Human vestibular perceptual thresholds for pitch tilt are slightly worse than for roll tilt across a range of frequencies

The tilt coordination technique is used in driving simulation for reproducing a sustained linear horizontal acceleration by tilting the simulator cabin. If combined with the translation motion of the simulator, this technique increases the acceleration rendering capabilities of the whole system. To perform this technique correctly, the rotational motion must be slow to remain under the perception threshold and thus be unnoticed by the driver. However, the acceleration to render changes quickly. Between the slow rotational motion limited by the tilt threshold and the fast change of acceleration to render, the design of the coupling between motions of rotation and translation plays a critical role in the realism of a driving simulator. This study focuses on the acceptance by drivers of different configurations for tilt restitution in terms of maximum tilt angle, tilt rate, and tilt acceleration. Two experiments were conducted, focusing respectively on roll tilt for a 0.2 Hz slaloming task and on pitch tilt for an acceleration/deceleration task. The results show what thresholds have to be followed in terms of amplitude, rate, and acceleration. These results are far superior to the standard human perception thresholds found in the literature.

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Activity of pursuit neurons in the caudal part of the frontal eye fields (FEF) during static roll-tilt

Neuroscience Research ◽

10.1016/j.neures.2007.06.1112 ◽

2007 ◽

Vol 58 ◽

pp. S94

Author(s):

Sergey Kurkin ◽

Teppei Akao ◽

Junko Fukushima ◽

Kikuro Fukushima

Keyword(s):

Frontal Eye Fields ◽

Caudal Part ◽

Roll Tilt ◽

Pursuit Neurons

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How to use body tilt for the simulation of linear self motion

Journal of Vestibular Research ◽

10.3233/ves-2004-14503 ◽

2004 ◽

Vol 14 (5) ◽

pp. 375-385 ◽

Cited By ~ 8

Author(s):

E.L. Groen ◽

W. Bles

Keyword(s):

Visual Motion ◽

Detection Threshold ◽

Stimulus Frequency ◽

Flight Simulation ◽

Body Tilt ◽

Whole Body ◽

Motion Percept ◽

Self Motion ◽

Rate Limit ◽

Pitch Tilt

We examined to what extent body tilt may augment the perception of visually simulated linear self acceleration. Fourteen subjects judged visual motion profiles of fore-aft motion at four different frequencies between 0.04âĂŞ0.33 Hz, and at three different acceleration amplitudes (0.44, 0.88 and 1.76 m / s 2 ). Simultaneously, subjects were tilted backward and forward about their pitch axis. The amplitude of pitch tilt was systematically varied. Using a two-alternative-forced-choice paradigm, psychometric curves were calculated in order to determine: 1) the minimum tilt amplitude required to generate a linear self-motion percept in more than 50% of the cases, and 2) the maximum tilt amplitude at which rotation remains sub-threshold in more than 50% of the cases. The results showed that the simulation of linear self motion became more realistic with the application of whole body tilt, as long as the tilt rate remained under the detection threshold of about 3 deg/s. This value is in close agreement with the empirical rate limit commonly used in flight simulation. The minimum required motion cue was inversely proportional to stimulus frequency, and increased with the amplitude of the visual displacement (rather than acceleration). As a consequence, the range of useful tilt stimuli became more critical with increasing stimulus frequency. We conclude that this psychophysical approach reveals valid parameters for motion driving algorithms used in motion base simulators.

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Human manual control precision depends on vestibular sensory precision and gravitational magnitude

Journal of Neurophysiology ◽

10.1152/jn.00565.2018 ◽

2018 ◽

Vol 120 (6) ◽

pp. 3187-3197 ◽

Cited By ~ 6

Author(s):

Marissa J. Rosenberg ◽

Raquel C. Galvan-Garza ◽

Torin K. Clark ◽

David P. Sherwood ◽

Laurence R. Young ◽

...

Keyword(s):

Manual Control ◽

Control Performance ◽

Control Task ◽

Altered Gravity ◽

Control Precision ◽

Functional Implications ◽

Potential Risk Factors ◽

And Performance ◽

Human Exploration ◽

Roll Tilt

Precise motion control is critical to human survival on Earth and in space. Motion sensation is inherently imprecise, and the functional implications of this imprecision are not well understood. We studied a “vestibular” manual control task in which subjects attempted to keep themselves upright with a rotational hand controller (i.e., joystick) to null out pseudorandom, roll-tilt motion disturbances of their chair in the dark. Our first objective was to study the relationship between intersubject differences in manual control performance and sensory precision, determined by measuring vestibular perceptual thresholds. Our second objective was to examine the influence of altered gravity on manual control performance. Subjects performed the manual control task while supine during short-radius centrifugation, with roll tilts occurring relative to centripetal accelerations of 0.5, 1.0, and 1.33 GC (1 GC = 9.81 m/s2). Roll-tilt vestibular precision was quantified with roll-tilt vestibular direction-recognition perceptual thresholds, the minimum movement that one can reliably distinguish as leftward vs. rightward. A significant intersubject correlation was found between manual control performance (defined as the standard deviation of chair tilt) and thresholds, consistent with sensory imprecision negatively affecting functional precision. Furthermore, compared with 1.0 GC manual control was more precise in 1.33 GC (−18.3%, P = 0.005) and less precise in 0.5 GC (+39.6%, P < 0.001). The decrement in manual control performance observed in 0.5 GC and in subjects with high thresholds suggests potential risk factors for piloting and locomotion, both on Earth and during human exploration missions to the moon (0.16 G) and Mars (0.38 G). NEW & NOTEWORTHY The functional implications of imprecise motion sensation are not well understood. We found a significant correlation between subjects’ vestibular perceptual thresholds and performance in a manual control task (using a joystick to keep their chair upright), consistent with sensory imprecision negatively affecting functional precision. Furthermore, using an altered-gravity centrifuge configuration, we found that manual control precision was improved in “hypergravity” and degraded in “hypogravity.” These results have potential relevance for postural control, aviation, and spaceflight.

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Neural Processing of Gravito-Inertial Cues in Humans. IV. Influence of Visual Rotational Cues During Roll Optokinetic Stimuli

Journal of Neurophysiology ◽

10.1152/jn.00513.2001 ◽

2003 ◽

Vol 89 (1) ◽

pp. 390-400 ◽

Cited By ~ 40

Author(s):

L. H. Zupan ◽

D. M. Merfeld

Keyword(s):

Visual Cues ◽

Gravitational Force ◽

Sensory Information ◽

Inertial Force ◽

Linear Acceleration ◽

Otolith Organs ◽

Optokinetic Stimulation ◽

The Difference ◽

The Right ◽

Roll Tilt

Sensory systems often provide ambiguous information. For example, otolith organs measure gravito-inertial force (GIF), the sum of gravitational force and inertial force due to linear acceleration. However, according to Einstein's equivalence principle, a change in gravitational force due to tilt is indistinguishable from a change in inertial force due to translation. Therefore the central nervous system (CNS) must use other sensory cues to distinguish tilt from translation. For example, the CNS might use dynamic visual cues indicating rotation to help determine the orientation of gravity (tilt). This, in turn, might influence the neural processes that estimate linear acceleration, since the CNS might estimate gravity and linear acceleration such that the difference between these estimates matches the measured GIF. Depending on specific sensory information inflow, inaccurate estimates of gravity and linear acceleration can occur. Specifically, we predict that illusory tilt caused by roll optokinetic cues should lead to a horizontal vestibuloocular reflex compensatory for an interaural estimate of linear acceleration, even in the absence of actual linear acceleration. To investigate these predictions, we measured eye movements binocularly using infrared video methods in 17 subjects during and after optokinetic stimulation about the subject's nasooccipital (roll) axis (60°/s, clockwise or counterclockwise). The optokinetic stimulation was applied for 60 s followed by 30 s in darkness. We simultaneously measured subjective roll tilt using a somatosensory bar. Each subject was tested in three different orientations: upright, pitched forward 10°, and pitched backward 10°. Five subjects reported significant subjective roll tilt (>10°) in directions consistent with the direction of the optokinetic stimulation. In addition to torsional optokinetic nystagmus and afternystagmus, we measured a horizontal nystagmus to the right during and following clockwise (CW) stimulation and to the left during and following counterclockwise (CCW) stimulation. These measurements match predictions that subjective tilt in the absence of real tilt should induce a nonzero estimate of interaural linear acceleration and, therefore, a horizontal eye response. Furthermore, as predicted, the horizontal response in the dark was larger for Tilters ( n = 5) than for Non-Tilters ( n= 12).

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Vestibular Perception and Action Employ Qualitatively Different Mechanisms. II. VOR and Perceptual Responses During Combined Tilt&Translation

Journal of Neurophysiology ◽

10.1152/jn.00905.2004 ◽

2005 ◽

Vol 94 (1) ◽

pp. 199-205 ◽

Cited By ~ 87

Author(s):

Daniel M. Merfeld ◽

Sukyung Park ◽

Claire Gianna-Poulin ◽

F. Owen Black ◽

Scott Wood

Keyword(s):

Perception And Action ◽

Rotation Axis ◽

Human Perception ◽

Linear Acceleration ◽

Otolith Organs ◽

Model Predictions ◽

Vestibular Perception ◽

Compare And Contrast ◽

High Pass ◽

Roll Tilt

II. VOR and perceptual responses during combined Tilt&Translation. To compare and contrast the neural mechanisms that contribute to vestibular perception and action, we measured vestibuloocular reflexes (VOR) and perceptions of tilt and translation. We took advantage of the well-known ambiguity that the otolith organs respond to both linear acceleration and tilt with respect to gravity and investigated the mechanisms by which this ambiguity is resolved. A new motion paradigm that combined roll tilt with inter-aural translation (“ Tilt&Translation”) was used; subjects were sinusoidally (0.8 Hz) roll tilted but with their ears above or below the rotation axis. This paradigm provided sinusoidal roll canal cues that were the same across trials while providing otolith cues that varied linearly with ear position relative to the earth-horizontal rotation axis. We found that perceived tilt and translation depended on canal cues, with substantial roll tilt and inter-aural translation perceptions reported even when the otolith organs measured no inter-aural force. These findings match internal model predictions that rotational cues from the canals influence the neural processing of otolith cues. We also found horizontal translational VORs that varied linearly with radius; a minimal response was measured when the otolith organs transduced little or no inter-aural force. Hence, the horizontal translational VOR was dependent on otolith cues but independent of canal cues. These findings match predictions that translational VORs are elicited by simple filtering of otolith signals. We conclude that internal models govern human perception of tilt and translation at 0.8 Hz and that high-pass filtering governs the human translational VOR at this same frequency.

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Spatial orientation of postrotatory nystagmus during static roll tilt in cats

Journal of Vestibular Research ◽

10.3233/ves-2002-12102 ◽

2002 ◽

Vol 12 (1) ◽

pp. 15-23

Author(s):

Keiko Yasuda ◽

Hiroaki Fushiki ◽

Rinnosuke Wada ◽

Yukio Watanabe

Keyword(s):

Spatial Orientation ◽

Vertical Axis ◽

Longitudinal Axis ◽

Velocity Storage ◽

Slow Phase ◽

Storage Mechanism ◽

Spatial Disorientation ◽

Acceleration And Deceleration ◽

Eye Velocity ◽

Roll Tilt

While the stimulation of otolith inputs reduces the duration of postrotatory nystagmus (PRN), there is still room for dialogue about the effect of static tilt on the orientation of PRN. We studied one possible influence of static roll tilt on the spatial orientation of PRN in cats. The animal was rotated about an earth-vertical axis (EVA) at a constant velocity of 100 deg/s with an acceleration and deceleration of 120 deg / s 2 . Within two seconds after stopping EVA rotation, the animal was passively tilted at 45 deg/s about its longitudinal axis by as much as ± 90 deg in steps of 15 deg. Eye movements were measured with magnetic search coils. The angle of the PRN plane and its slow phase eye velocity were measured. The time constant of PRN decreased with an increase in roll tilt. The PRN plane remained earth horizontal within a range of ± 30 deg roll tilt. Beyond this range, the velocity of PRN decreased too rapidly to measure any change in orientation. Our results indicate a spatially limited and temporally short interaction of the semicircular canal and otolith signals in the velocity storage mechanism of cat PRN. Our data, along with previous studies, suggest that different species show different solutions to the problem of the imbalance and spatial disorientation during contradictory stimuli.

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Neural Processing of Gravito-Inertial Cues in Humans. II. Influence of the Semicircular Canals During Eccentric Rotation

Journal of Neurophysiology ◽

10.1152/jn.2001.85.4.1648 ◽

2001 ◽

Vol 85 (4) ◽

pp. 1648-1660 ◽

Cited By ~ 65

Author(s):

D. M. Merfeld ◽

L. H. Zupan ◽

C. A. Gifford

Keyword(s):

Nervous System ◽

Time Course ◽

Rotation Speed ◽

Linear Acceleration ◽

Otolith Organs ◽

Centripetal Acceleration ◽

Variable Radius ◽

Fixed Radius ◽

The Subject ◽

Roll Tilt

All linear accelerometers, including the otolith organs, respond equivalently to gravity and linear acceleration. To investigate how the nervous system resolves this ambiguity, we measured perceived roll tilt and reflexive eye movements in humans in the dark using two different centrifugation motion paradigms (fixed radius and variable radius) combined with two different subject orientations (facing-motion and back-to-motion). In the fixed radius trials, the radius at which the subject was seated was held constant while the rotation speed was changed to yield changes in the centrifugal force. In variable radius trials, the rotation speed was held constant while the radius was varied to yield a centrifugal force that nearly duplicated that measured during the fixed radius condition. The total gravito-inertial force (GIF) measured by the otolith organs was nearly identical in the two paradigms; the primary difference was the presence (fixed radius) or absence (variable radius) of yaw rotational cues. We found that the yaw rotational cues had a large statistically significant effect on the time course of perceived tilt, demonstrating that yaw rotational cues contribute substantially to the neural processing of roll tilt. We also found that the orientation of the subject relative to the centripetal acceleration had a dramatic influence on the eye movements measured during fixed radius centrifugation. Specifically, the horizontal vestibuloocular reflex (VOR) measured in our human subjects was always greater when the subject faced the direction of motion than when the subjects had their backs toward the motion during fixed radius rotation. This difference was consistent with the presence of a horizontal translational VOR response induced by the centripetal acceleration. Most importantly, by comparing the perceptual tilt responses to the eye movement responses, we found that the translational VOR component decayed as the subjective tilt indication aligned with the tilt of the GIF. This was true for both the fixed radius and variable radius conditions even though the time course of the responses was significantly different for these two conditions. These findings are consistent with the hypothesis that the nervous system resolves the ambiguous measurements of GIF into neural estimates of gravity and linear acceleration. More generally, these findings are consistent with the hypothesis that the nervous system uses internal models to process and interpret sensory motor cues.

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