Related Experiment Video
Updated: Dec 17, 2025
07:12
Development of a Gaze-Contingent Display Framework Designed for Perceptual and Oculomotor Research with Simulated Central Vision Loss
Published on: April 11, 2025
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Altered large-scale organization of shape processing in visual agnosia
Erez Freud1, Marlene Behrmann2
1Department of Psychology and Centre for Vision Research, York University, Toronto, ON, Canada.
Summary
Visual agnosia, a shape perception deficit, can result from ventral pathway damage. This study shows a single lesion causes lasting, widespread changes in both dorsal and ventral visual pathways.
Area of Science:
- Neuroscience
- Cognitive Psychology
- Visual Perception
Background:
- The dorsal and ventral visual pathways are implicated in processing shape information.
- Damage to the ventral pathway can lead to visual agnosia, impairing shape recognition.
Observation:
- A patient with visual agnosia and a right hemisphere ventral lesion was studied.
- Longitudinal changes in neural shape representation were evaluated over two years.
Findings:
- A reduction in shape sensitivity was observed in the patient's right ventral pathway and the opposite (contralesional) left ventral pathway.
- Shape sensitivity also decreased bilaterally in posterior regions of the dorsal pathway.
- These neural alterations remained consistent over the two-year study period.
Implications:
- A focal cortical lesion can induce persistent, large-scale modifications in both major visual processing streams.
- Shape perception relies on a distributed network of brain regions, not solely the ventral pathway.
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