Stereoscopic vision in the absence of the lateral occipital cortex.
Both dorsal and ventral cortical visual streams contain neurons sensitive to binocular disparities, but the two streams may underlie different aspects of stereoscopic vision. Here we investigate stereopsis in the neurological patient D.F., whose ventral stream, specifically lateral occipital cortex, has been damaged bilaterally, causing profound visual form agnosia. Despite her severe damage to cortical visual areas, we report that DF's stereo vision is strikingly unimpaired. She is better than many control observers at using binocular disparity to judge whether an isolated object appears near or far, and to resolve ambiguous structure-from-motion. DF is, however, poor at using relative disparity between features at different locations across the visual field. This may stem from a difficulty in identifying the surface boundaries where relative disparity is available. We suggest that the ventral processing stream may play a critical role in enabling healthy observers to extract fine depth information from relative disparities within one surface or between surfaces located in different parts of the visual field.
Read
Jenny C A
JC
Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom.
Phillipson
Graeme P
GP
Serrano-Pedraza
Ignacio
I
Milner
A David
AD
Parker
Andrew J
AJ
D000328:Adult; D000369:Aged, 80 and over; D000377:Agnosia / Q000503:physiopathology / Q000523:psychology*; D003867:Depth Perception; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015357:Vision Disparity; D014793:Visual Cortex / Q000293:injuries / Q000503:physiopathology*