The perception threshold of the vestibular Coriolis illusion

2021 ◽  
pp. 1-8
Author(s):  
Mark M.J. Houben ◽  
Arjan J.H. Meskers ◽  
Eric L. Groen
Keyword(s):  
Head Movement ◽  
Generalized Linear Model ◽  
Peak Velocity ◽  
Head Rotation ◽  
Velocity Model ◽  
Whole Body ◽  
Laboratory Studies ◽  
Perception Threshold ◽  
Spatial Disorientation ◽  
S Peak

BACKGROUND: The vestibular Coriolis illusion is a disorienting sensation that results from a transient head rotation about one axis during sustained body rotation about another axis. Although often used in spatial disorientation training for pilots and laboratory studies on motion sickness, little is known about the minimum required rotation rate to produce the illusion. OBJECTIVE: This study determined the perception threshold associated with the Coriolis illusion. METHODS: Nineteen participants performed a standardized pitching head movement during continuous whole-body yaw rotation at rates varying between 5 to 50 deg/s. The participants reported their motion sensation in relation to three hypothesized perception thresholds: 1) any sense of motion, 2) a sense of rotation, and 3) a sense of rotation and its direction (i.e., the factual Coriolis illusion). The corresponding thresholds were estimated from curves fitted by a generalized linear model. RESULTS: On average threshold 1 was significantly lower (8 deg/s) than thresholds 2 and 3. The latter thresholds did not differ from each other and their pooled value was 10 deg/s. CONCLUSIONS: The Coriolis illusion is perceived at yaw rates exceeding 10 deg/s using a pitching head movement with 40 deg amplitude and 55 deg/s peak velocity. Model analysis shows that this corresponds to an internal rotation vector of 6 deg/s. With this vector the Coriolis perception threshold can be predicted for any other head movement.

Vestibular nuclear neuron activity during active and passive head movement in the alert rhesus monkey

1987 ◽  
Vol 57 (5) ◽  
pp. 1484-1497 ◽  
Author(s):  
S. B. Khalsa ◽  
R. D. Tomlinson ◽  
D. W. Schwarz ◽  
J. P. Landolt
Keyword(s):  
Head Movement ◽  
Head Rotation ◽  
Vestibular Nuclei ◽  
Cerebellar Nuclei ◽  
Head Movements ◽  
Neuronal Firing ◽  
Whole Body ◽  
Neuron Activity ◽  
Firing Patterns ◽  
Head Velocity

Responses of single neurons were recorded in the medial and descending vestibular nuclei (MVN and DVN) and in the deep cerebellar nuclei of three juvenile rhesus monkeys (Macaca mulatta). Neuronal activity was measured during both passive sinusoidal and nonsinusoidal whole body rotation (peak velocities were under 90 degrees/s) and during active head movements. Although the active head movements occasionally exceeded 300 degrees/s, most exhibited peak velocities of less than 200 degrees/s. A total of 133 units sensitive to horizontal head rotation were recorded, and of these, 38 were held for sufficient time to obtain both passive and active head movement data. Comparison of the neuronal firing patterns obtained during active and passive head movements revealed no apparent differences. Thus neurons that were observed to burst or pause during saccades with the head fixed continued to do so when the head was free. Both the sensitivity to head velocity and the "inferred" spontaneous firing rate were compared during active and passive head movements by plotting rate-velocity curves for both conditions. When the data points were fitted with linear regression lines, no statistically significant differences in either sensitivity or spontaneous rate were found. The present study provides no evidence that efferent vestibular activity alters the properties of afferent vestibular neurons during active head movements, as has previously been suggested (21). Furthermore, neurons in the rostral portions of the vestibular nuclei in primates encode head velocity based entirely on labyrinthine information. Neither neck proprioceptors nor an efference copy of the head movement motor program seem to contribute significantly to the firing patterns observed.

The High-Pull Exercise: A Comparison Between a VersaPulley Flywheel Device and the Free Weight

2017 ◽  
Vol 12 (4) ◽  
pp. 527-532 ◽  
Author(s):  
F. Javier Núñez ◽  
Luis J. Suarez-Arrones ◽  
Paul Cater ◽  
Alberto Mendez-Villanueva
Keyword(s):  
Blood Lactate ◽  
Peak Velocity ◽  
Lactate Concentration ◽  
Training Session ◽  
Blood Lactate Concentration ◽  
Free Weight ◽  
Force Velocity ◽  
S Peak ◽  
Rugby Players ◽  
Eccentric Overload

The aim of this study was to examine the kinematics and kinetics (force, velocity, and acceleration) and blood lactate concentration with the VersaPulley (VP) device in comparison with free-weight (FW) exercise at a similar external load. Fifteen rugby players randomly performed 2 training sessions of 6 sets of 6 repetitions with 20 s of recovery between sets of the high-pull exercise with the VP and the FW. The training sessions were separated by 72 h. Barbell displacement (cm), peak velocity (m/s), peak acceleration (m/s2), mean propulsive velocity (m/s), mean propulsive acceleration (m/s2), propulsive phase (%), and mean and maximal force (N) were continuously recorded during each repetition. Blood lactate concentration was measured after each training session (end) and 3 min and 5 min later. Barbell displacement (+4.8%, small ES), peak velocity (+4.5% small ES), mean propulsive acceleration (+8.8%, small ES), and eccentric force (+26.7, large ES) were substantially higher with VP than with FW. Blood lactate concentration was also greater after the VP exercise (end +32.9%, 3 min later +36%, 5 min later +33.8%; large ES). Maximal concentric force was substantially higher with FW than VP during the 6th set (+6.4%, small ES). In the cohort and exercise investigated in the current study, VP training can be considered an efficient training device to induce an accentuated eccentric overload and augmented metabolic demands (ie, blood lactate concentration).

Evaluation of the Torsional VOR in Weightlessness

1993 ◽  
Vol 3 (3) ◽  
pp. 207-218
Author(s):  
Andrew H. Clarke ◽  
Winfried Teiwes ◽  
Hans Scherer
Keyword(s):  
Head Movement ◽  
Angular Rate ◽  
Inertial Force ◽  
Semicircular Canals ◽  
Head Rotation ◽  
Video Data ◽  
Microgravity Conditions ◽  
Oculomotor Response ◽  
Roll Axis ◽  
Integrative Processing

The experimental concept and findings from a recent manned orbital spaceflight are described. Together with ongoing terrestrial and parabolic studies, the present experiment is intended to further our knowledge of the sensory integrative processing of information from the semicircular canals and the otolithic receptors, and to quantify the presumed otolithic adaptation to altered gravito-inertial force environments in a more reliable manner than to date. The experiment included measurement of the basic vestibulo-oculomotor response during active head rotation about each of the three orthogonal axes. Priority was given to the recording of ocular torsion, as elicited by head oscillation about the roll axis, and thus due to the concomitant stimulation of the semicircular canals and otolith receptors. Videooculography was employed for the measurement of eye movements; head movement was measured by three orthogonally arranged angular rate sensors and a triaxial linear accelerometer device. All signals were recorded synchronously on a video/data recorder. Preliminary results indicate alterations in the torsional VOR under zero-g conditions, suggesting an adaptive modification of the torsional VOR gain over the course of the 6-day orbital flight. In addition, the inflight test findings yielded discrepancies between intended and performed head movement indicating impairment in sensorimotor coordination under prolonged microgravity conditions.

Activity of Ventroposterior Thalamus Neurons During Rotation and Translation in the Horizontal Plane in the Alert Squirrel Monkey

2008 ◽  
Vol 99 (5) ◽  
pp. 2533-2545 ◽  
Author(s):  
Vladimir Marlinski ◽  
Robert A. McCrea
Keyword(s):  
Horizontal Plane ◽  
Peak Velocity ◽  
Discharge Rate ◽  
Stimulus Frequency ◽  
Squirrel Monkeys ◽  
Response Amplitude ◽  
Whole Body ◽  
Power Functions ◽  
Stimulus Velocity ◽  
Rotational Response

The firing behavior of 107 vestibular-sensitive neurons in the ventroposterior thalamus was studied in two alert squirrel monkeys during whole body rotation and translation in the horizontal plane. Vestibular-sensitive neurons were distributed primarily along the anterior and posterior borders of ventroposterior nuclei; three clusters of these neurons could be distinguished based on their location and inputs. Eighty-four neurons responded to rotation; 66 (78%) of them responded to rotation only and 18 (22%) to both rotation and translation. Forty-one neurons were sensitive to linear translation; 23 (56%) of them responded to translation only. The population rotational response to 0.5-Hz sinusoids with a peak velocity of 40°/s showed a gain of 0.23 ± 0.15 spike·s−1·deg−1·s−1 and phase lagging behind the angular velocity by −9.3 ± 34.1°. Although rotational response amplitude increased with the stimulus velocity across the range 4–100°/s, the rotational sensitivity decreased with and was inversely proportional to the stimulus velocity. The rotational response amplitude and sensitivity increased with the stimulus frequency across the range 0.2–4.0 Hz. The population response to sinusoidal translation at 0.5 Hz and 0.1 g amplitude had a gain of 111.3 ± 53.7 spikes·s−1· g−1 and lagged behind stimulus acceleration by −71.9 ± 42.6°. Translational sensitivity decreased as acceleration increased and this was inversely proportional to the square root of the acceleration. Results of this study imply that changes in the discharge rate of vestibular-sensitive thalamic neurons can be approximated using power functions of the angular and linear velocity of spatial motion.

Head-Unrestrained Gaze Shifts After Muscimol Injection in the Caudal Fastigial Nucleus of the Monkey

2007 ◽  
Vol 98 (6) ◽  
pp. 3269-3283 ◽  
Author(s):  
Julie Quinet ◽  
Laurent Goffart
Keyword(s):  
Feedback Control ◽  
Head Movement ◽  
Peak Velocity ◽  
Head Movements ◽  
Fastigial Nucleus ◽  
Gaze Shifts ◽  
Movement Accuracy ◽  
Central Target ◽  
Target Eccentricity ◽  
Vertical Gaze

The effects of unilateral cFN inactivation on horizontal and vertical gaze shifts generated from a central target toward peripheral ones were tested in two head unrestrained monkeys. After muscimol injection, the eye component was hypermetric during ipsilesional gaze shifts, hypometric during contralesional ones and deviated toward the injected side during vertical gaze shifts. The ipsilesional gaze hypermetria increased with target eccentricity until ∼24° after which it diminished and became smaller than the hypermetria of the eye component. Contrary to eye saccades, the amplitude and peak velocity of which were enhanced, the amplitude and peak velocity of head movements were reduced during ipsilesional gaze shifts. These changes in head movement were not correlated with those affecting the eye saccades. Head movements were also delayed relative to the onset of eye saccades. The alterations in head movement and the faster eye saccades likely explained the reduced head contribution to the amplitude of ipsilesional gaze shifts. The contralesional gaze hypometria increased with target eccentricity and was associated with uncorrelated reductions in eye and head peak velocities. When compared with control movements of similar amplitude, contralesional eye saccades had lower peak velocity and longer duration. This slowing likely accounted for the increase in head contribution to the amplitude of contralesional gaze shifts. These data suggest different pathways for the fastigial control of eye and head components during gaze shifts. Saccade dysmetria was not compensated by appropriate changes in head contribution, raising the issue of the feedback control of movement accuracy during combined eye-head gaze shifts.

Effect of Adaptation to Telescopic Spectacles on the Initial Human Horizontal Vestibuloocular Reflex

2000 ◽  
Vol 83 (1) ◽  
pp. 38-49 ◽  
Author(s):  
Benjamin T. Crane ◽  
Joseph L. Demer
Keyword(s):  
Head Rotation ◽  
Head Movements ◽  
Target Distance ◽  
Whole Body ◽  
Rotational Axis ◽  
Vestibuloocular Reflex ◽  
Head Acceleration ◽  
Gain Enhancement ◽  
Lower Head ◽  
Distant Target

Gain of the vestibuloocular reflex (VOR) not only varies with target distance and rotational axis, but can be chronically modified in response to prolonged wearing of head-mounted magnifiers. This study examined the effect of adaptation to telescopic spectacles on the variation of the VOR with changes in target distance and yaw rotational axis for head velocity transients having peak accelerations of 2,800 and 1,000°/s2. Eye and head movements were recorded with search coils in 10 subjects who underwent whole body rotations around vertical axes that were 10 cm anterior to the eyes, centered between the eyes, between the otoliths, or 20 cm posterior to the eyes. Immediately before each rotation, subjects viewed a target 15 or 500 cm distant. Lighting was extinguished immediately before and was restored after completion of each rotation. After initial rotations, subjects wore 1.9× magnification binocular telescopic spectacles during their daily activities for at least 6 h. Test spectacles were removed and measurement rotations were repeated. Of the eight subjects tolerant of adaptation to the telescopes, six demonstrated VOR gain enhancement after adaptation, while gain in two subjects was not increased. For all subjects, the earliest VOR began 7–10 ms after onset of head rotation regardless of axis eccentricity or target distance. Regardless of adaptation, VOR gain for the proximate target exceeded that for the distant target beginning at 20 ms after onset of head rotation. Adaptation increased VOR gain as measured 90–100 ms after head rotation onset by an average of 0.12 ± 0.02 (SE) for the higher head acceleration and 0.19 ± 0.02 for the lower head acceleration. After adaptation, four subjects exhibited significant increases in the canal VOR gain only, whereas two subjects exhibited significant increases in both angular and linear VOR gains. The latencies of linear and early angular target distance effects on VOR gain were unaffected by adaptation. The earliest significant change in angular VOR gain in response to adaptation occurred 50 and 68 ms after onset of the 2,800 and 1,000°/s2 peak head accelerations, respectively. The latency of the adaptive increase in linear VOR gain was ∼50 ms for the peak head acceleration of 2,800°/s2, and 100 ms for the peak head acceleration of 1,000°/s2. Thus VOR gain changes and latency were consistent with modification in the angular VOR in most subjects, and additionally in the linear VOR in a minority of subjects.

Visual and Postural Constraints in Coordinated Movements of the Head in Hand Reaching Tasks

2002 ◽  
Vol 46 (17) ◽  
pp. 1636-1640 ◽  
Author(s):  
K. Han Kim ◽  
Bernard J. Martin
Keyword(s):  
Hand Movement ◽  
Head Rotation ◽  
Head Movements ◽  
Whole Body ◽  
Movement Onset ◽  
Major Function ◽  
Target Eccentricity ◽  
The Right ◽  
Reach Movements ◽  
Assembly Tasks

The purpose of the present study is to investigate movements of the head spatially and temporally coordinated with hand reach movements simulating industrial assembly tasks. The motions recorded from thirty subjects performing reach movements with the right hand toward eccentric targets indicate that 1) hand movement onset lags head movement onset with a duration proportional to target eccentricity; 2) the head does not aim directly at a target, but travels only a fraction of target eccentricity and often deviates away from the target substantially; and 3) head movements are constrained by the strategy of either controlling the head position in space or controlling head rotation about the torso. These results indicate that head movements are constrained by both visual and non-visual factors. While the major function of the head is to displace the visual gaze toward the target, non-visual constraints, which include postural coordination with whole body movements, also significantly affect head movements.

scholarly journals Fetal brain venous return in complicated pregnancy

2002 ◽  
Vol 51 (1) ◽  
pp. 10-14
Author(s):  
Eduard K. Ailamazyan ◽  
Albert A. Polyanin ◽  
Igor Y. Kogan
Keyword(s):  
Blood Flow ◽  
Venous Return ◽  
Peak Velocity ◽  
Venous Blood ◽  
Fetal Brain ◽  
Venous Blood Flow ◽  
Mean Velocity ◽  
Complicated Pregnancy ◽  
S Peak ◽  
Ventricular Filling

Objective. To estimate the fetal brain venous return in the complicated pregnancy. Methods. Blood flow waveforms (BFW) in jugular vein (JV) were recorded in 162 fetuses from 13 to 40 weeks of normal gestation and in 63 growth restricted fetuses. Peak velocity in ventricular systole (S), peak velocity in early diastole which corresponds to passive ventricular filling (D), peak velocity in atria contraction with active ventricular filling (A), mean velocity (TAV) were measured and pulsatility index (PIV=S-A/TAV), systolic to diastolic ratio (S/D) were calculated. Results. S, D, A, TAV in growth restricted fetuses were significantly greater and PIV, S/D were significantly lower than in normal fetuses after 36 weeks of gestation. Conclusions. The results demonstrate that there are neuroprotective reactions of fetal cerebral venous blood flow after 36 weeks of gestation.

Influence of Gaze Rotation on the Visual Response of Primate MSTd Neurons

1999 ◽  
Vol 81 (6) ◽  
pp. 2764-2786 ◽  
Author(s):  
Krishna V. Shenoy ◽  
David C. Bradley ◽  
Richard A. Andersen
Keyword(s):  
Visual Motion ◽  
Visual Image ◽  
Head Rotation ◽  
Intermediate Stage ◽  
Whole Body ◽  
Visual Response ◽  
Retinal Position ◽  
Gaze Tracking ◽  
Temporal Area ◽  
Head Rotations

Influence of gaze rotation on the visual response of primate MSTd neurons. When we move forward, the visual image on our retina expands. Humans rely on the focus, or center, of this expansion to estimate their direction of heading and, as long as the eyes are still, the retinal focus corresponds to the heading. However, smooth rotation of the eyes adds nearly uniform visual motion to the expanding retinal image and causes a displacement of the retinal focus. In spite of this, humans accurately judge their heading during pursuit eye movements and during active, smooth head rotations even though the retinal focus no longer corresponds to the heading. Recent studies in macaque suggest that correction for pursuit may occur in the dorsal aspect of the medial superior temporal area (MSTd) because these neurons are tuned to the retinal position of the focus and they modify their tuning during pursuit to compensate partially for the focus shift. However, the question remains whether these neurons also shift focus tuning to compensate for smooth head rotations that commonly occur during gaze tracking. To investigate this question, we recorded from 80 MSTd neurons while monkeys tracked a visual target either by pursuing with their eyes or by vestibulo-ocular reflex cancellation (VORC; whole-body rotation with eyes fixed in head and head fixed on body). VORC is a passive, smooth head rotation condition that selectively activates the vestibular canals. We found that neurons shift their focus tuning in a similar way whether focus displacement is caused by pursuit or by VORC. Across the population, compensation averaged 88 and 77% during pursuit and VORC, respectively (tuning shift divided by the retinal focus to true heading difference). Moreover the degree of compensation during pursuit and VORC was correlated in individual cells ( P< 0.001). Finally neurons that did not compensate appreciably tended to be gain-modulated during pursuit and VORC and may constitute an intermediate stage in the compensation process. These results indicate that many MSTd cells compensate for general gaze rotation, whether produced by eye-in-head or head-in-world rotation, and further implicate MSTd as a critical stage in the computation of heading. Interestingly vestibular cues present during VORC allow many cells to compensate even though humans do not accurately judge their heading in this condition. This suggests that MSTd may use vestibular information to create a compensated heading representation within at least a subpopulation of cells, which is accessed perceptually only when additional cues related to active head rotations are also present.

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