Physiology of Three-Dimensional Eye Movements: Smooth Pursuit and Vestibulo-Ocular Reflex

2020 ◽  
pp. 141-159
Author(s):  
Hubert Misslisch
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Three Dimensional ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

scholarly journals Enhancement of the Vestibulo-Ocular Reflex by Prior Eye Movements

1999 ◽  
Vol 81 (6) ◽  
pp. 2884-2892 ◽  
Author(s):  
Vallabh E. Das ◽  
Louis F. Dell’Osso ◽  
R. John Leigh
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Initial Perturbation ◽  
Head Rotation ◽  
Gaze Shift ◽  
Stationary Target ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Head Rotations ◽  
Horizontal Head

Enhancement of the vestibulo-ocular reflex by prior eye movements. We investigated the effect of visually mediated eye movements made before velocity-step horizontal head rotations in eleven normal human subjects. When subjects viewed a stationary target before and during head rotation, gaze velocity was initially perturbed by ∼20% of head velocity; gaze velocity subsequently declined to zero within ∼300 ms of the stimulus onset. We used a curve-fitting procedure to estimate the dynamic course of the gain throughout the compensatory response to head rotation. This analysis indicated that the median initial gain of compensatory eye movements (mainly because of the vestibulo-ocular reflex, VOR) was 0.8 and subsequently increased to 1.0 after a median interval of 320 ms. When subjects attempted to fixate the remembered location of the target in darkness, the initial perturbation of gaze was similar to during fixation of a visible target (median initial VOR gain 0.8); however, the period during which the gain increased toward 1.0 was >10 times longer than that during visual fixation. When subjects performed horizontal smooth-pursuit eye movements that ended (i.e., 0 gaze velocity) just before the head rotation, the gaze velocity perturbation at the onset of head rotation was absent or small. The initial gain of the VOR had been significantly increased by the prior pursuit movements for all subjects ( P < 0.05; mean increase of 11%). In four subjects, we determined that horizontal saccades and smooth tracking of a head-fixed target (VOR cancellation with eye stationary in the orbit) also increased the initial VOR gain (by a mean of 13%) during subsequent head rotations. However, after vertical saccades or smooth pursuit, the initial gaze perturbation caused by a horizontal head rotation was similar to that which occurred after fixation of a stationary target. We conclude that the initial gain of the VOR during a sudden horizontal head rotation is increased by prior horizontal, but not vertical, visually mediated gaze shifts. We postulate that this “priming” effect of a prior gaze shift on the gain of the VOR occurs at the level of the velocity inputs to the neural integrator subserving horizontal eye movements, where gaze-shifting commands and vestibular signals converge.

scholarly journals The Cerebellar Dysplasia of Chiari II Malformation as Revealed by Eye Movements

2009 ◽  
Vol 36 (6) ◽  
pp. 713-724 ◽  
Author(s):  
Michael S. Salman ◽  
Maureen Dennis ◽  
James A. Sharpe
Keyword(s):  
Eye Movements ◽  
Posterior Fossa ◽  
Smooth Pursuit ◽  
Structural Changes ◽  
Visual Fixation ◽  
Quantitative Mri ◽  
Eye Tracker ◽  
Ocular Reflex ◽  
Cerebellar Dysplasia ◽  
Vestibulo Ocular Reflex

Introduction:Chiari type II malformation (CII) is a developmental deformity of the hindbrain. We have previously reported that many patients with CII have impaired smooth pursuit, while few make inaccurate saccades or have an abnormal vestibuloocular reflex. In contrast, saccadic adaptation and visual fixation are normal. In this report, we correlate results from several eye movement studies with neuroimaging in CII. We present a model for structural changes within the cerebellum in CII.Methods:Saccades, smooth pursuit, the vestibulo-ocular reflex, and visual fixation were recorded in 21 patients with CII, aged 8-19 years and 39 age-matched controls, using an infrared eye tracker. Qualitative and quantitative MRI data were correlated with eye movements in 19 CII patients and 28 controls.Results:Nine patients with CII had abnormal eye movements. Smooth pursuit gain was subnormal in eight, saccadic accuracy abnormal in four, and vestibulo-ocular reflex gain abnormal in three. None had fixation instability. Patients with CII had a significantly smaller cerebellar volume than controls, and those with normal eye motion had an expanded midsagittal vermis compared to controls. However, patients with abnormal eye movements had a smaller (non-expanded) midsagittal vermis area, posterior fossa area and medial cerebellar volumes than CII patients with normal eye movements.Conclusions:The deformity of CII affects the structure and function of the cerebellum selectively and differently in those with abnormal eye movements. We propose that the vermis can expand when compressed within a small posterior fossa in some CII patients, thus sparing its ocular motor functions.

The Linear Vestibulo-Ocular Reflex in Normal Subjects and Patients with Vestibular and Cerebellar Lesions

1995 ◽  
Vol 5 (5) ◽  
pp. 349-361
Author(s):  
Robert W. Baloh ◽  
Qing Yue ◽  
Joseph L. Demer
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Human Subjects ◽  
Cerebellar Atrophy ◽  
Linear Acceleration ◽  
Normal Subjects ◽  
Head Movements ◽  
Normal Velocity ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

We measured the horizontal linear vestibulo-ocular reflex (LVOR) in normal human subjects and patients with abnormal angular vestibulo-ocular reflexes (AVOR) and abnormal smooth pursuit. Eye movements were induced by sinusoidal linear acceleration along the interaural axis (0.8 Hz, 0.5 g peak acceleration) on a parallel swing. Horizontal movement of each eye was recorded with an infrared limbus tracking device. Normal subjects increased LVOR sensitivity as real or imagined targets moved closer. Perceived target distance was more important than the vergence angle since changing the vergence angle alone with prisms resulted in only a slight change in LVOR sensitivity. Subjects suppressed the LVOR with real or imagined head-fixed targets. Patients with decreased horizontal AVOR responses had decreased horizontal LVOR responses with imagined earth-fixed targets in the dark. They were able to generate normal velocity LVOR responses with real earth-fixed targets. Patients with increased AVOR responses and poor smooth pursuit due to cerebellar atrophy had low LVOR responses that were minimally affected by real or imagined earth-fixed or head-fixed targets. We conclude that the smooth pursuit system and the cerebellum are critical for generating the eye movements required as subjects fixate a near target during translational head movements.

New Concepts of Cerebellar Control of Eye Movements

1984 ◽  
Vol 92 (1) ◽  
pp. 59-62 ◽  
Author(s):  
David S. Zee
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Retinal Image ◽  
Saccade Amplitude ◽  
Ocular Reflex ◽  
New Concepts ◽  
Smooth Tracking ◽  
Vestibulo Ocular Reflex ◽  
Visual Modulation

We can now, at least tentatively, relegate some oculomotor functions to particular portions of the cerebellum and thus infer which cerebellar structures are malfunctioning in the presence of particular groups of oculomotor signs. The dorsal cerebellar vermis and underlying fastigial nuclei function in the control of saccade amplitude. Consequently, saccadic inaccuracy (dysmetria) and macrosaccadic oscillations are signs of pathology in the dorsal vermis/fastigial nuclei. The floccular-nodular lobe functions in the control of a number of retinal image-stabilizing reflexes, including smooth pursuit, visual modulation of the vestibulo-ocular reflex, and holding positions of gaze. Defective smooth tracking, impaired fixation suppression of caloric-induced nystagmus, and gaze-evoked nystagmus are signs of vestibulocerebellar lesions. Furthermore, the elaboration of long-term, adaptive changes in saccadic and vestibular performance depends on these same structures. Consequent defects are persistent oscillopsia and imbalance.

Three Dimensional Eye Movements of Squirrel Monkeys Following Postrotatory Tilt

1993 ◽  
Vol 3 (2) ◽  
pp. 123-139 ◽  
Author(s):  
Daniel M. Merfeld ◽  
Laurence R. Young ◽  
Gary D. Paige ◽  
David L. Tomko
Keyword(s):  
Eye Movements ◽  
Time Course ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Head Orientation ◽  
Ocular Reflex ◽  
Eye Rotation ◽  
Acceleration And Deceleration ◽  
Vestibulo Ocular Reflex ◽  
Vertical Nystagmus

Three-dimensional squirrel monkey eye movements were recorded during and immediately following rotation around an earth-vertical yaw axis (160∘/s steady state, 100∘/s2 acceleration and deceleration). To study interactions between the horizontal angular vestibulo-ocular reflex (VOR) and head orientation, postrotatory VOR alignment was changed relative to gravity by tilting the head out of the horizontal plane (pitch or roll tilt between 15∘ and 90∘) immediately after cessation of motion. Results showed that in addition to post rotatory horizontal nystagmus, vertical nystagmus followed tilts to the left or right (roll), and torsional nystagmus followed forward or backward (pitch) tilts. When the time course and spatial orientation of eye velocity were considered in three dimensions, the axis of eye rotation always shifted toward alignment with gravity, and the postrotatory horizontal VOR decay was accelerated by the tilts. These phenomena may reflect a neural process that resolves the sensory conflict induced by this postrotatory tilt paradigm.

Chromatic Contrast Sensitivity During Optokinetic Nystagmus, Visually Enhanced Vestibulo-ocular Reflex, and Smooth Pursuit Eye Movements

2009 ◽  
Vol 101 (5) ◽  
pp. 2317-2327 ◽  
Author(s):  
Alexander C. Schütz ◽  
Doris I. Braun ◽  
Karl R. Gegenfurtner
Keyword(s):  
Eye Movements ◽  
Contrast Sensitivity ◽  
Smooth Pursuit ◽  
Optokinetic Nystagmus ◽  
Slow Phase ◽  
Smooth Pursuit Eye Movements ◽  
Pursuit Eye Movements ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Slow Eye Movements

Recently we showed that sensitivity for chromatic- and high-spatial frequency luminance stimuli is enhanced during smooth-pursuit eye movements (SPEMs). Here we investigated whether this enhancement is a general property of slow eye movements. Besides SPEM there are two other classes of eye movements that operate in a similar range of eye velocities: the optokinetic nystagmus (OKN) is a reflexive pattern of alternating fast and slow eye movements elicited by wide-field visual motion and the vestibulo-ocular reflex (VOR) stabilizes the gaze during head movements. In a natural environment all three classes of eye movements act synergistically to allow clear central vision during self- and object motion. To test whether the same improvement of chromatic sensitivity occurs during all of these eye movements, we measured human detection performance of chromatic and luminance line stimuli during OKN and contrast sensitivity during VOR and SPEM at comparable velocities. For comparison, performance in the same tasks was tested during fixation. During the slow phase of OKN we found a similar enhancement of chromatic detection rate like that during SPEM, whereas no enhancement was observable during VOR. This result indicates similarities between slow-phase OKN and SPEM, which are distinct from VOR.

Dissociation of smooth pursuit and vestibulo-ocular reflex cancellation in SCA-6

Neurology ◽  
2000 ◽  
Vol 54 (4) ◽  
pp. 860-866 ◽  
Author(s):  
N. Takeichi ◽  
K. Fukushima ◽  
H. Sasaki ◽  
I. Yabe ◽  
K. Tashiro ◽  
...  
Keyword(s):  
Smooth Pursuit ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex

The vertical vestibulo-ocular reflex, and its interaction with vision during active head motion: Effects of aging

2001 ◽  
Vol 11 (1) ◽  
pp. 3-12
Author(s):  
Ji Soo Kim ◽  
James A. Sharpe
Keyword(s):  
Smooth Pursuit ◽  
Low Frequency ◽  
The Elderly ◽  
Head Motion ◽  
Head Tracking ◽  
Elderly Age ◽  
Ocular Reflex ◽  
Visual Enhancement ◽  
Vestibulo Ocular Reflex ◽  
Effects Of Aging

The effects of aging on the vertical vestibulo-ocular reflex (VOR), and its interactions with vision during active head motion had not been investigated. We measured smooth pursuit, combined eye-head tracking, the VOR, and its visual enhancement and cancellation during active head motion in pitch using a magnetic search coil technique in 21 younger (age < 65) and 10 elderly (age ⩾ 65) subjects. With the head immobile, subjects pursued a target moving sinusoidally with a frequency range of 0.125 to 2.0 Hz, and with peak target accelerations (PTAs) ranging from 12 to 789Âř/s 2 . Combined eye-head tracking, the VOR in darkness, and its visual enhancement during fixation of an earth-fixed target (VVOR) were measured during active sinusoidal head motion with a peak-to-peak amplitude of 20Âř at frequencies of 0.25, 0.5, 1.0 and 2.0 Hz. The efficacy of VOR cancellation was determined from VOR gains during combined eye-head tracking. VOR and VVOR gains were symmetrical in both directions and did not change with aging, except for reduced gains of the downward VOR and VVOR at low frequency (0.25 Hz). However, in the elderly, smooth pursuit, and combined eye-head tracking gains and the efficacy of cancellation of the VOR were significantly lower than in younger subjects. In both the young and elderly groups, VOR gain in darkness did not vary with the frequency of active head motion while the gains of smooth pursuit, combined eye-head tracking, and VVOR declined with increasing target frequency. VOR and VVOR performance in the elderly implicates relative preservation of neural structures subserving vertical vestibular smooth eye motion in senescence.

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