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PubMed1983

[Equipment and technic allowing a quantitative study of pursuit eye movements and saccadic movements].

Study of following eye movements (posterior oculogyric pathway) and saccadic eye movements (anterior oculogyric pathway) represents the principal advance in nystagmography in the past ten years. Use as a visual stimulus of the LED bar developed by one of the authors (E.U.) has proved to be clinically easy and gave results identical to those of the reference stimulation system (laser + mobile mirror). It is possible to quantify performance and abnormalities of these two oculogyric pathways using parameters calculated: - either using a micro-computer (Aurelia); - or manually following a technique which the authors describe in detail indicating normal results and limits in their variations. These parameters for the foveal following system are gain and total movement. For the saccadic system, they are the maximum speed of the saccade, latent period and its accuracy. Using such quantitative analysis, it has become possible not only to draw a distinction between peripheral and central disorders, but also to describe different topographical groups: lesion of the cerebellopontine angle, cerebellar lesion, intrinsic lesion of the brain stem or parietal lesion. These different patterns are illustrated by examples.

Electronystagmography↗
PubMed2004

Interactions between eye movement systems in cats and humans.

Eye movements can be broadly classified into target-selecting and gaze-stabilizing eye movements. How do the different systems interact under natural conditions? Here we investigate interactions between the optokinetic and the target-selecting system in cats and humans. We use combinations of natural and grating stimuli. The natural stimuli are movies and pictures taken from the cat's own point of view with a head-mounted camera while it moved about freely in an outdoor environment. We superimpose linear global motion on the stimuli and use measurements of optokinetic nystagmus as a probe to study the interaction between the different systems responsible for controlling eye movements. Cats display higher precision stabilizing eye movements in response to natural pictures as compared to drifting gratings. In contrast, humans perform similarly under these two conditions. This suggests an interaction of the optokinetic and the pursuit system. In cats, the natural movies elicit very weak optokinetic responses. In humans, by contrast, the natural movie stimuli elicit effectively stabilizing eye movements. In both species, we find a unimodal distribution of saccades for all stimulus velocities. This suggests an early interaction of target-selecting and gaze-stabilizing saccades. Thus, we argue for a more integrated view in humans of the different eye movement systems.

Animals↗
PubMed1991

A note on eye movements and relaxation.

Eye movements and certain visual mechanisms appear to be related to states of relaxation and levels of wakefulness. The hatha yoga tradition in its historical and contemporary forms uses certain eye 'exercises' or postures to induce relaxation and reduce arousal. Visual correlates of the alpha state are well known. These phenomena may be involved in the success of the new eye desensitization procedure.

Eye Movements↗
PubMed2000

Uncompetitive stimulation of rat brain Na-K ATPase activity by rapid eye movement sleep deprivation.

Rapid eye movement sleep deprivation is associated with an increase in Na-K ATPase activity. In order to understand the possible biochemical mechanism of this increase, the kinetics of Na-K ATPase was studied. Although the enzyme activity increased after the deprivation, the catalytic efficiency of the enzyme remained unaltered. The rapid eye movement sleep deprivation increased both the Vmax and the Km suggesting an uncompetitive stimulation of the enzyme. While increase in norepinephrine resulted in an increased Vmax, that of calcium increased the Km. Since an increase in norepinephrine has been suggested after deprivation, the increased Vmax is attributed to increased norepinephrine level following deprivation. However, since rapid eye movement sleep deprivation is reported to be associated with a decrease in calcium levels, the increase in Km following deprivation may be attributed to changes in factor(s) other than calcium.

Adenosine Triphosphate↗
PubMed2005

Dissociated eye movements: a clinical study.

CONCLUSIONS: Dissociation of eye movements is an important sign of functional or organic lesions of the central vestibular system. Qualitative differences in the movements of each eye appear to be more serious than quantitative differences. OBJECTIVE: To determine the significance of dissociated nystagmus in neurotological diagnosis. MATERIAL AND METHODS: Eye movements were recorded separately for each eye during the neurotological examination of patients with a suspicion of central vestibular system involvement. RESULTS: Of 137 patients, 38 had quantitative dissociation of eye movements and 59 had qualitative differences. A total of 66/137 patients had abnormal MRI scans: 55 of these patients presented dissociated eye movements and only 39 had other signs of central vestibular involvement.

Adolescent↗
PubMed1994

Effect of aging on smooth pursuit eye movement.

Examination of smooth pursuit eye movement is useful for detecting central nervous system disorders. It is important to take patient's age into consideration when evaluating smooth pursuit eye movement. The purpose of the present study was to clarify the effect of aging on smooth pursuit eye movement. Thirty healthy volunteers (three groups of 10 volunteers, in their fifties, sixties, and seventies and over, respectively) served as subjects, and 10 healthy young volunteers (23 to 33 years old: mean age 26) served as controls. The pursuit target was driven by sinusoidal waveform with various amplitudes and frequencies. Target peak velocities ranged from 12.6 to 94.2 degrees/s. Eye movement signals were recorded d.c. EOG and pursuit gain (ratio of eye peak velocity to target peak velocity) was measured by a computer. Pursuit gain decreased with increasing target frequency and velocity in all age groups. This tendency was more remarkable in the older groups than in the young controls; in particular, it was more frequently seen at a frequency of 0.5 Hz. On the other hand, there was no significant relationship between pursuit gain and the target amplitude. In the group in their seventies and over, pursuit gain was saturated at about 60 degrees/s.

Adult↗
PubMed1978

Cognitive style and lateral eye movements.

The lateral eye movement paradigm was employed to test the hypothesis that narrow categorizers, who are believed to be more analytic in information processing, make characteristic use of the left hemisphere, while broad categorizers, being more holistic, depend more on the right hemisphere. Data for narrow categorizers confirmed the hypothesis in that they tended to produce a majority of right shifts. Results from broad categorizers turned out to be less clear, although there was a tendency in the direction of left eye shift. Additionally, narrow categorizers made significantly more total LEMs than did broad categorizers. The results are discussed in terms of cerebral specialization underlying cognitive style.

Cognition↗
PubMed2005

The role of prosody in the interpretation of structural ambiguities: a study of anticipatory eye movements.

An eye-tracking experiment examined whether prosodic cues can affect the interpretation of grammatical functions in the absence of clear morphological information. German listeners were presented with scenes depicting three potential referents while hearing temporarily ambiguous SVO and OVS sentences. While case marking on the first noun phrase (NP) was ambiguous, clear case marking on the second NP disambiguated sentences towards SVO or OVS. Listeners interpreted case-ambiguous NP1s more often as Subject, and thus expected an Object as upcoming argument, only when sentence beginnings carried an SVO-type intonation. This was revealed by more anticipatory eye movements to suitable Patients (Objects) than Agents (Subjects) in the visual scenes. No such preference was found when sentence beginnings had an OVS-type intonation. Prosodic cues were integrated rapidly enough to affect listeners' interpretation of grammatical function before disambiguating case information was available. We conclude that in addition to manipulating attachment ambiguities, prosody can influence the interpretation of constituent order ambiguities.

Cognition↗
PubMed2000

[Three-dimensional analysis of eye movements induced by roll and pitch tilt].

The torsional eye movements induced by the right and left ear-down position are known as "ocular counter-rolling" but the mechanism of the horizontal and vertical eye movements has not been clarified. The vertical eye movements induced by backward tilt are known as the "doll reflex", but clear eye movements are induced by forward tilt. The mechanism of horizontal and torsional eye movements are unclear. To detect 3D eye movements in the roll and pitch planes, we performed 3D analysis of eye movements by our video-oculographic method. During roll tilt, counter-torsional eye movements were clearly induced, but no definite, eye movements were observed in the horizontal and vertical components of eye movements. During pitch tilt, downward eye movements were observed following backward tilt, but no clear eye movements were observed following forward tilt. Moreover, no clear horizontal or torsional eye movements were observed during pitch tilt. These results suggest that the response to pitch tilt depends on the saccular input.

Adult↗
PubMed1992

A methodological critique of the current status of eye movement desensitization (EMD).

Eye Movement Desensitization (EMD) has been recently advocated as a rapid treatment for the elimination of traumatic memories responsible for the maintenance of a number of anxiety disorders and their clinical correlates. Despite a limited conceptual framework, EMD has attracted considerable interest among clinicians and researchers. The popularity and interest generated by EMD will likely result in wide usage. We present a methodological critique of it with reference to assessment, treatment outcome, and treatment process. We also provide guidelines for judging the methodological adequacy of research on EMD and suggest intensive research to assess effectiveness, treatment components, and comparisons with other procedures.

Anxiety Disorders↗
PubMed1968

Operant control of eye movements.

In a monitoring situation eye movements were required in order for signals to be presented. Detection of signals was the reinforcement. A multiple schedule of fixed-interval reinforcement, differential reinforcement of low rate, and fixed-ratio reinforcement was established for eye movements. Results demonstrated that an eye movement can act as an operant controlled by its consequences. Operant control of eye movements has important implications for human factor analysts concerned with "attention".

Journal Article↗
PubMed1990

[Study of disorders of speech and thinking in schizophrenia by recording eye movements during reading].

Eye movements (EM) were recorded during reading in 16 patients with continuous schizophrenia of long (9 to 35 years) standing. EM in patients were found to differ materially from those in normals. Two pathological forms (strategies) of successive text review were revealed. As far as the first strategy is concerned, it is characterized by the predominance of disorganization of perceptive motor reading automatism. As to the second one, the reading automatism is on the whole retained but demonstrates the signs of stereotypy, loss of motivation to realization of the operations of control and adequate adaptive rearrangement. It is concluded that speech and thinking disorders formed as a result of long schizophrenia are pathogenetically non-uniform and reflect nonspecific regularities of psychotic responsiveness.

Adult↗
PubMed1996

Influence of foveal afterimage on non-visually induced pursuit eye movements.

Smooth pursuit eye movements (SPEMs) were measured during trials with an acoustic target, a somatosensory target (finger tip), and an imaginary target. Under these non-visual conditions the induced SPEMs were investigated both with and without a foveal afterimage. Ten normal subjects were examined. Considerable inter-individual differences were observed in performance of the non-visual SPEMs. However, the presence of an afterimage did not influence SPEMs during acoustic or somatosensory pursuit. It is concluded that the capacity for "visualization" may not involve the ability for non-visual SPEMs. As in imaginary target condition the subjects could not elicit SPEM without the afterimage, clearly the memory of target motion alone cannot generate SPEMs. The afterimage may help the subject to convert the memory of target motion into the perception of virtual target motion.

Acoustic Stimulation↗
PubMed2003

Effects of syntactic category assignment on lexical ambiguity resolution in reading: an eye movement analysis.

Readers' eye movements were monitored as they read sentences containing lexically ambiguous words whose meanings share a single syntactic category (e.g., calf), lexically ambiguous words whose meanings belong to different syntactic categories (e.g., duck), or unambiguous control words. Information provided prior to the target always unambiguously specified the context-appropriate syntactic-category assignment for the target. Fixation times were longer on ambiguous words whose meanings share a single syntactic category than on controls, both when prior context was semantically consistent with the subordinate interpretation of a biased ambiguous word (Experiment 1) and when prior context was semantically neutral as to the intended interpretation of a balanced ambiguous word (Experiment 2). These ambiguity effects, which resulted from differences in difficulty with meaning resolution, were not found when the ambiguity crossed syntactic categories. These data indicate that, in the absence of syntactic ambiguity, syntactic-category information mediates the semantic-resolution process.

Eye Movements↗
PubMed2005

Early and late processes in syllogistic reasoning: evidence from eye-movements.

An eye-movement monitoring experiment was carried out to examine the effects of the difficulty of the problem (simple versus complex problems) and the type of figure (figure 1 or figure 4) on the time course of processing categorical syllogisms. The results showed that the course of influence for these two factors is different. We found early processing effects for the figure but not for the difficulty of the syllogism and later processing effects for both the figure and the difficulty. These results lend support to the Model Theory (Johnson-Laird, P. N., Byrne, R. M. J. (1991). Deduction. Hillsdale, New Jersey: LEA.) as opposed to other theories of reasoning (Chater, N., Oaksford, M. (1999). The probability heuristics model of syllogistic reasoning. Cognitive Psychology, 38, 191-258; Rips, L. J. (1994). The psychology of proof. Cambridge, MA: MIT Press; Rips, L. J. (1994). The psychology of proof. Cambridge, MA: MIT Press).

Cognition↗
PubMed1980

Phasic tongue movements in human rapid eye-movement sleep.

Polygraphic recordings demonstrated complex tongue movements as unusual phasic phenomena during rapid-eye-movement (REM) sleep in patients with narcolepsy, sleep apnea syndrome, or posterior fossa lesions, and in normal controls. These tongue movements may counteract posterior displacement of the tongue to prevent obstructive sleep apnea, which may otherwise occur in REM sleep because of genioglossal hypotonia. Hypotonia affected not only the genioglossus but also other muscles innervated by pontomedullary neurons during non-REM-sleep-related apnea in patients with sleep apnea syndrome.

Adult↗
PubMed1987

Effect of eye movements on dynamic equilibrium.

The purpose of this study was to determine whether visual improvement of balance varies depending on the movement of the eye. Three movements were compared: static visual fixations, saccadic eye movements, and smooth pursuit eye movements. The subjects in this study were 35 healthy female volunteers. Balance was defined as the subjects' ability to maintain their equilibrium while keeping the unstable platform on which they stood within 5 degrees of the horizontal plane. The testing protocol consisted of five recorded practice trials, during which the subjects tried to maintain their balance without any visual instructions, and nine experimental trials, during which they tried to maintain their balance while visually following a videotaped target light projected onto a screen. The target light was sequenced randomly to remain stationary, move in a continuous horizontal path, or alternately jump between right and left. Data were analyzed using a one-way multivariate analysis of variance for repeated measures. A significant effect of vision on balance was found. The t tests for correlated samples revealed that time in balance during visual fixations and saccades was significantly longer than during tracking eye movements. We, therefore, concluded that tracking eye movements have a negative effect on balance. This information can be useful in treating patients with balance problems. For example, instructing patients to fixate visually on an object may aid their stability. Visual tracking of a moving limb, however, may impair a patient's stability.

Adolescent↗
PubMed1996

Suppression of motion-produced smear during smooth pursuit eye movements.

Humans make smooth tracking eye movements to keep the image of a moving target on the foveal region of the retina and, thereby, maintain acute vision. Although the images of physically stationary background stimuli sweep across the retina during smooth pursuit eye movements, non-pursued targets are usually perceived to be neither moving nor smeared. The lack of perceived movement of background stimuli is generally attributed to a 'cancellation' of the retinal image motion by extraretinal information about the eye movement [1,2]; this information comes primarily from a neural facsimile of the efferent command to move the eyes, augmented by afferent signals from receptors in the extraocular muscles [3,4]. Here, we show that a physically stationary target presented during smooth tracking is perceived to have considerably less smear than a target that moves comparably across the retina, but when the eye is stationary. This result implies that extraretinal signals for pursuit eye movements also contribute to the alleviation of perceived smear for non-tracked, background targets.

Eye Movements↗