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Journal of Neurology Sep 2019Gaze stabilisation exercises are a mainstay of vestibular rehabilitation (VR). They are frequently prescribed to patients with vestibular hypofunction with the aim of... (Review)
Review
Gaze stabilisation exercises are a mainstay of vestibular rehabilitation (VR). They are frequently prescribed to patients with vestibular hypofunction with the aim of improving the gain of the vestibular ocular reflex, improving visual acuity during head movement, and reducing the symptoms of dizziness and vertigo. This review will examine current evidence that has evaluated the efficacy of gaze stabilisation exercises on VOR gain, dynamic visual acuity and oscillopsia. In addition, recent experimental studies that have employed digital technologies and newer forms of gaze stabilisation exercises will be reviewed. The implications for future clinical practice and research in the area of VR will be discussed.
Topics: Exercise Therapy; Fixation, Ocular; Head Movements; Humans; Reflex, Vestibulo-Ocular; Vestibular Diseases; Vestibule, Labyrinth
PubMed: 31385017
DOI: 10.1007/s00415-019-09459-x -
Annual Review of Vision Science Sep 2023As we navigate and behave in the world, we are constantly deciding, a few times per second, where to look next. The outcomes of these decisions in response to visual... (Review)
Review
As we navigate and behave in the world, we are constantly deciding, a few times per second, where to look next. The outcomes of these decisions in response to visual input are comparatively easy to measure as trajectories of eye movements, offering insight into many unconscious and conscious visual and cognitive processes. In this article, we review recent advances in predicting where we look. We focus on evaluating and comparing models: How can we consistently measure how well models predict eye movements, and how can we judge the contribution of different mechanisms? Probabilistic models facilitate a unified approach to fixation prediction that allows us to use explainable information explained to compare different models across different settings, such as static and video saliency, as well as scanpath prediction. We review how the large variety of saliency maps and scanpath models can be translated into this unifying framework, how much different factors contribute, and how we can select the most informative examples for model comparison. We conclude that the universal scale of information gain offers a powerful tool for the inspection of candidate mechanisms and experimental design that helps us understand the continual decision-making process that determines where we look.
Topics: Fixation, Ocular; Eye Movements
PubMed: 37419107
DOI: 10.1146/annurev-vision-120822-072528 -
The Journal of Neuroscience : the... Feb 2022Omnipause neurons (OPNs) in the nucleus raphe interpositus have tonic activity while the eyes are stationary ("fixation") but stop firing immediately before and during...
Omnipause neurons (OPNs) in the nucleus raphe interpositus have tonic activity while the eyes are stationary ("fixation") but stop firing immediately before and during saccades. To locate the source of suppression, we analyzed synaptic inputs from the rostral and caudal superior colliculi (SCs) to OPNs by using intracellular recording and staining, and investigated pathways transmitting the inputs in anesthetized cats of both sexes. Electrophysiologically or morphologically identified OPNs received monosynaptic excitation from the rostral SCs with contralateral dominance, and received disynaptic inhibition from the caudal SCs with ipsilateral dominance. Cutting the tectoreticular tract transversely between the contralateral OPN and inhibitory burst neuron (IBN) regions eliminated inhibition from the caudal SCs, but not excitation from the rostral SCs in OPNs. In contrast, a midline section between IBN regions eliminated disynaptic inhibition in OPNs from the caudal SCs but did not affect the monosynaptic excitation from the rostral SCs. Stimulation of the contralateral IBN region evoked monosynaptic inhibition in OPNs, which was facilitated by preconditioning SC stimulation. Three-dimensional reconstruction of HRP-stained cells revealed that individual OPNs have axons that terminate in the opposite IBN area, while individual IBNs have axon collaterals to the opposite OPN area. These results show that there are differences in the neural circuit from the rostral and caudal SCs to the brainstem premotor circuitry and that IBNs suppress OPNs immediately before and during saccades. Thus, the IBNs, which are activated by caudal SC saccade neurons, shut down OPN firing and help to trigger saccades and suppress ("latch") OPN activity during saccades. Saccades are the fastest eye movements to redirect gaze to an object of interest and bring its image on the fovea for fixation. Burst neurons (BNs) and omnipause neurons (OPNs) which behave reciprocally in the brainstem, are important for saccade generation and fixation. This study investigated unsolved important questions about where these neurons receive command signals and how they interact for initiating saccades from visual fixation. The results show that the rostral superior colliculi (SCs) excite OPNs monosynaptically for fixation, whereas the caudal SCs monosynaptically excite inhibitory BNs, which then directly inhibit OPNs for the initiation of saccades. This inhibition from the caudal SCs may account for the omnipause behavior of OPNs for initiation and maintenance of saccades in all directions.
Topics: Animals; Brain Stem; Cats; Female; Fixation, Ocular; Inhibitory Postsynaptic Potentials; Male; Microelectrodes; Nerve Net; Saccades; Superior Colliculi; Synaptic Potentials
PubMed: 34880121
DOI: 10.1523/JNEUROSCI.1731-21.2021 -
Journal of Binocular Vision and Ocular... 2019The use of inverse occlusion and pleoptics came into favor in Europe and then in North America in the late 1940's, and fell out of favor less than 25 years later....
The use of inverse occlusion and pleoptics came into favor in Europe and then in North America in the late 1940's, and fell out of favor less than 25 years later. Introduced as a method of promoting foveal fixation, and improving binocularity and vision in cases of eccentric fixation, it did not outperform conventional occlusion prescribed at an earlier age.In this issue, Godts and Mathysen provide a case series of 11 contemporary patients treated with inverse occlusion after patching failure. In response, this article reviews the procedures and goals of inverse occlusion and pleoptics using the historic information available, in attempt to ascertain whether there is an indication for renewing their use.
Topics: Amblyopia; Europe; Fixation, Ocular; Humans; North America; Orthoptics
PubMed: 31697193
DOI: 10.1080/2576117X.2019.1662250 -
Journal of Pediatric Ophthalmology and... 2022
Topics: Humans; Fixation, Ocular
PubMed: 35611827
DOI: 10.3928/01913913-20220314-03 -
IEEE Transactions on Visualization and... May 2020Optimizing rendering performance is critical for a wide variety of virtual reality (VR) applications. Foveated rendering is emerging as an indispensable technique for...
Optimizing rendering performance is critical for a wide variety of virtual reality (VR) applications. Foveated rendering is emerging as an indispensable technique for reconciling interactive frame rates with ever-higher head-mounted display resolutions. Here, we present a simple yet effective technique for further reducing the cost of foveated rendering by leveraging ocular dominance - the tendency of the human visual system to prefer scene perception from one eye over the other. Our new approach, eye-dominance-guided foveated rendering (EFR), renders the scene at a lower foveation level (with higher detail) for the dominant eye than the non-dominant eye. Compared with traditional foveated rendering, EFR can be expected to provide superior rendering performance while preserving the same level of perceived visual quality.
Topics: Adolescent; Adult; Algorithms; Computer Graphics; Dominance, Ocular; Eye-Tracking Technology; Female; Fixation, Ocular; Humans; Male; Smart Glasses; User-Computer Interface; Virtual Reality; Visual Perception; Young Adult
PubMed: 32086213
DOI: 10.1109/TVCG.2020.2973442 -
Journal of Physiological Anthropology Sep 2020Saccadic eye movements can allude to emotional states and visual attention. Recent studies have shown that microsaccadic responses (i.e., small fixational eye movements)... (Review)
Review
Saccadic eye movements can allude to emotional states and visual attention. Recent studies have shown that microsaccadic responses (i.e., small fixational eye movements) reflect advanced brain activity during attentional and cognitive tasks. Moreover, the microsaccadic activity related to emotional attention provides new insights into this field. For example, emotional pictures attenuate the microsaccadic rate, and microsaccadic responses to covert attention occur in the direction opposite to a negative emotional target. However, the effects of various emotional events on microsaccadic activity remain debatable. This review introduces visual attention and eye movement studies that support findings on the modulation of microsaccadic responses to emotional events, comparing them with typical microsaccadic responses. This review also discusses the brain neuronal mechanisms governing microsaccadic responses to the attentional shifts triggered by emotion-related stimuli. It is hard to reveal the direct brain pathway of the microsaccadic modulation, especially in advanced (e.g., sustained anger, envy, distrust, guilt, frustration, delight, attraction, trust, and love), but also in basic human emotions (i.e., anger, disgust, fear, happiness, sadness, and surprise). However, non-human primates and human studies can uncover the possible brain pathways of emotional attention and microsaccades, thus providing future research directions. In particular, the facilitated (or reduced) attention is common evidence that microsaccadic activities change under a variety of social modalities (e.g., cognition, music, mental illness, and working memory) that elicit emotions and feelings.
Topics: Attention; Brain; Emotions; Fear; Fixation, Ocular; Humans; Mental Disorders; Saccades
PubMed: 32887665
DOI: 10.1186/s40101-020-00238-6 -
Journal of Vision Feb 2023Humans differ in the amount of time they direct their gaze toward different types of stimuli. Individuals' preferences are known to be reliable and can predict various...
Humans differ in the amount of time they direct their gaze toward different types of stimuli. Individuals' preferences are known to be reliable and can predict various cognitive and affective processes. However, it remains unclear whether humans are aware of their visual gaze preferences and are able to report it. In this study, across three different tasks and without prior warning, participants were asked to estimate the amount of time they had looked at a certain visual content (e.g., faces or texts) at the end of each experiment. The findings show that people can report accurately their visual gaze preferences. The implications are discussed in the context of visual perception, metacognition, and the development of applied diagnostic tools based on eye tracking.
Topics: Humans; Fixation, Ocular; Visual Perception; Awareness
PubMed: 36799868
DOI: 10.1167/jov.23.2.9 -
Continuum (Minneapolis, Minn.) Oct 2019This article provides an overview of nystagmus and saccadic intrusions with the goal of facilitating recognition and differentiation of abnormal eye movements to assist... (Review)
Review
PURPOSE OF REVIEW
This article provides an overview of nystagmus and saccadic intrusions with the goal of facilitating recognition and differentiation of abnormal eye movements to assist with accurate diagnosis of neurologic disease and evidence-based specific treatment of oscillopsia. Myriad advances have been made in the understanding of several types of nystagmus and saccadic intrusions, even in the past 5 to 10 years, especially regarding underlying pathophysiology, leading to pharmacologic advances rooted in physiologic principles.
RECENT FINDINGS
Specific recent advances in the study of nystagmus and saccadic intrusions include (1) improved understanding of the underlying etiologies and mechanisms of nystagmus enhanced or unmasked by provocative maneuvers such as supine position or head shaking; (2) recognition of the differences in behavior and treatment responsivity of acquired pendular nystagmus in demyelinating disease versus oculopalatal myoclonus; (3) recognition that oculopalatal myoclonus results from a dual mechanism of abnormal inferior olivary gap junction connection formation and maladaptive cerebellar learning; and (4) well-controlled clinical trials to evaluate the efficacy of pharmacologic interventions, such as memantine for acquired pendular nystagmus and 4-aminopyridine for downbeat nystagmus.
SUMMARY
Accurate recognition of nystagmus and saccadic intrusions, including familiarity with the subtleties of examination techniques that allow such eye movements to be unmasked, is critical to proper diagnosis and ultimate alleviation of the visual impairment these patients experience.
Topics: Adult; Female; Fixation, Ocular; Humans; Nystagmus, Pathologic; Ocular Motility Disorders; Saccades
PubMed: 31584542
DOI: 10.1212/CON.0000000000000772 -
Perception Dec 2021Another person's looking behavior is used by observers to judge gaze direction and fixation points. An important task in this context is the judgement of direct gaze,...
Another person's looking behavior is used by observers to judge gaze direction and fixation points. An important task in this context is the judgement of direct gaze, that is, the perception of being looked at. The cone of gaze can be defined as the range of fixation points that support direct gaze. The cone concept implies that this range lawfully increases with distance, but that the cone angle is constant. The present experiment tested the concept with a larger number and a more extended range of distances than previously done, and took care of possible directional errors. The gaze cone was found to be roughly linear, and stable between 1.6 m and 7.9 m - an almost perfect cone. The mean cone size subtended 5.2° in diameter when averaged over ascending and descending series. Measures differed, however, in ascending and descending series, consistent with a conservative bias. Also, the variability of judgements increased slightly with distance. Results are discussed considering whether cone size is actually smaller than often reported in the literature.
Topics: Fixation, Ocular; Humans; Judgment; Visual Perception
PubMed: 34841983
DOI: 10.1177/03010066211059930