Using fMRI BOLD imaging in normal adults, the researchers will determine how our brains “fill-in” normal blind spots that occur in our vision. This study will provide baseline information that can be used to explore how filling-in occurs following diseases that can affect vision, such as strokes and other brain traumas, as well as diseases that directly affect the eye’s retina, such as macular degeneration and diabetic retinopathy.
Everyone has visual blind spots, called scotomas, which are localized areas of blindness in the visual field. The brain fills-in these blind spots with perceptual texturing so people are unaware of them. The number of blind spots can increase exponentially, however, following stroke or other brain traumas, and in retinal diseases such as macular degeneration that occurs primarily in older people, and diabetic retinopathy, a complication of diabetes. The researchers hypothesize that filling-in occurs in the higher visual brain areas. The investigators will test this hypothesis by using fMRI BOLD to conduct physiological measurements of filling-in, while simultaneously obtaining perceptual reports from study participants of whether or not they experience blind spots under experimental conditions.
Significance: This project on how the brain fills-in blind spots will provide baseline information for future studies in patients with visual loss. The approach should provide a method for determining the limits of brain plasticity and functional reorganization following brain trauma or resulting from eye diseases, and the findings could lead to development of new therapies to improve visual function in these patients.