Rotational kinematics of the human vestibuloocular reflex. II. Velocity steps

1994 ◽  
Vol 72 (5) ◽  
pp. 2480-2489 ◽  
Author(s):  
D. Tweed ◽  
M. Fetter ◽  
D. Sievering ◽  
H. Misslisch ◽  
E. Koenig
Keyword(s):  
Cross Talk ◽  
Human Subjects ◽  
Head Rotation ◽  
Horizontal Axis ◽  
Main Diagonal ◽  
Velocity Storage ◽  
Vestibuloocular Reflex ◽  
Simple Explanation ◽  
Time Constants ◽  
Axis Rotation

1. Gain matrices were used to quantify the three-dimensional vestibuloocular reflex (VOR) in five human subjects who were accelerated over 1 s and then spun at a constant 150 degrees/s for 29 s in darkness. Rotations were torsional, vertical and horizontal, about earth-vertical and earth-horizontal axes. 2. Elements on the main diagonal of the gain matrices were much smaller than the optimal value of -1, and torsional gain was weaker than vertical or horizontal. Off-diagonal elements, indicating cross talk, were minimal except for a small but consistent horizontal response to torsional head rotation. 3. Downward slow phases were more than twice as fast as upward at the start of rotation about both earth-vertical and earth-horizontal axes, but the asymmetry vanished later in the rotation. 4. During earth-vertical-axis rotation, all matrix elements decayed to zero. The main-diagonal torsional and vertical gains waned with time constants close to that of the cupula (6.7 and 7.3 s). Velocity storage prolonged the horizontal response to horizontal head rotation (time constant 14.2 s) but not the horizontal response to torsion (7.7 s). A simple explanation is that velocity storage acts on a central estimate of head motion that accurately distinguishes horizontal from torsional and that the inappropriate horizontal eye velocity response to torsion occurs because of cross talk downstream from velocity storage. 5. During earth-horizontal-axis rotation, the torsional, vertical, and horizontal main-diagonal elements declined, with time constants of 7.6, 8.2, and 7.9 s, to maintained nonzero values, all equal to about -0.1. Off-diagonal elements, including the horizontal response to torsion, decayed to zero, so that the otolith-driven reflex, late in the rotation, was equally strong in all dimensions and almost free of detectable cross talk. 6. The difference between gain curves over the course of earth-vertical- and earth-horizontal-axis rotations was not constant but increased with time, suggesting that the VOR response to earth-horizontal-axis rotation is not a simple sum of canal and otolith reflexes.

Contribution of Vestibular Commissural Pathways to Spatial Orientation of the Angular Vestibuloocular Reflex

1997 ◽  
Vol 78 (2) ◽  
pp. 1193-1197 ◽  
Author(s):  
Susan Wearne ◽  
Theodore Raphan ◽  
Bernard Cohen
Keyword(s):  
Spatial Orientation ◽  
Semicircular Canal ◽  
Vertical Axis ◽  
Vestibular Stimulation ◽  
Velocity Storage ◽  
Vestibuloocular Reflex ◽  
Time Constants ◽  
Commissural Pathways ◽  
Before And After ◽  
Axis Rotation

Wearne, Susan, Theodore Raphan, and Bernard Cohen. Contribution of vestibular commissural pathways to spatial orientation of the angular vestibuloocular reflex. J. Neurophysiol. 78: 1193–1197, 1997. During nystagmus induced by the angular vestibuloocular reflex (aVOR), the axis of eye velocity tends to align with the direction of gravitoinertial acceleration (GIA), a process we term “spatial orientation of the aVOR.” We studied spatial orientation of the aVOR in rhesus and cynomolgus monkeys before and after midline section of the rostral medulla abolished all oculomotor functions related to velocity storage, leaving the direct optokinetic and vestibular pathways intact. Optokinetic afternystagmus and the bias component of off-vertical-axis rotation were lost, and the aVOR time constant was reduced to a value commensurate with the time constants of primary semicircular canal afferents. Spatial orientation of the aVOR, induced either during optokinetic or vestibular stimulation, was also lost. Vertical and roll aVOR time constants could no longer be lengthened in side-down or supine/prone positions, and static and dynamic tilts of the GIA no longer produced cross-coupling from the yaw to pitch and yaw to roll axes. Consequently, the induced nystagmus remained entirely in head coordinates after the lesion, regardless of the direction of the resultant GIA vector. Gains of the aVOR and of optokinetic nystagmus to steps of velocity were unaffected or slightly increased. These results are consistent with a model in which the direct aVOR pathways are organized in semicircular canal coordinates and spatial orientation is restricted to the indirect (velocity storage) pathways.

Compensatory and Orienting Eye Movements Induced By Off-Vertical Axis Rotation (OVAR) in Monkeys

2002 ◽  
Vol 88 (5) ◽  
pp. 2445-2462 ◽  
Author(s):  
Keisuke Kushiro ◽  
Mingjia Dai ◽  
Mikhail Kunin ◽  
Sergei B. Yakushin ◽  
Bernard Cohen ◽  
...  
Keyword(s):  
Eye Movements ◽  
Vertical Axis ◽  
Velocity Storage ◽  
Eye Position ◽  
Rotational Axis ◽  
Vestibuloocular Reflex ◽  
Time Constants ◽  
Head Velocity ◽  
Axis Rotation ◽  
Eye Velocity

Nystagmus induced by off-vertical axis rotation (OVAR) about a head yaw axis is composed of a yaw bias velocity and modulations in eye position and velocity as the head changes orientation relative to gravity. The bias velocity is dependent on the tilt of the rotational axis relative to gravity and angular head velocity. For axis tilts <15°, bias velocities increased monotonically with increases in the magnitude of the projected gravity vector onto the horizontal plane of the head. For tilts of 15–90°, bias velocity was independent of tilt angle, increasing linearly as a function of head velocity with gains of 0.7–0.8, up to the saturation level of velocity storage. Asymmetries in OVAR bias velocity and asymmetries in the dominant time constant of the angular vestibuloocular reflex (aVOR) covaried and both were reduced by administration of baclofen, a GABAB agonist. Modulations in pitch and roll eye positions were in phase with nose-down and side-down head positions, respectively. Changes in roll eye position were produced mainly by slow movements, whereas vertical eye position changes were characterized by slow eye movements and saccades. Oscillations in vertical and roll eye velocities led their respective position changes by ≈90°, close to an ideal differentiation, suggesting that these modulations were due to activation of the orienting component of the linear vestibuloocular reflex (lVOR). The beating field of the horizontal nystagmus shifted the eyes 6.3°/ g toward gravity in side down position, similar to the deviations observed during static roll tilt (7.0°/ g). This demonstrates that the eyes also orient to gravity in yaw. Phases of horizontal eye velocity clustered ∼180° relative to the modulation in beating field and were not simply differentiations of changes in eye position. Contributions of orientating and compensatory components of the lVOR to the modulation of eye position and velocity were modeled using three components: a novel direct otolith-oculomotor orientation, orientation-based velocity modulation, and changes in velocity storage time constants with head position re gravity. Time constants were obtained from optokinetic after-nystagmus, a direct representation of velocity storage. When the orienting lVOR was combined with models of the compensatory lVOR and velocity estimator from sequential otolith activation to generate the bias component, the model accurately predicted eye position and velocity in three dimensions. These data support the postulates that OVAR generates compensatory eye velocity through activation of velocity storage and that oscillatory components arise predominantly through lVOR orientation mechanisms.

Kinematics of the Rotational Vestibuloocular Reflex: Role of the Cerebellum

2007 ◽  
Vol 98 (1) ◽  
pp. 295-302 ◽  
Author(s):  
Mark F. Walker ◽  
Jing Tian ◽  
David S. Zee
Keyword(s):  
Tilt Angle ◽  
Three Dimensional ◽  
Head Rotation ◽  
Normal Subjects ◽  
Eye Position ◽  
Vestibuloocular Reflex ◽  
Gaze Stabilization ◽  
Eye Rotation ◽  
Axis Rotation ◽  
Head Impulses

We studied the effect of cerebellar lesions on the 3-D control of the rotational vestibuloocular reflex (RVOR) to abrupt yaw-axis head rotation. Using search coils, three-dimensional (3-D) eye movements were recorded from nine patients with cerebellar disease and seven normal subjects during brief chair rotations (200°/s2 to 40°/s) and manual head impulses. We determined the amount of eye-position dependent torsion during yaw-axis rotation by calculating the torsional-horizontal eye-velocity axis for each of three vertical eye positions (0°, ±15°) and performing a linear regression to determine the relationship of the 3-D velocity axis to vertical eye position. The slope of this regression is the tilt angle slope. Overall, cerebellar patients showed a clear increase in the tilt angle slope for both chair rotations and head impulses. For chair rotations, the effect was not seen at the onset of head rotation when both patients and normal subjects had nearly head-fixed responses (no eye-position-dependent torsion). Over time, however, both groups showed an increasing tilt-angle slope but to a much greater degree in cerebellar patients. Two important conclusions emerge from these findings: the axis of eye rotation at the onset of head rotation is set to a value close to head-fixed (i.e., optimal for gaze stabilization during head rotation), independent of the cerebellum and once the head rotation is in progress, the cerebellum plays a crucial role in keeping the axis of eye rotation about halfway between head-fixed and that required for Listing's Law to be obeyed.

Model-based study of the human cupular time constant

1999 ◽  
Vol 9 (4) ◽  
pp. 293-301 ◽  
Author(s):  
Mingjia Dai ◽  
Avniel Klein ◽  
Bernard Cohen ◽  
Theodore Raphan
Keyword(s):  
Time Constant ◽  
Human Subjects ◽  
Vestibular Nerve ◽  
Velocity Storage ◽  
Slow Phase ◽  
Initial Portion ◽  
Time Constants ◽  
Model Based ◽  
Double Exponential ◽  
Eye Velocity

The time constant of the angular vestibulo-ocular reflex (aVOR), measured from the response to steps of rotation about a yaw axis, has frequently been estimated as a single exponential. However, the slow phase velocity envelope during per- or post-rotatory nystagmus is more accurately represented by two exponential modes. One represents activity in the vestibular nerve induced by deflection of the cupula, the other by activation that the input from the canals produces in the central velocity storage integrator. The sum of the cupula and the integrator responses describes the overall response of slow phase eye velocity and can be approximated by a double exponential. Frequently, there is a plateau in the initial portion of eye velocity response, but this may be masked by habituation, making the cupula contribution unobservable and impossible to estimate. Using a model-based technique to analyze responses with a clear plateau, we estimated peripheral and central vestibular time constants by double exponential fits to slow phase eye velocity. Cupular time constants were varied from 1 to 10 s to identify values that gave optimal fits of the data according to a Chi-square criterion. The mean cupular time constant for 10 human subjects was 4.2 ± 0.6 s. Fits of the data were also good for time constants between 3.5 to 7 s, but not for 1 to 3 or 7.5 to 10 s. The estimated cupular time constants also fit responses where there was no plateau. In 8 monkeys, cupular time constants were estimated as 3.9 ± 0.5 s, which agreed with those derived from activity in the vestibular nerve. There was no difference between monkey and human cupular time constants from these estimates. It is likely that the human cupular time constant is similar to that of the monkey and shorter than previously thought.

Horizontal angular VOR changes in orbital and parabolic flight: human neurovestibular studies on SLS-2

1996 ◽  
Vol 81 (1) ◽  
pp. 69-81 ◽  
Author(s):  
C. M. Oman ◽  
C. F. Pouliot ◽  
A. Natapoff
Keyword(s):  
Computer Analysis ◽  
Parabolic Flight ◽  
The Other ◽  
Velocity Storage ◽  
Vestibuloocular Reflex ◽  
Time Constants ◽  
Adaptive Changes

Further evidence was found for adaptive changes in the vestibular "velocity storage" (VS) component of the vestibuloocular reflex in four shuttle astronauts tested in parabolic flight and before, during, and after a 14-day mission. Nystagmus was recorded during and after 1 min of 120 degrees/s rotation. Gains and time constants were determined by computer analysis. Responses correlated with experience. Two subjects were making their first spaceflight. In parabolic flight, their time constants shortened to an average of 60% of 1 G values, presumably because unfamiliar otolith cues reduced VS. However, after 4-10 days in orbit, their time constants were similar or greater than those preflight, indicating VS recovery. The other two subjects had previously flown in space. Their time constants shortened in orbit to an average of 69% of 1 G values, indicating a persisting reduction of VS. This correlation with spaceflight experience has been seen in 9 of 11 subjects on 3 missions. Head pitch did not significantly "dump" nystagmus as it does on Earth.

Control of Spatial Orientation of the Angular Vestibuloocular Reflex by the Nodulus and Uvula

1998 ◽  
Vol 79 (5) ◽  
pp. 2690-2715 ◽  
Author(s):  
Susan Wearne ◽  
Theodore Raphan ◽  
Bernard Cohen
Keyword(s):  
Spatial Orientation ◽  
Three Dimensional ◽  
Cross Coupling ◽  
Velocity Storage ◽  
Coordinate Frame ◽  
Vestibuloocular Reflex ◽  
Time Constants ◽  
Vertical Roll ◽  
Eye Rotation ◽  
Eye Velocity

Wearne, Susan, Theodore Raphan, and Bernard Cohen. Control of spatial orientation of the angular vestibuloocular reflex by the nodulus and uvula. J. Neurophysiol. 79: 2690–2715, 1998. Spatial orientation of the angular vestibuloocular reflex (aVOR) was studied in rhesus monkeys after complete and partial ablation of the nodulus and ventral uvula. Horizontal, vertical, and torsional components of slow phases of nystagmus were analyzed to determine the axes of eye rotation, the time constants (Tcs) of velocity storage, and its orientation vectors. The gravito-inertial acceleration vector (GIA) was tilted relative to the head during optokinetic afternystagmus (OKAN), centrifugation, and reorientation of the head during postrotatory nystagmus. When the GIA was tilted relative to the head in normal animals, horizontal Tcs decreased, vertical and/or roll time constants (Tcvert/roll) lengthened according to the orientation of the GIA, and vertical and/or roll eye velocity components appeared (cross-coupling). This shifted the axis of eye rotation toward alignment with the tilted GIA. Horizontal and vertical/roll Tcs varied inversely, with Tchor being longest and Tcvert/roll shortest when monkeys were upright, and the reverse when stimuli were around the vertical or roll axes. Vertical or roll Tcs were longest when the axes of eye rotation were aligned with the spatial vertical, respectively. After complete nodulo-uvulectomy, Tchor became longer, and periodic alternating nystagmus (PAN) developed in darkness. Tchor could not be shortened in any of paradigms tested. In addition, yaw-to-vertical/roll cross-coupling was lost, and the axes of eye rotation remained fixed during nystagmus, regardless of the tilt of the GIA with respect to the head. After central portions of the nodulus and uvula were ablated, leaving lateral portions of the nodulus intact, yaw-to-vertical/roll cross-coupling and control of Tcvert/roll was lost or greatly reduced. However, control of Tchor was maintained, and Tchor continued to vary as a function of the tilted GIA. Despite this, the eye velocity vector remained aligned with the head during yaw axis stimulation after partial nodulo-uvulectomy, regardless of GIA orientation to the head. The data were related to a three-dimensional model of the aVOR, which simulated the experimental results. The model provides a basis for understanding how the nodulus and uvula control processing within the vestibular nuclei responsible for spatial orientation of the aVOR. We conclude that the three-dimensional dynamics of the velocity storage system are determined in the nodulus and ventral uvula. We propose that the horizontal and vertical/roll Tcs are separately controlled in the nodulus and uvula with the dynamic characteristics of vertical/roll components modulated in central portions and the horizontal components laterally, presumably in a semicircular canal-based coordinate frame.

scholarly journals Individual motion perception parameters and motion sickness frequency sensitivity in fore-aft motion

2021 ◽  
Author(s):  
Tugrul Irmak ◽  
Ksander N. de Winkel ◽  
Daan M. Pool ◽  
Heinrich H. Bülthoff ◽  
Riender Happee
Keyword(s):  
Motion Sickness ◽  
Motion Perception ◽  
Time Constant ◽  
Storage Time ◽  
Velocity Storage ◽  
Strong Positive Correlation ◽  
Subjective Vertical ◽  
Time Constants ◽  
Frequency Sensitivity ◽  
Observer Model

AbstractPrevious literature suggests a relationship between individual characteristics of motion perception and the peak frequency of motion sickness sensitivity. Here, we used well-established paradigms to relate motion perception and motion sickness on an individual level. We recruited 23 participants to complete a two-part experiment. In the first part, we determined individual velocity storage time constants from perceived rotation in response to Earth Vertical Axis Rotation (EVAR) and subjective vertical time constants from perceived tilt in response to centrifugation. The cross-over frequency for resolution of the gravito-inertial ambiguity was derived from our data using the Multi Sensory Observer Model (MSOM). In the second part of the experiment, we determined individual motion sickness frequency responses. Participants were exposed to 30-minute sinusoidal fore-aft motions at frequencies of 0.15, 0.2, 0.3, 0.4 and 0.5 Hz, with a peak amplitude of 2 m/s2 in five separate sessions, approximately 1 week apart. Sickness responses were recorded using both the MIsery SCale (MISC) with 30 s intervals, and the Motion Sickness Assessment Questionnaire (MSAQ) at the end of the motion exposure. The average velocity storage and subjective vertical time constants were 17.2 s (STD = 6.8 s) and 9.2 s (STD = 7.17 s). The average cross-over frequency was 0.21 Hz (STD = 0.10 Hz). At the group level, there was no significant effect of frequency on motion sickness. However, considerable individual variability was observed in frequency sensitivities, with some participants being particularly sensitive to the lowest frequencies, whereas others were most sensitive to intermediate or higher frequencies. The frequency of peak sensitivity did not correlate with the velocity storage time constant (r = 0.32, p = 0.26) or the subjective vertical time constant (r = − 0.37, p = 0.29). Our prediction of a significant correlation between cross-over frequency and frequency sensitivity was not confirmed (r = 0.26, p = 0.44). However, we did observe a strong positive correlation between the subjective vertical time constant and general motion sickness sensitivity (r = 0.74, p = 0.0006). We conclude that frequency sensitivity is best considered a property unique to the individual. This has important consequences for existing models of motion sickness, which were fitted to group averaged sensitivities. The correlation between the subjective vertical time constant and motion sickness sensitivity supports the importance of verticality perception during exposure to translational sickness stimuli.

Vestibulo-ocular function in anxiety disorders

2007 ◽  
Vol 16 (4-5) ◽  
pp. 209-215
Author(s):  
Joseph M. Furman ◽  
Mark S. Redfern ◽  
Rolf G. Jacob
Keyword(s):  
Panic Disorder ◽  
Anxiety Disorders ◽  
Semicircular Canal ◽  
Constant Velocity ◽  
Vertical Axis ◽  
Velocity Storage ◽  
Movement Response ◽  
Ocular Reflex ◽  
Axis Rotation ◽  
High Degree

Previous studies of vestibulo-ocular function in patients with anxiety disorders have suggested a higher prevalence of peripheral vestibular dysfunction compared to control populations, especially in panic disorder with agoraphobia. Also, our recent companion studies have indicated abnormalities in postural control in patients with anxiety disorders who report a high degree of space and motion discomfort. The aim of the present study was to assess the VOR, including the semicircular canal-ocular reflex, the otolith-ocular reflex, and semicircular canal-otolith interaction, in a well-defined group of patients with anxiety disorders. The study included 72 patients with anxiety disorders (age 30.6 +/− 10.6 yrs; 60 (83.3% F) and 29 psychiatrically normal controls (age 35.0 +/minus; 11.6 yrs; 24 (82.8% F). 25 patients had panic disorder; 47 patients had non-panic anxiety. Patients were further categorized based on the presence (45 of 72) or absence (27 of 72) of height phobia and the presence (27 of 72) or absence (45 of 72) of excessive space and motion discomfort (SMD). Sinusoidal and constant velocity earth-vertical axis rotation (EVAR) was used to assess the semicircular canal-ocular reflex. Constant velocity off-vertical axis rotation (OVAR) was used to assess both the otolith-ocular reflex and static semicircular canal-otolith interaction. Sinusoidal OVAR was used to assess dynamic semicircular canal-otolith interaction. The eye movement response to rotation was measured using bitemporal electro-oculography. Results showed a significantly higher VOR gain and a significantly shorter VOR time constant in anxiety patients. The effect of anxiety on VOR gain was significantly greater in patients without SMD as compared to those with SMD. Anxiety patients without height phobia had a larger OVAR modulation. We postulate that in patients with anxiety, there is increased vestibular sensitivity and impaired velocity storage. Excessive SMD and height phobia seem to have a mitigating effect on abnormal vestibular sensitivity, possibly via a down-weighting of central vestibular pathways.

Ultralow vestibuloocular reflex time constants

1988 ◽  
Vol 23 (1) ◽  
pp. 32-37 ◽  
Author(s):  
R. W. Baloh ◽  
K. Beykirch ◽  
P. Tauchi ◽  
R. D. Yee ◽  
V. Honrubia
Keyword(s):  
Vestibuloocular Reflex ◽  
Time Constants ◽  
Reflex Time

Human Updating of Visual Motion Direction During Head Rotations

2008 ◽  
Vol 99 (5) ◽  
pp. 2558-2576
Author(s):  
Mario Ruiz-Ruiz ◽  
Julio C. Martinez-Trujillo
Keyword(s):  
Visual Motion ◽  
Human Subjects ◽  
Head Tilt ◽  
Head Rotation ◽  
Three Dimensions ◽  
Spatial Updating ◽  
Motion Direction ◽  
Direction Discrimination ◽  
Head Rotations ◽  
Stimulus Direction

Previous studies have demonstrated that human subjects update the location of visual targets for saccades after head and body movements and in the absence of visual feedback. This phenomenon is known as spatial updating. Here we investigated whether a similar mechanism exists for the perception of motion direction. We recorded eye positions in three dimensions and behavioral responses in seven subjects during a motion task in two different conditions: when the subject's head remained stationary and when subjects rotated their heads around an anteroposterior axis (head tilt). We demonstrated that after head-tilt subjects updated the direction of saccades made in the perceived stimulus direction (direction of motion updating), the amount of updating varied across subjects and stimulus directions, the amount of motion direction updating was highly correlated with the amount of spatial updating during a memory-guided saccade task, subjects updated the stimulus direction during a two-alternative forced-choice direction discrimination task in the absence of saccadic eye movements (perceptual updating), perceptual updating was more accurate than motion direction updating involving saccades, and subjects updated motion direction similarly during active and passive head rotation. These results demonstrate the existence of an updating mechanism for the perception of motion direction in the human brain that operates during active and passive head rotations and that resembles the one of spatial updating. Such a mechanism operates during different tasks involving different motor and perceptual skills (saccade and motion direction discrimination) with different degrees of accuracy.

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