BACKGROUND: Atopic keratoconjunctivitis (AKC) is a chronic eye disease with periods of exacerbations. Many patients experience no obvious seasonal variation, although a majority of patients are allergic to common airborne allergens. OBJECTIVE: To investigate the allergic reaction, to conjunctival provocation with airborne allergens, in patients with AKC. METHODS: Eleven patients ...

The most common families of mites found in house dust are Pyroglyphidae, Glycyphagidae and Acaridae; all are a source of many antigens responsible for allergic diseases. The aim of this study was to examine the seasonal dynamics of allergenic mite populations in dust samples collected from sleeping places in apartments ...

To assess connections between sleeping quality and hearing impairment due to prolonged exposure to industrial noise. Observational cross-sectional study. Occupational clinic of the Clalit Health Services in Israel. 298 male volunteers occupationally exposed to harmful noise, who had an audiometric examination performed by an occupational nurse as a part of ...

Purpose. The authors investigated whether pictures elicit superior response rates and eye movement dynamics on saccade and pursuit tasks than do dots or spots of light and whether the need for more interesting stimuli is age dependent. Methods. Using video eye tracking, horizontal eye movements were investigated in children and ...

Saccadic eye movements are driven by motor commands that are continuously modified so that errors created by eye muscle fatigue, injury, or-in humans-wearing spectacles can be corrected. It is possible to rapidly adapt saccades in the laboratory by introducing a discrepancy between the intended and actual saccadic target. Neurophysiological and ...

The visual system constantly utilizes regularities that are embedded in the environment and by doing so reduces the computational burden of processing visual information. Recent findings have demonstrated that probabilistic information can override attentional effects, such as the cost of making an eye movement away from a visual target (antisaccade ...

It has been suggested that space, time and number are represented on a common subjective scale. Saccadic eye movements provide a fascinating test. Saccades compress the perceived magnitude of spatial separations and temporal intervals to approximately half of their true value. The question arises as to whether saccades also compress ...

The location of motor-related activity in the deeper layers of the superior colliculus (SC) is thought to generate a desired displacement command specifying the amplitude and direction of saccadic eye movements. However, the amplitude of saccadic eye movements made to visual targets can be systematically altered by surreptitiously moving the ...

The delay between the signal to move the eyes, and the execution of the corresponding eye movement, is variable, and skewed; with an early peak followed by a considerable tail. This skewed distribution renders the answer to the question "What is the delay between language input and saccade execution?" problematic; ...

Although there is evidence to suggest visual illusions affect perceptual judgments more than actions, many studies have failed to detect task-dependant dissociations. In two experiments we attempt to resolve the contradiction by exploring the time-course of visual illusion effects on both saccadic eye movements and perceptual judgments, using the Judd ...

The oculomotor vermis (OMV) of the cerebellum is necessary for the generation of the accurate rapid eye movements called saccades. Large lesions of the midline cerebellar cortex involving the OMV cause saccades to become hypometric and more variable. However, saccades were not examined immediately after these lesions so the interpretation ...

Saccadic eye movements produce transient distortions in both space and time. Mounting evidence suggests that space and time perception are linked, and associated with the perception of another important perceptual attribute, numerosity. Here we investigate the effect of saccades on the perceived numerosity of briefly presented arrays of visual elements. ...

Even during active fixation, small eye movements persist that might be expected to interfere with vision. Numerous brain mechanisms probably contribute to discounting this jitter. Changes in the timing of responses in the visual thalamus associated with fixational saccades are considered in this study. Activity of single neurons in alert ...

Inhibition of Return (IOR, slower reaction times to previously cued or inspected locations) is observed both when eye movements are prohibited, and when the eyes move to the peripheral location and back to the centre before the target appears. It has been postulated that both effects are generated by a ...

Milner and Goodale's (1995) proposal of a functional division of labor between vision-for-perception and vision-for-action is supported by neuropsychological, brain-imaging, and psychophysical evidence. However, there remains considerable debate as to whether, as their proposal would predict, the effect of contextual illusions on vision-for-action can be dissociated from that on vision-for-perception. ...

Numerous studies have investigated the phenomenon of egocentric spatial updating in gaze-centered coordinates, and some have studied the use of allocentric cues in visually-guided movement, but it is not known how these two mechanisms interact. Here, we tested whether gaze-centered and allocentric information combine at the time of viewing the ...

An internal model for predictive saccades in frontal cortex was investigated by recording neurons in monkey frontal eye field (FEF) during an inferred motion task. Monkeys were trained to make saccades to the extrapolated position of a small moving target that was rendered temporarily invisible and whose trajectory was altered. ...

When an eye movement is prepared, attention is shifted toward the saccade end-goal. This coupling of eye movements and spatial attention is thought to be mediated by cortical connections between the FEFs and the visual cortex. Here, we present evidence for the existence of these connections. A visual discrimination task ...

A well-known eye movement paradigm combines saccades (fast eye movements) with a perceptual discrimination task. At a variable time after the onset of a central arrow cue indicating the target direction [the stimulus onset asynchrony (SOA)], discrimination symbols appear briefly at saccade target and non-target locations. A previous study revealed ...

The purpose of this study is to investigate the functional neural anatomy that generates vergence eye movement responses from predictive versus random symmetrical vergence step stimuli in humans and compare it to a similar saccadic task via the blood oxygenation level dependent signal from functional MRI. Eight healthy subjects participated ...

Anti-saccade performance, with strong contributions from frontal brain regions, reportedly deteriorates with age and maintenance of neck flexion and is known to cause brain activation. We investigated the effects of anti-saccade training on eye movement performance and frontal activity, and synergistic effects of training with neck flexion in the elderly. ...

In the present study, reaction time (RT) was measured in 12 healthy subjects in a saccade and antisaccade task while recording electroencephalographic activity (EEG) from 62 electrodes on the scalp. Event-related potentials averaged both on target appearance and on saccade onset were larger in amplitude (increased negativity) for the antisaccade ...

Background/aims Visually guided saccades and gaze-fixation ability were recorded in patients with early Parkinson's disease (PD). Methods Magnetic search coil system was used to measure horizontal and vertical eye positions. Results 'Staircase' visually guided saccades (multiple hypometric saccades separated by an intersaccadic interval) and 'staircase' square-wave jerks (SWJ) were present ...

It is widely assumed that intracranial recordings from the brain are only minimally affected by contamination due to ocular-muscle electromyogram (oEMG). Here we show that this is not always the case. In intracranial recordings from five surgical epilepsy patients we observed that eye movements caused a transient biphasic potential at ...

The pulvinar nucleus of the thalamus, with its connections to visual areas and to frontal and parietal oculomotor cortex, might serve as a nexus for integrating cortical control of voluntary eye movements with reflexive eye movements generated by the superior colliculus. To investigate this hypothesis, we tested five patients with ...

Why do movements take a characteristic amount of time, and why do diseases that affect the reward system alter control of movements? Suppose that the purpose of any movement is to position our body in a more rewarding state. People and other animals discount future reward as a hyperbolic function ...

Studies in 47 right-handed subjects with right and left leading eyes addressed the latent periods of visually-evoked saccades in the horizontal, vertical, and diagonal directions within the field of vision. Visual environments with three levels of temporospatial complexity and two standard time protocols of visual stimulation, with "gap" and "overlap," ...

With each eye movement, the image of the world received by the visual system changes dramatically. To maintain stable spatiotopic (world-centered) visual representations, the retinotopic (eye-centered) coordinates of visual stimuli are continually remapped, even before the eye movement is completed. Recent psychophysical work has suggested that updating of attended locations ...

Patients with multiple sclerosis commonly describe visual symptoms that result from several eye movement abnormalities that occur from disruption of critical pathways in the brainstem, cerebellum, and cerebral hemispheres. These abnormalities include internuclear ophthalmoplegia, ocular motor palsy, ocular misalignment, pathologic nystagmus, impaired saccades, saccadic intrusions, and impaired pursuit. Detailed knowledge ...

This analysis of time series of eye movements is a saccade-detection algorithm that is based on an earlier algorithm. It achieves substantial improvements by using an adaptive-threshold model instead of fixed thresholds and using the eye-movement acceleration signal. This has four advantages: (1) Adaptive thresholds are calculated automatically from the ...

Visual search can be made more efficient by adopting a passive cognitive strategy (i.e., letting the target "pop" into mind) rather than by trying to actively guide attention. In the present study, we examined how this strategic benefit is linked to eye movements. Results show that participants using a passive ...

Impairment of spatiotemporal visual processing is the hallmark of amblyopia, but its effects on eye movements during visuomotor tasks have rarely been studied. Here the authors investigate how visual deficits in anisometropic amblyopia affect saccadic eye movements. Thirteen patients with anisometropic amblyopia and 13 control subjects participated. Participants executed saccades ...

In an effort towards standardization, this paper evaluates the performance of five eye movement classification algorithms in terms of their assessment of oculomotor fixation and saccadic behavior. The results indicate that performance of these five commonly used algorithms vary dramatically even in the case of a simple stimulus evoked task ...

Saccadic suppression, a behavioral phenomenon in which perceptual thresholds are elevated before, during, and after saccadic eye movements, is an important mechanism for maintaining perceptual stability. However, even during fixation, the eyes never remain still, but undergo movements including microsaccades, drift, and tremor. The neural mechanisms for mediating perceptual stability ...

We constantly make eye movements to bring objects of interest onto the fovea for more detailed processing. Activity in area V4, a prestriate visual area, is enhanced at the location corresponding to the target of an eye movement. However, the precise role of activity in V4 in relation to these ...

OBJECTIVE: Recently, saccadic eye movement tasks have been used to assess the effects of nicotine on higher cognitive processes, including inhibitory control. Saccadic task switching methods suggest that there is prolonged inhibition of the saccadic eye movement system following antisaccade trials. The objective of this research was to examine effects ...

The path from perception to action involves the transfer of information across various reference frames. Here we applied a functional magnetic resonance imaging (fMRI) repetition suppression paradigm to determine the reference frame(s) in which the cortical activity is coded at several phases of the sensorimotor transformation for a saccade, including ...

Previously, we have shown that the reaction times (RTs) of exogenously generated saccadic eye movements decrease with an increase in the number of response alternatives (Lawrence et al. in J Vis 8(26):1-7, 2008; Lawrence and Gardella in Exp Brain Res 195(3):413-418, 2009). Because this pattern of RTs is in the ...

The Simon effect has most often been investigated with key-press responses and eye fixation. In the present study, we asked how the type of eye movement and the type of manual response affect response selection in a Simon task. We investigated three eye movement instructions (spontaneous, saccade, and fixation) while ...

Saccadic eye movements rapidly orient the line of sight towards the object of interest. Pre-motor burst neurons (BNs) controlling saccades receive excitation from superior colliculus and cerebellum, but inhibition by omnipause neurons (OPNs) prevents saccades. When the OPNs pause, BNs begin to fire. It has been presumed that part of ...

The optokinetic response (OKR) to a visual stimulus moving at constant velocity consists of a series of two alternating components, a slow phase, during which the eyes follow the stimulus, and a quick phase, which resets the eyes to begin a new response cycle. The quick phases of the OKR ...

Perceiving someone's averted eye-gaze is thought to result in an automatic shift of attention and in the preparation of an oculomotor response in the direction of perceived gaze. Although gaze cues have been regarded as being special in this respect, recent studies have found evidence for automatic attention shifts with ...

Saccadic adaptation maintains saccade accuracy and has been studied with the intrasaccadic target displacement procedure: displacing a target backwards (or forwards) during saccade execution gradually decreases (or increases) subsequent saccade amplitude. Adaptation has traditionally been studied with targeting saccades which bring the eyes onto a new object. Within-object saccades take ...

Changes in potential are known to occur in the orbital area during saccades. The sign of these changes depends on the position of the electrode and the direction of eye rotation, while their amplitude depends on the rotation angle. The patterns of potentials can be used to resolve the reverse ...

Spatial computations underlying the coordination of the hand and eye present formidable geometric challenges. One way for the nervous system to simplify these computations is to directly encode the relative position of the hand and the center of gaze. Neurons in the dorsal premotor cortex (PMd), which is critical for ...

The aim of the present study was to investigate how saccadic selection relates to people's awareness of the saliency and identity of a saccade goal. Observers were instructed to make an eye movement to either the most salient line segment (Experiment 1) or the only right-tilted element (Experiment 2) in ...

Eye movements during the reading of multi-line pages of texts were analyzed to determine the trajectory of reading saccades. The results of two experiments showed that the trajectory of the majority of forward-directed saccades was negatively biased, i.e., the trajectory fell below the start and end location of the saccadic ...

We present a model of the eye movement system in which the programming of an eye movement is the result of the competitive integration of information in the superior colliculi (SC). This brain area receives input from occipital cortex, the frontal eye fields, and the dorsolateral prefrontal cortex, on the ...

Studies in both humans and monkeys have indicated that blinks affect the central programming of saccades. In this study, we compared the influence of two types of reflex blinks on the trajectories and kinematics of memory-guided saccades in human subjects. We found that electrical stimulation of the supraorbital nerve shortly ...

We present a computational model and corresponding computer simulations that mimic phenomenologically the eye movement trajectories observed in a conjunctive visual search task. The element of randomness is captured in the model through a Monte Carlo selection of a particular eye movement based on its probability, which depends on three ...