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At least 91 records · Page 5Linked to original sources
PubMed1977

Saccadic eye movements and eye-head coordination in children.

The eye and head movements of nine children, ages 6 through 10, were measured in order to establish quantitative characteristics of eye movements and eye-head corrdination patterns of children with normal vision and reading levels. The relationship between saccade amplitude and duration was linear, but the slope of this relationship indicated that saccades in children may have higher velocities than they do in adults. One of three temporal patterns of head and saccadic eye movement occurred during shifts of gaze to visual targets, depending on the temporal and spatial predictability of the target. It is suggested that quantitative measurements such as these could be used to examine developmental characteristics of eye and eye-head movement control.

Child↗
PubMedDate not supplied

Disturbances in the control of saccadic eye movement and eye-head coordination in schizophrenics.

Some schizophrenic patients have been known to have frontal cortical dysfunction. In view of the evidence that voluntary purposive eye movements and rapid head movements involve areas of the frontal cortex, investigations of saccade performance have been carried out on schizophrenics in various laboratories. We have compared performance of schizophrenic patients in tasks involving inhibition of reflexive saccades (no-saccade) and initiation of saccades without target (memory-saccade) with performance in the antisaccade task. These measures were also compared with results of eye-head coordination tasks. Schizophrenics showed more errors and significantly longer latencies, with lower peak velocities at large amplitudes, in both the antisaccade task and the memory-saccade task. Performance with coordinated eye-head movement was basically similar, except for significantly longer latencies of head movement. These results suggest that schizophrenics may have a disturbance in initiating and executing purposive saccades without targets, and that dysfunction of the frontal cortex may contribute to this disturbance.

Adolescent↗
PubMed1988

The effects of emotion and ocular dominance on lateral eye movement.

Lateral eye movements (LEMs) in response to emotional and nonemotional instructions were examined. For the emotional task, a new procedure is utilized which requires subjects to generate emotional images of positive and negative valence in auditory, visual and tactile modalities. Forty-four normal adult males and females (22 right-handers, 22 left-handers) participated in the experiment. Overall, subjects looked significantly more to the left than to the right in response to emotional instructions, suggesting greater right hemisphere involvement in the generation of emotional images. The same subjects showed no directional bias in response to nonemotional instructions. Although gender, handedness and familial sinistrality did not mediate the direction of eye movements, ocular dominance had an effect. For left-handed subjects, the direction of eye movements to nonemotional instructions was consistent with eyedness, e.g., right-eyed subjects produced right-sided LEMs, and left-eyed subjects produced left-sided LEMs.

Adult↗
PubMed1985

Effects of subject-to-experimenter distance and instructions on lateral eye movement.

Lateral eye movements and heart rate were recorded as 32 right-handed men answered verbal and spatial questions. Experimenter-to-subject distance (.8 and 1.5 m) and attention demand of instructions were manipulated in a 2 X 2 design. A significant main effect for distance and an interaction of distance by instructions appeared on the direction of eye movements independent of type of question. The greatest number of leftward eye movements occurred at the short distance with instructions demanding higher attention. These findings are consistent with evidence that emotional arousal produces greater right- than left-hemisphere activation.

Anxiety↗
PubMed1980

Deficits in eye movements following frontal eye-field and superior colliculus ablations.

1. This study investigated the effects of frontal eye-field and superior colliculus ablations on fixation patterns and saccadic eye movements. Monkeys were trained to pick apple pieces out of a multiple-slotted apple board while their heads were fixed. Eye movement records were obtained using predominantly the implanted search-coil method. 2. Both unilateral and bilateral frontal eye-field lesions produced only temporary deficits in eye movements. Following surgery monkeys tended to neglect the contralateral peripheral visual field and made fewer saccades to peripheral targets. Recovery was virtually completed in 2-4 wk. 3. Superior colliculus ablation reduced fixation accuracy, saccade frequency, and saccade velocity. These deficits showed little recovery with time. 4. Paired frontal eye-field and superior colliculus lesions produced dramatic deficits in visually triggered eye movements. Animals could no longer fixate their eyes on visual targets with any degree of accuracy. The range of eye movements was greatly reduced, as was the frequency and velocity of saccades. These deficits showed little recovery with time. 5. These results suggest that visually triggered saccadic eye movements are controlled by two parallel channels, one involving the superior colliculus and the other the frontal eye field.

Animals↗
PubMed1999

Motoric response inhibition in finger movement and saccadic eye movement: a comparative study.

OBJECTIVE: To study cortical potentials associated with suppression of intended motoric actions. METHODS: Electro-encephalographic activity was recorded in a Go/NoGo reaction time paradigm. Subjects viewed computer-generated pacing stimuli, which provided information concerning the time at which an imperative Go/NoGo signal occurred. A motoric response was required following Go stimuli while motoric response inhibition was required following NoGo stimuli. To examine whether previously reported 'Go/NoGo effects' on event related potential (ERP) components may be generalized across movement modalities, the present experimental paradigm was performed with either finger movement or saccadic eye movement as required motoric response. RESULTS: For both movement modalities, comparable differences in the morphology, amplitude and scalp topography of ERP components were observed between Go trials, with proper movement execution, and NoGo trials, with complete suppression of motoric activity. In addition, for either movement modality a similar 'error related negativity' (ERN) was found for NoGo trials in which motoric activity was present. CONCLUSIONS: The results of the present study suggest that cortical activity underlying the Go/NoGo differences in ERP components represent general cortical processing associated with detection and/or suppression of inappropriate response behaviour, independent of movement modality.

Adult↗
PubMed1995

Imaginary gaze effects on eye movements induced by linear acceleration: involvement of vestibular induced smooth pursuit eye movement.

We investigated smooth eye movements elicited i) by linear acceleration in a space-fixed imaginary gaze condition (smooth component of eye movement induced by linear motion: LSEM) and ii) during acoustic pursuit of a moving sound source (smooth component of eye movement induced by acoustic pursuit of a sound source: SSPEM). The two conditions were examined using the same test subjects. LSEM and SSPEM performance was found to be positively correlated across the subject population. From the comparison of LSEM and SSPEM we propose the following hypothesis: LSEM consists not only of a pure translational vestibular-ocular reflex (tVOR) component but also of a component based on the perception of otolithic information. Accordingly, this second component is instrumental in the pursuit of an imaginary visual target during linear self-motion.

Acceleration↗
PubMed1979

Eye movements associated with eye closure. II. Down turning of eye ball elevation.

DC recordings of horizontal and vertical eye movements of various neurological patients were made in an attempt to specify the mechanism underlying sustained eye ball elevation associated with eye closure. Sudden or gradual down turning of vertical eye ball elevation was seen in the following groups: (1) acute stage of inner ear hypo- or afunction; (2) lateral lesions of the cerebellum; (3) acute stage of cerebellar inflammation, and (4) some cases of cerebral lesions. The following pathway seems to be the simplest which would account for these findings: anterior semicircular canal leads to superior vestibular nucleus leads to brachium conjunctivum leads to oculomotor nucleus leads to superior rectus muscle (ipsilateral) and inferior oblique muscle (contralateral).

Adult↗
PubMed1996

Functionally defined smooth and saccadic eye movement subregions in the frontal eye field of Cebus monkeys.

1. Intracortical microstimulation was used to localize and define the smooth and saccadic eye movement subregions of the frontal eye field (FEF) and the supplementary eye field (SEF) in nine hemispheres of six Cebus apella monkeys and to map the hand/arm areas in the dorsal premotor area and other adjacent areas in five hemispheres of three C. apella monkeys. Monkeys were anesthetized during experiments with Telazol, a dissociative agent that has no significant effect on microstimulation-induced eye movement parameters (current threshold, velocity, and duration). The functional subregions were defined with the use of low threshold current (< or = 50 microA). Electrically elicited eye movements were videotaped and quantified. The two types of eye movements were clearly distinguished by their significantly different duration and velocity (P < 0.0001) and their different responses to long stimulus trains. 2. The saccadic subregion of the FEF in Cebus monkeys is in the same location as in macaque monkeys (Walker's areas 8a and 45). Most of the functional and anatomic characteristics of the saccadic subregion of Cebus are the same as those reported in the saccadic FEF subregion of macaque monkeys. 3. A subregion in which only smooth eye movements were evoked was found in the posterior shoulder of the superior arcuate sulcus near its medial tip. A band of inexcitable cortex separated the SEF and this smooth eye movement subregion of the FEF. This supports the proposal that the smooth eye movement subregion is independent of the SEF but is analogous to the saccadic subregion of the FEF. The existence of two subregions of the FEF was further confirmed by single-unit recording results. It is proposed that the smooth eye movement subregion in Cebus monkeys may be comparable with the one described in macaque monkeys. 4. Both saccadic and smooth eye movements were also reliably evoked in the SEF in each hemisphere studied. This result strongly indicates that the SEF is concerned with not only saccadic eye movements, as previously reported, but also with smooth (pursuit) eye movements.

Animals↗
PubMed2004

Dreaming during non-rapid eye movement sleep in the absence of prior rapid eye movement sleep.

STUDY OBJECTIVES: There is a long-standing controversy surrounding the existence of dream experiences during non-rapid eye movement (NREM) sleep. Previous studies have not answered the question whether this "NREM dream" originates from the NREM sleep mechanism because the subject might simply be recalling experiences from the preceding rapid eye movement (REM) sleep. METHODS: We scheduled 11 healthy men to repeat 20-minute nap trials separated by 40-minute periods of enforced wakefulness across a period of 3 days. At the end of the nap trial, each participant answered questions regarding the formal aspects of his dream experiences during the nap trial, using the structured interviews. RESULTS: We obtained a total of 172 dream reports after naps containing REM sleep (REM naps) and 563 after naps consisting of only NREM sleep (NREM naps). Dream reports from NREM naps were less remarkable in quantity, vividness, and emotion than those from REM naps and were obtained more frequently during the morning hours when the occurrences of REM sleep were highest. CONCLUSIONS: These results suggest that the polysomnographic manifestations of REM sleep are not required for dream experiences but that the mechanisms driving REM sleep alter experiences during NREM sleep in the morning. A subcortical activation similar to REM sleep may occur in human NREM sleep during the morning when REM sleep is most likely to occur, resulting in dream experiences during NREM sleep.

Adult↗
PubMed1978

Saccades induced by stimulation of the frontal eye fields: interaction with voluntary and reflexive eye movements.

Saccadic eye movements were evoked in alert monkeys by electrical stimulation of the frontal eye fields (FEF). The interaction of FEF movements with voluntary saccades, pursuit, and vestibular nystagmus (VN) was examined. An FEF saccade in one direction could be evoked as little as 10 msec after the onset of a natural rapid movement (saccade, fast phase of VN) in the opposite direction. Thus, refractory periods between similar eye movements are directionally specific. The frequency of evoked FEF saccades following natural slow movements (pursuit, slow phase of VN) in either direction was reduced as though saccade thresholds were elevated. The FEF appears capable of modulating any ongoing eye movement.

Animals↗
PubMed1985

Effects of induced anxiety and question content on the direction and frequency of lateral eye movements.

Lateral eye movements were recorded electrically as 39 right-handed adults attempted to answer 48 questions that had been rated for anxiety content, visual imagery and difficulty. Subjects were assigned randomly to either a high or low anxiety treatment group. The anxiety treatment increased ocular motility and visuospatial questioning decreased motility, but neither variable had a significant effect on the direction to which the eyes were moved. The anxiety content of questions affected neither the number nor direction of gaze shifts. The results fail to support previous claims that lateral eye movements reflect the cerebral lateralization of emotion.

Adolescent↗
PubMed1986

Threshold perception and saccadic eye movements.

Involuntary eye movements were recorded during threshold detection tasks under various experimental conditions. The data were analyzed for interdependencies between stimulus parameters, detection performance, and oculomotor behaviour. The data demonstrate that under certain conditions, saccadic parameters are adaptive to specific stimulus properties. Further, the data suggest that for stationary patterns with low spatial frequencies and for gratings flickering with high temporal frequencies, detection is facilitated considerably by the occurrence of a saccadic eye movement. These facilitation effects are consistent with the predictions of a theoretical model presented in a previous paper.

Eye Movements↗
PubMed2004

Influence of lossy compression on eye movement signals.

Eye movements considered in our research are physiological signals that are measured in otoneurological balance tests. They are also investigated in other areas of medicine and in psychology. When great amounts of signals are measured in clinical and research work, signal compression is of great use in storing measurements for later investigations. In this research we assessed the influence of lossy compression on medically interesting parameter values that are computed from eye movement signals. We found that high compression ratios with bit rates lower than 1.5 bits per sample on signals with an original resolution of 13 bits per sample produced results without significant changes to the medical parameters values.

Data Compression↗