Factors in Learning And Plasticity: Healthy Vision (FLAP)
Characterization of Multiple Factors in Training and Plasticity in Central Vision Loss: Healthy Vision
Study Overview
Status
Status
Conditions
Conditions
Intervention / Treatment
Intervention / Treatment
Detailed Description
Study Type
Study Type
Enrollment (Estimated)
Enrollment
Phase
Phase
- Not Applicable
Contacts and Locations
Study Contact
Study Contact
- Name: Rachel A Chua, MS
- Phone Number: 205-410-4041
- Email: r2chel@uab.edu
Study Contact Backup
- Name: Kristina M Visscher, PhD
- Phone Number: 205-934-0497
- Email: kmv@uab.edu
Study Locations
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Alabama
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Birmingham, Alabama, United States, 35294
- UAB
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California
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Riverside, California, United States, 92521
- University of California, Riverside
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Participation Criteria
Eligibility Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Description
Inclusion Criteria:
- Aged 18-30
- Corrected vision (20/40 or better)
- No reported incidence of retinal pathology.
Exclusion Criteria:
- Pacemaker or any ferromagnetic metal implanted in their body
- Metal of any type implanted in their head (limited dental work is acceptable)
- Claustrophobia
- Needing non-standard glasses (other than the simple MR-compatible glasses that can be supplied) for best-corrected distance vision
- Being hearing-impaired
- Weight over 300 pounds
- Maximum body girth over 60 inches
- Previous serious head injury
- Presence of hallucinations or delusions
- Excessive old, or colorful tattoos, especially near the head
- Pregnancy
- Braces/permanent retainer
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Basic Science
- Allocation: Randomized
- Interventional Model: Parallel Assignment
- Masking: Single
Number of Arms
Arms and Interventions
Participant Group / ArmParticipant Group / Arm |
Intervention / TreatmentIntervention / Treatment |
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Experimental: Condition 1: Training visual sensitivity
A standard Perceptual Learning approach to train early visual processes of discriminating the orientation of Gabor patches presented at threshold- level contrast.
Preliminary data, using this method, in normally seeing and MD participants show both feasibility and preliminary evidence that this training gives rise to improvements in acuity.
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Investigators adopt a standard PL approach to train early visual processes of discriminating the orientation of Gabor patches presented at threshold contrast.
Across training blocks, Gabors will range in spatial frequency, where contrast is adapted with a 3/1 staircase.
Whenever a specific contrast threshold is reached, spatial frequency will increase by 2 cycles per degree and contrast will be reset.
Preliminary data from this method in normally seeing and MD participants show both feasibility and tentative evidence that this training gives rise to improvements in acuity.
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Experimental: Condition 2: Training spatial integration
Most visual tasks involve integrating features to discriminate objects, therefore requiring brain areas that can integrate features from multiple receptive fields from early visual areas.
Thus spatial integration involves what investigators refer to as mid-level vision.
Spatial integration is a particular concern in developing a PRL since an area of the visual periphery that is best suited to discriminate a simple visual feature may not be appropriate to integrate information across objects, such as in reading or recognizing facial identity or expression.
Investigators address this issue with a targeted spatial integration training approach developed by MPI Seitz and based on contour integration tasks used in previous PL studies to train mid-level visual processes.
Target stimuli consist of contours formed by spaced Gabors.
Difficulty of detecting the target is manipulated by varying orientation jitter of Gabors making up the target.
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Spatial integration involves what the investigators refer to as mid-level vision.
Spatial integration is a concern in developing a PRL since an area of the visual periphery that is best suited to discriminate a simple visual feature may not be appropriate to integrate information across objects, such as in reading or recognizing facial identity or expression.
The investigators address this issue with a targeted spatial integration training approach developed by MPI Seitz and based on contour integration tasks used in previous PL studies to train mid-level visual processes.
Target stimuli consist of contours formed by spaced Gabors.
The difficulty is manipulated by varying orientation jitter of Gabors.
Several optotypes will be included to promote generalization, including shapes and facial expressions.
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Experimental: Condition 3: Training spatial attention
A key attribute of most real-world visual tasks is that individuals alternate shifting and holding attention and eye movements to different objects in the visual field while searching for and discriminating possible sources of visual information.
To train this, investigators will implement a task structure that requires participants to alternate between holding and switching attention and making targeted eye movements.
The basic task is to press a key whenever a red circle appears in a series of other colored circles, with a target presented every 2 to 4s.
Participants must maintain vigilance for relatively long periods, detect objects in the near periphery, switch attention based upon exogenous and endogenous cues, and make eye- movements to move areas of spared vision to those locations.
These are aspects of attention and eye movements not incorporated in Conditions 1 and 2.
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The investigators will implement a task structure that requires participants to alternate between holding and switching attention and making targeted eye movements.
The basic task is to press a key whenever a red-circle appears in a series of other colored-circles, with a target presented every 2 to 4s.
Participants must maintain vigilance for relatively long periods, detect objects in the near periphery, switch attention based upon exogenous and endogenous cues, and make eye- movements to move areas of spared vision to those locations.
These are aspects of attention and eye movements not incorporated in Conditions 1 and 2.
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Experimental: Condition 4: Combination training
In Condition 4, investigators combine the elements of Conditions 1-3.
The investigators test the extent to which a combined training gives rise to the joint benefits of each training individually, or integrative benefits potentially surpass the benefits of the individual training alone.
The visual sensitivity task from Condition 1 will alternate across blocks with the spatial integration task from Condition 2, using the timing of targets and location switches from Condition 3; Gabors or contours are used as targets instead of the red- circle in Condition 3 and a fixation point is presented instead of distractors to maintain a similar stimulus configuration as Conditions 1 and 2.
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Daily tasks involve a combination of being sensitive to basic visual features, being able to integrate these features, and directing attention and eye movements to better evaluate the information of potential interest.
To address this integrative nature of real-world vision,Condition 4 combines the elements of Conditions 1-3.
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What is the study measuring?
Primary Outcome Measures
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
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Change from Baseline Radial Bias from the Crowding Task after completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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The ratio of the crowding threshold along the axis connected to the fovea vs. along the orthogonal axis.
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Saccadic Precision after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Consistency across trials in placement of the first saccade calculated by the distribution across trials (bivariate contour ellipse area) of the landing point of the first fixation of each trial.
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Fixation Stability after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Normalizing fixations in the PRL to the first fixation to that region and calculating the distribution of all fixation locations in this normalized space (measured as a bivariate contour ellipse area).
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Other Outcome Measures
Other Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
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Change from Baseline Acuity after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Acuity threshold from the Landolt C task.
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Contrast Sensitivity after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Threshold value from contrast sensitivity task.
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Minimal print size from the MNREAD task after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Minimal print size from the MNREAD task
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Precision of Reconstructed Representation of Stimulus Orientation after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Precision of reconstructed representation of stimulus orientation (quantified with FWHM)
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Population receptive field size in V1, V2 and V3 representations of URL and PRL after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Population receptive field size in V1, V2 and V3 representations of URL and PRL (quantified as PRF sigma in the swath of cortex associated with that retinal location).
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Cortical thickness in V1, V2 and V3 representations of the PRL and URL after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Cortical thickness in V1, V2 and V3 representations of the PRL and URL (quantified as mm of cortical thickness)
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Orientation jitter threshold in the contour integration task at PRL or URL after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Orientation jitter threshold in the contour integration task (quantified as threshold average jitter) at PRL or URL.
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Crowding Threshold after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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In the contour integration task stimuli are untrained contours of alphanumeric characters made of Gabor elements.
This test allows us to estimate how the magnitude of crowding may change at the PRL compared to the non-PRL.
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Decoding classification accuracy for an attended character after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Decoding classification accuracy for an attended character, based on decoding from MRI data within VWFA and LOC regions of interest.
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Strength of background connectivity between areas with larger receptive fields (V4) to the smaller receptive fields contributing information to that area. after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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This is measured as functional connectivity (z-transformed Pearson's r) between voxels in V1 to voxels in V4 in that represent the same portion of retinotopically mapped space.
Measured in portions of cortex representing PRL and URL.
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Sustained Attention after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Reaction time of detection of orientation of Landolt Cs presented in an RSVP stream at the beginning of each trial.
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Endogenous Attention after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Endogenous attention: reaction time when switching between locations due to an endogenous cue on valid vs nonvalid trials.
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Exogenous Attention after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Exogenous attention: reaction time when switching between locations due to an exogenous cue on valid vs. nonvalid trials.
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Saccadic Re-referencing after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Saccadic Re-referencing: number of first fixations that do not cover the target location with the scotoma.
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Decoding classification accuracy for decoding the locus of spatial attention (PRL or URL), regardless of stimulus type after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Decoding classification accuracy for decoding the locus of spatial attention (PRL or URL), regardless of stimulus type.
This will be examined in frontal (FEF), parietal (SPL/IPS) and higher order visual (LOC) regions.
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Top-down modulation of visual areas after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Top-down modulation of visual areas: background connectivity between frontoparietal control regions (FEF, SPL/IPS) and visual areas ( V1, V2, V3).
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Reading speed in the MNREAD task after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Reading speed in the MNREAD task (words per minute).
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Change from Baseline Completion time in the trail making task after Completion of Training at approximately 7 weeks
Time Frame: Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Completion time in the trail making task
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Baseline and Within 3 weeks of training completion, training is complete 7 weeks from baseline on average
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Collaborators and Investigators
Sponsor
Sponsor
Collaborators
Collaborators
Study record dates
Study Major Dates
Study Start (Actual)
Study Start
Primary Completion (Estimated)
Primary Completion
Study Completion (Estimated)
Study Completion
Study Registration Dates
First Submitted
First Submitted
First Submitted That Met QC Criteria
First Submitted That Met QC Criteria
First Posted (Actual)
First Posted
Study Record Updates
Last Update Posted (Actual)
Last Update Posted
Last Update Submitted That Met QC Criteria
Last Update Submitted That Met QC Criteria
Last Verified
Last Verified
More Information
Terms related to this study
Additional Relevant MeSH Terms
Other Study ID Numbers
Other Study ID Numbers
- 300006197 (Study 1)
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
IPD Plan Description
IPD Sharing Time Frame
IPD Sharing Supporting Information Type
- STUDY_PROTOCOL
- ICF
- ANALYTIC_CODE
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Studies a U.S. FDA-regulated device product
product manufactured in and exported from the U.S.
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