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Updated: Jul 24, 2025

Stimulus-specific Cortical Visual Evoked Potential Morphological Patterns
Published on: May 12, 2019
Neural patterns of conscious visual awareness in the Riddoch syndrome
Ahmad Beyh1, Samuel E Rasche1, Alexander Leff2
1Laboratory of Neurobiology, Department of Cell and Developmental Biology, University College London, London, UK.
Abstract:
The Riddoch syndrome is one in which patients blinded by lesions to their primary visual cortex can consciously perceive visual motion in their blind field, an ability that correlates with activity in motion area V5. Our assessment of the characteristics of this syndrome in patient ST, using multimodal MRI, showed that: 1. ST's V5 is intact, receives direct subcortical input, and decodable neural patterns emerge in it only during the conscious perception of visual motion; 2. moving stimuli activate medial visual areas but, unless associated with decodable V5 activity, they remain unperceived; 3. ST's high confidence ratings when discriminating motion at chance levels, is associated with inferior frontal gyrus activity. Finally, we report that ST's Riddoch Syndrome results in hallucinatory motion with hippocampal activity as a correlate. Our results shed new light on perceptual experiences associated with this syndrome and on the neural determinants of conscious visual experience.
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