Eye Movements, Visual Perception and Attention
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|ClinicalTrials.gov Identifier: NCT03884985|
Recruitment Status : Recruiting
First Posted : March 21, 2019
Last Update Posted : March 16, 2020
|Condition or disease||Intervention/treatment||Phase|
|Vision||Other: Visual stimulation||Not Applicable|
The goals of this study are to the following:
- Examine the resolution and time-course of attention within the foveola. Attentional control has been traditionally studied outside the foveola but the PI's recent work suggests that attentional shifts also play a critical role in the normal examination of fine spatial details. Building on our previous results, we will investigate the extent by which both voluntary and involuntary attention can be controlled at this scale. Specifically, we will (a) measure the resolution of attention, i.e., the minimum distance between two locations within the foveola that can elicit selective voluntary attentional shifts. We will (b) examine whether enhancements in fine spatial vision at selected foveal locations, such as those we have previously shown for voluntary attention, also occur with involuntary attention. Finally we will study (c) the time-course of attentional enhancements and inhibition of return at this scale. Moreover, to study how peripheral and foveal attention differ, we will compare the extent of exogenous attentional effects and their time-course within and outside the foveola.
- Map visual acuity and crowding across the foveola. Our research has shown that vision is not uniform across the foveola: discrimination of fine spatial patterns is already suboptimal just a few arcmins away from the center of gaze. This phenomenon could be caused by a decline in visual acuity outside the preferred retinal locus and/or the consequences of crowding, the negative influence resulting from objects adjacent to the target. Because of the difficulty in precisely controlling retinal stimulation at this scale, it is unclear whether crowding occurs in the foveola, and whether its influence changes with foveal eccentricity. We will measure both visual acuity (a), and crowding (b), and will assess their relative contribution over a range of foveal eccentricities, both nasally and temporally. In addition to examine visual acuity across subjects, we will also examine how it changes at the individual level.
- Link attention, fine spatial vision and oculomotor control. Microsaccades normally shift the retinal projection of the fixated object across the foveola. At a larger scale, visual resolution, attention, and eye movements are tightly coupled. But little is known on whether and how this interplay unfolds within the foveola. Here we will investigate how attention and vision interact with microsaccades preparation and execution. We will examine (a) whether microsaccades preparation yields attentional benefits at specific foveal locations; (b) the precision of microsaccades; (c) their impact in attenuating negative effects of reduced acuity and foveal crowding, and; (d) their impact on performance in natural high acuity tasks.
To address these goals psychophysics experimental paradigms and high-precision eyetracking will be used.
|Study Type :||Interventional (Clinical Trial)|
|Estimated Enrollment :||50 participants|
|Intervention Model:||Single Group Assignment|
|Masking:||None (Open Label)|
|Primary Purpose:||Basic Science|
|Official Title:||Eye Movements, Visual Perception and Attention|
|Actual Study Start Date :||January 1, 2015|
|Estimated Primary Completion Date :||February 1, 2023|
|Estimated Study Completion Date :||February 1, 2023|
Experimental: Normal Vision
This study examines high-acuity vision, oculomotor behavior recorded using high-resolution eyetracking. Healthy participants are asked to perform different types of visual tasks, ranging from letter identification to judging facial expressions while their eye movements will be recorded with high-precision together with their behavioral performance in the task.
Other: Visual stimulation
In the experiments, participants will sit in front of a computer monitor located a less than a meter of distance and will analyze the content of images extracted from collections of natural and computer-generated scenes. Subjects will be asked to report verbally or by pressing keys on a keyboard on image characteristics such as the locations of the objects present in the scenes, their number and/or their identities. Some experiments will involve a search paradigm in which subjects will have to report on the location and/or fine characteristics of a target element among a field of distracting similar elements, and/or visual discrimination tasks. The duration of the interval of time in which the image is maintained on the screen may be varied between few tens of milliseconds to several seconds. In a set of experiments, the eye movements performed by the subjects during the execution of the visual tasks will be recorded as explained below.
- Average Performance in Visual tasks [ Time Frame: Day 0 ]Proportion correct responses in visual tasks
- Microsaccades rate [ Time Frame: Day 0 ]Average number of microsaccades per second
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03884985
|Contact: Martina Poletti, Ph.D.||firstname.lastname@example.org|
|United States, New York|
|University of Rochester||Recruiting|
|Rochester, New York, United States, 14642|
|Contact: Martina Poletti, Ph.D. 617-595-3785 email@example.com|
|Principal Investigator:||Martina Poletti, Ph.D.||University of Rochester|