Inactivation of Semicircular Canals Causes Adaptive Increases in Otolith-Driven Tilt Responses

2002 ◽  
Vol 87 (3) ◽  
pp. 1635-1640 ◽  
Author(s):  
Dora E. Angelaki ◽  
Shawn D. Newlands ◽  
J. David Dickman
Keyword(s):  
Eye Movements ◽  
Semicircular Canal ◽  
Translational Motion ◽  
Semicircular Canals ◽  
Vertical Axis ◽  
Lateral Motion ◽  
Functional Interaction ◽  
Gaze Stabilization ◽  
Theoretical Evidence ◽  
Ocular System

Growing experimental and theoretical evidence suggests a functional synergy in the processing of otolith and semicircular canal signals for the generation of the vestibulo-ocular reflexes (VORs). In this study we have further tested this functional interaction by quantifying the adaptive changes in the otolith-ocular system during both rotational and translational movements after surgical inactivation of the semicircular canals. For 0.1–0.5 Hz (stimuli for which there is no recovery of responses from the plugged canals), pitch and roll VOR gains recovered during earth-horizontal (but not earth-vertical) axis rotations. Corresponding changes were also observed in eye movements elicited by translational motion (0.1–5 Hz). Specifically, torsional eye movements increased during lateral motion, whereas vertical eye movements increased during fore-aft motion. The findings indicate that otolith signals can be adapted according to a compromised strategy that leads to improved gaze stabilization during motion. Because canal-plugged animals permanently lose the ability to discriminate gravitoinertial accelerations, adapted animals can use the presence of gravity through otolith-driven tilt responses to assist gaze stabilization during earth-horizontal axis rotations.

scholarly journals Alexander's Law During High-Speed, Yaw-Axis Rotation: Adaptation or Saturation?

2020 ◽  
Vol 11 ◽  
Author(s):  
Claudia Lädrach ◽  
David S. Zee ◽  
Thomas Wyss ◽  
Wilhelm Wimmer ◽  
Athanasia Korda ◽  
...  
Keyword(s):  
Eye Movements ◽  
Phase Velocity ◽  
High Speed ◽  
Semicircular Canals ◽  
Vertical Axis ◽  
Normal Subjects ◽  
Vestibular Nuclei ◽  
Slow Phase ◽  
Slow Phase Velocity ◽  
Alexander’S Law

Objective: Alexander's law (AL) states the intensity of nystagmus increases when gaze is toward the direction of the quick phase. What might be its cause? A gaze-holding neural integrator (NI) that becomes imperfect as the result of an adaptive process, or saturation in the discharge of neurons in the vestibular nuclei?Methods: We induced nystagmus in normal subjects using a rapid chair acceleration around the yaw (vertical) axis to a constant velocity of 200°/second [s] and then, 90 s later, a sudden stop to induce post-rotatory nystagmus (PRN). Subjects alternated gaze every 2 s between flashing LEDs (right/left or up/down). We calculated the change in slow-phase velocity (ΔSPV) between right and left gaze when the lateral semicircular canals (SCC) were primarily stimulated (head upright) or, with the head tilted to the side, stimulating the vertical and lateral SCC together.Results: During PRN AL occurred for horizontal eye movements with the head upright and for both horizontal and vertical components of eye movements with the head tilted. AL was apparent within just a few seconds of the chair stopping when peak SPV of PRN was reached. When slow-phase velocity of PRN faded into the range of 6–18°/s AL could no longer be demonstrated.Conclusions: Our results support the idea that AL is produced by asymmetrical responses within the vestibular nuclei impairing the NI, and not by an adaptive response that develops over time. AL was related to the predicted plane of eye rotations in the orbit based on the pattern of SCC activation.

Off-Vertical Axis Rotation: A Test of the Otolith-Ocular Reflex

1992 ◽  
Vol 101 (8) ◽  
pp. 643-650 ◽  
Author(s):  
Joseph M. R. Furman ◽  
Robert H. Schor ◽  
Timothy L. Schumann
Keyword(s):  
Eye Movements ◽  
Semicircular Canal ◽  
Constant Velocity ◽  
Vertical Axis ◽  
Induced Response ◽  
Movement Response ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Axis Rotation ◽  
Asymptomatic Subjects

The vestibulo-ocular reflex was studied via off-vertical axis rotation (OVAR) in the dark. The axis of the turntable could be tilted from vertical by up to 30°. Eye movements were measured with electro-oculography. Results from healthy asymptomatic subjects indicated that 1) a reliable otolith-induced response could be obtained during constant velocity OVAR using a velocity of 60°/s with a tilt of 30°; 2) constant velocity OVAR rotation was nausea-producing and, especially if subjects were rotated in the dark about an earth-vertical axis prior to being tilted, disorienting; and 3) sinusoidal OVAR produced minimal nausea; the eye movement response appeared to be the result of a combination of semicircular canal and otolith components. We conclude that OVAR has the potential of becoming a useful method for clinically assessing both the otolith-ocular reflex and semicircular canal—otolith interaction.

The functional allometry of semicircular canals, fins, and body dimensions in the juvenile centrarchid fish, Lepomis gibbosus (L.)

Development ◽  
1973 ◽  
Vol 29 (3) ◽  
pp. 721-743
Author(s):  
Howard C. Howland ◽  
Joseph Masci
Keyword(s):  
Body Mass ◽  
Semicircular Canal ◽  
Semicircular Canals ◽  
Lepomis Gibbosus ◽  
Swimming Velocity ◽  
Body Dimensions ◽  
Moments Of Inertia ◽  
Significant Difference ◽  
Vertical Semicircular Canal ◽  
Vertical Semicircular Canals

1. The ontogenetic allometry of radii of curvature and the tube radii of the semicircular canals of approximately 85 juvenile (2–20 g) centrarchids of the species Lepomis gibbosus (L.) was investigated. The radii of curvature of the semicircular canals have different allometries; these arefor the anterior vertical, posterior vertical and horizontal canals respectively. The differences in growth exponents between the anterior and posterior vertical semicircular canals and between the anterior vertical and horizontal semicircular canals were statistically significant (P < 0·02 and P < 0·05 respectively). 2. Body mass and standard length were almost equally good predictors of the radii of curvature of the anterior vertical semicircular canals, but body mass was the better predictor of the radii of curvature of the posterior vertical and horizontal semicircular canals, as judged by the magnitude of the mean squares about the logarithmic regressions of radii on length and mass. 3. By measuring and estimating the area moments of the fins of the fish, the moments of inertia about various axes and the allometry of the characteristic swimming velocity of the fish, we attempted to account for the magnitude and direction of the differences in allometric growth exponents of the radii of curvature of the semicircular canals. Unexplained by our best estimate of growth exponents was the very high value observed for the posterior vertical semicircular canals. 4. No significant correlation could be found between the residuals of the major dimensions of the posterior vertical semicircular canals and those of body width or depth once the influence of body mass was removed. This finding suggests the rejection of the hypothesis that the allometry of this semicircular canal is simply correlated with overall body expansion in its plane. 5. The discrepancies between our predictions and observations of growth exponents could be explained by a gradual increase of the spring constant of the semicircular canals on the order ofthough they may also be due to other factors neglected in our model, e.g. the allometry of the added mass of the fish. 6. No evidence suggested that the shape of the semicircular canals was altered over the size range of the fish we studied. However, among the fins of the fish and the major body dimensions, only the width and the depth of the fish exhibited growth constants that did not differ significantly from each other. 7. We computed the effective toroidal radii of the non-toroidal-shaped vertical semicircular canals and found that the equivalent toroidal radius of the anterior vertical semicircular canal was consistently greater than that of the posterior vertical semicircular canal. This difference is explicable on the basis of the different moments of inertia of the animal about axes through the center of gravity and parallel to the axes of the semicircular canals. 8. We computed the allometry of the ratios R̄/r2 for all three semicircular canals and found in accordance with the prediction of Jones & Spells that they did not differ significantly from zero. 9. The allometry of the outer tube radii of the several semicircular canals was determined, and, while there was no significant difference in the growth exponents of the tube radii, it was noted that the tube radius of the horizontal semicircular canal was consistently and significantly smaller than that of the vertical semicircular canal. We suggested that this difference might be due to the broader range of frequencies that the fish experienced about its yaw axis. 10. Taken as a whole the data and calculations of this paper generally support the theory that the dimensions of the semicircular canals and the ontogenetic changes in them attune the semicircular canals to the angular frequency spectra that the fish experience about their axes.

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.

XVI Eye Movements from Semicircular Canal Nerve Stimulation in the Cat

1964 ◽  
Vol 73 (1) ◽  
pp. 153-169 ◽  
Author(s):  
Bernard Cohen ◽  
Jun-Ichi Suzuki ◽  
Morris B. Bender
Keyword(s):  
Eye Movements ◽  
Nerve Stimulation ◽  
Semicircular Canal

scholarly journals Biomechanical Analysis of Angular Motion in Association with Bilateral Semicircular Canal Function

2019 ◽  
Author(s):  
Shuang Shen ◽  
Fei Zhao ◽  
Zhaoyue Chen ◽  
Qingyin Zheng ◽  
Shen Yu ◽  
...  
Keyword(s):  
Theoretical Approach ◽  
Semicircular Canal ◽  
Amplitude Ratio ◽  
Semicircular Canals ◽  
Vestibular Dysfunction ◽  
Angular Motion ◽  
Biomechanical Analysis ◽  
Fe Model ◽  
Healthy Human ◽  
Horizontal Semicircular Canal

AbstractThe aim of this study was to develop a finite element (FE) model of bilateral human semicircular canals (SCCs) in order to simulate and analyze the complex fluid-structural interaction between the endolymph and cupulae by calculating the degree of cupular expansion and the cupular deflection. The results showed that cupular deflection responses were consistent with Ewald’s II law, whereas each pair of bilateral cupulae simultaneously expanded or compressed to the same degree. In addition, both the degree of cupular expansion and cupular deflection can be expressed as the solution of forced oscillation during head sinusoidal rotation, and the amplitude of cupular expansion was approximately two times greater than that of cupular deflection. Regarding the amplitude-frequency and phase-frequency characteristics, the amplitude ratios among the horizontal semicircular canal (HC) cupular expansion, the anterior semicircular canal (AC) cupular expansion, and the posterior semicircular canal (PC) cupular expansion was constant at 1:0.82:1.62, and the phase differences among them were constant at 0 or 180 degrees at the frequencies of 0.5 to 6 Hz. However, both the amplitude ratio and the phase differencies of the cupular deflection incresed nonlinearly with the increase of frequency and tended to be constant at the frequency band between 2 and 6 Hz. The results indicate that the responses of cupular expansion might only be related to the mass and rigidity of three cupulae and the endolymph, but the responses of cupular deflection are related to the mass, rigidity, or damping of them, and these physical properties would be affected by vestibular dysfunction. Therefore, both the degree of cupular expansion and cupular deflection should be considered important mechanical variables for induced neural signals. Such a numerical model can be further built to provide a useful theoretical approach for exploring the biomechanical nature underlying vestibular dysfunction.Statement of significanceBy taking the advantage of the torsional pendulum model and the FE model, a healthy human vestibular SCCs was developed to investigate the angular motion in association with SCC function. As a result, the responses of cupular expansion and deflection during head horizontal sinusoidal rotation were analyzed for the first time, showing quantitative correlation to the eye movement due to the vestibular ocular reflex (VOR) pathway. These responses play important roles in the cupular mechano-electrical transduction process. The significant outcome derived from this study provides a useful theoretical approach for further exploring the biomechanical nature underlying vestibular dysfunction.

Eye Movements and Motion Perception Induced by Off-vertical Axis Rotation (OVAR) at Small Angles of Tilt after Spaceflight

1995 ◽  
Vol 115 (5) ◽  
pp. 603-609 ◽  
Author(s):  
Gilles Clement ◽  
Christian Darlot ◽  
Anna Petropoulos ◽  
Alain Berthoz
Keyword(s):  
Eye Movements ◽  
Motion Perception ◽  
Vertical Axis ◽  
Axis Rotation

Horizontal Rotation Responses of Medullary Reticular Neurons in the Decerebrate Cat1

1995 ◽  
Vol 5 (3) ◽  
pp. 223-228
Author(s):  
Robert H. Schor ◽  
Bill J. Yates
Keyword(s):  
Spinal Cord ◽  
Reticular Formation ◽  
Semicircular Canal ◽  
Semicircular Canals ◽  
Response Dynamics ◽  
Medullary Reticular Formation ◽  
Decerebrate Cat ◽  
Reticular Neurons ◽  
Semicircular Canal Afferents

This study examines the response of neurons in the medullary reticular formation of the decerebrate cat to sinusoidal yaw rotations in the plane of the horizontal semicircular canals. Responsive neurons that could be antidromically activated from the spinal cord appeared to be less sensitive to the rotary stimulus than the rest of the population of responsive neurons. Most neurons had response dynamics similar to those of semicircular canal afferents.

Semicircular canal and saccular influence on the subjective visual horizontal during gondola centrifugation

1999 ◽  
Vol 9 (5) ◽  
pp. 347-357
Author(s):  
A. Tribukait
Keyword(s):  
Semicircular Canal ◽  
Semicircular Canals ◽  
Central Position ◽  
Otolith Organs ◽  
Force Vector ◽  
Time Constants ◽  
Storage Mechanism ◽  
Spatial Disorientation ◽  
Gravitoinertial Force ◽  
Vertical Semicircular Canals

Measurements of the subjective visual horizontal (SVH) were performed in 11 healthy test persons during an increase of the resultant gravitoinertial force vector in a large swing-out gondola centrifuge. Three levels of hypergravity (1.5g, 2.0g, 2.5g) were used, each with a duration of 4 minutes and with 1–2 minute pauses at 1.0g in between. The direction of the resultant gravitoinertial force vector was always parallel with the head and body length axis. Hence, there was no roll stimulus to the otolith organs. The swing-out of the gondola during acceleration, however, is sensed by the vertical semicircular canals as a change in roll head position, thus creating an otolith-semicircular canal conflict. After acceleration of the centrifuge there was a tilt of the SVH relative to the resultant gravitoinertial horizontal. This tilt gradually decayed during the 4-minute period of recordings. For a subgroup of seven test subjects who had completely normal ENG-recordings in 1g environment, the initial offset of SVH and the time constants for exponential decay were determined for each g level; initial offsets: 9 . 9 ∘ (1.5g), 7 . 7 ∘ (2.0g), 6 . 1 ∘ (2.5g); time constants: 89s (1.5g), 74s (2.0g), 37s (2.5g). The offset of SVH is interpreted as being the result of mainly the stimulus to the vertical semicircular canals during acceleration of the centrifuge. The slow decay, however, does not correspond to the dynamics of the semicircular canal system, and is suggested to reflect some kind of central position storage mechanism. A smaller offset and more rapid decay for the higher g loads may be explained by an increasing dominance of graviceptive input, presumably from the saccules. In conclusion, these results might suggest the role of the vertical semicircular canals as well as the sacculus in the formation of SVH. They may also have relevance with regard to the spatial disorientation problem in aviators.

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