Visual Mode Switching in Color Perception

Study Overview
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Brief Summary
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Participants will be given experience wearing colored lenses that add a tint to the environment. Changes in visual perception and neural processing that arise as a result of this experience will be measured. These are expected as participants learn to switch to colored lenses mode where the effects of the lenses are discounted and colors appear more normal as soon as the lenses are put on.

Detailed Description
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All participants will wear tinted lenses for 1 hour at a time, 5 times per day. Perception (behavior) and neural function (with functional MRI and EEG) before and after this experience will be measured. In the neural measurements, activity will be recorded while participants view stripes of many different colors both with the lenses on and off. In the perceptual measurements, participants will adjust the color of a small patch to appear neutral, neither red nor green. Behavior will be measured in a variety of conditions to test different hypotheses about the origins of the mode-switching effects. These include: 1) surrounding the patch with different colors, 2) preceding the presentation of the patch with presentation of different colors, 3) presenting the tests in a red-illuminated room, 4) presenting the tests in a completely darkened room, and 5) using a head-mount-display (virtual reality goggles) to present simulated lenses that gradually change in strength.

Official Title
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Visual Mode Switching in Color Perception

Conditions
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Perception of Things Changing Color, Adaptive Behavior

Intervention / Treatment
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* Behavioral: Mode Switching Training


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Normal or corrected to normal vision by contact lenses No known visual disorders Little to no experience in tinted environments (e.g. dark rooms, swimming goggles) Exclusion Criteria: Abnormal color vision

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: The interventional study type is correct. The investigative team is giving all subjects a treatment- behavioral training in visual mode switching- and measuring effects of that treatment, by comparing measures made before to measures made after the treatment. Thus, this is a within-subjects, repeated measures experimental design. The experimenters have 6 different measurements they are using this design in different groups of subjects run in parallel, all examining different effects of the same treatment. . This is why parallel study model is appropriate. These parallel groups with different measurements, but same treatment, are the arms of the study.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Color Contrast<br>Test patch is surrounded spatially by different colors | Behavioral: Mode Switching Training<br>* Wear of colored lenses for 1 hr, 5 times per day, for 5 days<br>|
| Experimental: Color Adaptation<br>Test patch is surrounded temporally (preceded) by different colors | Behavioral: Mode Switching Training<br>* Wear of colored lenses for 1 hr, 5 times per day, for 5 days<br>|
| Experimental: Neuroimaging<br>Functional MRI and Electroencephelography data are acquired for multiple test colors | Behavioral: Mode Switching Training<br>* Wear of colored lenses for 1 hr, 5 times per day, for 5 days<br>|
| Experimental: Red Room<br>Participants are tested in a red-illuminated room | Behavioral: Mode Switching Training<br>* Wear of colored lenses for 1 hr, 5 times per day, for 5 days<br>|
| Experimental: Dark Room<br>Participants are tested in a completely darkened room | Behavioral: Mode Switching Training<br>* Wear of colored lenses for 1 hr, 5 times per day, for 5 days<br>|
| Experimental: Gradual Change<br>Participants view a gradual change in tint, presented on a head-mounted display | Behavioral: Mode Switching Training<br>* Wear of colored lenses for 1 hr, 5 times per day, for 5 days<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in unique yellow settings | This is a standard psychophysical measure referenced in 100s of papers. Participants adjust a patch of color until it appears neither red nor green and this color is reported in standard colorimetric coordinates (e.g. CIE). | Change will be assessed over the entire study, by comparing a pre-test the day before the intevention (which lasts 5 days) to a post-test the day after the intervention. | 
| Change in BOLD functional MRI activity | Neural activation will be measured with functional MRI which will be used to measure BOLD activity with standard methods, and reported as percent change from rest, a standard measure, for each voxel in the brain. | Change will be assessed over the entire study, by comparing a pre-test the day before the intevention (which lasts 5 days) to a post-test the day after the intervention. | 
| Change in EEG activity | Neural activity will be measured with electroencephelography using standard techniques and will be reported as voltage changes over time for each electrode in a standard configuration. | Change will be assessed over the entire study, by comparing a pre-test the day before the intevention (which lasts 5 days) to a post-test the day after the intervention. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Visual Perception, Visual Adaptation, Color Perception