Ocular Responses to Head Rotations During Mirror Viewing

2001 ◽  
Vol 86 (5) ◽  
pp. 2323-2329 ◽  
Author(s):  
Yanning Han ◽  
Jeffrey T. Somers ◽  
Jae I. Kim ◽  
Arun N. Kumar ◽  
R. John Leigh
Keyword(s):  
Eye Movements ◽  
Control Experiment ◽  
Human Subjects ◽  
Head Rotation ◽  
Contextual Cues ◽  
Motion Vision ◽  
Stationary Target ◽  
Vestibular Response ◽  
Geometric Relationship ◽  
Head Rotations

The gain of the human vestibuloocular reflex (VOR) is influenced by the proximity of the object of regard. In six human subjects, we measured the eye rotations induced by passive, sinusoidal, horizontal head rotations at 2.0 Hz during binocular fixation of a stationary far target at 7 m; a stationary target close to the subject's near point of fixation (<15 cm); and the bridge of the subject's own nose, viewed through a mirror positioned so that, for each subject, the angle of vergence was similar to that during viewing of the near target. The median gain of compensatory eye movements for the group of subjects during far viewing was 0.99 (range 0.80–1.04), during near viewing was 1.21 (range 0.88–1.47), and during mirror viewing was 0.85 (range 0.71–1.01). The gain during near and mirror viewing was significantly different for each subject ( P < 0.001) even though the vergence angles were similar. The lower gain values during mirror viewing can be attributed to the geometric relationship between the head rotation, the position of the eyes in the head, and the movement of the subject's virtual image in the mirror. To determine whether visually mediated eye movements were responsible for the observed gain values, we conducted a control experiment in which subjects were rotated using a sum-of-sines stimulus that minimized the effects of predictive visual tracking; differences of gain values between near- and mirror-viewing conditions were similar to those during rotation at 2 Hz. We conclude that, in these experiments, target proximity and vergence angle were not the key determinants of gain of the visuo-vestibular response during head rotation while viewing a near target but that contextual cues from motion vision were more important in generating the appropriate response.

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.

Human Updating of Visual Motion Direction During Head Rotations

2008 ◽  
Vol 99 (5) ◽  
pp. 2558-2576
Author(s):  
Mario Ruiz-Ruiz ◽  
Julio C. Martinez-Trujillo
Keyword(s):  
Visual Motion ◽  
Human Subjects ◽  
Head Tilt ◽  
Head Rotation ◽  
Three Dimensions ◽  
Spatial Updating ◽  
Motion Direction ◽  
Direction Discrimination ◽  
Head Rotations ◽  
Stimulus Direction

Previous studies have demonstrated that human subjects update the location of visual targets for saccades after head and body movements and in the absence of visual feedback. This phenomenon is known as spatial updating. Here we investigated whether a similar mechanism exists for the perception of motion direction. We recorded eye positions in three dimensions and behavioral responses in seven subjects during a motion task in two different conditions: when the subject's head remained stationary and when subjects rotated their heads around an anteroposterior axis (head tilt). We demonstrated that after head-tilt subjects updated the direction of saccades made in the perceived stimulus direction (direction of motion updating), the amount of updating varied across subjects and stimulus directions, the amount of motion direction updating was highly correlated with the amount of spatial updating during a memory-guided saccade task, subjects updated the stimulus direction during a two-alternative forced-choice direction discrimination task in the absence of saccadic eye movements (perceptual updating), perceptual updating was more accurate than motion direction updating involving saccades, and subjects updated motion direction similarly during active and passive head rotation. These results demonstrate the existence of an updating mechanism for the perception of motion direction in the human brain that operates during active and passive head rotations and that resembles the one of spatial updating. Such a mechanism operates during different tasks involving different motor and perceptual skills (saccade and motion direction discrimination) with different degrees of accuracy.

Properties of Horizontal Saccades Accompanied by Blinks

1998 ◽  
Vol 79 (6) ◽  
pp. 2895-2902 ◽  
Author(s):  
Klaus G. Rottach ◽  
Vallabh E. Das ◽  
Walter Wohlgemuth ◽  
Ari Z. Zivotofsky ◽  
R. John Leigh
Keyword(s):  
Eye Movements ◽  
Peak Velocity ◽  
Dynamic Properties ◽  
Human Subjects ◽  
Saccadic Eye Movements ◽  
Stationary Target ◽  
Normal Human ◽  
The Right ◽  
Straight Ahead ◽  
Omnipause Neurons

Rottach, Klaus G., Vallabh E. Das, Walter Wohlgemuth, Ari Z. Zivotofsky, and R. John Leigh. Properties of horizontal saccades accompanied by blinks. J. Neurophysiol. 79: 2895–2902, 1998. Using the magnetic search coil technique to record eye and lid movements, we investigated the effect of voluntary blinks on horizontal saccades in five normal human subjects. The main goal of the study was to determine whether changes in the dynamics of saccades with blinks could be accounted for by a superposition of the eye movements induced by blinks as subjects fixated a stationary target and saccadic movements made without a blink. First, subjects made voluntary blinks as they fixed on stationary targets located straight ahead or 20° to the right or left. They then made saccades between two continuously visible targets 20 or 40° apart, while either attempting not to blink, or voluntarily blinking, with each saccade. During fixation of a target located straight ahead, blinks induced brief downward and nasalward deflections of eye position. When subjects looked at targets located at right or left 20°, similar initial movements were made by four of the subjects, but the amplitude of the adducted eye was reduced by 65% and was followed by a larger temporalward movement. Blinks caused substantial changes in the dynamic properties of saccades. For 20° saccades made with blinks, peak velocity and peak acceleration were decreased by ∼20% in all subjects compared with saccades made without blinks. Blinks caused the duration of 20° saccades to increase, on average, by 36%. On the other hand, blinks had only small effects on the gain of saccades. Blinks had little influence on the relative velocities of centrifugal versus centripetal saccades, and abducting versus adducting saccades. Three of five subjects showed a significantly increased incidence of dynamic overshoot in saccades accompanied by blinks, especially for 20° movements. Taken with other evidence, this finding suggests that saccadic omnipause neurons are inhibited by blinks, which have longer duration than the saccades that company them. In conclusion, the changes in dynamic properties of saccades brought about by blinks cannot be accounted for simply by a summation of gaze perturbations produced by blinks during fixation and saccadic eye movements made without blinks. Our findings, especially the appearance of dynamic overshoots, suggest that blinks affect the central programming of saccades. These effects of blinks need to be taken into account during studies of the dynamic properties of saccades.

scholarly journals Effect of Putting Grip on Eye and Head Movements During the Golf Putting Stroke

2003 ◽  
Vol 3 ◽  
pp. 122-137 ◽  
Author(s):  
George K. Hung
Keyword(s):  
Eye Movements ◽  
Sampling Rate ◽  
Head Rotation ◽  
Head Movements ◽  
Experimental Session ◽  
Forward Stroke ◽  
Different Types ◽  
The Subject ◽  
The One ◽  
Head Rotations

The objective of this article is to determine the effect of three different putting grips (conventional, cross-hand, and one-handed) on variations in eye and head movements during the putting stroke. Seven volunteer novice players, ranging in age from 21 to 22 years, participated in the study. During each experimental session, the subject stood on a specially designed platform covered with artificial turf and putted golf balls towards a standard golf hole. The three different types of grips were tested at two distances: 3 and 9 ft. For each condition, 20 putts were attempted. For each putt, data were recorded over a 3-s interval at a sampling rate of 100 Hz. Eye movements were recorded using a helmet-mounted eye movement monitor. Head rotation about an imaginary axis through the top of the head and its center-of-rotation was measured by means of a potentiometer mounted on a fixed frame and coupled to the helmet. Putter-head motion was measured using a linear array of infrared phototransistors embedded in the platform. The standard deviation (STD, relative to the initial level) was calculated for eye and head movements over the duration of the putt (i.e., from the beginning of the backstroke, through the forward stroke, to impact). The averaged STD for the attempted putts was calculated for each subject. Then, the averaged STDs and other data for the seven subjects were statistically compared across the three grip conditions. The STD of eye movements were greater (p < 0.1) for conventional than cross-hand (9 ft) and one-handed (3 and 9 ft) grips. Also, the STD of head movements were greater (p < 0.1; 3 ft) for conventional than cross-hand and one-handed grips. Vestibulo-ocular responses associated with head rotations could be observed in many 9 ft and some 3 ft putts. The duration of the putt was significantly longer (p < 0.05; 3 and 9 ft) for the one-handed than conventional and cross-hand grips. Finally, performance, or percentage putts made, was significantly better (p <0.05; 9 ft) for cross-hand than conventional grip. The smaller variations, both in eye movements during longer putts and head movements during shorter putts, using cross-hand and one-handed grips may explain why some golfers, based on their playing experience, prefer these over the conventional grip. Also, the longer duration for the one-handed grip, which improves tempo, may explain why some senior players prefer the long-shaft (effectively one-handed grip) putter.

The influence of light on modulation of the human vestibulo-ocular reflex

2000 ◽  
Vol 10 (1) ◽  
pp. 51-55
Author(s):  
Vallabh E. Das ◽  
Stacy Yaniglos ◽  
R. John Leigh
Keyword(s):  
Eye Movements ◽  
Contact Lenses ◽  
Mental Arithmetic ◽  
Peak Velocity ◽  
Target Information ◽  
Stationary Target ◽  
Retinal Slip ◽  
Ocular Reflex ◽  
Vestibulo Ocular Reflex ◽  
Head Rotations

The goal of this study was to investigate the influence of light, without retinal slip information, on the ability to generate eye movements to compensate for head rotations. Subjects were rotated sinusoidally at 1.0, 2.0 or 3.0 Hz at a peak velocity of 30 deg/sec while they: 1) performed mental arithmetic in darkness; 2) attempted to view the remembered location of a stationary target in darkness; 3) attempted to view the remembered location of the stationary target through translucent contact lenses that allowed the passage of light but did not provide any target information (ganzfeld stimulus); 4) directly viewed the illuminated stationary target. The gain of compensatory eye movements was least while subjects viewed through the translucent contact lenses (median = 0.76), intermediate while subjects either performed mental arithmetic in darkness (median = 0.84) or attempted to view the remembered location of the target in darkness (median = 0.84), and greatest if they actually viewed the target (median = 0.95). Our findings suggest that factors other than light alone account for the increased gain of compensatory eye movements that occurs when subjects view rather than imagine a stationary target.

Quantitative assessment of self-treated canalith repositioning procedures using inertial measurement unit sensors

2021 ◽  
pp. 1-9
Author(s):  
Chiheon Kwon ◽  
Yunseo Ku ◽  
Shinhye Seo ◽  
Eunsook Jang ◽  
Hyoun-Joong Kong ◽  
...  
Keyword(s):  
Evaluation Criteria ◽  
Head Rotation ◽  
Large Error ◽  
Head Movements ◽  
The Self ◽  
Measurement Unit ◽  
Success Rates ◽  
Home Based ◽  
Epley Maneuver ◽  
Head Rotations

BACKGROUND: Low success and high recurrence of benign paroxysmal positional vertigo (BPPV) after home-based self-treated Epley and Barbeque (BBQ) roll maneuvers is an important issue. OBJECTIVE: To quantify the cause of low success rate of self-treated Epley and BBQ roll maneuvers and provide a clinically acceptable criterion to guide self-treatment head rotations. METHODS: Twenty-five participants without active BPPV wore a custom head-mount rotation monitoring device for objective measurements. Self-treatment and specialist-assisted maneuvers were compared for head rotation accuracy. Absolute differences between the head rotation evaluation criteria (American Academy of Otolaryngology guidelines) and measured rotation angles were considered as errors. Self-treatment and specialist-treated errors in maneuvers were compared. Between-trial variations and age effects were evaluated. RESULTS: A significantly large error and between-trial variation occurred in step 4 of the self-treated Epley maneuver, with a considerable error in the second trial. The cumulative error of all steps of self-treated BBQ roll maneuver was significantly large. Age effect occurred only in the self-treated BBQ roll maneuver. Errors in specialist-treated maneuvers ranged from 10 to 20 degrees. CONCLUSIONS: Real-time feedback of head movements during simultaneous head-body rotations could increase success rates of self-treatments. Specialist-treated maneuvers can be used as permissible rotation margin criteria.

Neuronal Responses Related to Smooth Pursuit Eye Movements in the Periarcuate Cortical Area of Monkeys

1998 ◽  
Vol 80 (1) ◽  
pp. 28-47 ◽  
Author(s):  
Masaki Tanaka ◽  
Kikuro Fukushima
Keyword(s):  
Eye Movements ◽  
Smooth Pursuit ◽  
Cortical Area ◽  
Eye Position ◽  
Smooth Pursuit Eye Movements ◽  
Neuronal Responses ◽  
Stationary Target ◽  
Pursuit Eye Movements ◽  
Preferred Direction ◽  
Eye Velocity

Tanaka, Masaki and Kikuro Fukushima. Neuronal responses related to smooth pursuit eye movements in the periarcuate cortical area of monkeys. J. Neurophysiol. 80: 28–47, 1998. To examine how the periarcuate area is involved in the control of smooth pursuit eye movements, we recorded 177 single neurons while monkeys pursued a moving target in the dark. The majority (52%, 92/177) of task-related neurons responded to pursuit but had little or no response to saccades. Histological reconstructions showed that these neurons were located mainly in the posterior bank of the arcuate sulcus near the sulcal spur. Twenty-seven percent (48/177) changed their activity at the onset of saccades. Of these, 36 (75%) showed presaccadic burst activity with strong preference for contraversive saccades. Eighteen (10%, 18/177) were classified as eye-position–related neurons, and 11% (19/177) were related to other aspects of the stimuli or response. Among the 92 neurons that responded to pursuit, 85 (92%) were strongly directional with uniformly distributed preferred directions. Further analyses were performed in these directionally sensitive pursuit-related neurons. For 59 neurons that showed distinct changes in activity around the initiation of pursuit, the median latency from target motion was 96 ms and that preceding pursuit was −12 ms, indicating that these neuron can influence the initiation of pursuit. We tested some neurons by briefly extinguishing the tracking target ( n = 39) or controlling its movement with the eye position signal ( n = 24). The distribution of the change in pursuit-related activity was similar to previous data for the dorsomedial part of the medial superior temporal neurons ( Newsome et al. 1988) , indicating that pursuit-related neurons in the periarcuate area also carry extraretinal signals. For 22 neurons, we examined the responses when the animals reversed pursuit direction to distinguish the effects of eye acceleration in the preferred direction from oppositely directed eye velocity. Almost all neurons discharged before eye velocity reached zero, however, only nine neurons discharged before the eyes were accelerated in the preferred direction. The delay in neuronal responses relative to the onset of eye acceleration in these trials might be caused by suppression from oppositely directed pursuit velocity. The results suggest that the periarcuate neurons do not participate in the earliest stage of eye acceleration during the change in pursuit direction, although most of them may participate in the early stages of pursuit initiation in the ordinary step-ramp pursuit trials. Some neurons changed their activity when the animals fixated a stationary target, and this activity could be distinguished easily from the strong pursuit-related responses. Our results suggest that the periarcuate pursuit area carries extraretinal signals and affects the premotor circuitry for smooth pursuit.

Effects of galvanic mastoid stimulation in seated human subjects

2009 ◽  
Vol 106 (3) ◽  
pp. 893-903 ◽  
Author(s):  
Z. Ghanim ◽  
J. C. Lamy ◽  
A. Lackmy ◽  
V. Achache ◽  
N. Roche ◽  
...  
Keyword(s):  
Human Subjects ◽  
Normal Subjects ◽  
Standing Position ◽  
Reflex Response ◽  
Emg Activity ◽  
Free Standing ◽  
Vestibular Response ◽  
Vestibular Reflex ◽  
Tendon Jerk ◽  
Biphasic Responses

The vestibular responses evoked by transmastoid galvanic stimulation (GS) in the rectified soleus electromyogram (EMG) in freely standing human subjects disappear when seated. However, a GS-induced facilitation of the soleus monosynaptic (H and tendon jerk) reflex has been described in few experiments in subjects lying prone or seated. This study addresses the issue of whether this reflex facilitation while seated is of vestibulospinal origin. GS-induced responses in the soleus (modulation of the rectified ongoing EMG and of the monosynaptic reflexes) were compared in the same normal subjects while freely standing and sitting with back and head support. The polarity-dependent biphasic responses in the free-standing position were replaced by a non-polarity-dependent twofold facilitation while seated. The effects of GS were hardly detectable in the rectified ongoing voluntary EMG activity, weak for the H reflex, but large and constant for the tendon jerk. They were subject to habituation. Anesthesia of the skin beneath the GS electrodes markedly reduced the reflex facilitation, while a similar, although weaker, facilitation of the tendon jerk was observed when GS was replaced with purely cutaneous stimulation, a tap to the tendon of the sternomastoid muscle, or an auditory click. The stimulation polarity independence of the GS-induced reflex facilitation argues strongly against a vestibular response. However, the vestibular afferent volley, insufficient to produce a vestibular reflex response while seated, could summate with the GS-induced tactile or proprioceptive volley to produce a startle-like response responsible for the reflex facilitation.

scholarly journals Tachyons but Not Photons Might Generate Conscious Dreams

2019 ◽  
Author(s):  
Ahmad Yousef
Keyword(s):  
Eye Movements ◽  
Visual Information ◽  
Human Subjects ◽  
Visual Awareness ◽  
Human Eye ◽  
Rapid Eye Movements ◽  
Cognitive Vision ◽  
Human Awareness

We had learnt from cognitive vision that involuntarily visual awareness should be generated by exogenous stimuli; but not indigenous! Given the complexity of understanding the reasons behind the rapid eye movements during vivid dreams; dreams that carry highly bizarre information; dreams that disallow the human subjects to have control over what they see; these types of dreams should be therefore reside under the umbrella of the “involuntary human awareness”. We therefore suggest possibilities of physical particles that could carry the visual information of these extraordinary exogenous stimuli; particles that should be able to invade the human’s eyes while they are closed; particles that have the ability to move the eye rapidly aiming for perfect transformation of the visual information. The present research aims to talk about these particles, proposes scenarios of how human eye &amp; retina deal with them.

scholarly journals Electrical Stimulation of the Frontal Eye Field in a Monkey Produces Combined Eye and Head Movements

2000 ◽  
Vol 84 (2) ◽  
pp. 1103-1106 ◽  
Author(s):  
Tyson A. Tu ◽  
E. Gregory Keating
Keyword(s):  
Electrical Stimulation ◽  
Eye Movements ◽  
Head Movements ◽  
Frontal Eye Field ◽  
Gaze Shifts ◽  
Gaze Shift ◽  
Eye Field ◽  
A Site ◽  
Head Rotations ◽  
Stimulation Of

The frontal eye field (FEF), an area in the primate frontal lobe, has long been considered important for the production of eye movements. Past studies have evoked saccade-like movements from the FEF using electrical stimulation in animals that were not allowed to move their heads. Using electrical stimulation in two monkeys that were free to move their heads, we have found that the FEF produces gaze shifts that are composed of both eye and head movements. Repeated stimulation at a site evoked gaze shifts of roughly constant amplitude. However, that gaze shift could be accomplished with varied amounts of head and eye movements, depending on their (head and eye) respective starting positions. This evidence suggests that the FEF controls visually orienting movements using both eye and head rotations rather than just shifting the eyes as previously thought.

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