Factors in Learning And Plasticity: Healthy Vision (FLAP)
Central Visual Impairment, Macular Degeneration
About this trial
This is an interventional basic science trial for Central Visual Impairment focused on measuring plasticity, central vision loss, perceptual learning
Eligibility Criteria
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
Sites / Locations
- UABRecruiting
- University of California, RiversideRecruiting
Arms of the Study
Arm 1
Arm 2
Arm 3
Arm 4
Experimental
Experimental
Experimental
Experimental
Condition 1: Training visual sensitivity
Condition 2: Training spatial integration
Condition 3: Training spatial attention
Condition 4: Combination training
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.
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.
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.
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.