Conference on Cognitive Computational Neuroscience

There is a growing appreciation that visual perception is not built from the bottom-up, relying solely on retinal input, but is constructed internally using the brain's rich knowledge about the world. A particularly compelling demonstration of this is non-optic sight in blindness. We present a case study of this phenomenon: 34-year-old NS who, after losing her sight to retinal degeneration, now “sees” objects she touches or hears. Unlike imagery, these representations are determinate, involuntary, and persist as long as she understands the object to be within her line-of-sight. We used 3T fMRI to record BOLD activity while NS placed objects on a plexiglass tray that held them suspended in her field-of-view. A GLM analysis found significant patterns of activation in her visual cortex that resembled the patterns of activation in a sighted control who viewed the same objects through typical retinal vision. The presence of increased activity in visual areas of NS’s brain while “seeing” but no longer touching the objects is consistent with her reported vision-like experience. These findings suggest that visual cortex can support vivid visual experiences that accurately interpret non-retinal sensory input.