Investigation of the Horizontal, Vertical, and Oblique Optokinetic Nystagmus and Afternystagmus in Squirrel Monkeys

1995 ◽  
Vol 5 (3) ◽  
pp. 171-186
Author(s):  
J. Kröller ◽  
F. Behrens
Keyword(s):  
Eye Movements ◽  
Optokinetic Nystagmus ◽  
Two Dimensions ◽  
Movement Direction ◽  
Slow Phase ◽  
Vertical Search ◽  
Phase Direction ◽  
Pattern Movement ◽  
Eye Velocity ◽  
Stimulus Direction

A moving random dot pattern was projected onto a tangent screen in front of awake untrained monkeys that were always placed in upright position. Eye movements were recorded in two dimensions to study the oblique optokinetic nystagmus (OKN) and compare it to the horizontal and vertical OKN. Any direction of pattern movement across the screen could be achieved. The angular velocity of pattern movement was varied between 6 and 180°/s. To display off-horizontal and off-vertical eye movements, the instantaneous direction and velocity of the eye movements were computed from the horizontal and vertical search coil voltages. At pattern velocities below 90°/s, stimulus-direction and direction of the OKN slow phase matched very precisely. Above 90°/s the slow-phase eye movement direction was systematically shifted toward the horizontal except for pure vertical stimulation. The slow-phase eye velocity at off-horizontal stimulation was inconstant, however; stable periods occurred repeatedly that were used to define the gain of OKN. Up to stimulus speeds of about 90°/s the OKN gain did not depend on the direction of stimulation and of OKN. At higher velocities the gain decreased with the increasing angle between stimulus direction and horizontal. Practically no vertical optokinetic afternystagmus (OKAN) could be observed, in either the up or down direction. At the onset of afternystagmus after oblique stimulation the direction of the OKAN slow phase immediately shifted over to the horizontal. The data indicate that the slow-phase direction and gain of oblique OKN with the monkey’s head upright can be described by the sum of a horizontal and a vertical velocity vector obtained during stimulation in these cardinal directions.

Independent eye movements in the turtle

1990 ◽  
Vol 5 (1) ◽  
pp. 29-41 ◽  
Author(s):  
M. Ariel
Keyword(s):  
Eye Movements ◽  
Optokinetic Nystagmus ◽  
Contact Lenses ◽  
The Other ◽  
Slow Phase ◽  
Accessory Optic System ◽  
Retinal Slip ◽  
The Mean ◽  
The Difference ◽  
Eye Velocity

AbstractIn order to evaluate the normal eye movements of the turtle, Pseudemys scripta elegans, the positions of each eye were recorded simultaneously using two search-coil contact lenses. Optokinetic nystagmus (OKN) was strikingly unyoked in this animal such that one eye's slow-phase velocity was substantially independent of that of the other eye. On the other hand, the fast-phase motions of both eyes occurred more or less in synchrony.An eye's slow-phase gain is primarily dependent on the direction and velocity of the stimulus to that eye. Using monocular stimuli, the highest mean gain (0.54 ± 0.047; mean ± standard error of mean) occurred using temporal-to-nasal movement at 2.5 deg/s. The mean OKN gain for nasal-to-temporal movement was only 0.13 ± 0.015 at that velocity. Additionally, using the optimal monocular stimulus (temporal-to-nasal stimulation at 2.5 deg/s) only drove the occluded eye to move nasal-to-temporally at 0.085 deg/s, equivalent to a “gain” of only 0.034 ± 0.011.The binocular OKN gain during rotational stimuli was higher than monocular gain, especially during nasal-to-temporal movement at high velocities. Also the difference in slow-phase eye velocity between the two eyes was smaller during binocular rotational stimuli. In contrast, when each eye simultaneously viewed its temporal-to-nasal stimulus at an equal velocity, two behaviors were observed. Often, OKN alternated between an animal's left eye and right eye. Occasionally, both eyes moved at equal but opposite velocities.These behavioral data provide a quantitative baseline to interpret the properties of the retinal slip information in the turtle's accessory optic system. Those properties are similar to the behavior of the turtle in that both are tuned to direction and velocity independently for each eye (Rosenberg & Ariel, 1990).

Quantitative Analysis of Abducens Neuron Discharge Dynamics During Saccadic and Slow Eye Movements

1999 ◽  
Vol 82 (5) ◽  
pp. 2612-2632 ◽  
Author(s):  
Pierre A. Sylvestre ◽  
Kathleen E. Cullen
Keyword(s):  
Eye Movements ◽  
Firing Rate ◽  
Eye Movement ◽  
Neuronal Activity ◽  
Smooth Pursuit ◽  
Slow Phase ◽  
Vestibular Nystagmus ◽  
Firing Rates ◽  
Rapid Eye Movements ◽  
Eye Velocity

The mechanics of the eyeball and its surrounding tissues, which together form the oculomotor plant, have been shown to be the same for smooth pursuit and saccadic eye movements. Hence it was postulated that similar signals would be carried by motoneurons during slow and rapid eye movements. In the present study, we directly addressed this proposal by determining which eye movement–based models best describe the discharge dynamics of primate abducens neurons during a variety of eye movement behaviors. We first characterized abducens neuron spike trains, as has been classically done, during fixation and sinusoidal smooth pursuit. We then systematically analyzed the discharge dynamics of abducens neurons during and following saccades, during step-ramp pursuit and during high velocity slow-phase vestibular nystagmus. We found that the commonly utilized first-order description of abducens neuron firing rates (FR = b + kE + rE˙, where FR is firing rate, E and E˙ are eye position and velocity, respectively, and b, k, and r are constants) provided an adequate model of neuronal activity during saccades, smooth pursuit, and slow phase vestibular nystagmus. However, the use of a second-order model, which included an exponentially decaying term or “slide” (FR = b + kE + rE˙ + uË − c[Formula: see text]), notably improved our ability to describe neuronal activity when the eye was moving and also enabled us to model abducens neuron discharges during the postsaccadic interval. We also found that, for a given model, a single set of parameters could not be used to describe neuronal firing rates during both slow and rapid eye movements. Specifically, the eye velocity and position coefficients ( r and k in the above models, respectively) consistently decreased as a function of the mean (and peak) eye velocity that was generated. In contrast, the bias ( b, firing rate when looking straight ahead) invariably increased with eye velocity. Although these trends are likely to reflect, in part, nonlinearities that are intrinsic to the extraocular muscles, we propose that these results can also be explained by considering the time-varying resistance to movement that is generated by the antagonist muscle. We conclude that to create realistic and meaningful models of the neural control of horizontal eye movements, it is essential to consider the activation of the antagonist, as well as agonist motoneuron pools.

Oculomotor Reactions in the Cuttlefish, Sepia Officinalis

1970 ◽  
Vol 52 (2) ◽  
pp. 369-384 ◽  
Author(s):  
H. COLLEWIJN
Keyword(s):  
Eye Movements ◽  
Optokinetic Nystagmus ◽  
Eye Position ◽  
Sepia Officinalis ◽  
Search Coil ◽  
Passive Rotation ◽  
Eye Velocity ◽  
Search Coil Technique ◽  
Better Than

1. Eye position in Sepia was measured in restrained animals, using a scleral search coil technique. 2. Optokinetic nystagmus was elicited by drum rotations from 0.035 up to 35°/sec. 3. Passive rotation of Sepia in darkness evoked a transient nystagmus, followed by after-nystagmus at arrest. 4. Combination of these two stimuli yielded the best results, but the ratio eye velocity/surroundings velocity was usually not better than 0.5. 5. Eye movements were conjugate and a closed eye could be driven by a seeing eye. Monocular reactions were smaller than binocular ones, but equal in both directions. 6. Fixation movements could not be demonstrated in the present conditions.

Optokinetic Eye Movements Elicited by Radial Optic Flow in the Macaque Monkey

1998 ◽  
Vol 79 (3) ◽  
pp. 1461-1480 ◽  
Author(s):  
Markus Lappe ◽  
Martin Pekel ◽  
Klaus-Peter Hoffmann
Keyword(s):  
Eye Movements ◽  
Flow Field ◽  
Eye Movement ◽  
Optic Flow ◽  
Macaque Monkey ◽  
Flow Fields ◽  
Movement Direction ◽  
Slow Phase ◽  
Eye Position ◽  
Self Motion

Lappe, Markus, Martin Pekel, and Klaus-Peter Hoffmann. Optokinetic eye movements elicited by radial optic flow in the macaque monkey. J. Neurophysiol. 79: 1461–1480, 1998. We recorded spontaneous eye movements elicited by radial optic flow in three macaque monkeys using the scleral search coil technique. Computer-generated stimuli simulated forward or backward motion of the monkey with respect to a number of small illuminated dots arranged on a virtual ground plane. We wanted to see whether optokinetic eye movements are induced by radial optic flow stimuli that simulate self-movement, quantify their parameters, and consider their effects on the processing of optic flow. A regular pattern of interchanging fast and slow eye movements with a frequency of 2 Hz was observed. When we shifted the horizontal position of the focus of expansion (FOE) during simulated forward motion (expansional optic flow), median horizontal eye position also shifted in the same direction but only by a smaller amount; for simulated backward motion (contractional optic flow), median eye position shifted in the opposite direction. We relate this to a change in Schlagfeld typically observed in optokinetic nystagmus. Direction and speed of slow phase eye movements were compared with the local flow field motion in gaze direction (the foveal flow). Eye movement direction matched well the foveal motion. Small systematic deviations could be attributed to an integration of the global motion pattern. Eye speed on average did not match foveal stimulus speed, as the median gain was only ∼0.5–0.6. The gain was always lower for expanding than for contracting stimuli. We analyzed the time course of the eye movement immediately after each saccade. We found remarkable differences in the initial development of gain and directional following for expansion and contraction. For expansion, directional following and gain were initially poor and strongly influenced by the ongoing eye movement before the saccade. This was not the case for contraction. These differences also can be linked to properties of the optokinetic system. We conclude that optokinetic eye movements can be elicited by radial optic flow fields simulating self-motion. These eye movements are linked to the parafoveal flow field, i.e., the motion in the direction of gaze. In the retinal projection of the optic flow, such eye movements superimpose retinal slip. This results in complex retinal motion patterns, especially because the gain of the eye movement is small and variable. This observation has special relevance for mechanisms that determine self-motion from retinal flow fields. It is necessary to consider the influence of eye movements in optic flow analysis, but our results suggest that direction and speed of an eye movement should be treated differently.

Eye Movements in Cerebellar and Combined Cerebellobrainstem Diseases

1983 ◽  
Vol 92 (2) ◽  
pp. 165-171 ◽  
Author(s):  
Carsten Wennmo ◽  
Bengt Hindfelt ◽  
Ilmari Pyykkö
Keyword(s):  
Quantitative Analysis ◽  
Eye Movements ◽  
Eye Movement ◽  
Smooth Pursuit ◽  
Optokinetic Nystagmus ◽  
Vestibular Nystagmus ◽  
Full Field ◽  
Eye Velocity ◽  
Voluntary Saccades ◽  
Cerebellar Disorders

We report a quantitative analysis of eye movement disturbances in patients with isolated cerebellar disorders and patients with cerebellar disorders and concomitant brainstem involvement. The most characteristic abnormalities in the exclusively cerebellar patients were increased velocities of the slow phases of vestibular nystagmus induced by rotation in the dark and increased peak velocities of the fast phases of optokinetic nystagmus induced by full-field optokinetic stimuli. Dysmetria of saccades was found in three of six cerebellar patients and gaze nystagmus in all six patients. The typical findings in the combined cerebellobrainstem group were reduced peak velocities of voluntary saccades, defective smooth pursuit and reduced peak velocities of the fast component of nystagmus during rotation in both the dark and light. All patients with combined cerebellobrainstem disorder had dysmetric voluntary saccades and gaze nystagmus. The numbers of superimposed saccades during smooth pursuit were uniformly increased. Release of inhibition in cerebellar disorders may explain the hyperresponsiveness and inaccuracy of eye movements found in this study. In addition, when lesions also involve the brainstem, however, integrative centers coding eye velocity are affected, leading to slow and inaccurate eye movements. These features elicited clinically may be useful in the diagnosis of cerebellar and brainstem disorders.

scholarly journals Vestibular implantation and longitudinal electrical stimulation of the semicircular canal afferents in human subjects

2015 ◽  
Vol 113 (10) ◽  
pp. 3866-3892 ◽  
Author(s):  
James O. Phillips ◽  
Leo Ling ◽  
Kaibao Nie ◽  
Elyse Jameyson ◽  
Christopher M. Phillips ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Human Subjects ◽  
Vestibular Function ◽  
Slow Phase ◽  
Vestibular Loss ◽  
Stimulation Current ◽  
Eye Velocity ◽  
Over Time ◽  
Stimulation Of

Animal experiments and limited data in humans suggest that electrical stimulation of the vestibular end organs could be used to treat loss of vestibular function. In this paper we demonstrate that canal-specific two-dimensionally (2D) measured eye velocities are elicited from intermittent brief 2 s biphasic pulse electrical stimulation in four human subjects implanted with a vestibular prosthesis. The 2D measured direction of the slow phase eye movements changed with the canal stimulated. Increasing pulse current over a 0–400 μA range typically produced a monotonic increase in slow phase eye velocity. The responses decremented or in some cases fluctuated over time in most implanted canals but could be partially restored by changing the return path of the stimulation current. Implantation of the device in Meniere's patients produced hearing and vestibular loss in the implanted ear. Electrical stimulation was well tolerated, producing no sensation of pain, nausea, or auditory percept with stimulation that elicited robust eye movements. There were changes in slow phase eye velocity with current and over time, and changes in electrically evoked compound action potentials produced by stimulation and recorded with the implanted device. Perceived rotation in subjects was consistent with the slow phase eye movements in direction and scaled with stimulation current in magnitude. These results suggest that electrical stimulation of the vestibular end organ in human subjects provided controlled vestibular inputs over time, but in Meniere's patients this apparently came at the cost of hearing and vestibular function in the implanted ear.

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.

A review of the effects of space flight on the asymmetry of vertical optokinetic and vestibulo-ocular reflexes

2003 ◽  
Vol 13 (4-6) ◽  
pp. 255-263
Author(s):  
Gilles Clément
Keyword(s):  
Phase Velocity ◽  
Optokinetic Nystagmus ◽  
Visual Stimulation ◽  
Head Movements ◽  
Slow Phase ◽  
Eye Position ◽  
Slow Phase Velocity ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Eye Velocity

Prolonged microgravity during orbital flight is a unique way to modify the otolith inputs and to determine the extent of their contribution to the vertical vestibulo-ocular reflex (VOR) and optokinetic nystagmus (OKN). This paper reviews the data collected on 10 astronauts during several space missions and focuses on the changes in the up-down asymmetry. Both the OKN elicited by vertical visual stimulation and the active VOR elicited by voluntary pitch head movements showed an asymmetry before flight, with upward slow phase velocity higher than downward slow phase velocity. Early in-flight, this asymmetry was inverted, and a symmetry of both responses was later observed. An upward shift in the vertical mean eye position in both OKN and VOR suggests that these effects may be related to otolith-dependent changes in eye position which, in themselves, affect slow phase eye velocity.

scholarly journals Functional architecture underlying binocular coordination of eye position and velocity in the larval zebrafish hindbrain

BMC Biology ◽  
2019 ◽  
Vol 17 (1) ◽  
Author(s):  
Christian Brysch ◽  
Claire Leyden ◽  
Aristides B. Arrenberg
Keyword(s):  
Eye Movements ◽  
Position Control ◽  
Dynamic Range ◽  
Slow Phase ◽  
Eye Position ◽  
Persistent Activity ◽  
Oculomotor Neurons ◽  
Position Coding ◽  
Control Knowledge ◽  
Eye Velocity

Abstract Background The oculomotor integrator (OI) in the vertebrate hindbrain transforms eye velocity input into persistent position coding output, which plays a crucial role in retinal image stability. For a mechanistic understanding of the integrator function and eye position control, knowledge about the tuning of the OI and other oculomotor nuclei is needed. Zebrafish are increasingly used to study integrator function and sensorimotor circuits, yet the precise neuronal tuning to motor variables remains uncharacterized. Results Here, we recorded cellular calcium signals while evoking monocular and binocular optokinetic eye movements at different slow-phase eye velocities. Our analysis reveals the anatomical distributions of motoneurons and internuclear neurons in the nucleus abducens as well as those of oculomotor neurons in caudally adjacent hindbrain volumes. Each neuron is tuned to eye position and/or velocity to variable extents and is only activated after surpassing particular eye position and velocity thresholds. While the abducens (rhombomeres 5/6) mainly codes for eye position, in rhombomeres 7/8, a velocity-to-position coding gradient exists along the rostro-caudal axis, which likely corresponds to the oculomotor structures storing velocity and position, and is in agreement with a feedforward mechanism of persistent activity generation. Position encoding neurons are recruited at eye position thresholds distributed across the behaviourally relevant dynamic range, while velocity-encoding neurons have more centred firing thresholds for velocity. In the abducens, neurons coding exclusively for one eye intermingle with neurons coding for both eyes. Many of these binocular neurons are preferentially active during conjugate eye movements and less active during monocular eye movements. This differential recruitment during monocular versus conjugate tasks represents a functional diversification in the final common motor pathway. Conclusions We localized and functionally characterized the repertoire of oculomotor neurons in the zebrafish hindbrain. Our findings provide evidence for a mixed but task-specific binocular code and suggest that generation of persistent activity is organized along the rostro-caudal axis in the hindbrain.

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