16 research outputs found
Neural correlates of visual spatial selective attention are altered at early and late processing stages in human amblyopia
Amblyopia is a neurodevelopmental visual disorder which results in reduced visual acuity in one eye and impaired binocular interactions. Previous studies suggest attentional deficits in amblyopic individuals. However, spatial cues which orient attention to a visual field improved performance. Here, we investigate the neural correlates of auditoryâvisual spatial selective attention in amblyopia during EEG recording. An auditory cue, that was followed by the presentation of two Gabor patches presented in the lower left and right visual fields, indicated the most likely location of an upcoming target Gabor. The target Gabor differed in orientation from the more frequently presented nonâtarget Gabor patches. Adults with amblyopia and neurotypical observers were asked to detect the target Gabor monocularly at the cued location, while witholding their response to targets presented at the uncued location and to all nonâtarget Gabor patches. Higher response rates were observed for cued compared to uncued targets in both groups. However, amblyopic individuals detected targets less efficiently with their amblyopic eye as compared to their fellow eye. Correspondingly, eventârelated potentials (ERPs) recorded to the onset of the nonâtarget Gabor patches were delayed at early processing stages (150â300 ms: posterior N100) and reduced in amplitude at later time windows (150â350 ms: P200, 300â500 ms: sustained activity) in the amblyopic eye compared to the fellow eye. Such interocular differences were not observed in neurotypical observers. These findings suggest that neural resources allocated to the early formation of visual discrimination as well as later stimulus recognition processes are altered in the amblyopic eye
Intramodal cortical plastic changes after moderate visual impairment in human amblyopia
Early blindness results in alterations in the neural responses to auditory stimuli.
Here we show that even moderately reduced vision in one eye early in life is sufficient
to induce neural plastic changes in voice processing. We asked individuals
with reduced visual acuity in one eye due to amblyopia to attend to vocal cues
during electroencephalogram recording. We found enhanced frontal auditory responses
at 125 msâ225 ms, which were correlated with reduced vision in the
amblyopic eye, but not the fellow eye. Our results indicate intramodal reorganization,
typically observed after congenital profound visual deprivation
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Bridging the Gap: Understanding Eye Movements and Attentional Mechanisms is Key to Improving Amblyopia Treatment
Amblyopia is a developmental visual disorder resulting in sensory, motor and attentional deficits, including delays in both saccadic and manual reaction time. It is unclear whether this delay is due to differences in sensory processing of the stimulus, or the processes required to dis-engage/shift/re-engage attention when moving the eye from fixation to a saccadic target. In the first experiment we compare asymptotic saccadic and manual reaction times between the two eyes, using equivalent stimulus strength to account for differences in sensory processing. In a follow-up study, we modulate RT by removing the fixation dot, which is thought to release spatial attention at the fovea, and reduces reaction time in normal observers. Finally, we discuss the implications for these findings on future amblyopic treatment, specifically dichoptic video game playing. Playing videogames may help engage the attentional network, leading to greater improvements than traditional treatment of patching the non- amblyopic eye. Further, when treatment involves both eyes, fixation stability may be improved during the therapeutic intervention, yielding a better outcome than just playing a video game with a patch over the non-amblyopic eye
Both saccadic and manual responses in the amblyopic eye of strabismics are irreducibly delayed.
Escape Responses to Visual and Vibrational Stimuli in the Sand Fiddler Crab, Uca Pugilator
(Statement of Responsibility) by Christina Gambacorta(Thesis) Thesis (B.A.) -- New College of Florida, 2007(Electronic Access) RESTRICTED TO NCF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE(Bibliography) Includes bibliographical references.(Source of Description) This bibliographic record is available under the Creative Commons CC0 public domain dedication. The New College of Florida, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.(Local) Faculty Sponsor: Bauer, Gordo
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