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Acta Ophthalmologica Mar 2018To evaluate the role of neural integrators (NI) in the oculomotor system. (Review)
Review
PURPOSE
To evaluate the role of neural integrators (NI) in the oculomotor system.
METHODS
A literature search was carried out using several electronic databases during the months of June 2014 to March 2015. The following keywords were used to generate focused results: 'neural integrators', 'gaze-holding', 'oculomotor integration', 'impaired gaze-holding', 'gaze evoked nystagmus' and 'gaze dysfunction'. Further materials were found through searching relevant articles within reference lists. Seventy-one articles were sourced for this review which analysed animal and human subjects and network models; 45 were studies of humans, 16 studies of primates, three studies of felines and one study from rats and network models. The remaining articles were literature reviews.
RESULTS
The horizontal and vertical, including torsional, NI are located logically in the brainstem, nearby their appropriate target extraocular motoneuron nuclei for stable eye position in eccentric position. The nucleus prepositus hypoglossi (NPH) and medial vestibular nuclei (MVN) are closely linked at the caudal pons and dorsal rostral medulla, integrating horizontal conjugate eye movement. The interstitial nucleus of Cajal (INC) integrates vertical and torsional eye movement at the upper midbrain. The integrator time constant is averaged to 25 seconds in human horizontal and animal vertical NI to perform its function. Case reports revealed that dysfunction of horizontal NI also resulted in vertical ocular deviations, indicating some overlap of horizontal and vertical gaze control. Furthermore, pharmacological inactivation of NI exposed a population of inhibitory neurotransmitters that permits its mechanism of action; allowing for smooth conjugate movement.
CONCLUSIONS
Neural integrators operate to integrate eye velocity and eye position information to provide signals to extraocular motoneurons to attain and maintain a new position. Therefore, NI allow image stabilization during horizontal and vertical eye movements at eccentric positions for comfortable single vision.
Topics: Animals; Eye Movements; Fixation, Ocular; Humans; Oculomotor Nerve; Sensory Receptor Cells; Visual Fields
PubMed: 27874249
DOI: 10.1111/aos.13307 -
Neuroscience and Biobehavioral Reviews Oct 2016There has been considerable focus placed on how individuals with autism spectrum disorder (ASD) visually perceive and attend to social information, such as facial... (Meta-Analysis)
Meta-Analysis Review
There has been considerable focus placed on how individuals with autism spectrum disorder (ASD) visually perceive and attend to social information, such as facial expressions or social gaze. The role of eye movements is inextricable from visual perception, however this aspect is often overlooked. We performed a series of meta-analyses based on data from 28 studies of eye movements in ASD to determine whether there is evidence for ocular motor dysfunction in ASD. Tasks assessed included visually-guided saccade tasks, gap/overlap, anti-saccade, pursuit tasks and ocular fixation. These analyses revealed evidence for ocular motor dysfunction in ASD, specifically relating to saccade dysmetria, difficulty inhibiting saccades and impaired tracking of moving targets. However there was no evidence for deficits relating to initiating eye movements, or engaging and disengaging from simple visual targets. Characterizing ocular motor abnormalities in ASD may provide insight into the functional integrity of brain networks in ASD across development, and assist our understanding of visual and social attention in ASD.
Topics: Autism Spectrum Disorder; Eye Movements; Humans; Vision, Ocular
PubMed: 27527824
DOI: 10.1016/j.neubiorev.2016.08.007 -
Sports Medicine (Auckland, N.Z.) Apr 2016The quiet eye (final fixation to a specific target prior to movement initiation) is a perceptual skill robustly associated with expertise and superior performance. The... (Review)
Review
INTRODUCTION
The quiet eye (final fixation to a specific target prior to movement initiation) is a perceptual skill robustly associated with expertise and superior performance. The benefit of the phenomenon has been demonstrated in a range of sporting tasks. The mechanism(s) underpinning this phenomenon are much-debated and are associated with varying assumptions.
OBJECTIVE
This systematic review categorizes previous quiet eye research based on Newell's 1986 model of interacting constraints.
DATA SOURCES
Three electronic databases (Web of Science, Scopus, PubMed) were searched from inception until February 2015. Details of relevant studies were also obtained from one literature review and two book chapters.
ELIGIBILITY CRITERIA AND SYNTHESIS METHODS
To frame the discussion of research evidence concerning the quiet eye, previous studies were evaluated based on a classification of manipulating performer, environment, and task constraints. Additionally, associative studies (without specific constraints), and interacting constraints (affecting more than one constraint) were considered.
RESULTS
This review emphasizes that the quiet eye is beneficial for performing aiming tasks and that Newell's constraints model provides a useful framework for organizing knowledge in this area.
CONCLUSION
Despite the robust research on the value of the quiet eye, several gaps in current knowledge exist regarding the mechanism of the quiet eye effect.
Topics: Athletic Performance; Eye Movements; Fixation, Ocular; Humans; Motor Skills; Movement; Psychomotor Performance; Task Performance and Analysis
PubMed: 26712511
DOI: 10.1007/s40279-015-0442-4 -
PloS One 2015The purpose of this review was to build upon a recent review by Weigelt et al. which examined visual search strategies and face identification between individuals with... (Meta-Analysis)
Meta-Analysis Review
The purpose of this review was to build upon a recent review by Weigelt et al. which examined visual search strategies and face identification between individuals with autism spectrum disorders (ASD) and typically developing peers. Seven databases, CINAHL Plus, EMBASE, ERIC, Medline, Proquest, PsychInfo and PubMed were used to locate published scientific studies matching our inclusion criteria. A total of 28 articles not included in Weigelt et al. met criteria for inclusion into this systematic review. Of these 28 studies, 16 were available and met criteria at the time of the previous review, but were mistakenly excluded; and twelve were recently published. Weigelt et al. found quantitative, but not qualitative, differences in face identification in individuals with ASD. In contrast, the current systematic review found both qualitative and quantitative differences in face identification between individuals with and without ASD. There is a large inconsistency in findings across the eye tracking and neurobiological studies reviewed. Recommendations for future research in face recognition in ASD were discussed.
Topics: Autism Spectrum Disorder; Electroencephalography; Evoked Potentials; Eye Movements; Facial Recognition; Fixation, Ocular; Humans; Magnetic Resonance Imaging; Magnetoencephalography; Reaction Time
PubMed: 26252877
DOI: 10.1371/journal.pone.0134439 -
Ophthalmic & Physiological Optics : the... Jul 2014The global prevalence of age-related macular degeneration and associated central vision loss is rising. Central vision loss hinders the performance of many activities of... (Review)
Review
PURPOSE
The global prevalence of age-related macular degeneration and associated central vision loss is rising. Central vision loss hinders the performance of many activities of daily living. Adaptive strategies such as eccentric viewing and steady eye strategy may be used to compensate for central vision loss. In order to establish the potential of these rehabilitation strategies, this systematic review evaluates current literature regarding the effectiveness of eccentric viewing and steady eye strategy training in people with central vision loss.
RESULTS
The search strategies identified 2605 publications, 36 of which met the inclusion criteria for the review, but only three of which were randomised controlled trials. This literature shows that eccentric viewing and steady eye strategy training can improve near visual acuity, reading speed, and performance of activities of daily living in people with central vision loss. However, there was insufficient literature to establish a relationship between training and distance visual acuity or quality of life. There is no conclusive evidence to show that a particular model of eccentric viewing training is superior to another, little clear evidence of a relationship between participant characteristics and training outcomes and no data regarding the cost effectiveness of training.
CONCLUSION
This report highlights the need for further robust research to establish the true potential and cost effectiveness of eccentric viewing and steady eye strategy training as a rehabilitation strategy for individuals with central vision loss.
Topics: Activities of Daily Living; Fixation, Ocular; Humans; Macular Degeneration; Quality of Life; Scotoma; Visual Fields
PubMed: 24735182
DOI: 10.1111/opo.12132 -
NeuroRehabilitation 2014Eccentric viewing training can be successfully applied in the clinical setting based on positive evidence. Nonetheless, published research should be integrated to... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Eccentric viewing training can be successfully applied in the clinical setting based on positive evidence. Nonetheless, published research should be integrated to provide a conclusive perspective of the efficacy of eccentric viewing training.
OBJECTIVE
Meta-analysis was conducted to examine effectiveness of eccentric viewing training on daily visual activities for individuals with age-related macular degeneration (AMD).
METHODS
The papers used in this study were located through PubMed, Ovid, ProQuest, EBSCOhost, RISS, and KMbase on studies published between January, 1990 and December, 2012. The keywords for searching were "age-related macular degeneration" and "eccentric viewing", "eccentric fixation", "peripheral vision" or "preferred retinal loci". The effect sizes were calculated using Comprehensive Meta-Analysis 2.0 and interpreted according to Cohen's criteria.
RESULTS
A total of 258 studies were found, among which five papers suited the main selection criteria for final analysis. The entire effect size was 0.660 (95% CI, 0.232 ~ 1.088), indicating a moderate effect size of the eccentric viewing training for individuals with AMD in their daily visual activities (p < 0.05).
CONCLUSIONS
The results of this study demonstrated the clinical effectiveness of eccentric viewing training for individuals with AMD. This result should be interpreted cautiously, though, given the possibility of publication bias.
Topics: Activities of Daily Living; Female; Humans; Macular Degeneration; Ophthalmology; Retina; Vision Disorders; Vision, Ocular; Visual Acuity
PubMed: 24463233
DOI: 10.3233/NRE-141055 -
Psychological Bulletin Dec 1972
Review
Topics: Afterimage; Distance Perception; Eye Movements; Fixation, Ocular; Humans; Illusions; Models, Biological; Motion Perception; Motor Activity; Oculomotor Muscles; Orientation; Psychophysics; Reflex; Retina
PubMed: 4566651
DOI: 10.1037/h0033614