Spatial orientation of postrotatory nystagmus during static roll tilt in cats

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.

Role of irregular otolith afferents in the steady-state nystagmus during off-vertical axis rotation

1992 ◽  
Vol 68 (5) ◽  
pp. 1895-1900 ◽  
Author(s):  
D. E. Angelaki ◽  
A. A. Perachio ◽  
M. J. Mustari ◽  
C. L. Strunk
Keyword(s):  
Steady State ◽  
Vertical Axis ◽  
Dynamic Responses ◽  
Velocity Storage ◽  
Slow Phase ◽  
Otolith Organs ◽  
Galvanic Stimulation ◽  
Storage Mechanism ◽  
Velocity Storage Mechanism ◽  
Ocular Nystagmus

1. During constant velocity off-vertical axis rotations (OVAR) in the dark a compensatory ocular nystagmus is present throughout rotation despite the lack of a maintained signal from the semicircular canals. Lesion experiments and canal plugging have attributed the steady-state ocular nystagmus during OVAR to inputs from the otolith organs and have demonstrated that it depends on an intact velocity storage mechanism. 2. To test whether irregularly discharging otolith afferents play a crucial role in the generation of the steady-state eye nystagmus during OVAR, we have used anodal (inhibitory) currents bilaterally to selectively and reversibly block irregular vestibular afferent discharge. During delivery of DC anodal currents (100 microA) bilaterally to both ears, the slow phase eye velocity of the steady-state nystagmus during OVAR was reduced or completely abolished. The disruption of the steady-state nystagmus was transient and lasted only during the period of galvanic stimulation. 3. To distinguish a possible effect of ablation of the background discharge rates of irregular vestibular afferents on the velocity storage mechanism from specific contributions of the dynamic responses from irregular otolith afferents to the circuit responsible for the generation of the steady-state nystagmus, bilateral DC anodal galvanic stimulation was applied during optokinetic nystagmus (OKN) and optokinetic afternystagmus (OKAN). No change in OKN and OKAN was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Characteristics of Nystagmus Evoked by Electrical Stimulation of The Uvular/Nodular Lobules of the Cerebellum in Monkey

1992 ◽  
Vol 2 (3) ◽  
pp. 235-245
Author(s):  
S.J. Heinen ◽  
D.K. Oh ◽  
E.L. Keller
Keyword(s):  
Electrical Stimulation ◽  
Velocity Storage ◽  
Large Field ◽  
Slow Phase ◽  
Stimulus Pulse ◽  
Storage Mechanism ◽  
Velocity Storage Mechanism ◽  
Stimulus Offset ◽  
Eye Velocity ◽  
Stimulation Of

Electrical stimulation in the monkey vestibulocerebellum has previously been shown to produce ocular nystagmus, but large stimulating current values were used. Using long duration (⩽10-second) stimulus pulse trains and low current values (<50 μA), we studied the nystagmus evoked by microstimulation in the uvular/nodular regions of the cerebellum. In doing this, we found quantitative differences in the nystagmus evoked from these two regions. Stimulation of the nodulus typically produced a vigorous nystagmus with a contralateral slow phase and a prolonged afternystagmus in the same direction. In contrast, stimulation of the uvula typically produced a regular ipsilateral nystagmus pattern with a very short, if any, afternystagmus in the same direction. In addition, at some stimulation sites in the uvula we observed an adaptation in the slow phase eye velocity during the time that the stimulation remained on. This effect could result in a secondary nystagmus, with a slow phase velocity direction opposite to that first evoked by the stimulation, followed by a prolonged afternystagmus in the direction of the secondary nystagmus at stimulus offset. The nystagmus evoked by these cerebellar stimulations differs from both natural nystagmus produced by large field visual motion and from the nystagmus produced by electrical stimulation of the nucleus of the optic tract. The nystagmus produced by uvular and nodular stimulation shows a shorter latency and a more rapid slow phase eye velocity buildup. The uvula stimulations also showed a much shorter afternystagmus. Also, the same nystagmus was evoked whether the animal was in a lighted or dark surround. These characteristics and recent single-unit recording studies in the uvula seem to suggest that the uvula acts not as a direct input to the velocity storage mechanism, but instead perhaps as part of an internal regulator for balance between the bilateral vestibular nuclei which are normally part of the nystagmus response. On the other hand, the nodulus, with its prolonged afternystagmus in the same direction as the evoked nystagmus, may be involved as a part of the velocity storage mechanism.

Spatial Orientation of Caloric Nystagmus in Semicircular Canal-Plugged Monkeys

2002 ◽  
Vol 88 (2) ◽  
pp. 914-928 ◽  
Author(s):  
Yasuko Arai ◽  
Sergei B. Yakushin ◽  
Bernard Cohen ◽  
Jun-Ichi Suzuki ◽  
Theodore Raphan
Keyword(s):  
Phase Velocity ◽  
Spatial Orientation ◽  
Velocity Vector ◽  
Semicircular Canals ◽  
Velocity Storage ◽  
Slow Phase ◽  
Coordinate Frame ◽  
Slow Phase Velocity ◽  
Caloric Nystagmus ◽  
Eye Velocity

We studied caloric nystagmus before and after plugging all six semicircular canals to determine whether velocity storage contributed to the spatial orientation of caloric nystagmus. Monkeys were stimulated unilaterally with cold (≈20°C) water while upright, supine, prone, right-side down, and left-side down. The decline in the slow phase velocity vector was determined over the last 37% of the nystagmus, at a time when the response was largely due to activation of velocity storage. Before plugging, yaw components varied with the convective flow of endolymph in the lateral canals in all head orientations. Plugging blocked endolymph flow, eliminating convection currents. Despite this, caloric nystagmus was readily elicited, but the horizontal component was always toward the stimulated (ipsilateral) side, regardless of head position relative to gravity. When upright, the slow phase velocity vector was close to the yaw and spatial vertical axes. Roll components became stronger in supine and prone positions, and vertical components were enhanced in side down positions. In each case, this brought the velocity vectors toward alignment with the spatial vertical. Consistent with principles governing the orientation of velocity storage, when the yaw component of the velocity vector was positive, the cross-coupled pitch or roll components brought the vector upward in space. Conversely, when yaw eye velocity vector was downward in the head coordinate frame, i.e., negative, pitch and roll were downward in space. The data could not be modeled simply by a reduction in activity in the ipsilateral vestibular nerve, which would direct the velocity vector along the roll direction. Since there is no cross coupling from roll to yaw, velocity storage alone could not rotate the vector to fit the data. We postulated, therefore, that cooling had caused contraction of the endolymph in the plugged canals. This contraction would deflect the cupula toward the plug, simulating ampullofugal flow of endolymph. Inhibition and excitation induced by such cupula deflection fit the data well in the upright position but not in lateral or prone/supine conditions. Data fits in these positions required the addition of a spatially orientated, velocity storage component. We conclude, therefore, that three factors produce cold caloric nystagmus after canal plugging: inhibition of activity in ampullary nerves, contraction of endolymph in the stimulated canals, and orientation of eye velocity to gravity through velocity storage. Although the response to convection currents dominates the normal response to caloric stimulation, velocity storage probably also contributes to the orientation of eye velocity.

Spatial orientation of periodic alternating drift (PAD)

2007 ◽  
Vol 16 (4-5) ◽  
pp. 201-207
Author(s):  
Aldo Ferraresi ◽  
Gian Battista Azzena ◽  
Diana Troiani
Keyword(s):  
Prone Position ◽  
Time Constant ◽  
Spatial Orientation ◽  
Vertical Component ◽  
Vertical Axis ◽  
Longitudinal Axis ◽  
Vestibular Stimulation ◽  
Horizontal Component ◽  
Velocity Storage ◽  
Pigmented Rabbits

Sinusoidal vestibular stimulation induces in the intact rabbit in prone position a periodic alternating drift (PAD), evident in the earth horizontal plane when the animal is rotated about the vertical axis but weak in the vertical one when the animal is rotated about the longitudinal axis. It has been hypothesized that these oscillations are related to an intrinsic instability of the velocity storage, due to the length of its time constant. The velocity storage has the longest time constant aligned with the vertical axis, and it changes its orientation with the gravity vector. The present research examined the spatial orientation of PAD in relation to changes of the animal position with respect to gravity. Normal pigmented rabbits were sinusoidally oscillated about their longitudinal axes to evoke vertical eye responses. The stimulation was carried out with the animal in prone position and with the animal in nose-up condition. With the animal in prone position, PAD had a weak vertical component, but an evident horizontal component was visible. When the animal was in nose-up position, the horizontal component of PAD was clearly visible, while the vertical component was negligible. In both stimulation conditions PAD period and peak velocity were not modulated by the stimulus characteristics. These results are consistent with a model of PAD based on an interaction between velocity storage and the cerebellar adaptation-habituation circuit.

The Velocity Storage Mechanism of the Optokinetic Nystagmus Under Apparent Stimulus Movements in Squirrel Monkeys

1997 ◽  
Vol 7 (6) ◽  
pp. 441-451
Author(s):  
J. Kröller ◽  
F. Behrens ◽  
V.V. Marlinsky
Keyword(s):  
Steady State ◽  
Brain Stem ◽  
Apparent Movement ◽  
Squirrel Monkeys ◽  
Constant Light ◽  
Velocity Storage ◽  
Slow Phase ◽  
Stripe Pattern ◽  
Storage Mechanism ◽  
The Brain

Experiments in two awake untrained squirrel monkeys were performed to study the velocity storage mechanism during fast rise of OKN slow phase velocity. This was done by testing the monkey’s capability to perform OKN in response to a stationary-appearing stroboscopically illuminated stripe pattern of a horizontally rotating drum. Nystagmus was initially elicited during constant illumination lasting between 0.6 and 25 s. The periodicity of the stripe pattern was 2.37°. When after the constant light the flash illumination was switched on again, two types of behavior could occur, depending on the length of the constant light interval (CLI): 1) when the CLI was shorter than a threshold value of 6.2 seconds, the OKN ceased under the flash stimulation. Then a “post-OKN” occurred that increased with the length of the CLIs, indicating that the intermittently illuminated pattern did not provoke fixation suppression of OKN aftereffects. 2) when the CLI was above threshold, the OKN continued under the flash light: it will he called “apparent movement OKN.” The threshold CLI between the type 1 and the type 2 response did not depend on drum velocities between 21.5°/s and 71.3°/s. The average gain of the apparent movement OKN was 0.83 ± 0.04; gain and stability of slow phase eye movement velocity did not deviate systematically from the usually elicited OKN. OKAN after apparent movement OKN did not deviate from OKAN after constantly illuminated moving patterns. In response to the OKN initiation by a constantly illuminated pattern up to pattern velocities of 100°/s, the OKN steady state gain was reached within the first 2 or 3 nystagmus beats. We ascribe the increase of the post-OKN with CLI and the existence of a threshold constant light interval to activity-accumulation in the common velocity-to-position integrator (velocity storage) of the brain stem. Loading of the velocity storage takes place after the OKN gain has already reached the steady-state value. Apparent movement OKN could also be elicited in guinea pigs that lack an effective smooth pursuit system. We suggest that apparent movement OKN is produced by mechanisms located in the brain stem.

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.

Suppression of Optokinetic Velocity Storage in Humans by Static Tilt in Roll

1991 ◽  
Vol 1 (4) ◽  
pp. 347-355 ◽  
Author(s):  
S.H. Lafortune ◽  
D.J. Ireland ◽  
R.M. Jell
Keyword(s):  
Exponential Model ◽  
Velocity Storage ◽  
Slow Phase ◽  
Indirect Pathway ◽  
Otolith Organ ◽  
Storage Mechanism ◽  
3 Dimensional ◽  
Double Exponential ◽  
Double Exponential Model ◽  
Anterior Posterior

The effects of static tilts about the roll (anterior-posterior) axis on human horizontal optokinetic afternystagmus (HOKAN) were examined. Static tilts in roll, with subjects lying on their left side, produced significant tilt-dependent HOKAN suppression. Only the slow (indirect pathway) component time constant (1/D) of the double exponential model for human HOKAN decreased with angle of roll tilt. The effect was direction specific in that suppression occurred only following a leftward-going stimulus. These findings provide further support for the postulate that otolith-organ-mediated activity can couple to the horizontal velocity storage mechanism in humans. A slight trend towards a tilt-dependent reduction of coefficient A (initial slow phase velocity of fast component decay) was revealed, suggesting the possibility that otolith-organ-mediated activity could couple to direct (pursuit-mediated?) pathways as well. No horizontal-to-vertical cross-coupling occurred, indicating that this aspect of the 3-dimensional model for velocity storage proposed by Raphan & Cohen (1988) may not completely apply to humans.

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.

Discharge properties of morphologically identified vestibular neurons recorded during horizontal eye movements in the goldfish

2019 ◽  
Vol 121 (5) ◽  
pp. 1865-1878 ◽  
Author(s):  
A. M. Pastor ◽  
P. M. Calvo ◽  
R. R. de la Cruz ◽  
R. Baker ◽  
H. Straka
Keyword(s):  
Eye Movements ◽  
Velocity Storage ◽  
Slow Phase ◽  
Eye Position ◽  
Type I ◽  
Abducens Nucleus ◽  
Ancestral Condition ◽  
Vestibular Neurons ◽  
Prepositus Hypoglossi ◽  
Eye Velocity

Computational capability and connectivity are key elements for understanding how central vestibular neurons contribute to gaze-stabilizing eye movements during self-motion. In the well-characterized and segmentally distributed hindbrain oculomotor network of goldfish, we determined afferent and efferent connections along with discharge patterns of descending octaval nucleus (DO) neurons during different eye motions. Based on activity correlated with horizontal eye and head movements, DO neurons were categorized into two complementary groups that either increased discharge during both contraversive (type II) eye (e) and ipsiversive (type I) head (h) movements (eIIhI) or vice versa (eIhII). Matching time courses of slow-phase eye velocity and corresponding firing rates during prolonged visual and head rotation suggested direct causality in generating extraocular motor commands. The axons of the dominant eIIhI subgroup projected either ipsi- or contralaterally and terminated in the abducens nucleus, Area II, and Area I with additional recurrent collaterals of ipsilaterally projecting neurons within the parent nucleus. Distinct feedforward commissural pathways between bilateral DO neurons likely contribute to the generation of eye velocity signals in eIhII cells. The shared contribution of DO and Area II neurons to eye velocity storage likely represents an ancestral condition in goldfish that is clearly at variance with the task separation between mammalian medial vestibular and prepositus hypoglossi neurons. This difference in signal processing between fish and mammals might correlate with a larger repertoire of visuo-vestibular-driven eye movements in the latter species that potentially required a shift in sensitivity and connectivity within the hindbrain-cerebello-oculomotor network. NEW & NOTEWORTHY We describe the structure and function of neurons within the goldfish descending octaval nucleus. Our findings indicate that eye and head velocity signals are processed by vestibular and Area II velocity storage integrator circuitries whereas the velocity-to-position Area I neural integrator generates eye position solely. This ancestral condition differs from that of mammals, in which vestibular neurons generally lack eye position signals that are processed and stored within the nucleus prepositus hypoglossi.

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