rainer, N; Rakhmanov, M; Ray-Majumder, S; Re, V; Rehbein, H; Reid, S; Reitze, D H; Ribichini, L; Riesen, R; Riles, K; Rivera, B; Robertson, N A; Robinson, C; Robinson, E L; Roddy, S; Rodríguez, A; Rogan, A M; Rollins, J; Romano, J D; Romie, J; Route, R; Rowan, S; Rüdiger, A; Ruet, L; Russell, P; Ryan, K; Sakata, S; Samidi, M; Sancho de la Jordana, L; Sandberg, V; Sannibale, V; Saraf, S; Sarin, P; Sathyaprakash, B S; Sato, S; Saulson, P R; Savage, R; Savov, P; Schediwy, S; Schilling, R; Schnabel, R; Schofield, R; Schutz, B F; Schwinberg, P; Scott, S M; Searle, A C; Sears, B; Seifert, F; Sellers, D; Sengupta, A S; Shawhan, P; Shoemaker, D H; Sibley, A; Sidles, J A; Siemens, X; Sigg, D; Sinha, S; Sintes, A M; Slagmolen, B; Slutsky, J; Smith, J R; Smith, M R; Somiya, K; Strain, K A; Strom, D M; Stuver, A; Summerscales, T Z; Sun, K X; Sung, M; Sutton, P J; Takahashi, H; Tanner, D B; Tarallo, M; Taylor, R; Taylor, R; Thacker, J; Thorne, K A; Thorne, K S; Thüring, A; Tokmakov, K V; Torres, C; Torrie, C; Traylor, G; Trias, M; Tyler, W; Ugolini, D W; Ungarelli, C; Urbanek, K; Vahlbruch, H; Vallisneri, M; Van Den Broeck, C; Varvella, M; Vass, S; Vecchio, A; Veitch, J

2007-01-01

157

Resonant activation in a stochastic Hodgkin-Huxley model: Interplay between noise and suprathreshold driving effects  

NASA Astrophysics Data System (ADS)

The paper considers an excitable Hodgkin-Huxley system subjected to a strong periodic forcing in the presence of random noise. The influence of the forcing frequency on the response of the system is examined in the realm of suprathreshold amplitudes. Our results confirm that the presence of noise has a detrimental effect on the neuronal response. Fluctuations can induce significant delays in the detection of an external signal. We demonstrate, however, that this negative influence may be minimized by a resonant activation effect: Both the mean escape time and its standard deviation exhibit a minimum as functions of the forcing frequency. The destructive influence of noise on the interspike interval can also be reduced. With driving signals in a certain frequency range, the system can show stable periodic spiking even for relatively large noise intensities. Outside this frequency range, noise of similar intensity destroys the regularity of the spike trains by suppressing the generation of some of the spikes.

Pankratova, E. V.; Polovinkin, A. V.; Mosekilde, E.

2005-06-01

158

On visual-vestibular interaction  

NASA Technical Reports Server (NTRS)

Experimental evidence is presented regarding visual vestibular interaction, and the results of three studies on the subject are briefly noted. An attempt to put together some of these observations with elementary notions of a visual vestibular interaction program is shown in the form of a flow chart representation of a possible model. This is a nonlinear model in which visual and vestibular influences are linearly weighted when they are in relative agreement but switch to the more believable one when they are in disagreement. A solution to the human space orientation problem is depicted by a schema for optimal subjective orientation based on several sensory modalities.

Young, L. R.

1973-01-01

159

Vestibular-evoked myogenic potentials in vestibular migraine  

Microsoft Academic Search

Sound-induced vestibular-evoked myogenic potentials (VEMPs) can be used to investigate saccular function, measured from the\\u000a tonically contracted sternocleidomastoid muscles (SCM) in response to loud sound stimuli. The aim of the present study was\\u000a to assess VEMPs in patients with vestibular migraine and to determine whether saccular function is affected by the disease.\\u000a Furthermore, tests such as tilts of subjective visual

Bernhard Baier; N. Stieber; M. Dieterich

2009-01-01

160

Partial Recovery of Audiological, Vestibular, and Radiological Findings following Spontaneous Intralabyrinthine Haemorrhage  

PubMed Central

The diagnosis, work-up, and treatment of sudden sensorineural hearing loss and sudden vestibular loss vary widely between units. With the increasing access to both magnetic resonance imaging and objective vestibular testing, our understanding of the various aetiologies at hand is increasing. Despite this, the therapeutic options are limited and without a particularly strong evidence base. We present a rare, yet increasingly diagnosed, case of intralabyrinthine haemorrhage (ILH) together with radiological, audiological, and vestibular test results. Of note, this occurred spontaneously and has shown partial recovery in all the mentioned modalities. PMID:24455375

Pezier, Thomas; Hegemann, Stefan

2013-01-01

161

Vestibular function test program evaluation  

E-print Network

Subject: Bioengineering VESTIBULAR FUNCTION TEST PROGRAM EVALUATION A Thesis by GLENN FREDERIC SCMIDT Approved as to style and content by: Charles S. Lessard (Chair of Committee) Edward M. O' Brien (Member) rry Christensen (Member) G. K le Benne... Subject: Bioengineering VESTIBULAR FUNCTION TEST PROGRAM EVALUATION A Thesis by GLENN FREDERIC SCMIDT Approved as to style and content by: Charles S. Lessard (Chair of Committee) Edward M. O' Brien (Member) rry Christensen (Member) G. K le Benne...

Schmidt, Glenn Frederic

2012-06-07

162

Landscape, Flux, Correlation, Resonance, Coherence, Stability, and Key Network Wirings of Stochastic Circadian Oscillation  

PubMed Central

Circadian rhythms with a period of ?24 h, are natural timing machines. They are broadly distributed in living organisms, such as Neurospora, Drosophila, and mammals. The underlying natures of the rhythmic behavior have been explored by experimental and theoretical approaches. However, the global and physical natures of the oscillation under fluctuations are still not very clear. We developed a landscape and flux framework to explore the global stability and robustness of a circadian oscillation system. The potential landscape of the network is uncovered and has a global Mexican-hat shape. The height of the Mexican-hat provides a quantitative measure to evaluate the robustness and coherence of the oscillation. We found that in nonequilibrium dynamic systems, not only the potential landscape but also the probability flux are important to the dynamics of the system under intrinsic noise. Landscape attracts the systems down to the oscillation ring while flux drives the coherent oscillation on the ring. We also investigated the phase coherence and the entropy production rate of the system at different fluctuations and found that dissipations are less and the coherence is higher for larger number of molecules. We also found that the power spectrum of autocorrelation functions show resonance peak at the frequency of coherent oscillations. The peak is less prominent for smaller number of molecules and less barrier height and therefore can be used as another measure of stability of oscillations. As a consequence of nonzero probability flux, we show that the three-point correlations from the time traces show irreversibility, providing a possible way to explore the flux from the observations. Furthermore, we explored the escape time from the oscillation ring to outside at different molecular number. We found that when barrier height is higher, escape time is longer and phase coherence of oscillation is higher. Finally, we performed the global sensitivity analysis of the underlying parameters to find the key network wirings responsible for the stability of the oscillation system. PMID:21943414

Li, Chunhe; Wang, Erkang; Wang, Jin

2011-01-01

163

Neuropharmacology of Vestibular System Disorders  

PubMed Central

This work reviews the neuropharmacology of the vestibular system, with an emphasis on the mechanism of action of drugs used in the treatment of vestibular disorders. Otolaryngologists are confronted with a rapidly changing field in which advances in the knowledge of ionic channel function and synaptic transmission mechanisms have led to the development of new scientific models for the understanding of vestibular dysfunction and its management. In particular, there have been recent advances in our knowledge of the fundamental mechanisms of vestibular system function and drug mechanisms of action. In this work, drugs acting on vestibular system have been grouped into two main categories according to their primary mechanisms of action: those with effects on neurotransmitters and neuromodulator receptors and those that act on voltage-gated ion channels. Particular attention is given in this review to drugs that may provide additional insight into the pathophysiology of vestibular diseases. A critical review of the pharmacology and highlights of the major advances are discussed in each case. PMID:20808544

Soto, Enrique; Vega, Rosario

2010-01-01

164

Morphological studies of the vestibular nerve  

NASA Technical Reports Server (NTRS)

The anatomy of the intratemporal part of the vestibular nerve in man, and the possible age related degenerative changes in the nerve were studied. The form and structure of the vestibular ganglion was studied with the light microscope. A numerical analysis of the vestibular nerve, and caliber spectra of the myelinated fibers in the vestibular nerve branches were studied in individuals of varying ages. It was found that the peripheral endings of the vestibular nerve form a complicated pattern inside the vestibular sensory epithelia. A detailed description of the sensory cells and their surface organelles is included.

Bergstroem, B.

1973-01-01

165

Visual and proprioceptive interaction in patients with bilateral vestibular loss.  

PubMed

Following bilateral vestibular loss (BVL) patients gradually adapt to the loss of vestibular input and rely more on other sensory inputs. Here we examine changes in the way proprioceptive and visual inputs interact. We used functional magnetic resonance imaging (fMRI) to investigate visual responses in the context of varying levels of proprioceptive input in 12 BVL subjects and 15 normal controls. A novel metal-free vibrator was developed to allow vibrotactile neck proprioceptive input to be delivered in the MRI system. A high level (100 Hz) and low level (30 Hz) control stimulus was applied over the left splenius capitis; only the high frequency stimulus generates a significant proprioceptive stimulus. The neck stimulus was applied in combination with static and moving (optokinetic) visual stimuli, in a factorial fMRI experimental design. We found that high level neck proprioceptive input had more cortical effect on brain activity in the BVL patients. This included a reduction in visual motion responses during high levels of proprioceptive input and differential activation in the midline cerebellum. In early visual cortical areas, the effect of high proprioceptive input was present for both visual conditions but in lateral visual areas, including V5/MT, the effect was only seen in the context of visual motion stimulation. The finding of a cortical visuo-proprioceptive interaction in BVL patients is consistent with behavioural data indicating that, in BVL patients, neck afferents partly replace vestibular input during the CNS-mediated compensatory process. An fMRI cervico-visual interaction may thus substitute the known visuo-vestibular interaction reported in normal subject fMRI studies. The results provide evidence for a cortical mechanism of adaptation to vestibular failure, in the form of an enhanced proprioceptive influence on visual processing. The results may provide the basis for a cortical mechanism involved in proprioceptive substitution of vestibular function in BVL patients. PMID:25061564

Cutfield, Nicholas J; Scott, Gregory; Waldman, Adam D; Sharp, David J; Bronstein, Adolfo M

2014-01-01

166

Analysis of inverse stochastic resonance and the long-term firing of Hodgkin-Huxley neurons with Gaussian white noise  

NASA Astrophysics Data System (ADS)

In order to explain the occurrence of a minimum in firing rate which occurs for certain mean input levels ? as noise level ? increases (inverse stochastic resonance, ISR) in Hodgkin-Huxley (HH) systems, we analyze the underlying transitions from a stable equilibrium point to limit cycle and vice-versa. For a value of ? at which ISR is pronounced, properties of the corresponding stable equilibrium point are found. A linearized approximation around this point has oscillatory solutions from whose maxima spikes tend to occur. A one dimensional diffusion is also constructed for small noise. Properties of the basin of attraction of the limit cycle (spike) are investigated heuristically. Long term trials of duration 500000 ms are carried out for values of ? from 0 to 2.0. The graph of mean spike count versus ? is divided into 4 regions R1,…,R4, where R3 contains the minimum associated with ISR. In R1 transitions to the basin of attraction of the rest point are not observed until a small critical value of ?=? is reached, at the beginning of R2. The sudden decline in firing rate when ? is just greater than ? implies that there is only a small range of noise levels 0

Tuckwell, Henry C.; Jost, Jürgen

2012-11-01

167

Perceptual studies in patients with vestibular neurectomy.  

PubMed

Twelve patients undergoing unilateral vestibular neurectomy for the treatment of refractory vertigo were investigated. Vestibular motion perception was assessed using a self-rotational task and "vestibular remembered saccades". Cervical perception was also measured with remembered saccades. The tests were performed pre- and post-operatively to examine changes in vestibular and cervical perception following an acute vestibular lesion, and to monitor the progress of vestibular compensation. These perception tests were carried out in conjunction with a conventional evaluation of the vestibular ocular reflex (VOR), using electro-oculography. The patients' subjective symptoms at each stage of testing were also quantified with questionnaires. Generally, in the vestibular tests, for stimulation to the operated side, responses became strongly hypometric directly after the neurectomy, with a partial recovery during convalescence. In the cervical test, responses were bilaterally reduced immediately after operation. Results from both of the vestibular perception tests were significantly correlated with the VOR assessment of vestibular function. Scores for the patients' subjective symptoms of "vertigo" were only significantly correlated with the vestibular perception tests, and not with the conventional measures of vestibular function. Perceptual measurements afford useful complementary information in the assessment of vestibular patients. PMID:8749175

Kanayama, R; Bronstein, A M; Gresty, M A; Brookes, G B; Faldon, M E; Nakamura, T

1995-01-01

168

Vestibular cues and virtual environments: choosing the magnitude of the vestibular cue  

E-print Network

Vestibular cues and virtual environments: choosing the magnitude of the vestibular cue Laurence of adding vestibular cues during passive linear motion and showed an unexpected dom- inance of the vestibular cue in determining the mag- nitude of the perceived motion. Here we vary the relative magnitude

Jenkin, Michael R. M.

169

Vestibular cues and virtual environments: choosing the magnitude of the vestibular cue  

E-print Network

Vestibular cues and virtual environments: choosing the magnitude of the vestibular cue Laurence of adding vestibular cues during passive linear motion and showed an unexpected dom- inance of the vestibular cue in determining the mag- nitude of the perceived motion. Here we vary the rel- ative magnitude

Harris, Laurence R.

170

Eye movement studies with a vestibular prosthesis/  

E-print Network

Vestibular loss, which can manifest as dizziness, imbalance, or spatial disorientation, is widespread and often caused by inner ear hair cell malfunction. To address these problems, we are developing a vestibular implant ...

Saginaw, Michael A. (Michael Adlai)

2010-01-01

171

Spatio-temporal pattern of vestibular information processing after brief caloric stimulation.  

PubMed

Processing of vestibular information at the cortical and subcortical level is essential for head and body orientation in space and self-motion perception, but little is known about the neural dynamics of the brain regions of the vestibular system involved in this task. Neuroimaging studies using both galvanic and caloric stimulation have shown that several distinct cortical and subcortical structures can be activated during vestibular information processing. The insular cortex has been often targeted and presented as the central hub of the vestibular cortical system. Since very short pulses of cold water ear irrigation can generate a strong and prolonged vestibular response and a nystagmus, we explored the effects of this type of caloric stimulation for assessing the blood-oxygen-level-dependent (BOLD) dynamics of neural vestibular processing in a whole-brain event-related functional magnetic resonance imaging (fMRI) experiment. We evaluated the spatial layout and the temporal dynamics of the activated cortical and subcortical regions in time-locking with the instant of injection and were able to extract a robust pattern of neural activity involving the contra-lateral insular cortex, the thalamus, the brainstem and the cerebellum. No significant correlation with the temporal envelope of the nystagmus was found. The temporal analysis of the activation profiles highlighted a significantly longer duration of the evoked BOLD activity in the brainstem compared to the insular cortex suggesting a functional de-coupling between cortical and subcortical activity during the vestibular response. PMID:18342473

Marcelli, Vincenzo; Esposito, Fabrizio; Aragri, Adriana; Furia, Teresa; Riccardi, Pasquale; Tosetti, Michela; Biagi, Laura; Marciano, Elio; Di Salle, Francesco

2009-05-01

172

Modelling the vestibular head tilt response.  

PubMed

This paper attempts to verify the existence of potentially diagnostically significant periodic signals thought to exist in recordings of neural activity originating from the vestibular nerve, following a single tilt of the head. It then attempts to find the physiological basis of this signal, in particular focusing on the mechanical response of the vestibular system. Simple mechanical models of the semi circular canals having angular velocities applied to them were looked at. A simple single canal model was simulated using CFX software. Finally, a simple model of all three canals with elastic duct walls and a moving cupula was constructed. Pressure waves within the canals were simulated using water hammer or pressure transient theory. In particular, it was investigated whether pressure waves within the utricle following a square pulse angular velocity applied to the canal(s) may be responsible for quasi-periodic oscillatory signals. The simulations showed that there are no pressure waves resonating within the canals following a square pulse angular velocity applied to the canal(s). The results show that the oscillatory signals are most likely not mechanical in origin. It was concluded that further investigation is required. PMID:15920988

Heibert, D; Lithgow, B

2005-03-01

173

Vestibular modulation of spatial perception  

PubMed Central

Vestibular inputs make a key contribution to the sense of one’s own spatial location. While the effects of vestibular stimulation on visuo-spatial processing in neurological patients have been extensively described, the normal contribution of vestibular inputs to spatial perception remains unclear. To address this issue, we used a line bisection task to investigate the effects of galvanic vestibular stimulation (GVS) on spatial perception, and on the transition between near and far space. Brief left-anodal and right-cathodal GVS or right-anodal and left-cathodal GVS were delivered. A sham stimulation condition was also included. Participants bisected lines of different lengths at six distances from the body using a laser pointer. Consistent with previous results, our data showed an overall shift in the bisection bias from left to right as viewing distance increased. This pattern suggests leftward bias in near space, and rightward bias in far space. GVS induced strong polarity dependent effects in spatial perception, broadly consistent with those previously reported in patients: left-anodal and right-cathodal GVS induced a leftward bisection bias, while right-anodal and left-cathodal GVS reversed this effect, and produced bisection bias toward the right side of the space. Interestingly, the effects of GVS were comparable in near and far space. We speculate that vestibular-induced biases in space perception may optimize gathering of information from different parts of the environment. PMID:24133440

Ferre, Elisa R.; Longo, Matthew R.; Fiori, Federico; Haggard, Patrick

2013-01-01

174

The Vestibular System Michael E. Goldberg  

E-print Network

Back 40 The Vestibular System Michael E. Goldberg A. J. Hudspeth AIRPLANES AND SUBMARINES navigate, and invertebrates for still longer. The vestibular system is designed to answer two of the questions basic to human or vestibular labyrinth). Acceleration of the head deflects hair bundles attached to hair cells

Harris, Laurence R.

175

Habituation of vestibular responses: An overview  

NASA Technical Reports Server (NTRS)

An historical survey of vestibular habituation experiments has been undertaken. Methodological problems are presented briefly, and the influence of arousal on vestibular responses is detailed. Data obtained from animals and from man are treated separately. At least for man, the term habituation may be better defined by a dynamic change in the form of vestibular responses than by a simple response reduction.

Collins, W. E.

1973-01-01

176

Brainstem abnormalities and vestibular nerve enhancement in acute Neuroborreliosis  

PubMed Central

Background Borreliosis is a widely distributed disease. Neuroborreliosis may present with unspecific symptoms and signs and often remains difficult to diagnose in patients with central nervous system symptoms, particularly if the pathognomonic erythema chronica migrans does not develop or is missed. Thus, vigilance is mandatory in cases with atypical presentation of the disease and with potentially severe consequences if not recognized early. We present a patient with neuroborreliosis demonstrating brain stem and vestibular nerve abnormalities on magnetic resonance imaging. Case presentation A 28-year-old Caucasian female presented with headaches, neck stiffness, weight loss, nausea, tremor, and gait disturbance. Magnetic resonance imaging showed T2-weighted hyperintense signal alterations in the pons and in the vestibular nerves as well as bilateral post-contrast enhancement of the vestibular nerves. Serologic testing of the cerebrospinal fluid revealed the diagnosis of neuroborreliosis. Conclusion Patients infected with neuroborreliosis may present with unspecific neurologic symptoms and magnetic resonance imaging as a noninvasive imaging tool showing signal abnormalities in the brain stem and nerve root enhancement may help in establishing the diagnosis. PMID:24359885

2013-01-01

177

System identification of the vestibular ocular reflex via visual and vestibular co-stimulation  

E-print Network

The study of eye motions involved in the vestibular ocular reflex (VOR) is a key tool for understanding the performance of the vestibular system and for the diagnosis of dysfunction. Limitations in experimental equipment ...

Tangorra, James Louis, 1967-

2003-01-01

178

UNIVERSIDADE FEDERAL DE SANTA CATARINA COMISSO PERMANENTE DO VESTIBULAR  

E-print Network

UNIVERSIDADE FEDERAL DE SANTA CATARINA COMISSÃ?O PERMANENTE DO VESTIBULAR Dados Gerais do Vestibular : III - DESEMPENHO DOS CANDIDATOS NO VESTIBULAR 5758Total de Candidatos Classificados : 19089Total de

Floeter, Sergio Ricardo

179

Linear addition of optokinetic and vestibular signals in the vestibular nucleus  

Microsoft Academic Search

A simple model of the vestibuloocular reflex and the optokinetic system was used to simulate recent data on visual and vestibular responses of neurons in the vestibular nucleus. Contrary to a previous interpretation, the results support the hypothesis that the optokinetic and semicircular canal signals are combined simply by linear addition on the cells of the vestibular nucleus.

D. A. Robinson

1977-01-01

180

A vestibular phenotype for Waardenburg syndrome?  

NASA Technical Reports Server (NTRS)

OBJECTIVE: To investigate vestibular abnormalities in subjects with Waardenburg syndrome. STUDY DESIGN: Retrospective record review. SETTING: Tertiary referral neurotology clinic. SUBJECTS: Twenty-two adult white subjects with clinical diagnosis of Waardenburg syndrome (10 type I and 12 type II). INTERVENTIONS: Evaluation for Waardenburg phenotype, history of vestibular and auditory symptoms, tests of vestibular and auditory function. MAIN OUTCOME MEASURES: Results of phenotyping, results of vestibular and auditory symptom review (history), results of vestibular and auditory function testing. RESULTS: Seventeen subjects were women, and 5 were men. Their ages ranged from 21 to 58 years (mean, 38 years). Sixteen of the 22 subjects sought treatment for vertigo, dizziness, or imbalance. For subjects with vestibular symptoms, the results of vestibuloocular tests (calorics, vestibular autorotation, and/or pseudorandom rotation) were abnormal in 77%, and the results of vestibulospinal function tests (computerized dynamic posturography, EquiTest) were abnormal in 57%, but there were no specific patterns of abnormality. Six had objective sensorineural hearing loss. Thirteen had an elevated summating/action potential (>0.40) on electrocochleography. All subjects except those with severe hearing loss (n = 3) had normal auditory brainstem response results. CONCLUSION: Patients with Waardenburg syndrome may experience primarily vestibular symptoms without hearing loss. Electrocochleography and vestibular function tests appear to be the most sensitive measures of otologic abnormalities in such patients.

Black, F. O.; Pesznecker, S. C.; Allen, K.; Gianna, C.

2001-01-01

181

Finding physiological responses in vestibular evoked potentials.  

PubMed

Vestibular prostheses are regarded as a promising tool to restore lost sensation in patients with vestibular disorders. These prostheses often electrically stimulate the vestibular nerve and stimulation efficacy is evaluated by measuring the vestibulo-ocular reflex (VOR). However, eye movement recording as intuitive metric of vestibular functionality is difficult to obtain outside the laboratory environment, and hence not available as an error signal in a closed-loop prosthesis. Recently we investigated vestibular evoked potentials (VEPs) by stimulating and recording in the same semicircular canal of a guinea pig. Here we studied the correlation between VOR and one region of VEP. We further analyzed a second portion of VEP, where vestibular nerve activity should occur using rectified bin integration (RBI). To this end, stimulation artifact was significantly reduced by hardware and software approaches. We found a high VEP-VOR correlation (R-squared=0.86), suggesting that VEP could substitute VOR as metric of vestibular function. Differences between below and above vestibular threshold stimulation were seen for the second portion of VEP. Further investigations are required to determine the specific parts of VEP that accurately represents vestibular function(s). PMID:22254790

Nguyen, T A K; Kogler, V; DiGiovanna, J; Micera, S

2011-01-01

182

Vestibular Function Research aboard Spacelab  

NASA Technical Reports Server (NTRS)

NASA is planning to perform a series of Vestibular Function Research (VFR) investigations on the early STS missions to investigate those neurosensory and related physiological processes believed to be associated with the space flight nausea syndrome. The first flight is scheduled for the 1981 Spacelab III Mission in which four frog specimens, mounted on a frog tilting/centrifuge device, will be subjected to periodic acceleration stimuli and periods of artificial gravity. The vestibular nerve firing responses of each frog specimen will be monitored through implanted neutral bouyancy microelectrodes and transmitted to the ground for quick analysis during the flight. The experimentation will be directed at investigating: (1) adaptation to weightlessness; (2) response to acceleration stimuli; (3) response to artificial gravity (in a weightlessness environment) and (4) readaptation to earth's gravity upon return.

Mah, R. W.; Daunton, N. G.

1978-01-01

183

Occupational noise induced vestibular malfunction?  

PubMed Central

This paper comprises a review of the evidence for the possibility that exposure to noise may damage the vestibular receptors in the internal ear as well as those in the cochlea. The review covers lay and medical publications, observations on patients, experimental studies, and compensation claims. It concludes that the verdict must be "not proven"--that is, although such damage is possible, the evidence is not strong enough to regard it as probable. PMID:1733458

Hinchcliffe, R; Coles, R R; King, P F

1992-01-01

184

Resonance  

NSDL National Science Digital Library

For advanced undergraduate students: Observe resonance in a collection of driven, damped harmonic oscillators. Vary the driving frequency and amplitude, the damping constant, and the mass and spring constant of each resonator. Notice the long-lived transients when damping is small, and observe the phase change for resonators above and below resonance.

Simulations, Phet I.; Dubson, Michael; Loeblein, Patricia; Olson, Jonathan; Perkins, Kathy; Gratny, Mindy

2011-07-20

185

Lateralised vestibular hypofunction: Canal paresis and handedness  

Microsoft Academic Search

In this retrospective study it was found that 549 out of 1175 patients seen for vestibular assessment within an 8-year period within a district hospital service showed lateralised canal paresis as determined by caloric testing. It was found that there was a tendency for canal paresis, indicative of vestibular hypofunction, to be on the side of handedness. This bias showed

Anthony OBrien; Neil Gravill

2006-01-01

186

Vestibular-visual interactions in flight simulators  

NASA Technical Reports Server (NTRS)

The following research work is reported: (1) vestibular-visual interactions; (2) flight management and crew system interactions; (3) peripheral cue utilization in simulation technology; (4) control of signs and symptoms of motion sickness; (5) auditory cue utilization in flight simulators, and (6) vestibular function: Animal experiments.

Clark, B.

1977-01-01

187

The etiology of vestibular disorder in infants at risk  

Microsoft Academic Search

The vestibular system together with visual and proprioceptive systems provides information for maintenance of head and body posture, eye position and muscle tonus. We were interested in the factors of vestibular dysfunction in infants at risk of developmental disorder. There were 110 infants included in the study. The vestibular function was estimated by assessment of spontaneous symptoms of vestibular dysfunction

Jagoda Vatovec; Milivoj Veli?kovi?; Lojze Šmid; Anton Gros; Miha Zargi

2003-01-01

188

Vestibular nuclei in the guinea pig: Structural and topical organization  

Microsoft Academic Search

The topological and cytoarchitectonic organization of the vestibular nuclear complex was investigated in guinea pigs. The cellular composition of the superior, lateral, medial, and inferior vestibular nuclei was described by using neutral red stained preparations together with that of neuronal groups (I, F, Y, X, and Z) indirectly associated with the vestibular nuclear complex. Boundaries and stereotaxic coordinates of vestibular

L. Po Voitenko

1990-01-01

189

What spatial information can be derived from vestibular  

E-print Network

PM What spatial information can be derived from vestibular cues? We asked for distance, velocity distance and velocity from the vestibular cues. If the vestibular system is providing a spatial reference position. The vestibular system is known to measure changes in linear and angular position as acceleration

190

1526 IEEE TRANSACTIONS ON NEURAL NETWORKS, VOL. 15, NO. 6, NOVEMBER 2004 Adaptive Stochastic Resonance in Noisy Neurons  

E-print Network

and engineers have largely tried to filter noise or cancel it or mask it out of existence. The Noise Pollution' meaning seasickness. Noise is among the most pervasive pollutants today. Noise from road traffic, jet Resonance in Noisy Neurons Based on Mutual Information Sanya Mitaim and Bart Kosko Abstract--Noise can

Kosko, Bart

191

Virtual Labyrinth model of vestibular afferent excitation via implanted electrodes - Validation and application to design of a multichannel vestibular prosthesis  

PubMed Central

To facilitate design of a multichannel vestibular prosthesis that can restore sensation to individuals with bilateral loss of vestibular hair cell function, we created a virtual labyrinth model. Model geometry was generated through 3-dimensional (3D) reconstruction of microMRI and microCT scans of normal chinchillas (Chinchilla lanigera) acquired with 30–48 ?m and 12 ?m voxels, respectively. Virtual electrodes were positioned based on anatomic landmarks, and the extracellular potential field during a current pulse was computed using finite element methods. Potential fields then served as inputs to stochastic, nonlinear dynamic models for each of 2415 vestibular afferent axons with spiking dynamics based on a modified Smith and Goldberg model incorporating parameters that varied with fiber location in the neuroepithelium. Action potential propagation was implemented by a well validated model of myelinated fibers. We tested the model by comparing predicted and actual 3D angular vestibulo-ocular reflex (aVOR) axes of eye rotation elicited by prosthetic stimuli. Actual responses were measured using 3D video-oculography. The model was individualized for each animal by placing virtual electrodes based on microCT localization of real electrodes. 3D eye rotation axes were predicted from the relative proportion of model axons excited within each of the three ampullary nerves. Multiple features observed empirically were observed as emergent properties of the model, including effects of active and return electrode position, stimulus amplitude and pulse waveform shape on target fiber recruitment and stimulation selectivity. The modeling procedure is partially automated and can be readily adapted to other species, including humans. PMID:21380738

Hayden, Russell; Sawyer, Stacia; Frey, Eric; Mori, Susumu; Migliaccio, Americo A.; Della Santina, Charles C.

2012-01-01

192

The velocity response of vestibular nucleus neurons during vestibular, visual, and combined angular acceleration  

Microsoft Academic Search

In alert Rhesus monkeys neuronal activity in the vestibular nuclei was measured during horizontal angular acceleration in darkness, acceleration of an optokinetic stimulus, and combined visual-vestibular stimulation. The working ranges for visual input velocity and acceleration extend up to 60 °\\/s and 5 °\\/s2. The corresponding working range for vestibular input acceleration is wider and time-dependent. During combined stimulation, that

W. Waespe; V. Henn

1979-01-01

193

Progress Toward Development of a Multichannel Vestibular Prosthesis for Treatment of Bilateral Vestibular Deficiency  

PubMed Central

This article reviews vestibular pathology and the requirements and progress made in the design and construction of a vestibular prosthesis. Bilateral loss of vestibular sensation is disabling. When vestibular hair cells are injured by ototoxic medications or other insults to the labyrinth, the resulting loss of sensory input disrupts vestibulo-ocular reflexes (VORs) and vestibulo-spinal reflexes that normally stabilize the eyes and body. Affected individuals suffer poor vision during head movement, postural instability, chronic disequilibrium, and cognitive distraction. Although most individuals with residual sensation compensate for their loss over time, others fail to do so and have no adequate treatment options. A vestibular prosthesis analogous to cochlear implants but designed to modulate vestibular nerve activity during head movement should improve quality of life for these chronically dizzy individuals. We describe the impact of bilateral loss of vestibular sensation, animal studies supporting feasibility of prosthetic vestibular stimulation, the current status of multichannel vestibular sensory replacement prosthesis development, and challenges to successfully realizing this approach in clinical practice. In bilaterally vestibular-deficient rodents and rhesus monkeys, the Johns Hopkins multichannel vestibular prosthesis (MVP) partially restores the three-dimensional (3D) VOR for head rotations about any axis. Attempts at prosthetic vestibular stimulation of humans have not yet included the 3D eye movement assays necessary to accurately evaluate VOR alignment, but these initial forays have revealed responses that are otherwise comparable to observations in animals. Current efforts now focus on refining electrode design and surgical technique to enhance stimulus selectivity and preserve cochlear function, optimizing stimulus protocols to improve dynamic range and reduce excitation–inhibition asymmetry, and adapting laboratory MVP prototypes into devices appropriate for use in clinical trials. PMID:23044664

FRIDMAN, GENE Y.; DELLA SANTINA, CHARLES C.

2014-01-01

194

Vestibular-induced vomiting after vestibulocerebellar lesions  

NASA Technical Reports Server (NTRS)

Vestibular stimulation, by sinusoidal electrical polarization of the labyrinths of decerebrate cats which can produce vomiting and related activity which resembles motion sickness was examined. The symptoms include panting, salivation, swallowing, and retching as well as vomiting. These symptoms can be produced in cats with lesions of the posterior cerebellar vermis. It is suggested that a transcerebellar pathway from the vestibular apparatus through the nodulus and uvula to the vomiting center is not essential for vestibular induced vomiting and the occurrence of many symptoms of motion.

Miller, A. D.; Wilson, V. J.

1982-01-01

195

Vestibular-induced vomiting after vestibulocerebellar lesions  

NASA Technical Reports Server (NTRS)

Vestibular stimulation, by sinusoidal electrical polarization of the labyrinths of decerebrate cats which can produce vomiting and related activity which resembles motion sickness was examined. The symptoms include panting, salivation, swallowing, and retching as well as vomiting. These symptoms can be produced in cats with lesions of the posterior cerebellar vermis. It is suggested that a transcerebellar pathway from the vestibular apparatus through the nodulus and uvula to the vomiting center is not essential for vestibular induced vomiting and the occurrence of many symptoms of motion.

Miller, A. D.; Wilson, V. J.

1983-01-01

196

Normal and abnormal human vestibular ocular function  

NASA Technical Reports Server (NTRS)

The major motivation of this research is to understand the role the vestibular system plays in sensorimotor interactions which result in spatial disorientation and motion sickness. A second goal was to explore the range of abnormality as it is reflected in quantitative measures of vestibular reflex responses. The results of a study of vestibular reflex measurements in normal subjects and preliminary results in abnormal subjects are presented in this report. Statistical methods were used to define the range of normal responses, and determine age related changes in function.

Peterka, R. J.; Black, F. O.

1986-01-01

197

Resonance  

NSDL National Science Digital Library

All About Circuits is a website that âÂÂprovides a series of online textbooks covering electricity and electronics.â Written by Tony R. Kuphaldt, the textbooks available here are wonderful resources for students, teachers, and anyone who is interested in learning more about electronics. This specific section, Resonance, is the sixth chapter in the Volume II textbook. Topics covered in this chapter include: electric pendulum, simple parallel resonance, simple series resonance, resonance in series-parallel circuits, and Q and bandwidth of a resonant circuit. Diagrams and detailed descriptions of concepts are included throughout the chapter to provide users with a comprehensive lesson. Visitors to the site are also encouraged to discuss concepts and topics using the All About Circuits discussion forums (registration with the site is required to post materials).

Kuphaldt, Tony R.

2008-07-07

198

The Anatomical and Physiological Framework for Vestibular Prostheses  

PubMed Central

This article reviews the structure function of the vestibular system and its pathology with respect to requirements for the design and construction of a functional vestibular prosthesis. The ultimate goal of a vestibular prosthesis is to restore balance and equilibrium through direct activation of vestibular nerve fibers. An overview of the peripheral and central vestibular systems that highlights their most important functional aspects re: the design of a prosthesis is provided. Namely, the peripheral labyrinth faithfully transduces head motion and gravity in both the time and frequency domains. These signals are described in hopes that they may be prosthetically replicated. The peripheral and central connections of the vestibular nerve are also discussed in detail, as are the vestibular nuclei in the brainstem that receive VIIIth nerve innervation. Lastly, the functional effector pathways of the vestibular system, including the vestibulo-ocular, vestibulo-spinal, vestibulo-colic, vestibulo-autonomic, and vestibular efferent innervation of the labyrinth are reviewed. PMID:23044714

Highstein, Stephen M.; Holstein, Gay R.

2014-01-01

199

Primal Terror: A Perspective of Vestibular Dysfunction.  

ERIC Educational Resources Information Center

The effects of "primal terror", the emotional experience of one's inability to naturally maintain balance in opposition to gravity and to integrate vestibular input, are discussed for children with learning and perceptual problems. (CL)

Shaffer, Martin

1979-01-01

200

Vestibular-Visual Interactions in Flight Simulators.  

National Technical Information Service (NTIS)

The following research work is reported: (1) vestibular-visual interactions; (2) flight management and crew system interactions; (3) peripheral cue utilization in simulation technology; (4) control of signs and symptoms of motion sickness; (5) auditory cu...

B. Clark

1977-01-01

201

Fast-Growing Vestibular Schwannoma  

PubMed Central

A case of a Jehovah's witness affected by an intracanalicular vestibular schwannoma with an extremely fast growth rate is presented. Nine months after presentation, the tumor reached 23 mm in the cerebellopontine angle. A partial removal through a retrosigmoid approach was planned. Because of the presence of a dominant high jugular bulb masquering the internal auditory canal, the intracanalicular portion of the tumor was left in place. The residual tumor grew 12 mm in 2 months. Even after a gross total removal through a middle cranial fossa approach, the tumor recurred, reaching the size of 30 mm in 17 months. A modified transcochlear approach was then performed, and the patient was free of disease at the last radiologic follow-up, 8 months after the surgery. We illustrate our strategy in treating this aggressive benign lesion with unusual behavior. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5Figure 6Figure 7Figure 8Figure 9Figure 10 PMID:17171109

Falcioni, Maurizio; Taibah, Abdelkader; De Donato, Giuseppe; Piccirillo, Enrico; Russo, Alessandra; Sanna, Mario

2000-01-01

202

Basic Concepts in Understanding Recovery of Function in Vestibular Reflex Networks during Vestibular Compensation  

PubMed Central

Unilateral peripheral vestibular lesions produce a syndrome of oculomotor and postural deficits with the symptoms at rest, the static symptoms, partially or completely normalizing shortly after the lesion due to a process known as vestibular compensation. The symptoms are thought to result from changes in the activity of vestibular sensorimotor reflexes. Since the vestibular nuclei must be intact for recovery to occur, many investigations have focused on studying these neurons after lesions. At present, the neuronal plasticity underlying early recovery from the static symptoms is not fully understood. Here we propose that knowledge of the reflex identity and input–output connections of the recorded neurons is essential to link the responses to animal behavior. We further propose that the cellular mechanisms underlying vestibular compensation can be sorted out by characterizing the synaptic responses and time course for change in morphologically defined subsets of vestibular reflex projection neurons. Accordingly, this review focuses on the perspective gained by performing electrophysiological and immunolabeling studies on a specific subset of morphologically defined, glutamatergic vestibular reflex projection neurons, the principal cells of the chick tangential nucleus. Reference is made to pertinent findings from other studies on vestibular nuclei neurons, but no comprehensive review of the literature is intended since broad reviews already exist. From recording excitatory and inhibitory spontaneous synaptic activity in principal cells, we find that the rebalancing of excitatory synaptic drive bilaterally is essential for vestibular compensation to proceed. This work is important for it defines for the first time the excitatory and inhibitory nature of the changing synaptic inputs and the time course for changes in a morphologically defined subset of vestibular reflex projection neurons during early stages of vestibular compensation. PMID:22363316

Peusner, Kenna D.; Shao, Mei; Reddaway, Rebecca; Hirsch, June C.

2012-01-01

203

Vestibular development in marsupials and monotremes.  

PubMed

The young of marsupials and monotremes are all born in an immature state, followed by prolonged nurturing by maternal lactation in either a pouch or nest. Nevertheless, the level of locomotor ability required for newborn marsupials and monotremes to reach the safety of the pouch or nest varies considerably: some are transferred to the pouch or nest in an egg (monotremes); others are transferred passively by gravity (e.g. dasyurid marsupials); some have only a horizontal wriggle to make (e.g. peramelid and didelphid marsupials); and others must climb vertically for a long distance to reach the maternal pouch (e.g. diprotodontid marsupials). In the present study, archived sections of the inner ear and hindbrain held in the Bolk, Hill and Hubrecht collections at the Museum für Naturkunde, Berlin, were used to test the relationship between structural maturity of the vestibular apparatus and the locomotor challenges that face the young of these different mammalian groups. A system for staging different levels of structural maturity of the vestibular apparatus was applied to the embryos, pouch young and hatchlings, and correlated with somatic size as indicated by greatest body length. Dasyurids are born at the most immature state, with the vestibular apparatus at little more than the otocyst stage. Peramelids are born with the vestibular apparatus at a more mature state (fully developed semicircular ducts and a ductus reuniens forming between the cochlear duct and saccule, but no semicircular canals). Diprotodontids and monotremes are born with the vestibular apparatus at the most mature state for the non-eutherians (semicircular canals formed, maculae present, but vestibular nuclei in the brainstem not yet differentiated). Monotremes and marsupials reach the later stages of vestibular apparatus development at mean body lengths that lie within the range of those found for laboratory rodents (mouse and rat) reaching the same vestibular stage. PMID:24298911

Ashwell, Ken W S; Shulruf, Boaz

2014-04-01

204

Unilateral Vestibular Loss Impairs External Space Representation  

PubMed Central

The vestibular system is responsible for a wide range of postural and oculomotor functions and maintains an internal, updated representation of the position and movement of the head in space. In this study, we assessed whether unilateral vestibular loss affects external space representation. Patients with Menière's disease and healthy participants were instructed to point to memorized targets in near (peripersonal) and far (extrapersonal) spaces in the absence or presence of a visual background. These individuals were also required to estimate their body pointing direction. Menière's disease patients were tested before unilateral vestibular neurotomy and during the recovery period (one week and one month after the operation), and healthy participants were tested at similar times. Unilateral vestibular loss impaired the representation of both the external space and the body pointing direction: in the dark, the configuration of perceived targets was shifted toward the lesioned side and compressed toward the contralesioned hemifield, with higher pointing error in the near space. Performance varied according to the time elapsed after neurotomy: deficits were stronger during the early stages, while gradual compensation occurred subsequently. These findings provide the first demonstration of the critical role of vestibular signals in the representation of external space and of body pointing direction in the early stages after unilateral vestibular loss. PMID:24523916

Borel, Liliane; Redon-Zouiteni, Christine; Cauvin, Pierre; Dumitrescu, Michel; Deveze, Arnaud; Magnan, Jacques; Peruch, Patrick

2014-01-01

205

Vestibular stimulation affects optic-flow sensitivity.  

PubMed

Typically, multiple cues can be used to generate a particular percept. Our area of interest is the extent to which humans are able to synergistically combine cues that are generated when moving through an environment. For example, movement through the environment leads to both visual (optic-flow) and vestibular stimulation, and studies have shown that non-human primates are able to combine these cues to generate a more accurate perception of heading than can be obtained with either cue in isolation. Here we investigate whether humans show a similar ability to synergistically combine optic-flow and vestibular cues. This was achieved by determining the sensitivity to optic-flow stimuli while physically moving the observer, and hence producing a vestibular signal, that was either consistent with the optic-flow signal, eg a radially expanding pattern coupled with forward motion, or inconsistent with it, eg a radially expanding pattern with backward motion. Results indicate that humans are more sensitive to motion-in-depth optic-flow stimuli when they are combined with complementary vestibular signals than when they are combined with conflicting vestibular signals. These results indicate that in humans, like in nonhuman primates, there is perceptual integration of visual and vestibular signals. PMID:21180352

Edwards, Mark; O'Mahony, Simon; Ibbotson, Michael R; Kohlhagen, Stuart

2010-01-01

206

Vestibular facilitation of optic flow parsing.  

PubMed

Simultaneous object motion and self-motion give rise to complex patterns of retinal image motion. In order to estimate object motion accurately, the brain must parse this complex retinal motion into self-motion and object motion components. Although this computational problem can be solved, in principle, through purely visual mechanisms, extra-retinal information that arises from the vestibular system during self-motion may also play an important role. Here we investigate whether combining vestibular and visual self-motion information improves the precision of object motion estimates. Subjects were asked to discriminate the direction of object motion in the presence of simultaneous self-motion, depicted either by visual cues alone (i.e. optic flow) or by combined visual/vestibular stimuli. We report a small but significant improvement in object motion discrimination thresholds with the addition of vestibular cues. This improvement was greatest for eccentric heading directions and negligible for forward movement, a finding that could reflect increased relative reliability of vestibular versus visual cues for eccentric heading directions. Overall, these results are consistent with the hypothesis that vestibular inputs can help parse retinal image motion into self-motion and object motion components. PMID:22768345

MacNeilage, Paul R; Zhang, Zhou; DeAngelis, Gregory C; Angelaki, Dora E

2012-01-01

207

Vestibular function assessment using the NIH Toolbox  

PubMed Central

Objective: Development of an easy to administer, low-cost test of vestibular function. Methods: Members of the NIH Toolbox Sensory Domain Vestibular, Vision, and Motor subdomain teams collaborated to identify 2 tests: 1) Dynamic Visual Acuity (DVA), and 2) the Balance Accelerometry Measure (BAM). Extensive work was completed to identify and develop appropriate software and hardware. More than 300 subjects between the ages of 3 and 85 years, with and without vestibular dysfunction, were recruited and tested. Currently accepted gold standard measures of static visual acuity, vestibular function, dynamic visual acuity, and balance were performed to determine validity. Repeat testing was performed to examine reliability. Results: The DVA and BAM tests are affordable and appropriate for use for individuals 3 through 85 years of age. The DVA had fair to good reliability (0.41–0.94) and sensitivity and specificity (50%–73%), depending on age and optotype chosen. The BAM test was moderately correlated with center of pressure (r = 0.42–0.48) and dynamic posturography (r = ?0.48), depending on age and test condition. Both tests differentiated those with and without vestibular impairment and the young from the old. Each test was reliable. Conclusion: The newly created DVA test provides a valid measure of visual acuity with the head still and moving quickly. The novel BAM is a valid measure of balance. Both tests are sensitive to age-related changes and are able to screen for impairment of the vestibular system. PMID:23479540

Schubert, Michael C.; Whitney, Susan L.; Roberts, Dale; Redfern, Mark S.; Musolino, Mark C.; Roche, Jennica L.; Steed, Daniel P.; Corbin, Bree; Lin, Chia-Cheng; Marchetti, Greg F.; Beaumont, Jennifer; Carey, John P.; Shepard, Neil P.; Jacobson, Gary P.; Wrisley, Diane M.; Hoffman, Howard J.; Furman, Gabriel; Slotkin, Jerry

2013-01-01

208

Neuronal activity in the vestibular nuclei of the alert monkey during vestibular and optokinetic stimulation  

Microsoft Academic Search

Recordings from neurons of the vestibular nuclei were performed in alert monkeys. Type I and type II units were identified by rotating the monkey about a vertical axis. All neurons responded also when only the visual surround was rotated around the stationary monkey. The combination of visual and vestibular stimulation points towards non-algebraic summation characteristics for the two inputs, with

W. Waespe; V. Henn

1977-01-01

209

Neurotology symptoms at referral to vestibular evaluation  

PubMed Central

Background Dizziness-vertigo is common in adults, but clinical providers may rarely diagnose vestibular impairment and referral could be delayed. To assess neurotology symptoms (including triggers) reported by patients with peripheral vestibular disease, during the year just before their referral to vestibular evaluation. Methods 282 patients with peripheral vestibular disease and 282 control subjects accepted to participate. They had no middle ear, retinal, neurological, psychiatric, autoimmune or autonomic disorders. They reported their symptoms by a standardized questionnaire along with their anxiety/depression symptoms. Results Patients were referred after months or years from the onset of their symptoms, 24% of them reported frequent falls with a long clinical evolution; 10% of them reported no vertigo but instability related to specific triggers; 86% patients and 12% control subjects reported instability when moving the head rapidly and 79% patients and 6% control subjects reported instability when changing posture. Seven out of the 9 symptoms explored by the questionnaire allowed the correct classification of circa 95% of the participants (Discriminant function analysis, p?vestibular evaluation may underlie a history of frequent falls; some patients may not report vertigo, but instability related to specific triggers, which could be useful to prompt vestibular evaluation. High blood pressure, dyslipidemia and anxiety/depression symptoms may have a mild influence on the report of symptoms of vestibular disease in both, patients and control subjects. PMID:24279682

2013-01-01

210

Pharmacotherapy of vestibular disorders and nystagmus.  

PubMed

Vertigo and dizziness are with a life-time prevalence of ~30% among the most common symptoms and are often associated with nystagmus or other oculomotor disorders. The prerequisite for a successful treatment is a precise diagnosis of the underlying disorder. In this overview, the current pharmacological treatment options for peripheral and central vestibular, cerebellar, and oculomotor disorders including nystagmus are described. There are basically seven groups of drugs that can be used (the "7 As"): antiemetics; anti-inflammatory, anti-Menière's, and antimigraine medications; antidepressants, anticonvulsants, and aminopyridines. In acute vestibular neuritis, recovery of the peripheral vestibular function can be improved by treatment with oral corticosteroids. In Menière's disease, a long-term high-dose treatment with betahistine-dihydrochloride (at least 48 mg three times daily) had a significant effect on the frequency of the attacks; the underlying mode of action is evidently an increase in inner-ear blood flow. The use of aminopyridines is a well-established therapeutic principle in the treatment of downbeat and upbeat nystagmus as well as episodic ataxia type 2 and cerebellar gait disorders. As was shown in animal experiments, these potassium channel blockers increase the activity and excitability and normalize irregular firing of cerebellar Purkinje cells. They evidently augment the inhibitory influence of these cells on vestibular and deep cerebellar nuclei. A few studies showed that baclofen improves periodic alternating nystagmus; gabapentin and memantine improve pendular and infantile nystagmus. However, many other eye-movement disorders such as ocular flutter, opsoclonus, central positioning, and see-saw nystagmus are still difficult to treat. Although substantial progress has been made, further state-of-the-art trials must still be performed on many vestibular and oculomotor disorders, namely Menière's disease, vestibular paroxysmia, vestibular migraine, and many forms of central eye-movement disorders. PMID:24057832

Strupp, Michael; Kremmyda, Olympia; Brandt, Thomas

2013-07-01

211

Orbital Spaceflight During Pregnancy Shapes Function of Mammalian Vestibular System  

E-print Network

that prenatal spaceflight exposure shapes vestibular-mediated behavior and central morphology. Postflight testing revealed (a) delayed onset of body righting responses, (b) cardiac deceleration (bradycardia shape prenatal organization and function within the mammalian vestibular system. Keywords microgravity

212

Computational Approaches to Vestibular Research  

NASA Technical Reports Server (NTRS)

The Biocomputation Center at NASA Ames Research Center is dedicated to a union between computational, experimental and theoretical approaches to the study of neuroscience and of life sciences in general. The current emphasis is on computer reconstruction and visualization of vestibular macular architecture in three-dimensions (3-D), and on mathematical modeling and computer simulation of neural activity in the functioning system. Our methods are being used to interpret the influence of spaceflight on mammalian vestibular maculas in a model system, that of the adult Sprague-Dawley rat. More than twenty 3-D reconstructions of type I and type II hair cells and their afferents have been completed by digitization of contours traced from serial sections photographed in a transmission electron microscope. This labor-intensive method has now been replace d by a semiautomated method developed in the Biocomputation Center in which conventional photography is eliminated. All viewing, storage and manipulation of original data is done using Silicon Graphics workstations. Recent improvements to the software include a new mesh generation method for connecting contours. This method will permit the investigator to describe any surface, regardless of complexity, including highly branched structures such as are routinely found in neurons. This same mesh can be used for 3-D, finite volume simulation of synapse activation and voltage spread on neuronal surfaces visualized via the reconstruction process. These simulations help the investigator interpret the relationship between neuroarchitecture and physiology, and are of assistance in determining which experiments will best test theoretical interpretations. Data are also used to develop abstract, 3-D models that dynamically display neuronal activity ongoing in the system. Finally, the same data can be used to visualize the neural tissue in a virtual environment. Our exhibit will depict capabilities of our computational approaches and some of our findings from their application. For example, our research has demonstrated that maculas of adult mammals retain the property of synaptic plasticity. Ribbon synapses increase numerically and undergo changes in type and distribution (p<0.0001) in type II hair cells after exposure to microgravity for as few as nine days. The finding of macular synaptic plasticity is pertinent to the clinic, and may help explain some. balance disorders in humans. The software used in our investigations will be demonstrated for those interested in applying it in their own research.

Ross, Muriel D.; Wade, Charles E. (Technical Monitor)

1994-01-01

213

Auditory and Vestibular Issues Related to Human Spaceflight  

NASA Technical Reports Server (NTRS)

Human spaceflight provides unique opportunities to study human vestibular and auditory systems. This session will discuss 1) vestibular adaptive processes reflected by pronounced perceptual and motor coordination problems during, and after, space missions; 2) vestibular diagnostic and rehabilitative techniques (used to promote recovery after living in altered gravity environments) that may be relevant to treatment of vestibular disorders on earth; and 3) unique acoustical challenges to hearing loss prevention and crew performance during spaceflight missions.

Danielson, Richard W.; Wood, Scott J.

2009-01-01

214

Visual Dependency and Dizziness after Vestibular Neuritis  

PubMed Central

Symptomatic recovery after acute vestibular neuritis (VN) is variable, with around 50% of patients reporting long term vestibular symptoms; hence, it is essential to identify factors related to poor clinical outcome. Here we investigated whether excessive reliance on visual input for spatial orientation (visual dependence) was associated with long term vestibular symptoms following acute VN. Twenty-eight patients with VN and 25 normal control subjects were included. Patients were enrolled at least 6 months after acute illness. Recovery status was not a criterion for study entry, allowing recruitment of patients with a full range of persistent symptoms. We measured visual dependence with a laptop-based Rod-and-Disk Test and severity of symptoms with the Dizziness Handicap Inventory (DHI). The third of patients showing the worst clinical outcomes (mean DHI score 36–80) had significantly greater visual dependence than normal subjects (6.35° error vs. 3.39° respectively, p?=?0.03). Asymptomatic patients and those with minor residual symptoms did not differ from controls. Visual dependence was associated with high levels of persistent vestibular symptoms after acute VN. Over-reliance on visual information for spatial orientation is one characteristic of poorly recovered vestibular neuritis patients. The finding may be clinically useful given that visual dependence may be modified through rehabilitation desensitization techniques. PMID:25233234

Cousins, Sian; Cutfield, Nicholas J.; Kaski, Diego; Palla, Antonella; Seemungal, Barry M.; Golding, John F.; Staab, Jeffrey P.; Bronstein, Adolfo M.

2014-01-01

215

Morphological and neurochemical correlates of vestibular compensation.  

PubMed

Morphometric analysis of the cat's superior vestibulo-ocular neurons (SVON) 8 weeks, and 1 and 2 years following vestibular neurectomy or labyrinthectomy revealed similar changes which indicate that an excitatory mode of input to the denervated SVON is responsible for the behavioral recovery. These changes include an increased proportion of strong asymmetric synapses, somal spines surrounding the SP, increased size of and number of SP at long (> 1 year) survival periods. There is a parallel decrease < 1 year and increase > 1 year of contralateral vestibular nerve SP on SVON which matches in timing and magnitude the number of ipsilateral vestibular nerve SP after surgical ablation. These unexpected SVON are consistent with the hypothesis that neurotrophins regulate symmetry in the adult vestibular system. This hypothesis was tested in a series of 13 heterozygous brain derived neurotrophic factor (BDNF), neurotrophin 3 (NT3), and neurotrophin 4 (NT4) knockout mice. Following unilateral surgical labyrinthectomy the BDNF and NT4 knockout mice demonstrated no delay in behavioral recovery compared to their normal littermate controls. However, the NT3 knockout mice required twice the time to recover from balance deficits as their littermate controls. These results indicate that NT3 protein is important for normal vestibular function. PMID:9673734

Gacek, R R; Khetarpal, U; Schoonmaker, J

1998-05-01

216

[Is the sense of verticality vestibular?].  

PubMed

The vestibular system constitutes an inertial sensor, which detects linear (otoliths) and angular (semicircular canals) accelerations of the head in the three dimensions. The otoliths are specialized in the detection of linear accelerations and can be used by the brain as a "plumb line" coding earth gravity acceleration (direction). This property of otolithic system suggested that the sense of verticality is supported by the vestibular system. The preeminence of vestibular involvement in the sense of verticality stated in the 1900s was progressively supplanted by the notion of internal models of verticality. The internal models of verticality involve rules and properties of integration of vestibular graviception, somaesthesic graviception, and vision. The construction of a mental representation of verticality was mainly modeled as a bottom-up organization integrating visual, somatosensory and vestibular information without any cognitive modulations. Recent studies reported that the construction of internal models of verticality is not an automatic multi-sensory integration process but corresponds to more complex mechanisms including top-down influences such as awareness of body orientation or spatial representations. PMID:23856176

Barra, J; Pérennou, D

2013-06-01

217

Identifying visual–vestibular contributions during target-directed locomotion  

Microsoft Academic Search

The purpose of this experiment was to examine the potential interaction between visual and vestibular inputs as participants walked towards 1 of 3 targets located on a barrier 5m away. Visual and vestibular inputs were perturbed with displacing prisms and galvanic vestibular stimulation (GVS), respectively. For each target there were three vision conditions (no prisms, prisms left, and prisms right),

Anthony N. Carlsen; Paul M. Kennedy; Ken G. Anderson; Erin K. Cressman; Paul Nagelkerke; Romeo Chua

2005-01-01

218

Short communication Effectiveness of an electro-tactile vestibular substitution  

E-print Network

Short communication Effectiveness of an electro-tactile vestibular substitution system in improving upright postural control in unilateral vestibular-defective patients Nicolas Vuillerme a,*, Nicolas We investigated the effects of an electro-tactile vestibular substitution system (EVSS) on upright

Payan, Yohan

219

An Immersive Virtual Environment for Visuo-Vestibular Therapy  

E-print Network

An Immersive Virtual Environment for Visuo-Vestibular Therapy J.D. GASCUEL a , H. PAYNO a , S several interacting cues. On patients with vestibular loss, vision plays a major role. In this study to vestibular areflexic patients are composed of a repetition of dynamic op- tic flows, with varying speed

Paris-Sud XI, Université de

220

Vestibular cues and virtual environments Laurence Harris1;3  

E-print Network

Vestibular cues and virtual environments Laurence Harris1;3 Michael Jenkin2;3 Daniel C. Zikovitz3" and may a ect operator per- formance. Here we examine the role of vestibular cues to self-motion on an operator's sense of self-motion within a virtual environment. We show that the pres- ence of vestibular

Jenkin, Michael R. M.

221

ORIGINAL ARTICLE An Observed Relationship Between Vestibular Function and  

E-print Network

ORIGINAL ARTICLE An Observed Relationship Between Vestibular Function and Auditory Thresholds, PhD, and Anthony Brown, MPH Objective: We sought to examine the vestibular function and whether an association exists between vestibular function and hearing thresholds in a group of military aircraft

Boggess, May M.

222

A Vestibular Sensation: Probabilistic Approaches to Spatial Perception  

E-print Network

Neuron Review A Vestibular Sensation: Probabilistic Approaches to Spatial Perception Dora E.neuron.2009.11.010 The vestibular system helps maintain equilibrium and clear vision through reflexes, but it also contributes to spatial perception. In recent years, research in the vestibular field has expanded

Snyder, Larry

223

RESEARCH ARTICLE Vestibular contribution to the planning of reach trajectories  

E-print Network

RESEARCH ARTICLE Vestibular contribution to the planning of reach trajectories Christopher J. We investigated whether the nervous system uses vestibular signals of head rotation to predict stationary, but experienced a strong vestibular rotation signal. We achieved this by rotating subjects at 360

Haslwanter, Thomas

224

An Electronic Prosthesis Mimicking the Dynamic Vestibular Andrei M. Shkela  

E-print Network

An Electronic Prosthesis Mimicking the Dynamic Vestibular Function Andrei M. Shkela a, USA 92697 ABSTRACT This paper reports our progress toward development of a unilateral vestibular the corresponding vestibular nerve branch. Our preliminary experimental evaluations of the prosthesis on a rate

Tang, William C

225

Implementation of a neuromorphic vestibular sensor with analog VLSI neurons  

E-print Network

Implementation of a neuromorphic vestibular sensor with analog VLSI neurons Giovanni Passetti neuromorphic vestibular sensor using a commercial Inertial Mea- surement Unit (IMU) and a custom analog VLSI neuromorphic chip. We investigate a model of the vestibular sensor that emu- lates the spiking responses

226

RESEARCH ARTICLE Perceived timing of vestibular stimulation relative to touch,  

E-print Network

RESEARCH ARTICLE Perceived timing of vestibular stimulation relative to touch, light and sound. Here we measured the perceived timing of galvanic vestibular stimulation (GVS) relative to tactile for differences in processing times. Keywords Audition Á Galvanic vestibular stimulation Á Multisensory Á

Harris, Laurence R.

227

Visual-Vestibular Sensor Integration Follows a Max-Rule  

E-print Network

Visual-Vestibular Sensor Integration Follows a Max-Rule: Results from Psychophysical Experiments a vestibularly defined path twice, subjects (six in each group) were asked to reproduce it from memory. Fig. 3 (Stewart platform) and a head-mounted display for presenting vestibular and visual stimuli, respectively

228

An Electronic Prosthesis Mimicking the Dynamic Vestibular Function  

E-print Network

An Electronic Prosthesis Mimicking the Dynamic Vestibular Function Jiayin Liu Mechanical function of a unilateral semicircular canal of the vestibular system. The circuitry is an integral part a prosthesis that matches the signal recorded from the vestibular nerve in squirrel monkey experiments reported

Tang, William C

229

Neural Correlates of Sensory Substitution in Vestibular Pathways Following Complete Vestibular Loss  

PubMed Central

Sensory substitution is the term typically used in reference to sensory prosthetic devices designed to replace input from one defective modality with input from another modality. Such devices allow an alternative encoding of sensory information that is no longer directly provided by the defective modality in a purposeful and goal-directed manner. The behavioral recovery that follows complete vestibular loss is impressive and has long been thought to take advantage of a natural form of sensory substitution in which head motion information is no longer provided by vestibular inputs, but instead by extra-vestibular inputs such as proprioceptive and motor efference copy signals. Here we examined the neuronal correlates of this behavioral recovery after complete vestibular loss in alert behaving monkeys (Macaca mulata). We show for the first time that extra-vestibular inputs substitute for the vestibular inputs to stabilize gaze at the level of single neurons in the VOR premotor circuitry. The summed weighting of neck proprioceptive and efference copy information was sufficient to explain simultaneously observed behavioral improvements in gaze stability. Furthermore, by altering correspondence between intended and actual head movement we revealed a four-fold increase in the weight of neck motor efference copy signals consistent with the enhanced behavioral recovery observed when head movements are voluntary versus unexpected. Thus, taken together our results provide direct evidence that the substitution by extra-vestibular inputs in vestibular pathways provides a neural correlate for the improvements in gaze stability that are observed following the total loss of vestibular inputs. PMID:23077054

Sadeghi, Soroush G.; Minor, Lloyd B.; Cullen, Kathleen E.

2012-01-01

230

Optical nerve stimulation for a vestibular prosthesis  

NASA Astrophysics Data System (ADS)

Infrared Nerve Stimulation (INS) offers several advantages over electrical stimulation, including more precise spatial selectivity and improved surgical access. In this study, INS and electrical stimulation were compared in their ability to activate the vestibular branch of the VIIIth nerve, as a potential way to treat balance disorders. The superior and lateral canals of the vestibular system of Guinea pigs were identified and approached with the aid of precise 3-D reconstructions. A monopolar platinum stimulating electrode was positioned near the ampullae of the canals, and biphasic current pulses were used to stimulate vestibular evoked potentials and eye movements. Thresholds and input/output functions were measured for various stimulus conditions. A short pulsed diode laser (Capella, Lockheed Martin-Aculight, Inc., Bothell WA) was placed in the same anatomical position and various stimulus conditions were evaluated in their ability to evoke similar potentials and eye movements.

Harris, David M.; Bierer, Steven M.; Wells, Jonathon D.; Phillips, James O.

2009-02-01

231

Calcification of vestibular schwannoma: a case report and literature review  

PubMed Central

Calcification rarely occurs in vestibular schwannoma (VS), and only seven cases of calcified VS have been reported in the literature. Here, we report a 48-year-old man with VS, who had a history of progressive left-sided hearing loss for 3 years. Neurological examination revealed that he had left-sided hearing loss and left cerebellar ataxia. Magnetic resonance imaging and computerized tomography angiography showed a mass with calcification in the left cerebellopontine angle (CPA). The tumor was successfully removed via suboccipital craniotomy, and postoperative histopathology showed that the tumor was a schwannoma. We reviewed seven cases of calcified VS that were previously reported in the literature, and we analyzed and summarized the characteristics of these tumors, including the calcification, texture, and blood supply. We conclude that calcification in VS is associated with its texture and blood supply, and these characteristics affect the surgical removal of the tumor. PMID:23031739

2012-01-01

232

[Vestibular schwannoma: active treatment or follow-up?].  

PubMed

Vestibular schwannoma is a rare benign tumor of a cranial nerve. The symptom picture is usually a varying one, centering on otogenic symptoms, such as hearing loss, tinnitus and dizziness. The diagnosis is often made only after the patient has already had symptoms for a longer time. The number of tumors found yearly in Finland is estimated to be approximately 50 to 100. Even very small tumors are detected by contrast-enhanced magnetic resonance imaging. Since a significant proportion of the tumors remain unchanged in size over a follow-up observation period of several years, follow-up instead of surgical treatment is considered adequate for some of the patients. PMID:25158580

Blomstedt, Göran; Ramsay, Hans

2014-01-01

233

Current Treatment of Vestibular, Ocular Motor Disorders and Nystagmus  

PubMed Central

Vertigo and dizziness are among the most common complaints with a lifetime prevalence of about 30%. The various forms of vestibular disorders can be treated with pharmacological therapy, physical therapy, psychotherapeutic measures or, rarely, surgery. In this review, the current pharmacological treatment options for peripheral and central vestibular, cerebellar and ocular motor disorders will be described. They are as follows for peripheral vestibular disorders. In vestibular neuritis recovery of the peripheral vestibular function can be improved by treatment with oral corticosteroids. In Menière's disease a recent study showed long-term high-dose treatment with betahistine has a significant effect on the frequency of the attacks. The use of aminopyridines introduced a new therapeutic principle in the treatment of downbeat and upbeat nystagmus and episodic ataxia type 2 (EA 2). These potassium channel blockers presumably increase the activity and excitability of cerebellar Purkinje cells, thereby augmenting the inhibitory influence of these cells on vestibular and cerebellar nuclei. A few studies showed that baclofen improves periodic alternating nystagmus, and gabapentin and memantine, pendular nystagmus. However, many other eye movement disorders such as ocular flutter opsoclonus, central positioning, or see-saw nystagmus are still difficult to treat. Although progress has been made in the treatment of vestibular neuritis, downbeat and upbeat nystagmus, as well as EA 2, state-of-the-art trials must still be performed on many vestibular and ocular motor disorders, namely Menière's disease, bilateral vestibular failure, vestibular paroxysmia, vestibular migraine, and many forms of central eye movement disorders. PMID:21179531

Brandt, Thomas

2009-01-01

234

Cortical responses of vestibular reactions measured by topographic brain mapping and vestibular evoked potentials.  

PubMed

With the brain electrical activity mapping, we started to create typical patterns of potentials distributions on the scalp during various neurootological experiments. We are applying this technique for spatiotemporal analysis of cerebral evoked potentials due to vestibular stimulation. We obtain the vestibular evoked potentials (VbEP) using for the stimulation, the rotatory chair. We control it, with an external computer, that by means of an interactive program builds different sort of stimuli varying each one of the stimulus components. The electrodes are distributed on the scalp in agreement with the international system 10/20. We recognize with security, 4 positive-negative waves in a period among 70 to 490 ms. We designate the waves N1, N2, P2, N3 and N4. Vestibular evoked potentials is a newly developed tool, which we also can utilize for differentiating central and peripheral vestibular diseases. PMID:8749099

Bertora, G O; Bergmann, J M

1995-01-01

235

From ear to uncertainty: vestibular contributions to cognitive function  

PubMed Central

In addition to the deficits in the vestibulo-ocular and vestibulo-spinal reflexes that occur following vestibular dysfunction, there is substantial evidence that vestibular loss also causes cognitive disorders, some of which may be due to the reflexive deficits and some of which are related to the role that ascending vestibular pathways to the limbic system and neocortex play in spatial orientation. In this review we summarize the evidence that vestibular loss causes cognitive disorders, especially spatial memory deficits, in animals and humans and critically evaluate the evidence that these deficits are not due to hearing loss, problems with motor control, oscillopsia or anxiety and depression. We review the evidence that vestibular lesions affect head direction and place cells as well as the emerging evidence that artificial activation of the vestibular system, using galvanic vestibular stimulation (GVS), can modulate cognitive function. PMID:24324413

Smith, Paul F.; Zheng, Yiwen

2013-01-01

236

Stochastic current drive by wave  

SciTech Connect

A new mechanism of current drive by a wave is discussed. There are a series of resonant regions in the velocity space for a magnetized plasma interacting with a single wave. When the amplitude of the wave is larger than a threshold, some of the resonant regions will overlap each other and the stochastic effect will appear. If the overlapping region is asymmetric in the longitudinal velocity distribution of the electrons, a plasma current may be driven by the wave as a result of the stochastic effect.

Xia Meng-fen

1983-10-01

237

Perspectives in vestibular diagnostics and therapy  

PubMed Central

Vestibular diagnostics and therapy ist the mirror of technological, scientific and socio-economics trends as are other fields of clinical medicine. These trends have led to a substantial diversification of the field of neurotology. The improvements in diagnostics have been characterized by the introduction of new receptor testing tools (e.g., VEMPs), progress in imaging (e.g., the endolymphatic hydrops) and in the description of central-vestibular neuroplasticity. The etiopathology of vestibular disorders has been updated by geneticists (e.g., the description of the COCH gene mutations), the detection of structural abnormalities (e.g., dehiscence syndromes) and related disorders (e.g. migraine-associated vertigo). The therapeutic options were extended by re-evaluation of techniques known a long time ago (e.g., saccus exposure), the development of new approaches (e.g., dehiscence repair) and the introduction of new drug therapy concepts (e.g., local drug delivery). Implantable, neuroprosthetic solutions have not yet reached experimental safety and validity and are still far away. However, externally worn neuroprosthetic solution were introduced in the rehab of vestibular disorders (e.g., VertiGuard system). These and related trends point into a medical future which is characterized by presbyvertigo as classical sign of the demographic changes ahead, by shortage of financial resources and a medico-legally over-regulated, even hostile environment for physicians in clinical medicine. PMID:22558055

Ernst, Arneborg

2012-01-01

238

Vesibulotoxicity and Management of Vestibular Disorders  

ERIC Educational Resources Information Center

The toxicity of certain aminoglycoside antibiotics for vestibular hair cells has been used to special advantage in the treatment of Meniere's disease. Intratympanic (middle ear) injections of these drugs are being increasingly used to control vertigo in this disorder when it has not responded to medical therapy. The mechanisms by which these drugs…

Carey, John P.

2005-01-01

239

Vestibular dysfunction in Gulf War syndrome  

Microsoft Academic Search

Methods : Vestibular complaints of Gulf War veterans were characterized by a nested case-control study of 23 veterans with 3 different Gulf War syndromes and 20 matched control subjects. All subjects completed a standardized symptom questionnaire and underwent standard audiovestibular tests administered by audiologists blinded to group identities. Results : The prevalence of reported dizzy spells was higher in veterans

PETER S. ROLAND; ROBERT W. HALEY; WENDY YELLIN; KRIS OWENS; ANGELA G. SHOUP

2000-01-01

240

Flunarizine and Cinnarizine as Vestibular Depressants  

Microsoft Academic Search

The authors analysed the vestibular depressant activity of flunarizine and cinnarizine, as compared to a placebo, in 58 patients with peripheral labyrinthine disorders. The activity of the medications was judged by the reduction of the average velocity of the slow phase of the post-caloric nystagmus, before and after treatment. In spite of being administered in a smaller dosis, flunarizine appeared

Pedro L. Mangabeira-Albernaz; Mauricio Malavasi Ganança; Neil Ferreira Novo; Elias Rodrigues de Paiva

1978-01-01

241

Vestibular stimulation leads to distinct hemodynamic patterning  

NASA Technical Reports Server (NTRS)

Previous studies demonstrated that responses of a particular sympathetic nerve to vestibular stimulation depend on the type of tissue the nerve innervates as well as its anatomic location. In the present study, we sought to determine whether such precise patterning of vestibulosympathetic reflexes could lead to specific hemodynamic alterations in response to vestibular afferent activation. We simultaneously measured changes in systemic blood pressure and blood flow (with the use of Doppler flowmetry) to the hindlimb (femoral artery), forelimb (brachial artery), and kidney (renal artery) in chloralose-urethane-anesthetized, baroreceptor-denervated cats. Electrical vestibular stimulation led to depressor responses, 8 +/- 2 mmHg (mean +/- SE) in magnitude, that were accompanied by decreases in femoral vasoconstriction (23 +/- 4% decrease in vascular resistance or 36 +/- 7% increase in vascular conductance) and increases in brachial vascular tone (resistance increase of 10 +/- 6% and conductance decrease of 11 +/- 4%). Relatively small changes (<5%) in renal vascular tone were observed. In contrast, electrical stimulation of muscle and cutaneous afferents produced pressor responses (20 +/- 6 mmHg) that were accompanied by vasoconstriction in all three beds. These data suggest that vestibular inputs lead to a complex pattern of cardiovascular changes that is distinct from that which occurs in response to activation of other types of somatic afferents.

Kerman, I. A.; Emanuel, B. A.; Yates, B. J.

2000-01-01

242

Intrameatal thrombosed anterior inferior cerebellar artery aneurysm mimicking a vestibular schwannoma.  

PubMed

Aneurysms of the anterior inferior cerebellar artery (AICA) are a rare entity. Purely intrameatal aneurysms are even rarer. The authors report an intrameatal thrombosed AICA aneurysm mimicking a vestibular schwannoma that was treated by resection and end-to-end anastomosis. This 22-year-old man presented with acute hearing loss, vertigo, and moderate facial palsy. Magnetic resonance imaging showed an atypical intrameatal lesion with dilation of the internal auditory canal. Microsurgical inspection via a retrosigmoid approach and drilling of the posterior wall of the internal auditory canal revealed a thrombosed AICA aneurysm. The aneurysm was excised, and an end-to-end suture was performed to restore AICA continuity. Intraoperative indocyanine green videoangiography as well as postoperative digital substraction angiography showed a good revascularization. Intrameatal AICA aneurysms may present with symptoms similar to vestibular schwannomas. End-to-end reanastomosis after aneurysm resection is a treatment option when clipping is impossible. PMID:20964593

Päsler, Dennis; Baldauf, Jörg; Runge, Uwe; Schroeder, Henry W S

2011-04-01

243

Behavioral/Systems/Cognitive A Comparison of Vestibular Spatiotemporal Tuning in  

E-print Network

Behavioral/Systems/Cognitive A Comparison of Vestibular Spatiotemporal Tuning in Macaque Parietoinsular Vestibular Cortex, Ventral Intraparietal Area, and Medial Superior Temporal Area Aihua Chen,1, Center for Visual Science, University of Rochester, New York 14627 Vestibular responses have been

DeAngelis, Gregory

244

Information transmission and detection thresholds in the vestibular nuclei: single neurons vs. population encoding  

E-print Network

Information transmission and detection thresholds in the vestibular nuclei: single neurons vs. Information transmission and detection thresholds in the vestibular nuclei: single neurons vs. population. Peripheral vestibular afferents display differential variability that is correlated with the importance

Chacron, Maurice

245

Anxiety Changes Depersonalization and Derealization Symptoms in Vestibular Patients  

PubMed Central

Background. Depersonalization and derealization are common symptoms reported in the general population. Objective. The aim of the present study was to establish the relationship between anxiety and depersonalization and derealization symptoms in patients with peripheral vestibular disorders. Methods. Twenty-four vestibular patients with anxiety and 18 vestibular patients without anxiety were examined for depersonalization and derealization symptoms. They were also compared to healthy controls. Results. The results revealed that anxiety consistently changes depersonalization and derealization symptoms in vestibular patients. They are more frequent, more severe, and qualitatively different in vestibular patients with anxiety than in those without anxiety. Conclusion. Anxiety has an effect on depersonalization and derealization symptoms in vestibular patients. The various hypotheses about the underlying mechanism of this effect were discussed. PMID:24803735

Kolev, Ognyan I.; Georgieva-Zhostova, Spaska O.; Berthoz, Alain

2014-01-01

246

Recovery of vestibular function following hair cell destruction by streptomycin  

NASA Technical Reports Server (NTRS)

Can the vestibular periphery of warm-blooded vertebrates recover functionally from severe sensory hair cell loss? Recent findings in birds suggest a mechanism for recovery but in fact no direct functional evidence has been reported. We produced vestibular hair cell lesions using the ototoxic agent streptomycin sulfate (600 mg/kg/day, 8 days, chicks, Gallus domesticus). Compound action potentials of the vestibular nerve were used as a direct measure of peripheral vestibular function. Vestibular thresholds, neural activation latencies and amplitudes were documented. Eight days of drug treatment elevated thresholds significantly (P < 0.001) and eliminated all but remnants of vestibular activity. Virtually complete physiological recovery occurred in all animals studied over a period of 70 days following treatment. Thresholds recovered within two weeks of drug treatment whereas the return of response morphologies including activation latencies and amplitudes required an additional 6-8 weeks.

Jones, T. A.; Nelson, R. C.

1992-01-01

247

The vestibular contribution to the head direction signal and navigation.  

PubMed

Spatial learning and navigation depend on neural representations of location and direction within the environment. These representations, encoded by place cells and head direction (HD) cells, respectively, are dominantly controlled by visual cues, but require input from the vestibular system. Vestibular signals play an important role in forming spatial representations in both visual and non-visual environments, but the details of this vestibular contribution are not fully understood. Here, we review the role of the vestibular system in generating various spatial signals in rodents, focusing primarily on HD cells. We also examine the vestibular system's role in navigation and the possible pathways by which vestibular information is conveyed to higher navigation centers. PMID:24795578

Yoder, Ryan M; Taube, Jeffrey S

2014-01-01

248

Diverse spatial reference frames of vestibular signals in parietal cortex.  

PubMed

Reference frames are important for understanding how sensory cues from different modalities are coordinated to guide behavior, and the parietal cortex is critical to these functions. We compare reference frames of vestibular self-motion signals in the ventral intraparietal area (VIP), parietoinsular vestibular cortex (PIVC), and dorsal medial superior temporal area (MSTd). Vestibular heading tuning in VIP is invariant to changes in both eye and head positions, indicating a body (or world)-centered reference frame. Vestibular signals in PIVC have reference frames that are intermediate between head and body centered. In contrast, MSTd neurons show reference frames between head and eye centered but not body centered. Eye and head position gain fields were strongest in MSTd and weakest in PIVC. Our findings reveal distinct spatial reference frames for representing vestibular signals and pose new challenges for understanding the respective roles of these areas in potentially diverse vestibular functions. PMID:24239126

Chen, Xiaodong; Deangelis, Gregory C; Angelaki, Dora E

2013-12-01

249

Vestibular schwannoma with contralateral facial pain – case report  

E-print Network

© 2003 Eftekhar et al; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL. Background: Vestibular schwannoma (acoustic neuroma) most commonly presents with ipsilateral disturbances of acoustic, vestibular, trigeminal and facial nerves. Presentation of vestibular schwannoma with contralateral facial pain is quite uncommon. Case presentation: Among 156 cases of operated vestibular schwannoma, we found one case with unusual presentation of contralateral hemifacial pain. Conclusion: The presentation of contralateral facial pain in the vestibular schwannoma is rare. It seems that displacement and distortion of the brainstem and compression of the contralateral trigeminal nerve in Meckel's cave by the large mass lesion may lead to this atypical presentation. The best practice in these patients is removal of the tumour, although persistent contralateral pain after operation has been reported. Background Vestibular schwannoma (acoustic neuroma) most commonly

Bmc Neurology; Behzad Eftekhar; Mohammadreza Gheini; Mohammad Ghodsi; Ebrahim Ketabchi

2003-01-01

250

Stochastic model of the residual acceleration environment in microgravity  

NASA Technical Reports Server (NTRS)

We describe a theoretical investigation of the effects that stochastic residual accelerations (g-jitter) onboard spacecraft can have on experiments conducted in a microgravity environment. We first introduce a stochastic model of the residual acceleration field, and develop a numerical algorithm to solve the equations governing fluid flow that allow for a stochastic body force. We next summarize our studies of two generic situations: stochastic parametric resonance and the onset of convective flow induced by a fluctuating acceleration field.

Vinals, Jorge

1994-01-01

251

New methods for diagnosis and treatment of vestibular diseases  

PubMed Central

Dizziness and vertigo are common complaints, with a lifetime prevalence of over 30%. This review provides a brief summary of the recent diagnostic and therapeutic advances in the field of neuro-otology. A special focus is placed on the clinical usefulness of vestibular tests. While these have markedly improved over the years, treatment options for vestibular disorders still remain limited. Available therapies for selected vestibular diseases are discussed. PMID:21173877

Palla, Antonella

2010-01-01

252

Methylprednisolone, Valacyclovir, or the Combination for Vestibular Neuritis  

Microsoft Academic Search

background Vestibular neuritis is the second most common cause of peripheral vestibular vertigo. Its assumed cause is a reactivation of herpes simplex virus type 1 infection. Therefore, corticosteroids, antiviral agents, or a combination of the two might improve the out- come in patients with vestibular neuritis. methods We performed a prospective, randomized, double-blind, two-by-two factorial trial in which patients with

Michael Strupp; Vera Carina Zingler; Viktor Arbusow; Daniel Niklas; Klaus Peter Maag; Marianne Dieterich; Sandra Bense; Diethilde Theil; Klaus Jahn; Thomas Brandt

2010-01-01

253

Exploiting Vestibular Output during Learning Results in Naturally Curved Reaching Trajectories  

E-print Network

Exploiting Vestibular Output during Learning Results in Naturally Curved Reaching Trajectories a vestibular system. We show that this simplification introduces errors that are easily overcome by a standard

Scassellati, Brian

254

Direction specific biases in human visual and vestibular heading perception.  

PubMed

Heading direction is determined from visual and vestibular cues. Both sensory modalities have been shown to have better direction discrimination for headings near straight ahead. Previous studies of visual heading estimation have not used the full range of stimuli, and vestibular heading estimation has not previously been reported. The current experiments measure human heading estimation in the horizontal plane to vestibular, visual, and spoken stimuli. The vestibular and visual tasks involved 16 cm of platform or visual motion. The spoken stimulus was a voice command speaking a heading angle. All conditions demonstrated direction dependent biases in perceived headings such that biases increased with headings further from the fore-aft axis. The bias was larger with the visual stimulus when compared with the vestibular stimulus in all 10 subjects. For the visual and vestibular tasks precision was best for headings near fore-aft. The spoken headings had the least bias, and the variation in precision was less dependent on direction. In a separate experiment when headings were limited to ± 45°, the biases were much less, demonstrating the range of headings influences perception. There was a strong and highly significant correlation between the bias curves for visual and spoken stimuli in every subject. The correlation between visual-vestibular and vestibular-spoken biases were weaker but remained significant. The observed biases in both visual and vestibular heading perception qualitatively resembled predictions of a recent population vector decoder model (Gu et al., 2010) based on the known distribution of neuronal sensitivities. PMID:23236490

Crane, Benjamin T

2012-01-01

255

Vestibular schwannoma: dissecting the pathologic process and clinical applications.  

E-print Network

??Vestibular schwannomas continue to cause significant morbidity including hearing loss, facial nerve paralysis, brainstem compression and death. Although the gene responsible for maintaining tumor suppression… (more)

Welling, Duane Bradley

2003-01-01

256

Vestibular-ocular accommodation reflex in man  

NASA Technical Reports Server (NTRS)

Stimulation of the vestibular system by angular acceleration produces widespread sensory and motor effects. The present paper studies a motor effect which has not been reported in the literature, i.e., the influence of rotary acceleration of the body on ocular accommodation. The accommodation of 10 young men was recorded before and after a high-level deceleration to zero velocity following 30 sec of rotating. Accommodation was recorded continuously on an infrared optometer for 110 sec under two conditions: while the subjects observed a target set at the far point, and while they viewed the same target through a 0.3-mm pinhole. Stimulation by high-level rotary deceleration produced positive accommodation or a pseudomyopia under both conditions, but the positive accommodation was substantially greater and lasted much longer during fixation through the pinhole. It is hypothesized that this increase in accommodation is a result of a vestibular-ocular accommodation reflex.

Clark, B.; Randle, R. J.; Stewart, J. D.

1975-01-01

257

Status of vestibular function after prolonged bedrest  

NASA Astrophysics Data System (ADS)

6 young, healthy, male volunteers were submitted to one week of head down (-4°) bedrest. This position simulates the cerebral hemodynamic conditions in weightlessness. Measurements of vestibular equilibrium and of oculomotor system function were made before and after the prolonged bedrest. Analysis of the results indicates that vestibular responses, as measured by the maximal speed of the slow phase of the provoked nystagmus (caloric and sinusoidal rotatory stimulations), are decreased after prolonged bedrest. This statistically significant diminution requires confirmation with a greater number of cases. The reflex conflicting or interacting with the cervico-ocular and optokinetic reflexes on the one hand and the foveal vision on the other, is one of several possible explanations for the observed changes.

Burgeat, M.; Toupet, M.; Loth, D.; Ingster, I.; Guell, A.; Coll, J.

258

The vestibular system of the owl  

NASA Technical Reports Server (NTRS)

Five owls were given vestibular examinations, and two of them were sacrificed to provide serial histological sections of the temporal bones. The owls exhibited a curious variability in the postrotatory head nystagmus following abrupt deceleration; sometimes a brisk nystagnus with direction opposite to that appropriate to the stimulus would occur promptly after deceleration. It was found also that owls can exhibit a remarkable head stability during angular movement of the body about any axis passing through the skull. The vestibular apparatus in the owl is larger than in man, and a prominent crista neglecta is present. The tectorial membrane, the cupula, and the otolithic membranes of the utricle, saccule, and lagena are all attached to surfaces in addition to the surfaces hearing hair cells. These attachments are very substantial in the utricular otolithic membrane and in the cupula.

Money, K. E.; Correia, M. J.

1973-01-01

259

Vestibular activation of sympathetic nerve activity  

NASA Technical Reports Server (NTRS)

AIM: The vestibulosympathetic reflex refers to sympathetic nerve activation by the vestibular system. Animal studies indicate that the vestibular system assists in blood pressure regulation during orthostasis. Although human studies clearly demonstrate activation of muscle sympathetic nerve activity (MSNA) during engagement of the otolith organs, the role of the vestibulosympathetic reflex in maintaining blood pressure during orthostasis is not well-established. Examination of the vestibulosympathetic reflex with other cardiovascular reflexes indicates that it is a powerful and independent reflex. Ageing, which is associated with an increased risk for orthostatic hypotension, attenuates the vestibulosympathetic reflex. The attenuated reflex is associated with a reduction in arterial pressure. CONCLUSION: These findings suggest that the vestibulosympathetic reflex assists in blood pressure regulation in humans, but future studies examining this reflex in other orthostatically intolerant populations are necessary to address this hypothesis.

Ray, C. A.; Carter, J. R.

2003-01-01

260

Visualizing How the Vestibular System Works  

NSDL National Science Digital Library

In this activity (page 59 of the PDF), learners spin and observe false eyelashes in jars of water (prepared at least 1 day ahead of time) to investigate the effects of different types of motion on the hairs suspended in fluid in the inner ear. The model also demonstrates how the vestibular system maintains or restores equilibrium despite movement. The lesson guide, part of NASA's "The Brain in Space: A Teacher's Guide with Activities for Neuroscience," includes background information, evaluation strategies and handouts.

Macleish, Marlene Y.; Mclean, Bernice R.

2012-06-26

261

Recurrence of Vestibular Schwannomas after Surgery  

Microsoft Academic Search

The issue of recurrence of vestibular schwannomas is poorly studied by the surgical literature and is probably underestimated. Our own long-term retrospective analysis after translabyrinthine approach has indicated a 9.2% recurrence rate. This long-term event is mainly due to regrowth of microfragments that have been left in the operative field along the course of the facial nerve or at the

P. Roche; T. Ribeiro; M. Khalil; O. Soumare; J. Thomassin; W. Pellet

2008-01-01

262

Vestibular compensation and orientation during locomotion  

NASA Technical Reports Server (NTRS)

Body, head, and eye movements were studied in three dimensions while walking and turning to determine the role of the vestibular system in directing gaze and maintaining spatial orientation. The body, head, and eyes were represented as three-dimensional coordinate frames, and the movement of these frames was related to a trajectory frame that described the motion of the body on a terrestrial plane. The axis-angle of the body, head, and eye rotation were then compared to the axis-angle of the rotation of the gravitoinertial acceleration (GIA). We inferred the role of the vestibular system during locomotion and the contributions of the VCR and VOR by examining the interrelationship between these coordinate frames. Straight walking induced head and eye rotations in a compensatory manner to the linear accelerations, maintaining head pointing and gaze along the direction of forward motion. Turning generated a combination of compensation and orientation responses. The head leads and steers the turn while the eyes compensate to maintain stable horizontal gaze in space. Saccades shift horizontal gaze as the turn is executed. The head pitches, as during straight walking. It also rolls so that the head tends to align with the orientation of the GIA. Head orientation changes anticipate orientation changes of the GIA. Eye orientation follows the changes in GIA orientation so that the net orientation gaze is closer to the orientation of the GIA. The study indicates that the vestibular system utilizes compensatory and orienting mechanisms to stabilize spatial orientation and gaze during walking and turning.

Raphan, T.; Imai, T.; Moore, S. T.; Cohen, B.

2001-01-01

263

Posture control in vestibular-loss patients.  

PubMed

Patients with chronic bilateral loss of vestibular functions normally replace these by visual or haptic referencing to stationary surroundings, resulting in an almost normal stance control. But with eyes closed, they show abnormally large body sway, and may tend to fall when there are external disturbances to the body or when standing on an unstable support surface. Patients' postural responses depend on joint angle proprioception and ground reaction-force cues (occasionally referred to as "somatosensory graviception"). It is asked why the force cues do not allow patients to fully substitute loss of the vestibular cues. In recent years, four sets of observations of experimental situations where patients, eyes closed, show impaired stance control or even may fall were identified: (1) with unstable or compliant support ("inevitable falls"); (2) with large external disturbances such as support surface tilts or pull stimuli impacting on their bodies (leading to abnormally large body movements); (3) with fast body-support tilts (also abnormally large body movements); and (4) with transient support tilt (overshooting body-support stabilization and abnormaly late body-space [BS] stabilization). When patients' data were modeled, it was found that their problems stem mainly from the force cues. It was hypothesized that patients have difficulties decomposing this sensory information into its constituents in order to be able to get rid of an active force component. Normals do not have this difficulty, because the vestibular system performs the decomposition. PMID:19645901

Mergner, Thomas; Schweigart, Georg; Fennell, Luminous; Maurer, Christoph

2009-05-01

264

Integration of vestibular and head movement signals in the vestibular nuclei during whole-body rotation  

NASA Technical Reports Server (NTRS)

Single-unit recordings were obtained from 107 horizontal semicircular canal-related central vestibular neurons in three alert squirrel monkeys during passive sinusoidal whole-body rotation (WBR) while the head was free to move in the yaw plane (2.3 Hz, 20 degrees /s). Most of the units were identified as secondary vestibular neurons by electrical stimulation of the ipsilateral vestibular nerve (61/80 tested). Both non-eye-movement (n = 52) and eye-movement-related (n = 55) units were studied. Unit responses recorded when the head was free to move were compared with responses recorded when the head was restrained from moving. WBR in the absence of a visual target evoked a compensatory vestibulocollic reflex (VCR) that effectively reduced the head velocity in space by an average of 33 +/- 14%. In 73 units, the compensatory head movements were sufficiently large to permit the effect of the VCR on vestibular signal processing to be assessed quantitatively. The VCR affected the rotational responses of different vestibular neurons in different ways. Approximately one-half of the units (34/73, 47%) had responses that decreased as head velocity decreased. However, the responses of many other units (24/73) showed little change. These cells had signals that were better correlated with trunk velocity than with head velocity. The remaining units had responses that were significantly larger (15/73, 21%) when the VCR produced a decrease in head velocity. Eye-movement-related units tended to have rotational responses that were correlated with head velocity. On the other hand, non-eye-movement units tended to have rotational responses that were better correlated with trunk velocity. We conclude that sensory vestibular signals are transformed from head-in-space coordinates to trunk-in-space coordinates on many secondary vestibular neurons in the vestibular nuclei by the addition of inputs related to head rotation on the trunk. This coordinate transformation is presumably important for controlling postural reflexes and constructing a central percept of body orientation and movement in space.

Gdowski, G. T.; McCrea, R. A.; Peterson, B. W. (Principal Investigator)

1999-01-01

265

Otolith-Canal Convergence in Vestibular Nuclei Neurons  

NASA Technical Reports Server (NTRS)

During manned spaceflight, acute vestibular disturbances often occur, leading to physical duress and a loss of performance. Vestibular adaptation to the weightless environment follows within two to three days yet the mechanisms responsible for the disturbance and subsequent adaptation are still unknown In order to understand vestibular system function in space and normal earth conditions the basic physiological mechanisms of vestibular information co coding must be determined. Information processing regarding head movement and head position with respect to gravity takes place in the vestibular nuclei neurons that receive signals From the semicircular canals and otolith organs in the vestibular labyrinth. These neurons must synthesize the information into a coded output signal that provides for the head and eye movement reflexes as well as the conscious perception of the body in three-dimensional space The current investigation will for the first time. determine how the vestibular nuclei neurons quantitatively synthesize afferent information from the different linear and angular acceleration receptors in the vestibular labyrinths into an integrated output signal. During the second year of funding, progress on the current project has been focused on the anatomical orientation of semicircular canals and the spatial orientation of the innervating afferent responses. This information is necessary in order to understand how vestibular nuclei neurons process the incoming afferent spatial signals particularly with the convergent otolith afferent signals that are also spatially distributed Since information from the vestibular nuclei is presented to different brain regions associated with differing reflexive and sensory functions it is important to understand the computational mechanisms used by vestibular neurons to produce the appropriate output signal.

Dickman, J. David

1996-01-01

266

Differential central projections of vestibular afferents in pigeons  

NASA Technical Reports Server (NTRS)

The question of whether a differential distribution of vestibular afferent information to central nuclear neurons is present in pigeons was studied using neural tracer compounds. Discrete tracing of afferent fibers innervating the individual semicircular canal and otolith organs was produced by sectioning individual branches of the vestibular nerve that innervate the different receptor organs and applying crystals of horseradish peroxidase, or a horseradish peroxidase/cholera toxin mixture, or a biocytin compound for neuronal uptake and transport. Afferent fibers and their terminal distributions within the brainstem and cerebellum were visualized subsequently. Discrete areas in the pigeon central nervous system that receive primary vestibular input include the superior, dorsal lateral, ventral lateral, medial, descending, and tangential vestibular nuclei; the A and B groups; the intermediate, medial, and lateral cerebellar nuclei; and the nodulus, the uvula, and the paraflocculus. Generally, the vertical canal afferents projected heavily to medial regions in the superior and descending vestibular nuclei as well as the A group. Vertical canal projections to the medial and lateral vestibular nuclei were observed but were less prominent. Horizontal canal projections to the superior and descending vestibular nuclei were much more centrally located than those of the vertical canals. A more substantial projection to the medial and lateral vestibular nuclei was seen with horizontal canal afferents compared to vertical canal fibers. Afferents innervating the utricle and saccule terminated generally in the lateral regions of all vestibular nuclei in areas that were separate from the projections of the semicircular canals. In addition, utricular fibers projected to regions in the vestibular nuclei that overlapped with the horizontal semicircular canal terminal fields, whereas saccular afferents projected to regions that received vertical canal fiber terminations. Lagenar afferents projected throughout the cochlear nuclei, to the dorsolateral regions of the cerebellar nuclei, and to lateral regions of the superior, lateral, medial, and descending vestibular nuclei.

Dickman, J. D.; Fang, Q.

1996-01-01

267

Stochastic thermodynamics  

NASA Astrophysics Data System (ADS)

'Stochastic thermodynamics as a conceptual framework combines the stochastic energetics approach introduced a decade ago by Sekimoto [1] with the idea that entropy can consistently be assigned to a single fluctuating trajectory [2]'. This quote, taken from Udo Seifert's [3] 2008 review, nicely summarizes the basic ideas behind stochastic thermodynamics: for small systems, driven by external forces and in contact with a heat bath at a well-defined temperature, stochastic energetics [4] defines the exchanged work and heat along a single fluctuating trajectory and connects them to changes in the internal (system) energy by an energy balance analogous to the first law of thermodynamics. Additionally, providing a consistent definition of trajectory-wise entropy production gives rise to second-law-like relations and forms the basis for a 'stochastic thermodynamics' along individual fluctuating trajectories. In order to construct meaningful concepts of work, heat and entropy production for single trajectories, their definitions are based on the stochastic equations of motion modeling the physical system of interest. Because of this, they are valid even for systems that are prevented from equilibrating with the thermal environment by external driving forces (or other sources of non-equilibrium). In that way, the central notions of equilibrium thermodynamics, such as heat, work and entropy, are consistently extended to the non-equilibrium realm. In the (non-equilibrium) ensemble, the trajectory-wise quantities acquire distributions. General statements derived within stochastic thermodynamics typically refer to properties of these distributions, and are valid in the non-equilibrium regime even beyond the linear response. The extension of statistical mechanics and of exact thermodynamic statements to the non-equilibrium realm has been discussed from the early days of statistical mechanics more than 100 years ago. This debate culminated in the development of linear response theory for small deviations from equilibrium, in which a general framework is constructed from the analysis of non-equilibrium states close to equilibrium. In a next step, Prigogine and others developed linear irreversible thermodynamics, which establishes relations between transport coefficients and entropy production on a phenomenological level in terms of thermodynamic forces and fluxes. However, beyond the realm of linear response no general theoretical results were available for quite a long time. This situation has changed drastically over the last 20 years with the development of stochastic thermodynamics, revealing that the range of validity of thermodynamic statements can indeed be extended deep into the non-equilibrium regime. Early developments in that direction trace back to the observations of symmetry relations between the probabilities for entropy production and entropy annihilation in non-equilibrium steady states [5-8] (nowadays categorized in the class of so-called detailed fluctuation theorems), and the derivations of the Bochkov-Kuzovlev [9, 10] and Jarzynski relations [11] (which are now classified as so-called integral fluctuation theorems). Apart from its fundamental theoretical interest, the developments in stochastic thermodynamics have experienced an additional boost from the recent experimental progress in fabricating, manipulating, controlling and observing systems on the micro- and nano-scale. These advances are not only of formidable use for probing and monitoring biological processes on the cellular, sub-cellular and molecular level, but even include the realization of a microscopic thermodynamic heat engine [12] or the experimental verification of Landauer's principle in a colloidal system [13]. The scientific program Stochastic Thermodynamics held between 4 and 15 March 2013, and hosted by The Nordic Institute for Theoretical Physics (Nordita), was attended by more than 50 scientists from the Nordic countries and elsewhere, amongst them many leading experts in the field. During the program, the most recent developments, open quest

Eichhorn, Ralf; Aurell, Erik

2014-04-01

268

QB1 - Stochastic Gene Regulation  

SciTech Connect

Summaries of this presentation are: (1) Stochastic fluctuations or 'noise' is present in the cell - Random motion and competition between reactants, Low copy, quantization of reactants, Upstream processes; (2) Fluctuations may be very important - Cell-to-cell variability, Cell fate decisions (switches), Signal amplification or damping, stochastic resonances; and (3) Some tools are available to mode these - Kinetic Monte Carlo simulations (SSA and variants), Moment approximation methods, Finite State Projection. We will see how modeling these reactions can tell us more about the underlying processes of gene regulation.

Munsky, Brian [Los Alamos National Laboratory

2012-07-23

269

Stochastic cooling  

SciTech Connect

Stochastic cooling is the damping of betatron oscillations and momentum spread of a particle beam by a feedback system. In its simplest form, a pickup electrode detects the transverse positions or momenta of particles in a storage ring, and the signal produced is amplified and applied downstream to a kicker. The time delay of the cable and electronics is designed to match the transit time of particles along the arc of the storage ring between the pickup and kicker so that an individual particle receives the amplified version of the signal it produced at the pick-up. If there were only a single particle in the ring, it is obvious that betatron oscillations and momentum offset could be damped. However, in addition to its own signal, a particle receives signals from other beam particles. In the limit of an infinite number of particles, no damping could be achieved; we have Liouville's theorem with constant density of the phase space fluid. For a finite, albeit large number of particles, there remains a residue of the single particle damping which is of practical use in accumulating low phase space density beams of particles such as antiprotons. It was the realization of this fact that led to the invention of stochastic cooling by S. van der Meer in 1968. Since its conception, stochastic cooling has been the subject of much theoretical and experimental work. The earliest experiments were performed at the ISR in 1974, with the subsequent ICE studies firmly establishing the stochastic cooling technique. This work directly led to the design and construction of the Antiproton Accumulator at CERN and the beginnings of p anti p colliding beam physics at the SPS. Experiments in stochastic cooling have been performed at Fermilab in collaboration with LBL, and a design is currently under development for a anti p accumulator for the Tevatron.

Bisognano, J.; Leemann, C.

1982-03-01

270

Visual, vestibular and voluntary contributions to human head stabilization  

Microsoft Academic Search

We have investigated the ability of humans to stabilize their heads in space and assessed the influence of mental set and the relative importance of visual and vestibular cues. Ten normal subjects and 3 patients with bilateral vestibular loss were studied. Subjects were fixed firmly to the chair of a turntable facing a screen on which was projected a target

D. Guitton; R. E. Kearney; N. Wereley; B. W. Peterson

1986-01-01

271

Responses of guinea pig primary vestibular neurons to clicks  

Microsoft Academic Search

Responses of single neurons in the vestibular nerve to high-intensity clicks were studied by extracellular recording in anaesthetised guinea pigs. One hundred and two neurons in the posterior division of the superior branch or in the inferior branch of the vestibular nerve were activated at short latency by intense clicks. The latency of activation was short (median 0.9 ms) and

Toshihisa Murofushi; Ian S. Curthoys; Ann N. Topple; James G. Colebatch; G. Michael Halmagyi

1995-01-01

272

Postural strategies associated with somatosensory and vestibular loss  

Microsoft Academic Search

This study examines the roles of somatosensory and vestibular information in the coordination of postural responses. The role of somatosensory information was examined by comparing postural responses of healthy control subjects prior to and following somatosensory loss due to hypoxic anesthesia of the feet and ankles. The role of vestibular information was evaluated by comparing the postural responses of control

F. B. Horak; L. M. Nashner; H. C. Diener

1990-01-01

273

Human ocular torsional position before and after unilateral vestibular neurectomy  

Microsoft Academic Search

The static ocular torsional position of both eyes of 23 patients was measured by means of fundus photographs one day before and one week after unilateral vestibular neurectomy for the treatment of acoustic neuroma, Ménière's disease or paroxysmal vertigo. The results showed that in all patients the vestibular neurectomy caused both eyes to tort (i.e. to roll around the visual

I. S. Curthoys; M. J. Dai; G. M. Halmagyi

1991-01-01

274

Selective effect of cinnarizine on the vestibular nucleus neurons  

Microsoft Academic Search

Effects of cinnarizine were studied on the lateral vestibular nucleus (LVN) and spinal trigeminal nucleus (STN) of cats anesthetized with a-chloralose. Cinnarizine did not produce any obvious alterations of the field potential and spike generation of type B interneurons in STN elicited by trigeminal nerve stimulation as well as the field potential in LVN by vestibular nerve stimulation. Spike generation

Sakae Fujimoto; Masashi Sasa; Shuji Takaori; Izuru Matsuoka

1978-01-01

275

Vestibular Pharmacology of Flunarizine Compared to that of Cinnarizine  

Microsoft Academic Search

Flunarizine markedly depressed vestibular activity in rabbits. The vestibular effect was also evaluated in a double-blind multiple cross-over study in human volunteers, using cinnarizine as a reference drug. Dosage was 10 and 30 mg of e and 15 and 45 mg of Flunarizine cinnarizine. Electronystagmographic tracings were taken at different time intervals after drug intake. There was a good correlation

W. J. Oosterveld

1974-01-01

276

Balancing the mind: vestibular induced facilitation of egocentric mental transformations.  

PubMed

The body schema is a key component in accomplishing egocentric mental transformations, which rely on bodily reference frames. These reference frames are based on a plurality of different cognitive and sensory cues among which the vestibular system plays a prominent role. We investigated whether a bottom-up influence of vestibular stimulation modulates the ability to perform egocentric mental transformations. Participants were significantly faster to make correct spatial judgments during vestibular stimulation as compared to sham stimulation. Interestingly, no such effects were found for mental transformation of hand stimuli or during mental transformations of letters, thus showing a selective influence of vestibular stimulation on the rotation of whole-body reference frames. Furthermore, we found an interaction with the angle of rotation and vestibular stimulation demonstrating an increase in facilitation during mental body rotations in a direction congruent with rightward vestibular afferents. We propose that facilitation reflects a convergence in shared brain areas that process bottom-up vestibular signals and top-down imagined whole-body rotations, including the precuneus and tempero-parietal junction. Ultimately, our results show that vestibular information can influence higher-order cognitive processes, such as the body schema and mental imagery. PMID:22750744

Falconer, Caroline J; Mast, Fred W

2012-01-01

277

Bayesian integration of visual and vestibular signals for heading.  

PubMed

Self-motion through an environment involves a composite of signals such as visual and vestibular cues. Building upon previous results showing that visual and vestibular signals combine in a statistically optimal fashion, we investigated the relative weights of visual and vestibular cues during self-motion. This experiment was comprised of three experimental conditions: vestibular alone, visual alone (with four different standard heading values), and visual-vestibular combined. In the combined cue condition, inter-sensory conflicts were introduced (? = ±6° or ±10°). Participants performed a 2-interval forced choice task in all conditions and were asked to judge in which of the two intervals they moved more to the right. The cue-conflict condition revealed the relative weights associated with each modality. We found that even when there was a relatively large conflict between the visual and vestibular cues, participants exhibited a statistically optimal reduction in variance. On the other hand, we found that the pattern of results in the unimodal conditions did not predict the weights in the combined cue condition. Specifically, visual-vestibular cue combination was not predicted solely by the reliability of each cue, but rather more weight was given to the vestibular cue. PMID:20884518

Butler, John S; Smith, Stuart T; Campos, Jennifer L; Bülthoff, Heinrich H

2010-01-01

278

Virtual reality and vestibular rehabilitation: Seven-years experience  

Microsoft Academic Search

Objectives: Antivertiginous drugs, antihistaminics or vasodilators, are known to give temporary relief but literature suggests the counterproductive effects of these drugs. Once the severe acute symptoms subside the antivertiginous drug therapy should be stopped and the patient should be considered for vestibular rehabilitation therapy. Current rehabilitation efforts are intended to drive the nervous system to adapt to the disordered vestibular

Enzo Mora presenter; Francesco Mora; Barbara Crippa; Renzo Mora; Marco Barbieri

2004-01-01

279

Vestibular influences on autonomic cardiovascular control in humans  

NASA Technical Reports Server (NTRS)

There is substantial evidence that anatomical connections exist between vestibular and autonomic nuclei. Animal studies have shown functional interactions between the vestibular and autonomic systems. The nature of these interactions, however, is complex and has not been fully defined. Vestibular stimulation has been consistently found to reduce blood pressure in animals. Given the potential interaction between vestibular and autonomic pathways this finding could be explained by a reduction in sympathetic activity. However, rather than sympathetic inhibition, vestibular stimulation has consistently been shown to increase sympathetic outflow in cardiac and splanchnic vascular beds in most experimental models. Several clinical observations suggest that a link between vestibular and autonomic systems may also exist in humans. However, direct evidence for vestibular/autonomic interactions in humans is sparse. Motion sickness has been found to induce forearm vasodilation and reduce baroreflex gain, and head down neck flexion induces transient forearm and calf vasoconstriction. On the other hand, studies using optokinetic stimulation have found either very small, variable, or inconsistent changes in heart rate and blood pressure, despite substantial symptoms of motion sickness. Furthermore, caloric stimulation severe enough to produce nystagmus, dizziness, and nausea had no effect on sympathetic nerve activity measured directly with microneurography. No effect was observed on heart rate, blood pressure, or plasma norepinephrine. Several factors may explain the apparent discordance of these results, but more research is needed before we can define the potential importance of vestibular input to cardiovascular regulation and orthostatic tolerance in humans.

Biaggioni, I.; Costa, F.; Kaufmann, H.; Robertson, D. (Principal Investigator)

1998-01-01

280

Equipment For the following stabilization task humans mainly use the vestibular, visual, and  

E-print Network

· Equipment For the following stabilization task humans mainly use the vestibular, visual with six degrees of freedom for the vestibular stimulus, a head mounted display (HMD than with vestibular stimulus (pre-test: vestibular 6.89°, visual 3.83°, t(7)=12.3, pvestibular

281

Galvanic vestibular stimulation in humans produces online arm movement deviations when reaching towards memorized  

E-print Network

Galvanic vestibular stimulation in humans produces online arm movement deviations when reaching galvanic vestibular stimulation (GVS), we tested whether a change in vestibular input at the onset of goal. The likely goal of these online deviations of arm trajectory was to compensate for a vestibular

Jirsa, Viktor

282

Manual do Candidato -Vestibular PuC-rio 2013 2 APRESENTAO  

E-print Network

Manual do Candidato Vestibular puC-rio 2013 #12;Manual do Candidato - Vestibular PuC-rio 2013 2 APRESENTA��O Este Manual fornece informações relevantes para os candidatos ao Concurso Vestibular da PUC-Rio. Antes de se inscrever para o Concurso Vestibular, o candidato deve conhecer as normas que regem o

283

Behavioral/Systems/Cognitive Macaque Parieto-Insular Vestibular Cortex: Responses to  

E-print Network

Behavioral/Systems/Cognitive Macaque Parieto-Insular Vestibular Cortex: Responses to Self The parieto-insular vestibular cortex (PIVC) is thought to contain an important representation of vestibular information. Here we describe responses of macaque PIVC neurons to three-dimensional (3D) vestibular and optic

DeAngelis, Gregory

284

Behavioral/Systems/Cognitive Spatial Reference Frames of Visual, Vestibular, and  

E-print Network

Behavioral/Systems/Cognitive Spatial Reference Frames of Visual, Vestibular, and Multimodal Heading that generally requires the integration of visual and vestibular cues. This sensory integration is complicated-centered; vestibular, head-centered). Visual and vestibular heading signals converge in the primate dorsal subdivision

DeAngelis, Gregory

285

Vestibular adaptation exercises and recovery: Acute stage after acoustic neuroma resection  

Microsoft Academic Search

The use of exercises in the treatment of patients with vestibular deficits has become increasingly popular, and evidence exists that these exercises are beneficial in patients with chronic vestibular deficits. The question as to whether patients with acute unilateral vestibular loss would benefit from vestibular adaptation exercises is particularly compelling, however, because animal studies have demonstrated that the acute stage

SUSAN J. HERDMAN; RICHARD A. CLENDANIEL; DOUGLAS E. MATTOX; MICHAEL J. HOLLIDAY; JOHN K. NIPARKO

1995-01-01

286

The role of the vestibular system in manual target localization  

NASA Technical Reports Server (NTRS)

Astronauts experience perceptual and sensory-motor disturbances during spaceflight and immediately after return to the 1-g environment of Earth. During spaceflight, sensory information from the eyes, limbs and vestibular organs is reinterpreted by the central nervous system so that astronauts can produce appropriate body movements in microgravity. Alterations in sensory-motor function may affect eye-head-hand coordination and, thus, the crewmember's ability to manually locate objects in extrapersonal space. Previous reports have demonstrated that crewmembers have difficulty in estimating joint and limb position and in pointing to memorized target positions on orbit and immediately postflight. One set of internal cues that may assist in the manual localization of objects is information from the vestibular system. This system contributes to our sense of the body's position in space by providing information on head position and movement and the orientation of the body with respect to gravity. Research on the vestibular system has concentrated on its role in oculo-motor control. Little is known about the role that vestibular information plays in manual motor control, such as reaching and pointing movements. Since central interpretation of vestibular information is altered in microgravity, it is important to determine its role in this process. This summer, we determined the importance of vestibular information in a subject's ability to point accurately toward a target in extrapersonal space. Subjects were passively rotated across the earth-vertical axis and then asked to point back to a previously-seen target. In the first paradigm, the subjects used both visual and vestibular cues for the pointing response, while, in the second paradigm, subjects used only vestibular information. Subjects were able to point with 85 percent accuracy to a target using vestibular information alone. We infer from this result that vestibular input plays a role in the spatial programming of manual responses.

Barry, Susan R.; Mueller, S. Alyssa

1995-01-01

287

Interacting stochastic oscillators  

NASA Astrophysics Data System (ADS)

Stochastic coherence (SC) and self-induced stochastic resonance (SISR) are two distinct mechanisms of noise-induced coherent motion. For interacting SC and SISR oscillators, we find that whether or not phase synchronization is achieved depends sensitively on the coupling strength and noise intensities. Specifically, in the case of weak coupling, individual oscillators are insensitive to each other, whereas in the case of strong coupling, one fixed oscillator with optimal coherence can be entrained to the other, adjustable oscillator (i.e., its noise intensity is tunable), achieving phase-locking synchronization, as long as the tunable noise intensity is not beyond a threshold; such synchronization is lost otherwise. For an array lattice of SISR oscillators, except for coupling-enhanced coherence similar to that found in the case of coupled SC oscillators, there is an optimal network topology degree (i.e., number of coupled nodes), such that coherence and synchronization are optimally achieved, implying that the system-size resonance found in an ensemble of noise-driven bistable systems can occur in coupled SISR oscillators.

Zhang, Jiajun; Yuan, Zhanjiang; Wang, Junwei; Zhou, Tianshou

2008-02-01

288

Vestibular schwannoma in patients with sudden sensorineural hearing loss.  

PubMed

Sudden sensorineural hearing loss (SSNHL) has several etiologies. It may be a presenting symptom of vestibular schwannoma (VS). This study aimed to establish the incidence of VS in patients with SSNHL, and we report several unusual cases among these patients. We reviewed retrospectively the charts and magnetic resonance imaging (MRI) findings of all adult patients who presented with SSNHL between 2002 and 2008. We utilized three-dimensional fast imaging with steady-state acquisition temporal MRI as a screening method. Of the 295 patients with SSNHL, VS was found in 12 (4%). All patients had intrameatal or small to medium-sized tumors. There were three cases with SSNHL in one ear and an incidental finding of intracanalicular VS in the contralateral ear. There were four cases of VS that showed good recovery from SSNHL with corticosteroid treatment. There were two cases that mimicked labyrinthitis with hearing loss and vertigo. A greater number of cases than expected of VS were detected in patients with SSNHL, as a result of increasing widespread use of MRI. Various unusual findings in these patients were identified. MRI would seem to be mandatory in all cases of SSNHL. PMID:22451804

Lee, Jong Dae; Lee, Byung Don; Hwang, Sun Chul

2011-03-01

289

Vestibular Schwannoma in Patients with Sudden Sensorineural Hearing Loss  

PubMed Central

Sudden sensorineural hearing loss (SSNHL) has several etiologies. It may be a presenting symptom of vestibular schwannoma (VS). This study aimed to establish the incidence of VS in patients with SSNHL, and we report several unusual cases among these patients. We reviewed retrospectively the charts and magnetic resonance imaging (MRI) findings of all adult patients who presented with SSNHL between 2002 and 2008. We utilized three-dimensional fast imaging with steady-state acquisition temporal MRI as a screening method. Of the 295 patients with SSNHL, VS was found in 12 (4%). All patients had intrameatal or small to medium-sized tumors. There were three cases with SSNHL in one ear and an incidental finding of intracanalicular VS in the contralateral ear. There were four cases of VS that showed good recovery from SSNHL with corticosteroid treatment. There were two cases that mimicked labyrinthitis with hearing loss and vertigo. A greater number of cases than expected of VS were detected in patients with SSNHL, as a result of increasing widespread use of MRI. Various unusual findings in these patients were identified. MRI would seem to be mandatory in all cases of SSNHL. PMID:22451804

Lee, Jong Dae; Lee, Byung Don; Hwang, Sun Chul

2010-01-01

290

Influence of galvanic vestibular stimulation on egocentric and object-based mental transformations  

Microsoft Academic Search

The vestibular system analyses angular and linear accelerations of the head that are important information for perceiving\\u000a the location of one’s own body in space. Vestibular stimulation and in particular galvanic vestibular stimulation (GVS) that\\u000a allow a systematic modification of vestibular signals has so far mainly been used to investigate vestibular influence on sensori-motor\\u000a integration in eye movements and postural

Bigna Lenggenhager; Christophe Lopez; Olaf Blanke

2008-01-01

291

InXuence of galvanic vestibular stimulation on egocentric and object-based mental transformations  

Microsoft Academic Search

The vestibular system analyses angular and lin- ear accelerations of the head that are important information for perceiving the location of one's own body in space. Vestibular stimulation and in particular galvanic vestibular stimulation (GVS) that allow a systematic modiWcation of vestibular signals has so far mainly been used to investigate vestibular inXuence on sensori-motor integration in eye movements and

Bigna Lenggenhager; Christophe Lopez; Olaf Blanke

292

Altered vestibular function in fetal and newborn rats gestated in space  

NASA Technical Reports Server (NTRS)

Researchers evaluated vestibular development and function in rat pups flown during gestation on the NASA-NIH R1 and R2 missions. Fetal and postnatal vestibular function were examined. Altered vestibular-mediated responses in the experimental fetal pups are attributed to either direct effect of gravity on the vestibular system or indirect effects of microgravity transduced through the mother. The postnatal tests confirmed the hypothesis that the vestibular system continually adapts and responds to tonic stimulation.

Ronca, A. E.; Alberts, J. R.

1997-01-01

293

Vestibular effects of lidocaine intratympanic injection in rats.  

PubMed

When lidocaine is locally delivered into the inner ear, it rapidly paralyzes the peripheral vestibular afferent neurons and induces unilateral vestibular loss. The goals of this study were to explore the possibility of developing intratympanic injection (IT) of lidocaine as a modality for treating acute vertigo. To evaluate the minimum concentration required, latent time, action duration, and possibility of lidocaine IT readministration to the vestibular system, we compared the development of horizontal nystagmus after IT of 2, 4, 6, 8, and 10% lidocaine solutions in rats. To identify the induction of vestibular compensation, c-Fos-like protein expression was observed in the vestibular nucleus. Results of our investigation showed that lidocaine IT concentrations greater than 4% induced vestibular hyporeflexia in the injected ear. In order to induce hyporeflexia 4 and 6% lidocaine solutions could also be repeatedly injected. Regardless of concentration, effects of the lidocaine IT dissipated gradually over time. Our findings could be used to develop novel methods for symptom control in vestibular disorder patients. PMID:24505049

Lee, Hh; Kim, Mj; Jo, Yk; Kim, Jy; Han, Gc

2014-11-01

294

Responses evoked by a vestibular implant providing chronic stimulation.  

PubMed

Patients with bilateral vestibular loss experience dehabilitating visual, perceptual, and postural difficulties, and an implantable vestibular prosthesis that could improve these symptoms would be of great benefit to these patients. In previous work, we have shown that a one-dimensional, unilateral canal prosthesis can improve the vestibulooccular reflex (VOR) in canal-plugged squirrel monkeys. In addition to the VOR, the potential effects of a vestibular prosthesis on more complex, highly integrative behaviors, such as the perception of head orientation and posture have remained unclear. We tested a one-dimensional, unilateral prosthesis in a rhesus monkey with bilateral vestibular loss and found that chronic electrical stimulation partially restored the compensatory VOR and also that percepts of head orientation relative to gravity were improved. However, the one-dimensional prosthetic stimulation had no clear effect on postural stability during quiet stance, but sway evoked by head-turns was modestly reduced. These results suggest that not only can the implementation of a vestibular prosthesis provide partial restitution of VOR but may also improve perception and posture in the presence of bilateral vestibular hypofunction (BVH). In this review, we provide an overview of our previous and current work directed towards the eventual clinical implementation of an implantable vestibular prosthesis. PMID:22699148

Thompson, Lara A; Haburcakova, Csilla; Gong, Wangsong; Lee, Daniel J; Wall, Conrad; Merfeld, Daniel M; Lewis, Richard F

2012-01-01

295

Adaptive plasticity in vestibular influences on cardiovascular control  

NASA Technical Reports Server (NTRS)

Data collected in both human subjects and animal models indicate that the vestibular system influences the control of blood pressure. In animals, peripheral vestibular lesions diminish the capacity to rapidly and accurately make cardiovascular adjustments to changes in posture. Thus, one role of vestibulo-cardiovascular influences is to elicit changes in blood distribution in the body so that stable blood pressure is maintained during movement. However, deficits in correcting blood pressure following vestibular lesions diminish over time, and are less severe when non-labyrinthine sensory cues regarding body position in space are provided. These observations show that pathways that mediate vestibulo-sympathetic reflexes can be subject to plastic changes. This review considers the adaptive plasticity in cardiovascular responses elicited by the central vestibular system. Recent data indicate that the posterior cerebellar vermis may play an important role in adaptation of these responses, such that ablation of the posterior vermis impairs recovery of orthostatic tolerance following subsequent vestibular lesions. Furthermore, recent experiments suggest that non-labyrinthine inputs to the central vestibular system may be important in controlling blood pressure during movement, particularly following vestibular dysfunction. A number of sensory inputs appear to be integrated to produce cardiovascular adjustments during changes in posture. Although loss of any one of these inputs does not induce lability in blood pressure, it is likely that maximal blood pressure stability is achieved by the integration of a variety of sensory cues signaling body position in space.

Yates, B. J.; Holmes, M. J.; Jian, B. J.

2000-01-01

296

Biomimetic smart sensors for autonomous robotic behavior II: vestibular processing  

NASA Astrophysics Data System (ADS)

Limited autonomous behaviors are fast becoming a critical capability in the field of robotics as robotic applications are used in more complicated and interactive environments. As additional sensory capabilities are added to robotic platforms, sensor fusion to enhance and facilitate autonomous behavior becomes increasingly important. Using biology as a model, the equivalent of a vestibular system needs to be created in order to orient the system within its environment and allow multi-modal sensor fusion. In mammals, the vestibular system plays a central role in physiological homeostasis and sensory information integration (Fuller et al, Neuroscience 129 (2004) 461-471). At the level of the Superior Colliculus in the brain, there is multimodal sensory integration across visual, auditory, somatosensory, and vestibular inputs (Wallace et al, J Neurophysiol 80 (1998) 1006-1010), with the vestibular component contributing a strong reference frame gating input. Using a simple model for the deep layers of the Superior Colliculus, an off-the-shelf 3-axis solid state gyroscope and accelerometer was used as the equivalent representation of the vestibular system. The acceleration and rotational measurements are used to determine the relationship between a local reference frame of a robotic platform (an iRobot Packbot®) and the inertial reference frame (the outside world), with the simulated vestibular input tightly coupled with the acoustic and optical inputs. Field testing of the robotic platform using acoustics to cue optical sensors coupled through a biomimetic vestibular model for "slew to cue" gunfire detection have shown great promise.

Xue, Shuwan; Deligeorges, Socrates; Soloway, Aaron; Lichtenstein, Lee; Gore, Tyler; Hubbard, Allyn

2009-05-01

297

Vestibular rehabilitation therapy: review of indications, mechanisms, and key exercises.  

PubMed

Vestibular rehabilitation therapy (VRT) is an exercise-based treatment program designed to promote vestibular adaptation and substitution. The goals of VRT are 1) to enhance gaze stability, 2) to enhance postural stability, 3) to improve vertigo, and 4) to improve activities of daily living. VRT facilitates vestibular recovery mechanisms: vestibular adaptation, substitution by the other eye-movement systems, substitution by vision, somatosensory cues, other postural strategies, and habituation. The key exercises for VRT are head-eye movements with various body postures and activities, and maintaining balance with a reduced support base with various orientations of the head and trunk, while performing various upper-extremity tasks, repeating the movements provoking vertigo, and exposing patients gradually to various sensory and motor environments. VRT is indicated for any stable but poorly compensated vestibular lesion, regardless of the patient's age, the cause, and symptom duration and intensity. Vestibular suppressants, visual and somatosensory deprivation, immobilization, old age, concurrent central lesions, and long recovery from symptoms, but there is no difference in the final outcome. As long as exercises are performed several times every day, even brief periods of exercise are sufficient to facilitate vestibular recovery. Here the authors review the mechanisms and the key exercises for each of the VRT goals. PMID:22259614

Han, Byung In; Song, Hyun Seok; Kim, Ji Soo

2011-12-01

298

Vestibular inputs to human motion-sensitive visual cortex.  

PubMed

Two crucial sources of information available to an organism when moving through an environment are visual and vestibular stimuli. Macaque cortical area MSTd processes visual motion, including cues to self-motion arising from optic flow and also receives information about self-motion from the vestibular system. In humans, whether human MST (hMST) receives vestibular afferents is unknown. We have combined 2 techniques, galvanic vestibular stimulation and functional MRI (fMRI), to show that hMST is strongly activated by vestibular stimulation in darkness, whereas adjacent area MT is unaffected. The activity cannot be explained in terms of somatosensory stimulation at the electrode site. Vestibular input appears to be confined to the anterior portion of hMST, suggesting that hMST as conventionally defined may contain 2 subregions. Vestibular activity was also seen in another area previously implicated in processing visual cues to self-motion, namely the cingulate sulcus visual area (CSv), but not in visual area V6. The results suggest that cross-modal convergence of cues to self-motion occurs in both hMST and CSv. PMID:21743097

Smith, Andrew T; Wall, Matthew B; Thilo, Kai V

2012-05-01

299

Pharmacotherapy of vestibular and ocular motor disorders, including nystagmus.  

PubMed

We review current pharmacological treatments for peripheral and central vestibular disorders, and ocular motor disorders that impair vision, especially pathological nystagmus. The prerequisites for successful pharmacotherapy of vertigo, dizziness, and abnormal eye movements are the "4 D's": correct diagnosis, correct drug, appropriate dosage, and sufficient duration. There are seven groups of drugs (the "7 A's") that can be used: antiemetics; anti-inflammatory, anti-Ménière's, and anti-migrainous medications; anti-depressants, anti-convulsants, and aminopyridines. A recovery from acute vestibular neuritis can be promoted by treatment with oral corticosteroids. Betahistine may reduce the frequency of attacks of Ménière's disease. The aminopyridines constitute a novel treatment approach for downbeat and upbeat nystagmus, as well as episodic ataxia type 2 (EA 2); these drugs may restore normal "pacemaker" activity to the Purkinje cells that govern vestibular and cerebellar nuclei. A limited number of trials indicate that baclofen improves periodic alternating nystagmus, and that gabapentin and memantine improve acquired pendular and infantile (congenital) nystagmus. Preliminary reports suggest suppression of square-wave saccadic intrusions by memantine, and ocular flutter by beta-blockers. Thus, although progress has been made in the treatment of vestibular neuritis, some forms of pathological nystagmus, and EA 2, controlled, masked trials are still needed to evaluate treatments for many vestibular and ocular motor disorders, including betahistine for Ménière's disease, oxcarbazepine for vestibular paroxysmia, or metoprolol for vestibular migraine. PMID:21461686

Strupp, Michael; Thurtell, Matthew J; Shaikh, Aasef G; Brandt, Thomas; Zee, David S; Leigh, R John

2011-07-01

300

Vestibular influence on auditory metrical interpretation.  

PubMed

When we move to music we feel the beat, and this feeling can shape the sound we hear. Previous studies have shown that when people listen to a metrically ambiguous rhythm pattern, moving the body on a certain beat--adults, by actively bouncing themselves in synchrony with the experimenter, and babies, by being bounced passively in the experimenter's arms--can bias their auditory metrical representation so that they interpret the pattern in a corresponding metrical form [Phillips-Silver, J., & Trainor, L. J. (2005). Feeling the beat: Movement influences infant rhythm perception. Science, 308, 1430; Phillips-Silver, J., & Trainor, L. J. (2007). Hearing what the body feels: Auditory encoding of rhythmic movement. Cognition, 105, 533-546]. The present studies show that in adults, as well as in infants, metrical encoding of rhythm can be biased by passive motion. Furthermore, because movement of the head alone affected auditory encoding whereas movement of the legs alone did not, we propose that vestibular input may play a key role in the effect of movement on auditory rhythm processing. We discuss possible cortical and subcortical sites for the integration of auditory and vestibular inputs that may underlie the interaction between movement and auditory metrical rhythm perception. PMID:18234407

Phillips-Silver, Jessica; Trainor, Laurel J

2008-06-01

301

http://www.tutis.ca/NeuroMD/index.htm 20 February 2013 Vestibular System and Eye Movements  

E-print Network

1 http://www.tutis.ca/NeuroMD/index.htm 20 February 2013 Vestibular System and Eye Movements #12;2 http://www.tutis.ca/NeuroMD/index.htm 20 February 2013 Contents Vestibular System and Eye Movements and vestibular systems. The vestibular system is responsible for one's sense of balance. The vestibular system

Vilis, Tutis

302

Fluoxetine for vestibular dysfunction and anxiety: a prospective pilot study.  

PubMed

Anxiety states and disorders amplify the symptoms and impairment associated with vestibular dysfunction. Five patients with inner ear vestibular dysfunction and anxiety were prospectively treated with fluoxetine, 20-60 mg/day, and received an extensive battery of assessments at baseline and after 12 weeks of treatment. Fluoxetine led to significant or near significant reductions in anxiety measures and in impairment due to dizziness; improvements in clinical balance function and vestibular function were less clear. The data add to the literature suggesting a role for selective serotonin reuptake inhibitors in the treatment of dizziness and anxiety. PMID:16000676

Simon, Naomi M; Parker, Stephen W; Wernick-Robinson, Mara; Oppenheimer, Julia E; Hoge, Elizabeth A; Worthington, John J; Korbly, Nicole B; Pollack, Mark H

2005-01-01

303

Optokinetic and Vestibular Responsiveness in the Macaque Rostral Vestibular and Fastigial Nuclei  

PubMed Central

We recorded from rostral vestibular (VN) and rostral fastigial nuclei (FN) neurons that did not respond to eye movements during three-dimensional (3D) vestibular and optokinetic stimulation (OKS). The majority of neurons in both areas (76 and 69% in VN and FN, respectively) responded during both rotational and translational motion. Preferred directions scattered throughout 3D space for translation but showed some preference for pitch/roll over yaw for rotation. VN/FN neurons were also tested during OKS while monkeys suppressed their optokinetic nystagmus by fixating a head-fixed target. Only a handful of cells (VN: 17%, FN: 6%) modulated during 0.5-Hz OKS suppression, but the number of responsive cells increased (VN: 40%, FN: 48%) during 0.02-Hz OKS. Preferred directions for rotation and OKS were not matched on individual neurons, and OKS gains were smaller than the respective gains during rotation. These results were generally similar for VN and FN neurons. We conclude that optokinetic-vestibular convergence might not be as prevalent as earlier studies have suggested. PMID:19073813

Bryan, Ayanna S.; Angelaki, Dora E.

2009-01-01

304

Weightlessness and the ontogeny of vestibular function - Evidence for persistent vestibular threshold shifts in chicks incubated in space  

NASA Technical Reports Server (NTRS)

The effect of microgravity on the embryonic development of the vestibular function was investigated by comparing the vestibular function parameters measured in 21-old chicks incubated as embryos aboard the Space Shuttle Discovery with those of age-matched synchronous controls incubated on earth. Measurements of the electrophysiological responses in both groups of chicks indicated that the exposure of embryos to weightlessness resulted in altered sensitivity of embryonic vestibular sensors. Moreover, the effect of space flight was persistent: it was still present one month after the spacecraft landed on earth.

Jones, Timothy A.; Vellinger, John; Hester, Patricia Y.; Fermin, Cesar

1991-01-01

305

Modeling the electrical stimulation of peripheral vestibular nerves  

E-print Network

The research conducted for this thesis investigated the theoretical placement of electrodes for a proposed implantable vestibular prosthesis to aid patients suffering from balance related disorders. The most likely sites ...

Parikh, Ketul M

2006-01-01

306

Surgical access to separate branches of the cat vestibular nerve  

NASA Technical Reports Server (NTRS)

A posteroventral approach for access to separate branches of the cat vestibular nerve is presented which permits simultaneous surgical access to the ampullary and otolithic nerves. Surgical procedures are discussed.

Radkevich, L. A.; Ayzikov, G. S.

1981-01-01

307

Vestibular Evoked Myogenic Potentials : physiology, variability, and statistical characteristics  

E-print Network

Vestibular Evoked Myogenic Potentials (VEMPs) are electrical signals recorded from the skin overlying skeletal muscles of the head and neck in response to high-intensity acoustic stimuli. VEMPs have been observed in stimulus ...

Prakash, Srinivasamurthy Ravi

2009-01-01

308

Mutations of ESPN cause autosomal recessive deafness and vestibular dysfunction.  

PubMed

We mapped a human deafness locus DFNB36 to chromosome 1p36.3 in two consanguineous families segregating recessively inherited deafness and vestibular areflexia. This phenotype co-segregates with either of two frameshift mutations, 1988delAGAG and 2469delGTCA, in ESPN, which encodes a calcium-insensitive actin-bundling protein called espin. A recessive mutation of ESPN is known to cause hearing loss and vestibular dysfunction in the jerker mouse. Our results establish espin as an essential protein for hearing and vestibular function in humans. The abnormal vestibular phenotype associated with ESPN mutations will be a useful clinical marker for refining the differential diagnosis of non-syndromic deafness. PMID:15286153

Naz, S; Griffith, A J; Riazuddin, S; Hampton, L L; Battey, J F; Khan, S N; Riazuddin, S; Wilcox, E R; Friedman, T B

2004-08-01

309

The European vestibular experiments in spacelab-1  

NASA Astrophysics Data System (ADS)

A series of experiments /1/ were performed in the Spacelab-1 mission on November/December, 1983, pre-, in-, and postflight. These experiments covered various aspects of the functions of the vestibular system, the inflight tests comprising threshold measurements for linear movements in three orthogonal axes, optokinetic stimulation, vestibulo-ocular reflexes under linear and angular accelerations, caloric stimulation with and without linear accelerations; pre- and postflight tests repeated the inflight protocol with the addition of subjective vertical and eye counter-rotation measurements using a tilt table. One of the most surprising and significant results was the caloric test: strong caloric nystagmus on the two subjects tested was recorded inflight; this was contrary to what was expected from Barany's convection hypothesis for caloric nystagmus.

Kass, J.; von Baumgarten, R.; Vogel, H.; Wetzig, J.; Benson, A.; Berthoz, A.; Vieville, Th.; Brandt, Th.; Probst, Th.; Brand, U.; Bruzek, W.; Dichgans, J.; Scherer, H.

310

Effect of gravity on vestibular neural development  

NASA Technical Reports Server (NTRS)

The timing, molecular basis, and morphophysiological and behavioral consequences of the interaction between external environment and the internal genetic pool that shapes the nervous system over a lifetime remain important questions in basic neuroscientific research. Space station offers the opportunity to study this interaction over several life cycles in a variety of organisms. This short review considers past work in altered gravity, particularly on the vestibular system, as the basis for proposing future research on space station, and discusses the equipment necessary to achieve goals. It is stressed that, in keeping with the international investment being made in this research endeavor, both the questions asked and the technologies to be developed should be bold. Advantage must be taken of this unique research environment to expand the frontiers of neuroscience. Copyright 1998 Published by Elsevier Science B.V.

Ross, M. D.; Tomko, D. L.

1998-01-01

311

Intraoperative Monitoring and Facial Nerve Outcomes after Vestibular Schwannoma Resection  

Microsoft Academic Search

Objective: To determine the predictive value of proximal fa- cial nerve electrical threshold and proximal-to-distal facial muscle compound action potential amplitude ratio on facial nerve outcomes after resection of vestibular schwannomas. Study Design: Retrospective case review. Setting: Tertiary care hospital. Patients: Two hundred twenty-nine patients undergoing resec- tion of vestibular schwannomas with intraoperative facial nerve monitoring at a single institution.

Brandon Isaacson; Paul R. Kileny; Hussam El-Kashlan

2003-01-01

312

HIV-associated cerebral lymphocyte infiltration mimicking vestibular schwannoma  

Microsoft Academic Search

The association of unilateral, rapidly progressive hearing loss, tinnitus and vestibular dysfunction in combination with a\\u000a contrast-enhancing mass within the internal auditory canal on MRI is suggestive of a vestibular schwannoma (VS). We report\\u000a the rare finding of a HIV-associated cerebral lymphocyte infiltration, most probably malignant lymphoma, which was presumed\\u000a initially to be a VS. A 36-year-old male presented with

Gentiana I. Wenzel; Friedrich Götz; Thomas Lenarz; Timo Stöver

2008-01-01

313

Early and Phasic Cortical Metabolic Changes in Vestibular Neuritis Onset  

PubMed Central

Functional brain activation studies described the presence of separate cortical areas responsible for central processing of peripheral vestibular information and reported their activation and interactions with other sensory modalities and the changes of this network associated to strategic peripheral or central vestibular lesions. It is already known that cortical changes induced by acute unilateral vestibular failure (UVF) are various and undergo variations over time, revealing different cortical involved areas at the onset and recovery from symptoms. The present study aimed at reporting the earliest change in cortical metabolic activity during a paradigmatic form of UVF such as vestibular neuritis (VN), that is, a purely peripheral lesion of the vestibular system, that offers the opportunity to study the cortical response to altered vestibular processing. This research reports [18F]fluorodeoxyglucose positron emission tomography brain scan data concerning the early cortical metabolic activity associated to symptoms onset in a group of eight patients suffering from VN. VN patients’ cortical metabolic activity during the first two days from symptoms onset was compared to that recorded one month later and to a control healthy group. Beside the known cortical response in the sensorimotor network associated to vestibular deafferentation, we show for the first time the involvement of Entorhinal (BAs 28, 34) and Temporal (BA 38) cortices in early phases of symptomatology onset. We interpret these findings as the cortical counterparts of the attempt to reorient oneself in space counteracting the vertigo symptom (Bas 28, 34) and of the emotional response to the new pathologic condition (BA 38) respectively. These interpretations were further supported by changes in patients’ subjective ratings in balance, anxiety, and depersonalization/derealization scores when tested at illness onset and one month later. The present findings contribute in expanding knowledge about early, fast-changing, and complex cortical responses to pathological vestibular unbalanced processing. PMID:23505435

Alessandrini, Marco; Pagani, Marco; Napolitano, Bianca; Micarelli, Alessandro; Candidi, Matteo; Bruno, Ernesto; Chiaravalloti, Agostino; Di Pietro, Barbara; Schillaci, Orazio

2013-01-01

314

Early and phasic cortical metabolic changes in vestibular neuritis onset.  

PubMed

Functional brain activation studies described the presence of separate cortical areas responsible for central processing of peripheral vestibular information and reported their activation and interactions with other sensory modalities and the changes of this network associated to strategic peripheral or central vestibular lesions. It is already known that cortical changes induced by acute unilateral vestibular failure (UVF) are various and undergo variations over time, revealing different cortical involved areas at the onset and recovery from symptoms. The present study aimed at reporting the earliest change in cortical metabolic activity during a paradigmatic form of UVF such as vestibular neuritis (VN), that is, a purely peripheral lesion of the vestibular system, that offers the opportunity to study the cortical response to altered vestibular processing. This research reports [(18)F]fluorodeoxyglucose positron emission tomography brain scan data concerning the early cortical metabolic activity associated to symptoms onset in a group of eight patients suffering from VN. VN patients' cortical metabolic activity during the first two days from symptoms onset was compared to that recorded one month later and to a control healthy group. Beside the known cortical response in the sensorimotor network associated to vestibular deafferentation, we show for the first time the involvement of Entorhinal (BAs 28, 34) and Temporal (BA 38) cortices in early phases of symptomatology onset. We interpret these findings as the cortical counterparts of the attempt to reorient oneself in space counteracting the vertigo symptom (Bas 28, 34) and of the emotional response to the new pathologic condition (BA 38) respectively. These interpretations were further supported by changes in patients' subjective ratings in balance, anxiety, and depersonalization/derealization scores when tested at illness onset and one month later. The present findings contribute in expanding knowledge about early, fast-changing, and complex cortical responses to pathological vestibular unbalanced processing. PMID:23505435

Alessandrini, Marco; Pagani, Marco; Napolitano, Bianca; Micarelli, Alessandro; Candidi, Matteo; Bruno, Ernesto; Chiaravalloti, Agostino; Di Pietro, Barbara; Schillaci, Orazio

2013-01-01

315

Vestibular stimulation affects medium latency postural muscle responses  

Microsoft Academic Search

This study explores whether galvanic vestibular stimulation can alter automatic postural muscle responses triggered 100 ms\\u000a after surface translations. Our previous study concluded that a step of bipolar, galvanic vestibular stimulation delivered\\u000a 500 ms prior to a platform translation tilted the internal representation of vertical because subjects’ final center of foot\\u000a pressure and center of mass equilibrium position shifted toward the anode

Fay B. Horak; Frantisek Hlavacka

2002-01-01

316

Mutations of ESPN cause autosomal recessive deafness and vestibular dysfunction  

Microsoft Academic Search

We mapped a human deafness locus DFNB36 to chromosome 1p36.3 in two consanguineous families segregating recessively inherited deafness and vestibular areflexia. This phenotype co-segregates with either of two frameshift mutations, 1988delAGAG and 2469delGTCA, in ESPN, which encodes a calcium-insensitive actin-bundling protein called espin. A recessive mutation of ESPN is known to cause hearing loss and vestibular dysfunction in the jerker

S Naz; A J Griffith; S Riazuddin; L L Hampton; J F Battey; S N Khan; E R Wilcox; T B Friedman

2004-01-01

317

Vestibular activity and cognitive development in children: perspectives  

PubMed Central

Vestibular signals play an essential role in oculomotor and static and dynamic posturomotor functions. Increasing attention is now focusing on their impact on spatial and non-spatial cognitive functions. Movements of the head in space evoke vestibular signals that make important contributions during the development of brain representations of body parts relative to one another as well as representations of body orientation and position within the environment. A central nervous system pathway relays signals from the vestibular nuclei to the hippocampal system where this input is indispensable for neuronal responses selective for the position and orientation of the head in space. One aspect of the hippocampal systems’ processing to create episodic and contextual memories is its role in spatial orientation and navigation behaviors that require processing of relations between background cues. These are also impaired in adult patients with vestibular deficits. However little is known about the impact of vestibular loss on cognitive development in children. This is investigated here with a particular emphasis upon the hypothetical mechanisms and potential impact of vestibular loss at critical ages on the development of respective spatial and non-spatial cognitive processes and their brain substrates. PMID:24376403

Wiener-Vacher, Sylvette R.; Hamilton, Derek A.; Wiener, Sidney I.

2013-01-01

318

Patterning of sympathetic nerve activity in response to vestibular stimulation  

NASA Technical Reports Server (NTRS)

Growing evidence suggests a role for the vestibular system in regulation of autonomic outflow during postural adjustments. In the present paper we review evidence for the patterning of sympathetic nerve activity elicited by vestibular stimulation. In response to electrical activation of vestibular afferents, firing of sympathetic nerves located throughout the body is altered. However, activity of the renal nerve is most sensitive to vestibular inputs. In contrast, high-intensity simultaneous activation of cutaneous and muscle inputs elicits equivalent changes in firing of the renal, superior mesenteric and lumbar colonic nerves. Responses of muscle vasoconstrictor (MVC) efferents to vestibular stimulation are either inhibitory (Type I) or are comprised of a combination of excitation and inhibition (Type II). Interestingly, single MVC units located in the hindlimb exhibited predominantly Type I responses while those located in the forelimb and face exhibited Type II responses. Furthermore, brachial and femoral arterial blood flows were dissociated in response to vestibular stimulation, such that brachial vascular resistance increased while femoral resistance decreased. These studies demonstrate that vestibulosympathetic reflexes are patterned according to both the anatomical location and innervation target of a particular sympathetic nerve, and can lead to distinct changes in local blood flow.

Kerman, I. A.; McAllen, R. M.; Yates, B. J.

2000-01-01

319

Vestibular activity and cognitive development in children: perspectives.  

PubMed

Vestibular signals play an essential role in oculomotor and static and dynamic posturomotor functions. Increasing attention is now focusing on their impact on spatial and non-spatial cognitive functions. Movements of the head in space evoke vestibular signals that make important contributions during the development of brain representations of body parts relative to one another as well as representations of body orientation and position within the environment. A central nervous system pathway relays signals from the vestibular nuclei to the hippocampal system where this input is indispensable for neuronal responses selective for the position and orientation of the head in space. One aspect of the hippocampal systems' processing to create episodic and contextual memories is its role in spatial orientation and navigation behaviors that require processing of relations between background cues. These are also impaired in adult patients with vestibular deficits. However little is known about the impact of vestibular loss on cognitive development in children. This is investigated here with a particular emphasis upon the hypothetical mechanisms and potential impact of vestibular loss at critical ages on the development of respective spatial and non-spatial cognitive processes and their brain substrates. PMID:24376403

Wiener-Vacher, Sylvette R; Hamilton, Derek A; Wiener, Sidney I

2013-01-01

320

Vestibular information is required for dead reckoning in the rat.  

PubMed

Dead reckoning is an on-line form of spatial navigation used by an animal to identify its present location and return directly to a starting location, even after circuitous outward trips. At present, it is not known which of several self-movement cues (efferent copy from movement commands, proprioceptive information, sensory flow, or vestibular information) are used to compute homeward trajectories. To determine whether vestibular information is important for dead reckoning, the impact of chemical labyrinthectomy was evaluated in a test that demanded on-line computation of a homeward trajectory. Rats were habituated to leave a refuge that was visible from all locations on a circular table to forage for large food pellets, which they carried back to the refuge to eat. Two different probe trials were given: (1) the rats foraged from the same spatial location from a hidden refuge in the light and so were able to use visual cues to navigate; (2) the same procedure took place in the dark, constraining the animals to dead reckon. Although control rats carried food directly and rapidly back to the refuge on both probes, the rats with vestibular lesions were able to do so on the hidden refuge but not on the dark probe. The scores of vestibular reflex tests predicted the dead reckoning deficit. The vestibular animals were also impaired in learning a new piloting task. This is the first unambiguous demonstration that vestibular information is used in dead reckoning and also contributes to piloting. PMID:12427858

Wallace, Douglas G; Hines, Dustin J; Pellis, Sergio M; Whishaw, Ian Q

2002-11-15

321

Stochastic Electron Dynamics Due to Drift Waves in a Sheared Magnetic Field and Other Drift Motion Problems.  

National Technical Information Service (NTIS)

Electron motion in a single electrostatic wave in a sheared magnetic field is shown to become stochastic in the presence of a second wave at an amplitude well below that obtained from the overlapping pendulum resonance approximation. The enhanced stochast...

J. A. Robertson

1986-01-01

322

Virtual labyrinth model of vestibular afferent excitation via implanted electrodes: validation and application to design of a multichannel vestibular prosthesis  

Microsoft Academic Search

To facilitate design of a multichannel vestibular prosthesis that can restore sensation to individuals with bilateral loss\\u000a of vestibular hair cell function, we created a virtual labyrinth model. Model geometry was generated through 3-dimensional (3D) reconstruction of microMRI and microCT scans of normal chinchillas\\u000a (Chinchilla lanigera) acquired with 30–48 ?m and 12 ?m voxels, respectively. Virtual electrodes were positioned based on anatomic

Russell Hayden; Stacia Sawyer; Eric Frey; Susumu Mori; Americo A. Migliaccio; Charles C. Della Santina

2011-01-01

323

Vestibular rehabilitation ameliorates chronic dizziness through the SIRT1 axis  

PubMed Central

Dizziness is a common clinical symptom frequently referred to general neurologists and practitioners. Exercise intervention, in the form of vestibular rehabilitation, is known as an effective clinical management for dizziness. This intervention is reported to have a functional role in correcting dizziness, improving gaze stability, retraining balance and gait, and enhancing physical fitness. Dizziness is known to be highly related to inflammation and oxidative stress. SIRT1 is a major molecule for the regulation of inflammation and mitigation of oxidative stress in chronic diseases such as atherosclerosis and chronic obstructive pulmonary disease. However, the bio-molecular roles of SIRT1 involved in the pathogenesis of dizziness are still largely unclear. In this study, a total of 30 subjects were recruited (15 patients with chronic dizziness, and 15 age/gender matched non-dizzy control subjects). The dizzy subjects group received 18 sessions of 30-min vestibular training. We found that the mRNA and protein expression levels of SIRT1 in the blood samples of chronic dizzy patients were repressed compared with those of healthy controls. After vestibular training, the dizzy patients had significant symptomatic improvements. The SIRT1 expression and its downstream genes (PPAR-? and PGC-1?) were upregulated after vestibular exercises in dizzy subjects. Notably, the catalytic activity of SIRT1, NADPH and antioxidant enzyme activities were also activated in dizzy patients after vestibular training. Furthermore, vestibular exercise training reduced oxidative events and p53 expression in patients with dizziness. This study demonstrated that vestibular exercise training improved dizziness symptoms, and mechanisms for alleviation of chronic dizziness may partly involve the activation of the SIRT1 axis and the repression of redox status. PMID:24624081

Kao, Chung-Lan; Tsai, Kun-Ling; Cheng, Yuan-Yang; Kuo, Chia-Hua; Lee, Shin-Da; Chan, Rai-Chi

2014-01-01

324

Effects of Galvanic vestibular stimulation on cognitive function.  

PubMed

Although imaging studies suggest activation of cortical areas by vestibular input, there is little evidence of an adverse effect of non-veridical vestibular input on cognitive function. To test the hypothesis that degraded vestibular afferent input adversely affects cognition, we compared performance on a cognitive test battery in a group undergoing suprathreshold bilateral bipolar Galvanic vestibular stimulation (GVS) with a control group receiving no GVS or subthreshold stimulation. The battery consisted of six cognitive tests as follows: reaction time, dual tasking, Stroop, mental rotation, perspective-taking and matching-to-sample, as well as a simple visuomotor (manual tracking) task. Subjects performed the test battery before, during and after suprathreshold GVS exposure or subthreshold stimulation. Suprathreshold GVS significantly increased error rate for the match-to-sample and perspective-taking tasks relative to the subthreshold group, demonstrating a negative effect of non-veridical vestibular input in these specific cognitive tasks. Reaction time, dual tasking, mental rotation and manual tracking were unaffected by GVS exposure. The adverse effect of suprathreshold GVS on perspective taking but not mental rotation is consistent with imaging studies, which have demonstrated that egocentric mental transformations (perspective taking) occur primarily in cortical areas that receive vestibular input (the parietal-temporal junction and superior parietal lobule), whereas object-based transformations (mental rotation) occur in the frontoparietal region. The increased error rate during the match-to-sample task is likely due to interference with hippocampal processing related to spatial memory, as suggested by imaging studies on vestibular patients. PMID:22076407

Dilda, Valentina; MacDougall, Hamish G; Curthoys, Ian S; Moore, Steven T

2012-01-01

325

Click-evoked responses in vestibular afferents in rats.  

PubMed

Sound activates not only the cochlea but also the vestibular end organs. Research on this phenomenon led to the discovery of the sound-evoked vestibular myogenic potentials recorded from the sternocleidomastoid muscles (cervical VEMP, or cVEMP). Since the cVEMP offers simplicity and the ability to stimulate each labyrinth separately, its values as a test of human vestibular function are widely recognized. Currently, the cVEMP is interpreted as a test of saccule function based on the assumption that clicks primarily activate the saccule. However, sound activation of vestibular end organs other than the saccule has been reported. To provide the neural basis for interpreting clinical VEMP testing, we employed the broadband clicks used in clinical VEMP testing to examine the sound-evoked responses in a large sample of vestibular afferents in Sprague-Dawley rats. Recordings were made from 924 vestibular afferents from 106 rats: 255 from the anterior canal (AC), 202 from the horizontal canal (HC), 177 from the posterior canal (PC), 207 from the superior vestibular nerve otolith (SO), and 83 from the inferior nerve otolith (IO). Sound sensitivity of each afferent was quantified by computing the cumulative probability of evoking a spike (CPE). We found that clicks activated irregular afferents (normalized coefficient of variation of interspike intervals >0.2) from both the otoliths (81%) and the canals (43%). The order of end organ sound sensitivity was SO = IO > AC > HC > PC. Since the sternocleidomastoid motoneurons receive inputs from both the otoliths and the canals, these results provide evidence of a possible contribution from both of them to the click-evoked cVEMP. PMID:21613592

Zhu, Hong; Tang, Xuehui; Wei, Wei; Mustain, William; Xu, Youguo; Zhou, Wu

2011-08-01

326

Ghost-vibrational resonance S. Rajamani a  

E-print Network

Ghost-vibrational resonance S. Rajamani a , S. Rajasekar a, , M.A.F. Sanjuán b a School of Physics Keywords: Ghost resonance Multi-frequency signal Duffing oscillator a b s t r a c t Ghost-stochastic resonance is a noise-induced resonance at a fundamental frequency miss- ing in the input signal. We

Rey Juan Carlos, Universidad

327

Fifth Symposium on the Role of the Vestibular Organs in Space Exploration  

NASA Technical Reports Server (NTRS)

Vestibular problems of manned space flight are investigated for weightlessness and reduced gravity conditions with emphasis on space station development. Intensive morphological studies on the vestibular system and its central nervous system connections are included.

1973-01-01

328

Sensitivity of human visual and vestibular cortical regions to egomotion-compatible visual stimulation.  

PubMed

The analysis and representation of visual cues to self-motion (egomotion) is primarily associated with cortical areas MST, VIP, and (recently) cingulate sulcus visual area (CSv). Various other areas, including visual areas V6 and V6A, and vestibular areas parietoinsular vestibular cortex (PIVC), putative area 2v (p2v), and 3aNv, are also potentially suited to processing egomotion (in some cases based on multisensory cues), but it is not known whether they are in fact involved in this process. In a functional magnetic resonance imaging (fMRI) experiment, we presented human participants with 2 types of random dot kinematograms. Both contained coherent motion but one simulated egomotion while the other did not. An area in the parieto-occipital sulcus that may correspond to V6, PIVC, and p2v were all differentially responsive to egomotion-compatible visual stimuli, suggesting that they may be involved in encoding egomotion. More generally, we show that the use of such stimuli provides a simple and reliable fMRI localizer for human PIVC and p2v, which hitherto required galvanic or caloric stimulation to be identified. PMID:20034998

Cardin, Velia; Smith, Andrew T

2010-08-01

329

Quantum Stochastic Heating of a Trapped Ion  

E-print Network

The resonant heating of a harmonically trapped ion by a standing-wave light field is described as a quantum stochastic process combining a coherent Schroedinger evolution with Bohr-Einstein quantum jumps. Quantum and semi-quantum treatments are compared.

L. Horvath; R. Fisher; M. J. Collett; H. J. Carmichael

2007-11-09

330

Effects of microgravity on vestibular ontogeny: direct physiological and anatomical measurements following space flight (STS-29)  

NASA Technical Reports Server (NTRS)

Does space flight change gravity receptor development? The present study measured vestibular form and function in birds flown as embryos for 5 days in earth orbit (STS-29). No major changes in vestibular gross morphology were found. Vestibular response mean amplitudes and latencies were unaffected by space flight. However, the results of measuring vestibular thresholds were mixed and abnormal responses in 3 of the 8 flight animals raise important questions.

Jones, T. A.; Fermin, C.; Hester, P. Y.; Vellinger, J.

1993-01-01

331

The role of stereo vision in visual-vestibular integration.  

PubMed

Self-motion through an environment stimulates several sensory systems, including the visual system and the vestibular system. Recent work in heading estimation has demonstrated that visual and vestibular cues are typically integrated in a statistically optimal manner, consistent with Maximum Likelihood Estimation predictions. However, there has been some indication that cue integration may be affected by characteristics of the visual stimulus. Therefore, the current experiment evaluated whether presenting optic flow stimuli stereoscopically, or presenting both eyes with the same image (binocularly) affects combined visual-vestibular heading estimates. Participants performed a two-interval forced-choice task in which they were asked which of two presented movements was more rightward. They were presented with either visual cues alone, vestibular cues alone or both cues combined. Measures of reliability were obtained for both binocular and stereoscopic conditions. Group level analyses demonstrated that when stereoscopic information was available there was clear evidence of optimal integration, yet when only binocular information was available weaker evidence of cue integration was observed. Exploratory individual analyses demonstrated that for the stereoscopic condition 90% of participants exhibited optimal integration, whereas for the binocular condition only 60% of participants exhibited results consistent with optimal integration. Overall, these findings suggest that stereo vision may be important for self-motion perception, particularly under combined visual-vestibular conditions. PMID:21888763

Butler, John S; Campos, Jennifer L; Bülthoff, Heinrich H; Smith, Stuart T

2011-01-01

332

Sensory convergence in the parieto-insular vestibular cortex.  

PubMed

Vestibular signals are pervasive throughout the central nervous system, including the cortex, where they likely play different roles than they do in the better studied brainstem. Little is known about the parieto-insular vestibular cortex (PIVC), an area of the cortex with prominent vestibular inputs. Neural activity was recorded in the PIVC of rhesus macaques during combinations of head, body, and visual target rotations. Activity of many PIVC neurons was correlated with the motion of the head in space (vestibular), the twist of the neck (proprioceptive), and the motion of a visual target, but was not associated with eye movement. PIVC neurons responded most commonly to more than one stimulus, and responses to combined movements could often be approximated by a combination of the individual sensitivities to head, neck, and target motion. The pattern of visual, vestibular, and somatic sensitivities on PIVC neurons displayed a continuous range, with some cells strongly responding to one or two of the stimulus modalities while other cells responded to any type of motion equivalently. The PIVC contains multisensory convergence of self-motion cues with external visual object motion information, such that neurons do not represent a specific transformation of any one sensory input. Instead, the PIVC neuron population may define the movement of head, body, and external visual objects in space and relative to one another. This comparison of self and external movement is consistent with insular cortex functions related to monitoring and explains many disparate findings of previous studies. PMID:24671533

Shinder, Michael E; Newlands, Shawn D

2014-06-15

333

A volumetric comparison of the vestibular nuclei in primates.  

PubMed

The volumes of each of the four vestibular nuclei, superior, lateral, medial and descending, were measured in 80 brains from 2 species of Scandentia, 18 species of prosimians, and 26 species of anthropoids. Size indices were calculated by comparing species-specific points to the nucleus volume-body weight allometry in prosimians, where the average prosimian was set at 1.00. The indices range from 1.78 in Saimiri to 0.48 in Gorilla, and the distributions by families overlap partially or completely. The observed trend in size indices is independent of changes in the neocortex and the ventral pons; average indices are 1.35 in New World monkeys, 1.20 in Old World monkeys, 0.74 in apes, 0.82 in man. Among prosimians, Galago, Galagoides and Tarsius (leaping locomotion) show significantly higher indices than Nycticebus, Loris and Perodicticus (slow movement without leaping). The lateral vestibular nuclear indices in Pongidae and man are extremely low, about half of those of the average prosimians. Correlation coefficients of size indices between the vestibular nuclei and other motor nuclei, such as the cerebellar nuclei, ventral pons and striatum, are analysed. The ratio of the vestibular nuclear volumes to the total brain volumes and the distribution of percentages of each vestibular nuclear volume to the total complex are also obtained. PMID:3609971

Matano, S

1986-01-01

334

Isolated floccular infarction: impaired vestibular responses to horizontal head impulse.  

PubMed

Isolated floccular infarction is extremely rare, and impairments of the vestibulo-ocular reflex (VOR) have not been explored in humans with isolated floccular lesions. The purpose of this study was to examine and report selective impairment of VOR in response to high acceleration using head impulse in a patient with isolated floccular infarction. The patient underwent bedside and laboratory evaluation of vestibular function, which included video-oculography, ocular torsion and the subjective visual vertical, cervical and ocular vestibular-evoked myogenic potentials, bithermal caloric irrigation, rotatory chair test, and the head impulse test (HIT) using search coils. A 70-year-old woman with a unilateral floccular infarction presented with an acute vestibular syndrome with spontaneous nystagmus beating to the lesion side, impaired ipsilesional pursuit, contraversive ocular torsion and tilt of the subjective visual vertical. With rotatory chair testing at low frequencies, horizontal VOR gains were increased. However, VOR gains were decreased with the higher-frequency, higher-speed HIT. While HIT is often normal in patients with central vestibular disorders, decreased HIT responses do not exclude an isolated cerebellar lesion as a cause of the acute vestibular syndrome. PMID:23370610

Park, Hong-Kyun; Kim, Ji-Soo; Strupp, Michael; Zee, David S

2013-06-01

335

The Vestibular System Implements a LinearNonlinear Transformation In Order to Encode Self-Motion  

E-print Network

The Vestibular System Implements a Linear­Nonlinear Transformation In Order to Encode Self understood. Here we show that self-motion (i.e. vestibular) sensory information encoded by VIIIth nerve afferents is integrated nonlinearly by post-synaptic central vestibular neurons. This response nonlinearity

Chacron, Maurice

336

Control of hair cell excitability by vestibular primary sensory neurons Journal: Journal of Neuroscience  

E-print Network

Control of hair cell excitability by vestibular primary sensory neurons Journal: Journal, utricle, voltage-gated sodium channel Themes & Topics: a. Hair celss, endorgans, and nerve Vestibular of Neuroscience 27, 13 (2007) 3503-11 #12;1 Title: Control of hair cell excitability by vestibular primary sensory

Paris-Sud XI, Université de

337

Behavioral/Systems/Cognitive Does the Middle Temporal Area Carry Vestibular Signals  

E-print Network

Behavioral/Systems/Cognitive Does the Middle Temporal Area Carry Vestibular Signals Related to Self described vestibular responses in the dorsal medial superior temporal area (MSTd), a region of extrastriate visual cortex thought to be involved in self-motion perception. The pathways by which vestibular signals

DeAngelis, Gregory

338

Spatial Memory and Hippocampal Volume in Humans With Unilateral Vestibular Deafferentation  

E-print Network

Spatial Memory and Hippocampal Volume in Humans With Unilateral Vestibular Deafferentation Brandt1,3 ABSTRACT: Patients with acquired chronic bilateral vestibular loss were recently found to have that spatial memory and navigation also rely on vestibular input. In the present study 16 patients

Hamilton, Derek

339

Behavioral/Systems/Cognitive Dynamic Reweighting of Visual and Vestibular Cues during  

E-print Network

Behavioral/Systems/Cognitive Dynamic Reweighting of Visual and Vestibular Cues during Self of multiple sensory cues, especially from the visual and vestibular systems. However, the reliability. Dynamic cue reweighting has not been examined for combinations of visual and vestibular cues, nor has

DeAngelis, Gregory

340

Freund Publishing House Ltd., 2000 1 AUDITORY AND VESTIBULAR MOUSE MUTANTS  

E-print Network

©Freund Publishing House Ltd., 2000 1 AUDITORY AND VESTIBULAR MOUSE MUTANTS: MODELS FOR HUMAN cloned /1/. Genes that cause non- syndromic hearing loss (NSHL) and vestibular dysfunction are difficult can teach us a great deal about the human auditory and vestibular systems. Techniques such as electron

Avraham, Karen

341

Systems/Circuits Statistics of the Vestibular Input Experienced during Natural  

E-print Network

Systems/Circuits Statistics of the Vestibular Input Experienced during Natural Self Itiswidelybelievedthatsensorysystemsareoptimizedforprocessingstimulioccurringinthenaturalenvironment.However,itremains unknown whether this principle applies to the vestibular system, which and motor coordination. Here we quantified, for the first time, the statistics of natural vestibular inputs

Chacron, Maurice

342

A Critical Look at Vestibular Dysfunction in Learning-Disabled Children.  

ERIC Educational Resources Information Center

The vestibular function was examined in 40 learning disabled and 40 non LD children. Data indicated no significant difference between normal and LD Ss, no significant correlation between vestibular function and academic achievement, and no significant educational relevance in categorizing LD Ss according to vestibular dimensions. (CL)

Polatajko, Helene J.

1985-01-01

343

In vivo Conditions Induce Faithful Encoding of Stimuli by Reducing Nonlinear Synchronization in Vestibular  

E-print Network

in Vestibular Sensory Neurons Adam D. Schneider1 , Kathleen E. Cullen2 , Maurice J. Chacron1,2 * 1 Department, Montreal, Quebec, Canada Abstract Previous studies have shown that neurons within the vestibular nuclei (VN natural (i.e. in vivo) conditions, the vestibular system uses increased variability to promote fidelity

Chacron, Maurice

344

BASIC AND CLINICAL ASPECTS OF VERTIGO AND DIZZINESS Posture Control in Vestibular-Loss Patients  

E-print Network

BASIC AND CLINICAL ASPECTS OF VERTIGO AND DIZZINESS Posture Control in Vestibular-Loss Patients of vestibular functions normally replace these by visual or haptic referencing to stationary surroundings not allow patients to fully substitute loss of the vestibular cues. In recent years, four sets

Sergio, Lauren E.

345

Behavioral/Systems/Cognitive Convergence of Vestibular and Visual Self-Motion Signals in  

E-print Network

Behavioral/Systems/Cognitive Convergence of Vestibular and Visual Self-Motion Signals in an Area Convergence of visual motion information (optic flow) and vestibular signals is important for self) and ventral intraparietal areas. In contrast, the parieto-insular vestibular cortex (PIVC), a cortical

DeAngelis, Gregory

346

1 Introduction Research has shown that the visual and vestibular systems play particularly important  

E-print Network

1 Introduction Research has shown that the visual and vestibular systems play particularly and Lee 1973). However, the vestibular system of the inner ear can only detect accelerations of the head to henceforth as `visual ^ vestibular conflict' theory (eg Zacharias and Young 1981).(1) According

Allison, Robert

347

MORPHOLOGICALLY MIXED CHEMICALELECTRICAL SYNAPSES FORMED BY PRIMARY AFFERENTS IN RODENT VESTIBULAR NUCLEI  

E-print Network

MORPHOLOGICALLY MIXED CHEMICAL­ELECTRICAL SYNAPSES FORMED BY PRIMARY AFFERENTS IN RODENT VESTIBULAR/electrical synapses in the lateral vestibular nucleus of rat were described over 40 years ago. Because gap junctions the distribution and cellular localization of electrical synapses in the adult and develop- ing rodent vestibular

Rash, John E.

348

Journal of Vestibular Research 17 (2007) 271277 271 Effect of field of view on the Levitation  

E-print Network

Journal of Vestibular Research 17 (2007) 271­277 271 IOS Press Effect of field of view on at least three cues to judge self- orientation (see [4] for a review): vestibular informa- tion (signalled primarily from the otolith division of the vestibular system), orientation of the body, and visual cues from

Jenkin, Michael R. M.

349

Evaluation of the chemical model of vestibular lesions induced by arsanilate in rats  

SciTech Connect

Several animal models of vestibular deficits that mimic the human pathology phenotype have previously been developed to correlate the degree of vestibular injury to cognate vestibular deficits in a time-dependent manner. Sodium arsanilate is one of the most commonly used substances for chemical vestibular lesioning, but it is not well described in the literature. In the present study, we used histological and functional approaches to conduct a detailed exploration of the model of vestibular lesions induced by transtympanic injection of sodium arsanilate in rats. The arsanilate-induced damage was restricted to the vestibular sensory organs without affecting the external ear, the oropharynx, or Scarpa's ganglion. This finding strongly supports the absence of diffusion of arsanilate into the external ear or Eustachian tubes, or through the eighth cranial nerve sheath leading to the brainstem. One of the striking observations of the present study is the complete restructuring of the sensory epithelia into a non sensory epithelial monolayer observed at 3 months after arsanilate application. This atrophy resembles the monolayer epithelia observed postmortem in the vestibular epithelia of patients with a history of lesioned vestibular deficits such as labyrinthectomy, antibiotic treatment, vestibular neuritis, or Ménière's disease. In cases of Ménière's disease, aminoglycosides, and platinum-based chemotherapy, vestibular hair cells are destroyed, regardless of the physiopathological process, as reproduced with the arsanilate model of vestibular lesion. These observations, together with those presented in this study of arsanilate vestibular toxicity, suggest that this atrophy process relies on a common mechanism of degeneration of the sensory epithelia.

Vignaux, G. [INSERM, ERI27, Caen, F-14000 (France) [INSERM, ERI27, Caen, F-14000 (France); Univ Caen, Caen, F-14000 (France); Chabbert, C.; Gaboyard-Niay, S.; Travo, C. [INSERM U1051, Institut des Neurosciences de Montpellier, Montpellier, F-34090,France (France)] [INSERM U1051, Institut des Neurosciences de Montpellier, Montpellier, F-34090,France (France); Machado, M.L. [INSERM, ERI27, Caen, F-14000 (France) [INSERM, ERI27, Caen, F-14000 (France); Univ Caen, Caen, F-14000 (France); Denise, P. [INSERM, ERI27, Caen, F-14000 (France) [INSERM, ERI27, Caen, F-14000 (France); Univ Caen, Caen, F-14000 (France); CHRU Caen, Explorations Fonctionnelles, Caen, F-14000 (France); Comoz, F. [CHRU Caen, Laboratoire d'anatomopathologie, Caen, F-14000 (France)] [CHRU Caen, Laboratoire d'anatomopathologie, Caen, F-14000 (France); Hitier, M. [CHRU Caen, Service d'Otorhinolaryngologie, Caen, F-14000,France (France)] [CHRU Caen, Service d'Otorhinolaryngologie, Caen, F-14000,France (France); Landemore, G. [CHRU Caen, Laboratoire d'anatomopathologie, Caen, F-14000 (France)] [CHRU Caen, Laboratoire d'anatomopathologie, Caen, F-14000 (France); Philoxène, B. [INSERM, ERI27, Caen, F-14000 (France) [INSERM, ERI27, Caen, F-14000 (France); Univ Caen, Caen, F-14000 (France); CHRU Caen, Explorations Fonctionnelles, Caen, F-14000 (France); Besnard, S., E-mail: besnard-s@phycog.org [INSERM, ERI27, Caen, F-14000 (France); Univ Caen, Caen, F-14000 (France); CHRU Caen, Explorations Fonctionnelles, Caen, F-14000 (France)

2012-01-01

350

A General Framework for Neurobiological Modeling: An Application to the Vestibular  

E-print Network

A General Framework for Neurobiological Modeling: An Application to the Vestibular System 1 Chris@medicine.wustl.edu Abstract The otolith organs in the vestibular system are excellent detectors of linear accel- erations accelerations can be computed based on vestibular signals [1]. We have constructed a realistic, detailed model

Eliasmith, Chris

351

Abstract. With galvanic vestibular stimulation (GVS), electrical current is delivered transcutaneously to the  

E-print Network

Abstract. With galvanic vestibular stimulation (GVS), electrical current is delivered transcutaneously to the vestibular aerents through electrodes placed over the mastoid bones. This serves to modulate the continuous ®ring levels of the vestibular aerents, and causes a standing subject to lean

Collins, James J.

352

Enhanced smooth pursuit eye movements in patients with bilateral vestibular decits  

E-print Network

Enhanced smooth pursuit eye movements in patients with bilateral vestibular de¢cits Christopher J Patients with bilateral vestibular de¢cits experience unsteady gait and oscillopsia that can reduce of adaptation couldbe the ability of sensory-motor systems to compensate for the vestibular loss by adaptive

Haslwanter, Thomas

353

Journal of Vestibular Research 14 (2004) 307319 307 Postural responses exhibit multisensory  

E-print Network

Journal of Vestibular Research 14 (2004) 307­319 307 IOS Press Postural responses exhibit and proprioceptive/vestibular systems. Eleven healthy subjects (25­38 yrs) received either fore-aft translations reality, vestibular, postural control, motion analysis, sensory re-weighting 1. Introduction

354

Integration of Visual-Vestibular Self Motion: Comparison of Landmark and Optic Flow Information  

E-print Network

Integration of Visual-Vestibular Self Motion: Comparison of Landmark and Optic Flow Information MPI = vestibular · Conclusions · Results II - varied gain factors, average turn angle· Introduction · Methods and vestibular information: Additive, multiplicative, and the "max-rule" model. Markus

355

Identification of the central vestibular projections in man: a positron emission tomography activation study  

Microsoft Academic Search

The cerebral representation of space depends on the integration of many different sensory inputs. The vestibular system provides one such input and its dysfunction can cause profound spatial disorientation. Using positron emission tomography (PET), we measured regional cerebral perfusion with various vestibular stimulations to map central vestibular projections and to investigate the cerebral basis of spatial disorientation. We showed that

Gabriella Bottini; Roberto Sterzi; Eraldo Paulesu; Giuseppe Vallar; Stefano F. Cappa; Francesco Erminio; Richard E. Passingham; Chris D. Frith; Richard S. J. Frackowiak

1994-01-01

356

Behavioral/Systems/Cognitive Representation of Vestibular and Visual Cues to Self-Motion  

E-print Network

Behavioral/Systems/Cognitive Representation of Vestibular and Visual Cues to Self-Motion in Ventral Convergence of vestibular and visual motion information is important for self-motion perception. One cortical area that combines vestibular and optic flow signals is the ventral intraparietal area (VIP). We

DeAngelis, Gregory

357

Behavioral/Systems/Cognitive Vestibular Heading Discrimination and Sensitivity to Linear  

E-print Network

Behavioral/Systems/Cognitive Vestibular Heading Discrimination and Sensitivity to Linear of linear self-motion, i.e., heading. The vestibular cue to heading is the direction of inertial. The otoliths also respond to gravitational acceleration, so vestibular heading discrimination could depend

Banks, Marty

358

Journal of Vestibular Research 13 (2003) 7991 79 Eye-head coordination in darkness  

E-print Network

Journal of Vestibular Research 13 (2003) 79­91 79 IOS Press Eye-head coordination in darkness 2003 Abstract. Passive head rotation in darkness produces vestibular nystagmus, consisting of slow in darkness are generated, assuming the only available sensory information is that provided by the vestibular

Ramat, Stefano

359

A functional link between area MSTd and heading perception based on vestibular signals  

E-print Network

A functional link between area MSTd and heading perception based on vestibular signals Yong Gu1, Gregory C DeAngelis1,2 & Dora E Angelaki1,2 Recent findings of vestibular responses in part of the visual cortex--the dorsal medial superior temporal area (MSTd)--indicate that vestibular signals might

DeAngelis, Gregory

360

Effects of otitis media with effusion on the vestibular system in children  

Microsoft Academic Search

Middle ear effusion has been considered the most common cause of vestibular disturbance in children. However, there have been only a few studies on vestibular disturbance in children with otitis media with effusion. We studied the vestibular systems of 30 children with otitis media with effusion aged 8 to 13 years and compared the results with 15 age- and sex-matched

MEHMET KOYUNCU; M. MUH?TT?N SAKA; YÜCEL TANYER?; TEOMAN ?E?EN; RECEP ÜNAL; AT?LLA TEKAT; FAT?H YILMAZ

1999-01-01

361

Vestibular nuclei activity during optokinetic after-nystagmus (OKAN) in the alert monkey  

Microsoft Academic Search

Neurons which receive an input from the horizontal semicircular canals were recorded from the vestibular nuclei in chronically prepared monkeys (Macaca mulatta) during optokinetic after-nystagmus (OKAN). In complete darkness the vestibular neurons showed activity changes which closely paralleled the strength of nystagmus. The activity of vestibular units returned to baseline levels of spontaneous discharge only when all after-nystagmus had ceased,

W. Waespe; V. Henn

1977-01-01

362

Microgravity vestibular investigations (10-IML-1)  

NASA Technical Reports Server (NTRS)

Our perception of how we are oriented in space is dependent on the interaction of virtually every sensory system. For example, to move about in our environment we integrate inputs in our brain from visual, haptic (kinesthetic, proprioceptive, and cutaneous), auditory systems, and labyrinths. In addition to this multimodal system for orientation, our expectations about the direction and speed of our chosen movement are also important. Changes in our environment and the way we interact with the new stimuli will result in a different interpretation by the nervous system of the incoming sensory information. We will adapt to the change in appropriate ways. Because our orientation system is adaptable and complex, it is often difficult to trace a response or change in behavior to any one source of information in this synergistic orientation system. However, with a carefully designed investigation, it is possible to measure signals at the appropriate level of response (both electrophysiological and perceptual) and determine the effect that stimulus rearrangement has on our sense of orientation. The environment of orbital flight represents the stimulus arrangement that is our immediate concern. The Microgravity Vestibular Investigations (MVI) represent a group of experiments designed to investigate the effects of orbital flight and a return to Earth on our orientation system.

Reschke, Millard F.

1992-01-01

363

Tumor pseudoprogression following radiosurgery for vestibular schwannoma  

PubMed Central

We sought to characterize vestibular schwannoma (VS) pseudoprogression after radiosurgery to assess its incidence, causative factors, and association with radiation-induced adverse effects. We performed a retrospective study of VS treated with Gamma Knife radiosurgery during 2005–2009. Seventy-five patients had at least 24 months of clinical and radiographic follow-up (median, 29 months) and were included. Tumor response was calculated volumetrically using Gamma plan software on consecutive MRIs. All treatment plans were reviewed for dosimetry characteristics. Forty-nine VS (65%) were stable or regressed after treatment. Seventeen (23%) underwent pseudoprogression, with onset of enlargement at 6 months. Seven (9%) remained larger than initial treatment volume at last follow-up. Nine (12%) had persistent growth. Three patients underwent subsequent microsurgery. One patient required intervention at 3 months for cystic enlargement; otherwise, all patients with progressive enlargement had stable VS until at least 24 months. Twenty-six patients (34.7%) developed nonauditory adverse radiation effects after treatment, including cranial neuropathy, ataxia, and hydrocephalus. There was no statistical association between onset of clinical deterioration and tumor response. Volume changes in the first 24 months after radiosurgery rarely herald treatment failure. Any volume change after 24 months is indicative of treatment failure. Pseudoprogression does not appear to be independently linked to radiation-induced morbidity, and there are no patient-related or radiosurgical parameters that predict tumor response. PMID:22028389

Hayhurst, Caroline; Zadeh, Gelareh

2012-01-01

364

Spatial orientation - Visual-vestibular-somatic interaction  

NASA Technical Reports Server (NTRS)

The compensation signals from somatosensory and vestibular receptors, which act to compensate for disturbances produced by the displacement of our eyes relative to other parts of our bodies and for visual disturbances such as tilted frames or moving visual fields, are investigated. Disturbances were evoked by tilting the head and by rotating a large visual display, while compensation signals related to gravity were altered by placing the subjects horizontally on a board or seating them vertically. The first experiment studied the effects of visual disturbance on the ability of supine observers to set a line to the longitudinal body axis while the head was tilted toward one shoulder or while the head was straight. Results showed that the effects of the visual disturbance were greater when the head was tilted than when it was straight, which indicates that the effects of visual disturbance were greater for a task that required compensation. The second experiment compared the performance of supine and erect observers. No differences were found between the performance of observers on a task requiring the use of compensation signals under these two conditions, which suggests that the enrichment of compensatory signals did not reduce the effects of visual disturbancs.

Parker, D. E.; Poston, R. L.; Gulledge, W. L.

1983-01-01

365

Stochastic Optimization Modeling  

E-print Network

study, the expected profit of the stochastic approach has been favorably compared with the ex- ..... An experimental case is analyzed for showing the improvement that the ..... Competitive advertising under uncertainty: A stochastic differential.

2014-07-04

366

A real-time research platform to study vestibular implants with gyroscopic inputs in vestibular deficient subjects.  

PubMed

Researchers have succeeded in partly restoring damaged vestibular functionality in several animal models. Recently, acute interventions have also been demonstrated in human patients. Our previous work on a vestibular implant for humans used predefined stimulation patterns; here we present a research tool that facilitates motion-modulated stimulation. This requires a system that can process gyroscope measurements and send stimulation parameters to a hybrid vestibular-cochlear implant in real-time. To match natural vestibular latencies, the time from sensor input to stimulation output should not exceed 6.5 ms. We describe a system based on National Instrument's CompactRIO platform that can meet this requirement and also offers floating point precision for advanced transfer functions. It is designed for acute clinical interventions, and is sufficiently powerful and flexible to serve as a development platform for evaluating prosthetic control strategies. Amplitude and pulse frequency modulation to predetermined functions or sensor inputs have been validated. The system has been connected to human patients, who each have received a modified MED-EL cochlear implant for vestibular stimulation, and patient tests are ongoing. PMID:25073124

Nguyen, T A Khoa; Ranieri, Maurizio; DiGiovanna, Jack; Peter, Otto; Genovese, Vincenzo; Perez Fornos, Angelica; Micera, Silvestro

2014-08-01

367

Visual gravitational motion and the vestibular system in humans  

PubMed Central

The visual system is poorly sensitive to arbitrary accelerations, but accurately detects the effects of gravity on a target motion. Here we review behavioral and neuroimaging data about the neural mechanisms for dealing with object motion and egomotion under gravity. The results from several experiments show that the visual estimates of a target motion under gravity depend on the combination of a prior of gravity effects with on-line visual signals on target position and velocity. These estimates are affected by vestibular inputs, and are encoded in a visual-vestibular network whose core regions lie within or around the Sylvian fissure, and are represented by the posterior insula/retroinsula/temporo-parietal junction. This network responds both to target motions coherent with gravity and to vestibular caloric stimulation in human fMRI studies. Transient inactivation of the temporo-parietal junction selectively disrupts the interception of targets accelerated by gravity. PMID:24421761

Lacquaniti, Francesco; Bosco, Gianfranco; Indovina, Iole; La Scaleia, Barbara; Maffei, Vincenzo; Moscatelli, Alessandro; Zago, Myrka

2013-01-01

368

An electronic prosthesis mimicking the dynamic vestibular function  

NASA Astrophysics Data System (ADS)

This paper reports our progress toward development of a unilateral vestibular prosthesis. The sensing element of the prosthesis is a custom designed one-axis MEMS gyroscope. Similarly to the natural semicircular canal, the microscopic gyroscope senses angular motion of the head and generates voltages proportional to the corresponding angular accelerations. Then, voltages are sent to the pulse generating unit where angular motion is translated into voltage pulses. The voltage pulses are converted into current pulses and are delivered through specially designed electrodes, conditioned to stimulate the corresponding vestibular nerve branch. Our preliminary experimental evaluations of the prosthesis on a rate table indicate that the device's output matches the average firing rate of vestibular neurons to those in animal models reported in the literature. The proposed design is scalable; the sensing unit, pulse generator, and the current source can be potentially implemented on a single chip using integrated MEMS technology.

Shkel, Andrei M.

2006-03-01

369

Abstract--This pilot study aimed at assessing the feasibility and the effectiveness of an electro-tactile vestibular substitution  

E-print Network

-tactile vestibular substitution system (EVSS) in patients with unilateral vestibular loss under normal and altered somatosensory conditions from the foot and ankle. Four unilateral vestibular-defective patients voluntarily suggest that patients with unilateral vestibular loss were able to take advantage to an head position

Paris-Sud XI, Université de

370

Neural basis for eye velocity generation in the vestibular nuclei of alert monkeys during off-vertical axis rotation  

Microsoft Academic Search

Activity of “vestibular only” (VO) and “vestibular plus saccade” (VPS) units was recorded in the rostral part of the medial vestibular nucleus and caudal part of the superior vestibular nucleus of alert rhesus monkeys. By estimating the “null axes” of recorded units (n = 79), the optimal plane of activation was approximately the mean plane of reciprocal semicircular canals, i.e.,

Harvey Reisine; Theodore Raphan

1992-01-01

371

Short latency vestibular evoked potentials in the chicken embryo  

NASA Technical Reports Server (NTRS)

Electrophysiological responses to pulsed linear acceleration stimuli were recorded in chicken embryos incubated for 19 or 20 days (E19/E20). Responses occurred within the first 16 ms following the stimulus onset. The evoked potentials disappeared following bilateral labyrinthectomy, but persisted following cochlear destruction alone, thus demonstrating that the responses were vestibular. Approximately 8 to 10 response peaks could be identified. The first 4 positive and corresponding negative components (early peaks with latencies < 6.0 ms) were scored and latencies and amplitudes quantified. Vestibular response latencies were significantly longer (P < 0.01) and amplitudes significantly smaller (P < 0.001) than those observed in 2-week-old birds. Mean response threshold for anesthetized embryos was -15.9dBre 1.0 g/ms, which was significantly higher (P < 0.03) than those observed in 2-week-old birds (-23.0dBre 1.0 g/ms). Latency/intensity functions (that is, slopes) were not significantly different between embryos and 2-week-old animals, but amplitude/intensity functions for embryos were significantly shallower than those for 2-week-old birds (P < 0.001). We presume that these differences reflect the refinement of sensory function that occurs following 19 to 20 days of incubation. The recording of vestibular evoked potentials provides an objective, direct and noninvasive measure of peripheral vestibular function in the embryo and, as such, the method shows promise as an investigative tool. The results of the present study form the definitive basis for using vestibular evoked potentials in the detailed study of avian vestibular ontogeny and factors that may influence it.

Jones, S. M.; Jones, T. A.

1996-01-01

372

Stochastic amplification in epidemics  

E-print Network

REPORT Stochastic amplification in epidemics David Alonso1, *, Alan J. McKane2 and Mercedes Pascual, we present a stochastic theory for the major dynamical transitions in epidemics from regular in nonlinear ecological systems in general. Keywords: epidemics; oscillations; stochastic modelling; childhood

McKane, Alan

373

Volumetric Modulated Arc Radiotherapy for Vestibular Schwannomas  

SciTech Connect

Purpose: To evaluate volumetric modulated arc radiotherapy (RapidArc [RA]), a novel approach allowing for rapid treatment delivery, for the treatment of vestibular schwannoma (VS). Methods and Materials: The RA plans were generated for a small (0.5 cm{sup 3}), intermediate (2.8 cm{sup 3}), and large (14.8 cm{sup 3}) VS. The prescription dose was 12.5 Gy to the encompassing 80% isodose. The RA plans were compared with conventional radiosurgery plans using both a single dynamic conformal arc (1DCA) and five noncoplanar dynamic conformal arcs (5DCA). Conformity indices (CI) and dose-volume histograms of critical organs were compared. The RA plan for the medium-sized VS was measured in a phantom using Gafchromic EBT films and compared with calculated dose distributions. Results: The RA planning was completed within 30 min in all cases, and calculated treatment delivery time (after patient setup) was 5 min vs. 20 min for 5DCA. A superior CI was achieved with RA, with a substantial decrease in low-dose irradiation of the normal brain achieved relative to 5DCA plans. Maximum doses to critical organs were similar for RA and 5DCA but were higher for 1DCA. Film measurements showed the differences between calculated and measured doses to be smaller than 1.5% in the high-dose area and smaller than 3% in the low-dose area. Conclusion: The RA plans consistently achieved a higher CI and decrease in areas of low-dose irradiation. This, together with shorter treatment delivery times, has led to RA replacing our conventional five-arc radiosurgery technique for VS.

Lagerwaard, Frank J. [Department of Radiation Oncology, VU University Medical Center, Amsterdam (Netherlands)], E-mail: fj.lagerwaard@vumc.nl; Meijer, Otto W.M.; Hoorn, Elles A.P. van der; Verbakel, Wilko; Slotman, Ben J.; Senan, Suresh [Department of Radiation Oncology, VU University Medical Center, Amsterdam (Netherlands)

2009-06-01

374

Polyamines in the lateral vestibular nuclei of the squirrel monkey and their potential role in vestibular compensation  

NASA Technical Reports Server (NTRS)

Polyamine synthesis increases in response to injurious stimuli including axotomy and denervation. Reduced eye nystagmus and head-deviation have been observed in unilateral labyrinthectomized (UL) guinea pigs treated with an inhibitor of polyamine synthesis, alpha-difluoromethylornithine (DFMO). We quantified polyamines in the lateral vestibular nuclei (LVN) of control and UL squirrel monkeys during the phase of vestibular compensation (VC) and performed an experiment to determine if DFMO reduces nystagmus previously observed in the guinea pig. Polyamines were detected in the LVN of control and UL squirrel monkeys. Putrescine and spermidine increased in the ipsilateral LVN 3 days after UL with no change in the contralateral LVN. No left-right differences were noted in the 5-day post-UL monkey. DFMO reduced nystagmus in a UL squirrel monkey. These findings suggest that polyamines are important in vestibular function and may contribute to nystagmus observed in VC.

Henley, C.; Igarashi, M.

1993-01-01

375

Posterior parietal rTMS disrupts human Path Integration during a vestibular navigation task.  

PubMed

In contrast to vision, the neuro-anatomical substrates of vestibular perception are obscure. The vestibular apparati provide a head angular velocity signal allowing perception of self-motion velocity. Perceived change of angular position-in-space can also be obtained from the vestibular head velocity signal via a process called Path Integration (so-called since displacement is obtained by a mathematical temporal integration of the vestibular velocity signal). It is unknown however, if distinct cortical loci sub-serve vestibular perceptions of velocity versus displacement (i.e. Path Integration). Previous studies of human brain activity have not used head motion stimuli hence precluding localisation of vestibular cortical areas specialised for Path Integration distinct from velocity perception. We inferred vestibular cortical function by measuring the disrupting effect of repetitive transcranial magnetic stimulation on the performance of a displacement-dependent vestibular navigation task. Our data suggest that posterior parietal cortex is involved in encoding contralaterally directed vestibular-derived signals of perceived angular displacement and a similar effect was found for both hemispheres. We separately tested whether right posterior parietal cortex was involved in vestibular-sensed velocity perception but found no association. Overall, our data demonstrate that posterior parietal cortex is involved in human Path Integration but not velocity perception. We suggest that there are separate brain areas that process vestibular signals of head velocity versus those involved in Path Integration. PMID:18440143

Seemungal, Barry M; Rizzo, Vincenzo; Gresty, Michael A; Rothwell, John C; Bronstein, Adolfo M

2008-05-30

376

Differentiating ascending vestibular pathways to the cortex involved in spatial cognition.  

PubMed

Vestibular information is an important factor in maintaining accurate spatial awareness. Yet, each of the cortical areas involved in processing vestibular information has unique functionality. Further, the anatomical pathways that provide vestibular input for cognitive processes are also distinct. This review outlines some of the current understanding of vestibular pathways contributing to the perception of self-motion in the cortex. The vestibulo-thalamic pathway is associated with self-motion cues for updating motor behaviors, spatial representations, and self versus object motion distinctions. The mammillo-tegmental pathway supplies vestibular input to create a cognitive representation of head direction. Self-motion and head direction information then converge to define self-location. By outlining the functional anatomy of the vestibular cortical pathways, a multi-sensory and multi-faceted view of vestibular related spatial awareness emerges. PMID:20555163

Shinder, Michael E; Taube, Jeffrey S

2010-01-01

377

[A electromyographic study of the vestibular reflexes. A clinical experimental study on human beings (author's transl)].  

PubMed

It is reported about myography on testpersons with normal vestibular function as well as on patients after operativ dissection of the VIII. nerve, neuropathia nerv. vest. and M. Menière. On the base of these findings it is supposed that myography proofes to be a useful help in the judgement of the specific influence of the vestibular organs on the motoric system. The myographic changes of the muscular activity after caloric stimulation give exact information about the entire vestibular system and especially about the vestibular-spinal-pathways. The best way of testing the vestibular activity is performed on musculars with symmetric, simultaneous and reziproke intented innervation, f.i. on the sternocleidomastoidei muscels in slight deflected position of the head. Most significant for the vestibular influence are an increase of the base-activity and the appearance of groups of potentials which are related to the vestibular stimulus in time and intensity. PMID:169443

Emami-Nouri, M

1975-06-01

378

Organization of projections from the raphe nuclei to the vestibular nuclei in rats  

NASA Technical Reports Server (NTRS)

Previous anatomic and electrophysiological evidence suggests that serotonin modulates processing in the vestibular nuclei. This study examined the organization of projections from serotonergic raphe nuclei to the vestibular nuclei in rats. The distribution of serotonergic axons in the vestibular nuclei was visualized immunohistochemically in rat brain slices using antisera directed against the serotonin transporter. The density of serotonin transporter-immunopositive fibers is greatest in the superior vestibular nucleus and the medial vestibular nucleus, especially along the border of the fourth ventricle; it declines in more lateral and caudal regions of the vestibular nuclear complex. After unilateral iontophoretic injections of Fluoro-Gold into the vestibular nuclei, retrogradely labeled neurons were found in the dorsal raphe nucleus (including the dorsomedial, ventromedial and lateral subdivisions) and nucleus raphe obscurus, and to a minor extent in nucleus raphe pallidus and nucleus raphe magnus. The combination of retrograde tracing with serotonin immunohistofluorescence in additional experiments revealed that the vestibular nuclei receive both serotonergic and non-serotonergic projections from raphe nuclei. Tracer injections in densely innervated regions (especially the medial and superior vestibular nuclei) were associated with the largest numbers of Fluoro-Gold-labeled cells. Differences were observed in the termination patterns of projections from the individual raphe nuclei. Thus, the dorsal raphe nucleus sends projections that terminate predominantly in the rostral and medial aspects of the vestibular nuclear complex, while nucleus raphe obscurus projects relatively uniformly throughout the vestibular nuclei. Based on the topographical organization of raphe input to the vestibular nuclei, it appears that dense projections from raphe nuclei are colocalized with terminal fields of flocculo-nodular lobe and uvula Purkinje cells. It is hypothesized that raphe-vestibular connections are organized to selectively modulate processing in regions of the vestibular nuclear complex that receive input from specific cerebellar zones. This represents a potential mechanism whereby motor activity and behavioral arousal could influence the activity of cerebellovestibular circuits.

Halberstadt, A. L.; Balaban, C. D.

2003-01-01

379

Vestibular Stimulation and Development of the Small Premature Infant.  

ERIC Educational Resources Information Center

This study was designed to explore the effects of vestibular stimulation on the developmental behavior, respiratory functioning, weight and length gains, and morbidity and mortality rates of premature infants. A total of 20 infants participated in this study in 4 groups of 5 infants each. Group A infants were placed in a motorized hammock within…

Neal, Mary V.

380

Galvanic vestibular stimulation influences randomness of number generation.  

PubMed

Successful interaction with the external environment requires a balance between novel or exploratory and routine or exploitative behaviours. This distinction is often expressed in terms of location or orientation of the body relative to surrounding space: functions in which the vestibular system plays an important role. However, the distinction can also be applied to novel versus repetitive production of any behaviour or symbol. Here, we investigated whether vestibular inputs contribute to the balance between novel and routine behaviours, independently of their effects on spatial orienting, by assessing effects of galvanic vestibular stimulation (GVS) on a random number generation task. Right-anodal/left-cathodal GVS, which preferentially activates the left cerebral hemisphere decreased the randomness of the sequence, while left-anodal/right-cathodal GVS, which preferentially activates the right hemisphere increased it. GVS did not induce any spatial biases in locations chosen from the number line. Our results suggest that vestibular stimulation of each hemisphere has a specific effect on the balance between novel and routine actions. We found no evidence for effects of non-specific arousal due to GVS on random number generation, and no evidence for effects on number generation consistent with modulation of spatial attention due to GVS. PMID:23111396

Ferrè, Elisa Raffaella; Vagnoni, Eleonora; Haggard, Patrick

2013-01-01

381

Linear Path Integration Deficits in Patients with Abnormal Vestibular Afference  

PubMed Central

Effective navigation requires the ability to keep track of one’s location and maintain orientation during linear and angular displacements. Path integration is the process of updating the representation of body position by integrating internally-generated self-motion signals over time (e.g., walking in the dark). One major source of input to path integration is vestibular afference. We tested patients with reduced vestibular function (unilateral vestibular hypofunction, UVH), patients with aberrant vestibular function (benign paroxysmal positional vertigo, BPPV), and healthy participants (controls) on two linear path integration tasks: experimenter-guided walking and target-directed walking. The experimenter-guided walking task revealed a systematic underestimation of self-motion signals in UVH patients compared to the other groups. However, we did not find any difference in the distance walked between the UVH group and the control group for the target-directed walking task. Results from neuropsychological testing and clinical balance measures suggest that the errors in experimenter-guided walking were not attributable to cognitive and/or balance impairments. We conclude that impairment in linear path integration in UVH patients stem from deficits in self-motion perception. Importantly, our results also suggest that patients with a UVH deficit do not lose their ability to walk accurately without vision to a memorized target location. PMID:22726251

Arthur, Joeanna C.; Kortte, Kathleen B.; Shelhamer, Mark; Schubert, Michael C.

2014-01-01

382

Physiological responses of frog vestibular fibers to horizontal angular rotation  

Microsoft Academic Search

1.Single neuronal discharges in frog's vestibular nerve were recorded in unanesthetized preparations with glass microelectrodes. The nerve fibers supplying the horizontal semicircular canal are divided into two types according to the characteristics of their frequency responses to natural stimulation of the horizontal canal. The afferent fibers increase their firing rate only on ipsilateral rotation and cease to fire on contralateral

W. Precht; R. Llinás; M. Clarke

1971-01-01

383

Astronauts Conrad and Kerwin practice Human Vestibular Function experiment  

NASA Technical Reports Server (NTRS)

Astronaut Charles Conrad Jr., commander of the first manned Skylab mission, checks out the Human Vestibular Function, Experiment M131, during Skylab training at JSC. Scientist-Astronaut Joseph P. Kerwin, science pilot of the mission, goes over a checklist. The two men are in the work and experiments compartment of the crew quarters of the Skylab Orbital Workshop (OWS) trainer at JSC.

1973-01-01

384

Galvanic vestibular stimulation for analysis of postural adaptation and stability  

Microsoft Academic Search

Human postural dynamics was investigated in 12 normal subjects by means of a force platform recording body sway, induced by bipolar transmastoid galvanic stimulation of the vestibular nerve and labyrinth. The model adopted was that of an inverted segmented pendulum, the dynamics of postural control being assumed to be reflected in the stabilizing forces actuated by the feet as a

Rolf Johansson; Miins Magnusson; Per A. Fransson

1995-01-01

385

Postural control adaptation during galvanic vestibular and vibratory proprioceptive stimulation  

Microsoft Academic Search

The objective for this study was to investigate whether the adaptation of postural control was similar during galvanic vestibular stimulation and during vibratory proprioceptive stimulation of the calf muscles. Healthy subjects were tested during erect stance with eyes open or closed. An analysis method designed to consider the adaptive adjustments was used to evaluate the motion dynamics and the evoked

Per-Anders Fransson; Anna Hafström; Mikael Karlberg; Måns Magnusson; Annika Tjäder; Rolf Johansson

2003-01-01

386

Acoustically Responsive Fibers in the Vestibular Nerve of the Cat  

Microsoft Academic Search

Recordings were made from single afferent fibers in the inferior vestibular nerve, which innervates the saccule and posterior semicircular canal. A substantial portion of the fi- bers with irregular background activity increased their firing in response to moderately intense clicks and tones. In responsive fibers, acoustic clicks evoked action poten- tials with minimum latencies of I 1 .O msec. Fibers

Michael P. McCue; John J. Guinan

1994-01-01

387

Complex vestibular macular anatomical relationships need a synthetic approach  

NASA Technical Reports Server (NTRS)

Mammalian vestibular maculae are anatomically organized for complex parallel processing of linear acceleration information. Anatomical findings in rat maculae are provided in order to underscore this complexity, which is little understood functionally. This report emphasizes that a synthetic approach is critical to understanding how maculae function and the kind of information they conduct to the brain.

Ross, M. D.

2001-01-01

388

Functional characterization of primary vestibular afferents in the frog  

Microsoft Academic Search

1.In order to more accurately identify the nature of the vestibular input to central neurons, the response properties of single semicircular canal and otolith units in the frog VIIIth nerve were studied in curarized preparations.2.An equation describing the response plane was calculated for each canal on the basis of null point measurements. These results show that the ipsilateral canal planes

R. H. I. Blanks; W. Precht

1976-01-01

389

The use of optokinetic stimulation in vestibular rehabilitation.  

PubMed

Individuals with vestibular dysfunction may experience visual vertigo (VV), in which symptoms are provoked or exacerbated by excessive or disorienting visual stimuli (eg, supermarkets). Individuals with VV are believed to be overly reliant on visual input for balance (ie, visually dependent). VV can significantly improve when customized vestibular rehabilitation exercises are combined with exposure to optokinetic stimuli. However, the frequency of treatment sessions (twice weekly for 8 weeks) and the equipment used (expensive and space consuming) make it difficult to incorporate these techniques into everyday clinical practice where exercises may be practiced unsupervised. The aim of this focused review is to provide an overview of recent findings investigating (a) responses of individuals with vestibular deficits to a customized exercise program incorporating exposure to optokinetic stimuli via a "high-tech" visual environment rotator or a "low-tech" DVD with and without supervision, and (b) the mechanism of recovery. Optokinetic stimulation will also be discussed in relation to other new innovations in vestibular rehabilitation techniques and future work. PMID:20588097

Pavlou, Marousa

2010-06-01

390

Vestibular benefits to task savings in motor adaptation.  

PubMed

In everyday life, we seamlessly adapt our movements and consolidate them to multiple behavioral contexts. This natural flexibility seems to be contingent on the presence of movement-related sensorimotor cues and cannot be reproduced when static visual or haptic cues are given to signify different behavioral contexts. So far, only sensorimotor cues that dissociate the sensorimotor plans prior to force field exposure have been successful in learning two opposing perturbations. Here we show that vestibular cues, which are only available during the perturbation, improve the formation and recall of multiple control strategies. We exposed subjects to inertial forces by accelerating them laterally on a vestibular platform. The coupling between reaching movement (forward-backward) and acceleration direction (leftward-rightward) switched every 160 trials, resulting in two opposite force environments. When exposed for a second time to the same environment, with the opposite environment in between, subjects showed retention resulting in an ?3 times faster adaptation rate compared with the first exposure. Our results suggest that vestibular cues provide contextual information throughout the reach, which is used to facilitate independent learning and recall of multiple motor memories. Vestibular cues provide feedback about the underlying cause of reach errors, thereby disambiguating the various task environments and reducing interference of motor memories. PMID:23785131

Sarwary, A M E; Selen, L P J; Medendorp, W P

2013-09-01

391

Effects of Tactile and Audio Cues on Reducing Vestibular Illusions.  

National Technical Information Service (NTIS)

The effect of multisensory cues (3-D, audio, tactile belt) to overcome a vestibular illusion in a rotating Barany Chair was investigated. Seated subjects were rotated about their spinal axis (Z axis) from a standing stop to a predetermined velocity. The a...

D. Bowden, L. Guzy, W. Albery

2006-01-01

392

Staged Resection of Large Hypervascular Vestibular Schwannomas in Young Adults  

PubMed Central

Two young adults underwent resection of large hypervascular vestibular schwannomas (acoustic neuromas) via two-stage surgery. The first patient, a 27-year-old woman with hydrocephalus, had a large hypervascular vestibular tumor in the left cerebellopontine angle (CPA) supplied by the left anterior inferior cerebellar artery (AICA) and posterior inferior cerebellar artery (PICA). The second patient, a 34-year-old woman, had a large AICA-supplied hypervascular vestibular tumor in the left CPA that displaced the brain stem significantly. At the initial stage, only the lateral aspect of the tumor was debulked due to excessive bleeding from the tumor bed. Angiography 1 or 2 months after the initial operation showed that the tumor was hypovascular. At the second stage, the remnant medial aspect of the tumor was relatively avascular and nonadherent to the brain stem. Without blood transfusion during the second stage, the tumor was removed totally in the first patient and subtotally in the second patient. Pathological examination revealed that dilatated blood vessels were prominently increased at the first surgery; however, at the second surgery, the number of blood vessels had decreased, showing necrosis and degeneration. Although there are no absolute indications for the staged resection of vestibular schwannomas, this procedure may represent one of the safest options for these difficult lesions in young adults. ImagesFigure 1p201-bFigure 1p202-bFigure 2p203-bFigure 2p204-b PMID:17167621

Abe, Takumi; Izumiyama, Hitoshi; Imaizumi, Youichi; Kobayashi, Shinsuke; Shimazu, Motohiko; Sasaki, Ken; Matsumoto, Kiyoshi; Kushima, Miki

2001-01-01

393

Craniofacial development of the rat with respect to vestibular orientation  

Microsoft Academic Search

The vestibular orientation was applied in the present work. Its purpose was to contribute to the knowledge of the craniofacial development of the growing rat. Sagittal cuts were made in 91 crania from Wistar rats (44 males and 47 females) at 8, 15, 30 and 60 days of age. The x and y coordinates of the sagittal points were determined.

Héctor M. Pucciarelli

1978-01-01

394

Shape Analysis of Vestibular Systems in Adolescent Idiopathic Scoliosis  

E-print Network

Shape Analysis of Vestibular Systems in Adolescent Idiopathic Scoliosis Using Geodesic Spectra Wei, Stony Brook, NY 11794, USA Abstract. Adolescent Idiopathic Scoliosis (AIS) characterized by the 3D spine Scoliosis (AIS) is a 3 spinal deformity which affects about 4% schoolchildren worldwide. It is believed

Hua, Jing

395

Shape Analysis of Vestibular Systems in Adolescent Idiopathic Scoliosis  

E-print Network

Shape Analysis of Vestibular Systems in Adolescent Idiopathic Scoliosis Using Geodesic Spectra Abstract. Adolescent Idiopathic Scoliosis (AIS) characterized by the 3D spine deformity affects about 4-thoracic AIS and normal subjects. 1 Introduction Adolescent Idiopathic Scoliosis (AIS) is a 3 spinal deformity

396

Research Report Progressive vestibular mutation leads to elevated anxiety  

E-print Network

Research Report Progressive vestibular mutation leads to elevated anxiety Shahar Shefera , Carlos R 4 January 2010 Anxiety disorders are among the most common mental disorders, and are comorbid anxiety and balance disorders are causally related, and what direction this causality may take. We argue

Avraham, Karen

397

Presynaptic Calcium Stores Modulate Afferent Release in Vestibular Hair Cells  

Microsoft Academic Search

Hair cells, the mechanoreceptors of the acoustic and vestibular system, are presynaptic to primary afferent neurons of the eighth nerve and excite neural activity by the release of glutamate. In the present work, the role played by intracellular Ca 2 stores in afferent transmission was investigated, at the presynaptic level, by monitoring changes in the intracellular Ca 2 concentration ((Ca

Andrea Lelli; Paola Perin; Marta Martini; Catalin D. Ciubotaru; Ivo Prigioni; Paolo Valli; Maria L. Rossi; Fabio Mammano

2003-01-01

398

Mechanisms for vestibular disorders in space flight. Facts and hypotheses  

NASA Technical Reports Server (NTRS)

This article discusses the vestibular disorders associated with space flight. It is found there is still no complete understanding of the changes occurring in the sensory systems of the body during weightlessness. Results of studies are presented, including results of a ground model.

Matsnev, E. I.

1980-01-01

399

Medial vestibular connections with the hypocretin (orexin) system  

NASA Technical Reports Server (NTRS)

The mammalian medial vestibular nucleus (MVe) receives input from all vestibular endorgans and provides extensive projections to the central nervous system. Recent studies have demonstrated projections from the MVe to the circadian rhythm system. In addition, there are known projections from the MVe to regions considered to be involved in sleep and arousal. In this study, afferent and efferent subcortical connectivity of the medial vestibular nucleus of the golden hamster (Mesocricetus auratus) was evaluated using cholera toxin subunit-B (retrograde), Phaseolus vulgaris leucoagglutinin (anterograde), and pseudorabies virus (transneuronal retrograde) tract-tracing techniques. The results demonstrate MVe connections with regions mediating visuomotor and postural control, as previously observed in other mammals. The data also identify extensive projections from the MVe to regions mediating arousal and sleep-related functions, most of which receive immunohistochemically identified projections from the lateral hypothalamic hypocretin (orexin) neurons. These include the locus coeruleus, dorsal and pedunculopontine tegmental nuclei, dorsal raphe, and lateral preoptic area. The MVe itself receives a projection from hypocretin cells. CTB tracing demonstrated reciprocal connections between the MVe and most brain areas receiving MVe efferents. Virus tracing confirmed and extended the MVe afferent connections identified with CTB and additionally demonstrated transneuronal connectivity with the suprachiasmatic nucleus and the medial habenular nucleus. These anatomical data indicate that the vestibular system has access to a broad array of neural functions not typically associated with visuomotor, balance, or equilibrium, and that the MVe is likely to receive information from many of the same regions to which it projects.

Horowitz, Seth S.; Blanchard, Jane; Morin, Lawrence P.

2005-01-01

400

Hyperventilation-induced nystagmus in patients with vestibular schwannoma  

E-print Network

demyelinated axons. Key words: Acoustic neuroma--Recovery nystagmus--Three-dimensional eye movements. Nystagmus has been observed following hyperventilation in patients with acous- tic neuroma.2,3 Although termed "acoustic," these schwannomas actually arise from the vestibular por- tion of the eighth cranial

Haslwanter, Thomas

401

Vestibular factors influencing the biomedical support of humans in space  

NASA Technical Reports Server (NTRS)

This paper will describe the biomedical support aspects of humans in space with respect to the vestibular system. The vestibular system is thought to be the primary sensory system involved in the short-term effects of space motion sickness although there is increasing evidence that many factors play a role in this complex set of symptoms. There is the possibility that an individual's inner sense of orientation may be strongly coupled with the susceptibility to space motion sickness. A variety of suggested countermeasures for space motion sickness will be described. Although there are no known ground-based tests that can predict space motion sickness, the search should go on. The long term effects of the vestibular system in weightlessness are still relatively unknown. Some preliminary data has shown that the otoconia are irregular in size and distribution following extended periods of weightlessness. The ramifications of this data are not yet known and because the data was obtained on lower order animals, definitive studies and results must wait until the space station era when higher primates can be studied for long durations. This leads us to artificial gravity, the last topic of this paper. The vestibular system is intimately tied to this question since it has been shown on Earth that exposure to a slow rotating room causes motion sickness for some period of time before adaptation occurs. If the artificial gravity is intermittent, will this mean that people will get sick every time they experience it? The data from many astronauts returning to Earth indicates that a variety of sensory illusions are present, especially immediately upon return to a 1-g environment. Oscillopsia or apparent motion of the visual surround upon head motion along with inappropriate eye motions for a given head motion, all indicate that there is much to be studied yet about the vestibular and CNS systems reaction to a sudden application of a steady state acceleration field like 1-g. From the above information it is obvious that the vestibular system does have unique requirements when it comes to the biomedical support of space flight. This is not to say that other areas such as cardiovascular, musculo-skeletal, immunological and hematological systems do not have their own unique requirements but that possible solutions to one system can provide continuing problems to another system. For example, artificial gravity might be helpful for long term stabilization of bone demineralization or cardiovascular deconditioning but might introduce a new set of problems in orientation, vestibular conflict and just plain body motion in a rotating space vehicle.

Lichtenberg, B. K.

1988-01-01

402

Spatiotemporal Properties of Vestibular Responses in Area MSTd  

PubMed Central

Recent studies have shown that many neurons in the primate dorsal medial superior temporal area (MSTd) show spatial tuning during inertial motion and that these responses are vestibular in origin. Given their well-studied role in processing visual self-motion cues (i.e., optic flow), these neurons may be involved in the integration of visual and vestibular signals to facilitate robust perception of self-motion. However, the temporal structure of vestibular responses in MSTd has not been characterized in detail. Specifically, it is not known whether MSTd neurons encode velocity, acceleration, or some combination of motion parameters not explicitly encoded by vestibular afferents. In this study, we have applied a frequency-domain analysis to single-unit responses during translation in three dimensions (3D). The analysis quantifies the stimulus-driven temporal modulation of each response as well as the degree to which this modulation reflects the velocity and/or acceleration profile of the stimulus. We show that MSTd neurons signal a combination of velocity and acceleration components with the velocity component being stronger for most neurons. These two components can exist both within and across motion directions, although their spatial tuning did not show a systematic relationship across the population. From these results, vestibular responses in MSTd appear to show characteristic features of spatiotemporal convergence, similar to previous findings in the brain stem and thalamus. The predominance of velocity encoding in this region may reflect the suitability of these signals to be integrated with visual signals regarding self-motion perception. PMID:20631212

Fetsch, Christopher R.; Rajguru, Suhrud M.; Karunaratne, Anuk; Gu, Yong; Angelaki, Dora E.

2010-01-01

403

Spatiotemporal properties of vestibular responses in area MSTd.  

PubMed

Recent studies have shown that many neurons in the primate dorsal medial superior temporal area (MSTd) show spatial tuning during inertial motion and that these responses are vestibular in origin. Given their well-studied role in processing visual self-motion cues (i.e., optic flow), these neurons may be involved in the integration of visual and vestibular signals to facilitate robust perception of self-motion. However, the temporal structure of vestibular responses in MSTd has not been characterized in detail. Specifically, it is not known whether MSTd neurons encode velocity, acceleration, or some combination of motion parameters not explicitly encoded by vestibular afferents. In this study, we have applied a frequency-domain analysis to single-unit responses during translation in three dimensions (3D). The analysis quantifies the stimulus-driven temporal modulation of each response as well as the degree to which this modulation reflects the velocity and/or acceleration profile of the stimulus. We show that MSTd neurons signal a combination of velocity and acceleration components with the velocity component being stronger for most neurons. These two components can exist both within and across motion directions, although their spatial tuning did not show a systematic relationship across the population. From these results, vestibular responses in MSTd appear to show characteristic features of spatiotemporal convergence, similar to previous findings in the brain stem and thalamus. The predominance of velocity encoding in this region may reflect the suitability of these signals to be integrated with visual signals regarding self-motion perception. PMID:20631212

Fetsch, Christopher R; Rajguru, Suhrud M; Karunaratne, Anuk; Gu, Yong; Angelaki, Dora E; Deangelis, Gregory C

2010-09-01

404

Stochastic counterfactuals and stochastic sufficient causes  

PubMed Central

Most work in causal inference concerns deterministic counterfactuals; the literature on stochastic counterfactuals is small. In the stochastic counterfactual setting, the outcome for each individual under each possible set of exposures follows a probability distribution so that for any given exposure combination, outcomes vary not only between individuals but also probabilistically for each particular individual. The deterministic sufficient cause framework supplements the deterministic counterfactual framework by allowing for the representation of counterfactual outcomes in terms of sufficient causes or causal mechanisms. In the deterministic sufficient cause framework it is possible to test for the joint presence of two causes in the same causal mechanism, referred to as a sufficient cause interaction. In this paper, these ideas are extended to the setting of stochastic counterfactuals and stochastic sufficient causes. Formal definitions are given for a stochastic sufficient cause framework. It is shown that the empirical conditions that suffice to conclude the presence of a sufficient cause interaction in the deterministic sufficient cause framework suffice also to conclude the presence of a sufficient cause interaction in the stochastic sufficient cause framework. Two examples from the genetics literature, in which there is evidence that sufficient cause interactions are present, are discussed in light of the results in this paper.

VANDERWEELE, TYLER J.; ROBINS, JAMES M.

2014-01-01

405

Artificial Balance: Restoration of the Vestibulo-Ocular Reflex in Humans with a Prototype Vestibular Neuroprosthesis  

PubMed Central

The vestibular system plays a crucial role in the multisensory control of balance. When vestibular function is lost, essential tasks such as postural control, gaze stabilization, and spatial orientation are limited and the quality of life of patients is significantly impaired. Currently, there is no effective treatment for bilateral vestibular deficits. Research efforts both in animals and humans during the last decade set a solid background to the concept of using electrical stimulation to restore vestibular function. Still, the potential clinical benefit of a vestibular neuroprosthesis has to be demonstrated to pave the way for a translation into clinical trials. An important parameter for the assessment of vestibular function is the vestibulo-ocular reflex (VOR), the primary mechanism responsible for maintaining the perception of a stable visual environment while moving. Here we show that the VOR can be artificially restored in humans using motion-controlled, amplitude modulated electrical stimulation of the ampullary branches of the vestibular nerve. Three patients received a vestibular neuroprosthesis prototype, consisting of a modified cochlear implant providing vestibular electrodes. Significantly higher VOR responses were observed when the prototype was turned ON. Furthermore, VOR responses increased significantly as the intensity of the stimulation increased, reaching on average 79% of those measured in healthy volunteers in the same experimental conditions. These results constitute a fundamental milestone and allow us to envision for the first time clinically useful rehabilitation of patients with bilateral vestibular loss. PMID:24808890

Perez Fornos, Angelica; Guinand, Nils; van de Berg, Raymond; Stokroos, Robert; Micera, Silvestro; Kingma, Herman; Pelizzone, Marco; Guyot, Jean-Philippe

2014-01-01

406

New measures and effects of stochastic resonance  

E-print Network

is the total output AC voltage in the case of no signal. In the simulations the input was a sinusoidal signal of a fixed frequency and the output was the input signal corrupted with additive white gaussian noise of a fixed variance. Both the classical... of amplitude 0.5 V and frequency 5 Hz and the output signal was the input signal corrupted with additive white Gaussian noise of variance 1. The threshold U t , of the asymmetric LCD was set to Threshold Signal + Noise Signal Input...

Sethuraman, Swaminathan

2005-11-01

407

Visual and vestibular contributions to pitch sway stabilization in the ankle muscles of normals and patients with bilateral peripheral vestibular deficits  

Microsoft Academic Search

Vestibular, visual, and proprioceptive influences on muscle activity correcting for backwards body tilt were investigated in normals and patients with bilateral peripheral vestibular deficits. Body tilt was induced by a dorsi-flexion rotation of the feet about the ankle joints while the subject stood on a force measuring platform. Ankle muscle activity and torque were monitored as upright stance was reestablished,

J. H. J. Allure; C. R. Pfaltz

1985-01-01

408

The appreciation of stochastic motion in particle accelerators  

SciTech Connect

A description is given of the analytic and numerical work, performed from July 1955 through August 1956, so as to develop, and then study, the process of making intense proton beams, suitable for colliding beams. It is shown how this investigation led, in a most natural way, to the realization that stochasticity can arise in a simple Hamiltonian system. Furthermore, the criterion for the onset of stochasticity was understood, and carefully studied, in two different situations. The first situation was the proposed (and subsequently used) ''stacking process'' for developing an intense beam, where stochasticity occurs as additional particles are added to the intense circulating beam. The second situation occurs when one seeks to develop ''stochastic accelerators'' in which particles are accelerated (continuously) by a collection of radio frequency systems. It was in the last connection that the well-known criterion for stochasticity, resonance overlap, was obtained.

Symon, Keith; Sessler, Andrew

2003-08-03

409

Visual-vestibular integration motion perception reporting  

NASA Technical Reports Server (NTRS)

Self-orientation and self/surround-motion perception derive from a multimodal sensory process that integrates information from the eyes, vestibular apparatus, proprioceptive and somatosensory receptors. Results from short and long duration spaceflight investigations indicate that: (1) perceptual and sensorimotor function was disrupted during the initial exposure to microgravity and gradually improved over hours to days (individuals adapt), (2) the presence and/or absence of information from different sensory modalities differentially affected the perception of orientation, self-motion and surround-motion, (3) perceptual and sensorimotor function was initially disrupted upon return to Earth-normal gravity and gradually recovered to preflight levels (individuals readapt), and (4) the longer the exposure to microgravity, the more complete the adaptation, the more profound the postflight disturbances, and the longer the recovery period to preflight levels. While much has been learned about perceptual and sensorimotor reactions and adaptation to microgravity, there is much remaining to be learned about the mechanisms underlying the adaptive changes, and about how intersensory interactions affect perceptual and sensorimotor function during voluntary movements. During space flight, SMS and perceptual disturbances have led to reductions in performance efficiency and sense of well-being. During entry and immediately after landing, such disturbances could have a serious impact on the ability of the commander to land the Orbiter and on the ability of all crew members to egress from the Orbiter, particularly in a non-nominal condition or following extended stays in microgravity. An understanding of spatial orientation and motion perception is essential for developing countermeasures for Space Motion Sickness (SMS) and perceptual disturbances during spaceflight and upon return to Earth. Countermeasures for optimal performance in flight and a successful return to Earth require the development of preflight and in-flight training to help astronauts acquire and maintain a dual adaptive state. Despite the considerable experience with, and use of, an extensive set of countermeasures in the Russian space program, SMS and perceptual disturbances remain an unresolved problem on long-term flights. Reliable, valid perceptual reports are required to develop and refine stimulus rearrangements presented in the PAT devices currently being developed as countermeasures for the prevention of motion sickness and perceptual disturbances during spaceflight, and to ensure a less hazardous return to Earth. Prior to STS-8, crew member descriptions of their perceptual experiences were, at best, anecdotal. Crew members were not schooled in the physiology or psychology of sensory perception, nor were they exposed to the appropriate professional vocabulary. However, beginning with the STS-8 Shuttle flight, a serious effort was initiated to teach astronauts a systematic method to classify and quantify their perceptual responses in space, during entry, and after flight. Understanding, categorizing, and characterizing perceptual responses to spaceflight has been greatly enhanced by implementation of that training system.

Harm, Deborah L.; Reschke, Millard R.; Parker, Donald E.

1999-01-01

410

A neuroscientific account of how vestibular disorders impair bodily self-consciousness  

PubMed Central

The consequences of vestibular disorders on balance, oculomotor control, and self-motion perception have been extensively described in humans and animals. More recently, vestibular disorders have been related to cognitive deficits in spatial navigation and memory tasks. Less frequently, abnormal bodily perceptions have been described in patients with vestibular disorders. Altered forms of bodily self-consciousness include distorted body image and body schema, disembodied self-location (out-of-body experience), altered sense of agency, as well as more complex experiences of dissociation and detachment from the self (depersonalization). In this article, I suggest that vestibular disorders create sensory conflict or mismatch in multisensory brain regions, producing perceptual incoherence and abnormal body and self perceptions. This hypothesis is based on recent functional mapping of the human vestibular cortex, showing vestibular projections to the primary and secondary somatosensory cortex and in several multisensory areas found to be crucial for bodily self-consciousness. PMID:24367303

Lopez, Christophe

2013-01-01

411

A neuroscientific account of how vestibular disorders impair bodily self-consciousness.  

PubMed

The consequences of vestibular disorders on balance, oculomotor control, and self-motion perception have been extensively described in humans and animals. More recently, vestibular disorders have been related to cognitive deficits in spatial navigation and memory tasks. Less frequently, abnormal bodily perceptions have been described in patients with vestibular disorders. Altered forms of bodily self-consciousness include distorted body image and body schema, disembodied self-location (out-of-body experience), altered sense of agency, as well as more complex experiences of dissociation and detachment from the self (depersonalization). In this article, I suggest that vestibular disorders create sensory conflict or mismatch in multisensory brain regions, producing perceptual incoherence and abnormal body and self perceptions. This hypothesis is based on recent functional mapping of the human vestibular cortex, showing vestibular projections to the primary and secondary somatosensory cortex and in several multisensory areas found to be crucial for bodily self-consciousness. PMID:24367303

Lopez, Christophe

2013-01-01

412

DIFFERENTIAL EXPLORATION OF COCHLEAR AND VESTIBULAR RECEPTORS BY INTERACTION OF ARTIFICIAL AND NATURAL STIMULI  

Microsoft Academic Search

An electrical excitation of the VIIIth nerve was used in combination with either an acoustic or a vestibular stimulus (white noise or horizontal angular acceleration respectively) to derive artefact-free responses with either cochlear or vestibular specificity. In the guinea pig, the Electrical-Vestibular response (EVAP) appeared to be monophasic with it few tens microvolts amplitude and a typical 0.3 ms latency,

R. CHARLET DE SAUVAGE; G. DOLIVET; J.-P. ERRE; J.-M. ARAN

1990-01-01

413

Complementary roles of BDNF and NT3 in vestibular and auditory development  

Microsoft Academic Search

The physiological role of BDNF and NT-3 in the development of the vestibular and auditory systems was investigated in mice that carry a deleted BDNF and\\/or NT-3 gene. BDNF was the major survival factor for vestibular ganglion neurons, and NT-3, for spiral ganglion neurons. Lack of BDNF and NT-3 did not affect ingrowth of nerve fibers into the vestibular epithelium,

Patrik Ernfors; Thomas Van De Water; Janet Loring; Rudolf Jaenisch

1995-01-01

414

Experimental vestibular pharmacology: a minireview with special reference to neuroactive substances and antivertigo drugs.  

PubMed

Neurotransmitters and neuromodulators involved in the function of vestibular nuclei were reviewed with special reference to drugs used for treatment of motion sickness and vertigo. Biochemical, histochemical and electrophysiological studies have demonstrated that acetylcholine is a transmitter candidate from the afferent vestibular nerve to the lateral vestibular nucleus (LVN), because acetylcholine satisfies most criteria for a chemical transmitter in the central nervous system. It is unlikely, however, that monoamines such as noradrenaline, dopamine and serotonin are transmitters in the vestibular neurons, since cell bodies and nerve terminals containing the monoamines have not been detected yet in the vestibular nuclei. Although histamine and H1-receptor blockers inhibit neuron activities in the vestibular nuclei, it is unclear at present whether histaminergic system is directly related to the function of vestibular neurons. It has been established that GABA is an inhibitory transmitter from the cerebellar Purkinje cells to the LVN neurons. Diazepam is considered to enhance the GABA effect on the LVN, thereby modifying the vestibular neuronal firing. Enkephalin-containing cell bodies and nerve terminals are found in the medial vestibular nucleus, and a few substance P-containing neurons have been observed in the vestibular nuclei. However, the functional role of these peptides on the vestibular system remains to be determined. Unlike histamine H1-receptor blockers, vasodilators such as cinnarizine, ifenprodil and adenosine triphosphate, which are effective in treatment of vertigo, produce an enhancement of responsiveness of neuron activities in the vestibular nuclei, probably as a result of an increase in blood flow in the brain.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6399658

Matsuoka, I; Ito, J; Takahashi, H; Sasa, M; Takaori, S

1984-01-01

415

Inhibition of voltage-gated calcium currents in type II vestibular hair cells by cinnarizine  

Microsoft Academic Search

Cinnarizine is pharmaceutically used in conditions with vestibular vertigo such as Meniere’s disease. It is thought to act on extra-vestibular targets. We hypothesized that cinnarizine, as a blocker of L-type Ca 2+ channels, may directly target vestibular hair cells where Ca 2+ currents are important for the mechano-electrical transduction and transmitter release. Our aim was to clarify whether cinnarizine affected

Sonja F. Arab; Philip Düwel; Eberhard Jüngling; Martin Westhofen; Andreas Lückhoff

2004-01-01

416

Stochastic Processes for Physicists  

NASA Astrophysics Data System (ADS)

1. A review of probability theory; 2. Differential equations; 3. Stochastic equations with Gaussian noise; 4. Further properties of stochastic processes; 5. Some applications of Gaussian noise; 6. Numerical methods for Gaussian noise; 7. Fokker-Planck equations and reaction-diffusion systems; 8. Jump processes; 9. Levy processes; 10. Modern probability theory; Appendix; References; Index.

Jacobs, Kurt

2010-02-01

417

Experimental and clinical study of EHF treatment of vascular-vestibular dysfunction  

SciTech Connect

The authors present the results of a study of the effectiveness of EHF radiation on the cerebral hemodynamics, bioelectrical activity of the cerebral cortex, and functional state of the vestibular analyzer in chronic studies of cats using a model of vascular-vestibular dysfunction. The clinical part of the work reflects the results of studies of the functional state of cerebral blood circulation and the vestibular analyzer during the EHF treatment of angiovertebrogenic vestibular dysfunction in a background of initial manifestations of cerebral blood supply deficiency (angiodistonic variant).

Mal`tsev, A.E.; Abakarov, A.T.; Istomin, V.S. [and others

1994-07-01

418

Vestibular function in the temporal and parietal cortex: distinct velocity and inertial processing pathways  

PubMed Central

A number of behavioral and neuroimaging studies have reported converging data in favor of a cortical network for vestibular function, distributed between the temporo-parietal cortex and the prefrontal cortex in the primate. In this review, we focus on the role of the cerebral cortex in visuo-vestibular integration including the motion sensitive temporo-occipital areas i.e., the middle superior temporal area (MST) and the parietal cortex. Indeed, these two neighboring cortical regions, though they both receive combined vestibular and visual information, have distinct implications in vestibular function. In sum, this review of the literature leads to the idea of two separate cortical vestibular sub-systems forming (1) a velocity pathway including MST and direct descending pathways on vestibular nuclei. As it receives well-defined visual and vestibular velocity signals, this pathway is likely involved in heading perception and rapid top-down regulation of eye/head coordination and (2) an inertial processing pathway involving the parietal cortex in connection with the subcortical vestibular nuclei complex responsible for velocity storage integration. This vestibular cortical pathway would be implicated in high-order multimodal integration and cognitive functions, including world space and self-referential processing. PMID:25071481

Ventre-Dominey, Jocelyne

2014-01-01

419

Schwannoma do nervo vestibular (neurinoma do acustico) : diagnostico e tratamento com variação da abordagem cirurgica.  

E-print Network

??O autor apresenta um estudo descritivo-retrospectivo, envolvendo 240 pacientes portadores de Schwannoma do Vestibular (SV) que foram operados em decúbito dorsal (posição de mastóide), monitorizados… (more)

Arquimedes Cavalcante Cardoso

2007-01-01

420

Input/output properties of the lateral vestibular nucleus  

NASA Technical Reports Server (NTRS)

This article is a review of work in three species, squirrel monkey, cat, and rat studying the inputs and outputs from the lateral vestibular nucleus (LVN). Different electrophysiological shock paradigms were used to determine the synaptic inputs derived from thick to thin diameter vestibular nerve afferents. Angular and linear mechanical stimulations were used to activate and study the combined and individual contribution of inner ear organs and neck afferents. The spatio-temporal properties of LVN neurons in the decerebrated rat were studied in response to dynamic acceleration inputs using sinusoidal linear translation in the horizontal head plane. Outputs were evaluated using antidromic identification techniques and identified LVN neurons were intracellularly injected with biocytin and their morphology studied.

Boyle, R.; Bush, G.; Ehsanian, R.

2004-01-01

421

Metachronous schwannoma in the colon with vestibular schwannoma  

PubMed Central

We experienced a case of vestibular schwannoma and metachronous schwannoma in the colon. A 59-year-old female presented with a 1-month history of hematochezia. She had undergone suboccipital craniectomy resulting in radical subtotal resection, followed by gamma knife radiosurgery for a large left vestibular schwannoma 4 years prior to admission. On preoperative colonoscopy, a huge mass through which the colonoscope could not be passed was detected. CT scans showed colo-colonic intussusception with a 4.8-cm-sized mass in the descending colon. PET/CT revealed hypermetabolism of the descending colon tumor and pericolic lymph nodes. We performed left hemicolectomy under the preoperative impression of colon cancer with intussusception. A pathological diagnosis of benign schwannoma of the colon was made in this patient. PMID:25247171

Jung, Eun-Joo; Han, Hye Seung; Koh, Young-Cho; Cho, Joon; Ryu, Chun-Geun; Paik, Jin Hee

2014-01-01

422

Research on biophysical evaluation of the human vestibular system  

NASA Technical Reports Server (NTRS)

The human vestibular function was studied by the combined approach of advanced measurement and mathematical modelling. Fundamental measurements of some physical properties of endolymph and perilymph, combined with nystagmus measurements and fluid mechanical analysis of semicircular canal function furthered the theory of canal mechanical response to angular acceleration, caloric stimulation and relating linear acceleration. The effects of adaptation seen at low frequency angular stimulation were studied and modelled to remove some shortcomings of the torsion pendulum models. Otolith function was also studied experimentally and analytically, leading to a new set of models for subjective orientation. Applications to special problems of space, including the case of rotating spacecraft were investigated and the interaction of visual and vestibular cues and their relation to proprioceptive information was explored relative to postural control.

Young, L. R.

1974-01-01

423

A model describing vestibular detection of body sway motion.  

NASA Technical Reports Server (NTRS)

An experimental technique was developed which facilitated the formulation of a quantitative model describing vestibular detection of body sway motion in a postural response mode. All cues, except vestibular ones, which gave a subject an indication that he was beginning to sway, were eliminated using a specially designed two-degree-of-freedom platform; body sway was then induced and resulting compensatory responses at the ankle joints measured. Hybrid simulation compared the experimental results with models of the semicircular canals and utricular otolith receptors. Dynamic characteristics of the resulting canal model compared closely with characteristics of models which describe eye movement and subjective responses to body rotational motions. The average threshold level, in the postural response mode, however, was considerably lower. Analysis indicated that the otoliths probably play no role in the initial detection of body sway motion.

Nashner, L. M.

1971-01-01

424

Comparative Transduction Mechanisms of Vestibular Otolith Hair Cells  

NASA Technical Reports Server (NTRS)

Hair cells in the bullfrog vestibular otolith organs regenerate following aminoglycoside ototoxicity. Hair cells in these organs are differentially sensitive to gentamicin, with saccular hair cells and hair cells in the utricular striola being damaged at lower gentamicin concentrations than hair cells in the utricular extrastriola. Regenerating hair cells in these organs have short hair bundles and can be classified into a number of phenotypes using the same morphological criteria used to identify their mature counterparts. Our studies suggest that some supporting cells can convert, or transdifferentiate,into hair cells without an intervening cell division. By stimulating these processes in humans, clinicians may be able to alleviate human deafness and peripheral vestibular disorders by regenerating and replacing lost hair cells. In vivo and in vitro studies were done on cell proliferation and hair cell regeneration.

Baird, Richard A.

1994-01-01

425

Antagonistic otolith-visual units in cat vestibular nuclei  

NASA Technical Reports Server (NTRS)

The nature of neural coding of visual (Vis) and vestibular (Vst) information on translational motion in the region of the vestibular nuclei was investigated using extracellular single-unit recordings in alert adult cats. Responses were recorded and averaged over 60 cycles of stimulation in the vertical and horizontal planes, which included the Vst (movement of the animal in the dark), Vis (movement within lighted visual surround), and combined Vis and Vst (movement of the animal within the lighted stationary visual surround). Data are reported on responses to stimulations along the axis showing maximal sensitivity. A small number of units were identified that showed an antagonistic relationship between their Vis and Vst responses (since they were maximally excited by Vis and by Vst stimulations in the same direction). Results suggest that antagonistic units may belong to an infrequently encountered, but functionally distinct, class of neurons.

Daunton, Nancy G.; Christensen, Carol A.

1992-01-01

426

Quality of Life in Sporadic Vestibular Schwannoma: A Review  

Microsoft Academic Search

Quality of life (QoL) measures are increasingly used as outcome measures in the assessment of different treatment options in clinical practice and as endpoints in clinical trials. Methods and questionnaires currently used for QoL assessment in vestibular schwannoma (VS) patients, studies evaluating QoL before and after treatment, studies on patients managed conservatively and studies evaluating facial-nerve-function-related QoL in VS patients

Haralampos T. Gouveris; Wolf J. Mann

2010-01-01

427

Non-linear effects in visual suppression of vestibular nystagmus  

Microsoft Academic Search

Visual-vestibular interaction in the control of eye movement was investigated in six subjects during exposure to a low frequency (0.05 Hz) angular oscillation about the longitudinal axis of the body at four levels of peak head velocity: 30, 60, 90 and 120°\\/s. Eye movements were recorded whilst the subject was presented with a head-fixed visual display consisting of either a

G. R. Barnes; A. Edge

1983-01-01

428

The effects of cochlear implantation on vestibular function  

PubMed Central

Objective Determine the risk posed by cochlear implantation (CI) to the labyrinth. Study Design Prospective cohort study. Setting Academic tertiary referral center. Patients Thirty-six ears belonging to 35 adult CI candidates (mean: 46, range: 23–69 years old). Intervention Cochlear implantation. Main Outcome Measures Vestibular function was assessed using the quantitative 3D head impulse test (qHIT), clinical head impulse test (cHIT), post-headshake nystagmus (HSN), caloric electronystagmography (ENG), vestibular-evoked myogenic potentials (VEMP), dynamic visual acuity (DVA), and Dizziness Handicap Inventory (DHI). Results All 36 ears were tested using qHIT before CI, and 28 ears were tested 4–8 weeks after CI. Quantitative HIT showed 1/28 of ears suffered reduced function. Clinical HIT was 44% sensitive and 94% specific for identification of severe-to-profound vestibular hypofunction confirmed by qHIT. HSN was unchanged in 11/11 subjects. New hyporeflexia was found in 1/16 of ENG-tested ears. VEMP showed either a disappearance of response or an increase in threshold by >10dB in 5/16 ears. Passive DVA showed no change in 16/16 ears. DHI scores worsened in 3/28 and improved in 4/28 subjects. Conclusions Although small, the observed rate of labyrinthine injury was comparable to that for other risks of CI. Thus, it is important to educate CI candidates about possible risk to balance function, particularly when CI of an “only balancing ear” is contemplated. Clinical HIT is useful for detecting severe high-frequency vestibular hypofunction and should be part of the pre-CI physical examination. PMID:19108038

Melvin, Thuy-Anh N.; Della Santina, Charles C.; Carey, John P.; Migliaccio, Americo A.

2009-01-01

429

Neurophysiological activation by vestibular or cranial nerve stimulation  

US Patent & Trademark Office Database

A method of treating a disorder may include positioning a thermoelectric device in the ear canal of a subject and activating the thermoelectric device to deliver caloric vestibular stimulation and/or cranial nerve stimulation effective to treat the disorder. In some embodiments, the ear canal may be cooled sufficiently to treat the disorder. In alternative embodiments, the ear canal may be warmed sufficiently to treat the disorder.

2012-09-18

430

[Cystic lesion in the area of the vestibular folds].  

PubMed

Warthin tumor is the second most frequently seen benign tumor of the salivary glands and is generally located in the parotid gland. Although extraparotideal manifestations in the small salivary glands are rare, the occurrence of cystic lesions in the area of the nasopharynx, eyelid, oral cavity or vestibular folds should include the Warthin tumor in the differential diagnosis. The therapy of choice is complete surgical tumor resection. PMID:22051803

Pump, J B; Schröck, A; Ozreti?, L; Bootz, F

2012-03-01

431

Afferent diversity and the organization of central vestibular pathways  

Microsoft Academic Search

This review considers whether the vestibular system includes separate populations of sensory axons innervating individual\\u000a organs and giving rise to distinct central pathways. There is a variability in the discharge properties of afferents supplying\\u000a each organ. Discharge regularity provides a marker for this diversity since fibers which differ in this way also differ in\\u000a many other properties. Postspike recovery of

Jay M. Goldberg

2000-01-01

432

Vestibular caloric responses and behavioral state in the fetal sheep  

Microsoft Academic Search

Functional activity of the vestibular system in relation to behavioral state of fetal sheep in utero was studied by cooling and heating of the fetal middle ear and skin (control) with implanted copper-tube heat exchangers. Eye movements and fetal cortical activity were assessed before, during, and after 2 min irrigations with water at 6, 46, or 39.5°C (isothermic). Cold water

Robert M Abrams; Matthias Schwab; Kenneth J Gerhardt; Reinhard Bauer; Thomas Bludau; Patrick J Antonelli

1998-01-01

433

Delayed microsurgery for vestibular schwannoma after gamma knife radiosurgery  

Microsoft Academic Search

Stereotactic radiosurgery for vestibular schwannomas (VSs) has become popular during the last decade with promising clinical\\u000a results after long-term follow-up. However, on rare occasions, some cases have needed traditional microsurgery to remove the\\u000a tumor several months or years after radiosurgery. We present a retrospective analysis of data acquired during a 16-year period\\u000a in delayed microsurgery of seven patients with VSs

Cheng-Chia Lee; Yu-Shu Yen; David Hung-Chi Pan; Wen-Yuh Chung; Hsin-Mei Wu; Wan-Yuo Guo; Ming-Te Chen; Kang-Du Liu; Yang-Hsin Shih

2010-01-01

434

Counteracting Muscle Atrophy using Galvanic Stimulation of the Vestibular System  

NASA Technical Reports Server (NTRS)

The unloading of weight bearing from antigravity muscles during space flight produces significant muscle atrophy and is one of the most serious health problems facing the space program. Various exercise regimens have been developed and used either alone or in combination with pharmacological techniques to ameliorate this atrophy, but no effective countermeasure exists for this problem. The research in this project was conducted to evaluate the potential use of vestibular galvanic stimulation (VGS) to prevent muscle atrophy resulting from unloading of weight bearing from antigravity muscles. This approach was developed based on two concepts related to the process of maintaining the status of the anti-gravity neuromuscular system. These two premises are: (1) The "tone," or bias on spinal motorneurons is affected by vestibular projections that contribute importantly to maintaining muscle health and status. (2) VGS can be used to modify the excitability, or 'tone' of motorneuron of antigravity muscles. Thus, the strategy is to use VGS to modify the gain of vestibular projections to antigravity muscles and thereby change the general status of these muscles.

Fox, Robert A.; Polyakov, Igor

1999-01-01

435

Regional differences in lectin binding patterns of vestibular hair cells  

NASA Technical Reports Server (NTRS)

Surface glycoconjugates of hair cells and supporting cells in the vestibular endorgans of the bullfrog were identified using biotinylated lectins with different carbohydrate specificities. Lectin binding in hair cells was consistent with the presence of glucose and mannose (CON A), galactose (RCA-I), N-acetylglucosamine (WGA), N-acetylgalactosamine (VVA), but not fucose (UEA-I) residues. Hair cells in the bullfrog sacculus, unlike those in the utriculus and semicircular canals, did not strain for N-acetylglucosamine (WGA) or N-acetylgalactosamine (VVA). By contrast, WGA and, to a lesser extent, VVA, differentially stained utricular and semicircular canal hair cells, labeling hair cells located in peripheral, but not central, regions. In mammals, WGA uniformly labeled Type I hair cells while labeling, as in the bullfrog, Type II hair cells only in peripheral regions. These regional variations were retained after enzymatic digestion. We conclude that vestibular hair cells differ in their surface glycoconjugates and that differences in lectin binding patterns can be used to identify hair cell types and to infer the epithelial origin of isolated vestibular hair cells.

Baird, R. A.; Schuff, N. R.; Bancroft, J.

1993-01-01

436

Acquired intolerance to organic solvents and results of vestibular testing  

SciTech Connect

Among 160 consecutive patients referred to the Clinic of Occupational Medicine, Rigshospitalet, for symptoms connected with exposure to organic solvents, 20 exhibited symptoms of acquired intolerance to minor amounts of organic solvents. Later, an additional 30 consecutive patients with symptoms of acquired intolerance were included, yielding a total of 43 men and 7 women. The characteristics of the clinical syndrome described are complaints of dizziness, nausea, and weakness after exposure to minimal solvent vapor concentrations. After having tolerated long-term occupational exposure to moderate or high air concentrations of various organic solvents, the patients became intolerant within a short period of time. Since dizziness was a frequent complaint, we tried to obtain a measure of the patients' complaints using vestibular tests. As a diagnostic test the combined vestibular tests had a sensitivity of 0.55 and a specificity of 0.87. No differences between patients with and w