Altered large-scale organization of shape processing in visual agnosia. (August 2020)

• Record Type: Journal Article
• Authors: Freud, Erez; Behrmann, Marlene
• Is Part Of: Cortex. Volume 129(2020)
• Page Start: 423
• Page End: 435
• Publication Date: 2020-08
• Subjects: Visual agnosia -- Object recognition -- Two visual pathways -- fMRI; Neuropsychology -- Periodicals; Nervous system -- Periodicals; Neurology -- Periodicals; Psychophysiology -- Periodicals; Behavior -- Periodicals; Neurology -- Periodicals; 612.825
• DOI: 10.1016/j.cortex.2020.05.009
• Languages: English
• ISSNs: 0010-9452

Abstract

Abstract: Recent findings suggest that both dorsal and ventral visual pathways process shape information. Nevertheless, a lesion to the ventral pathway alone can result in visual agnosia, an impairment in shape perception. Here, we explored the neural basis of shape processing in a patient with visual agnosia following a circumscribed right hemisphere ventral lesion and evaluated longitudinal changes in the neural profile of shape representations. The results revealed a reduction of shape sensitivity slopes along the patient's right ventral pathway and a similar reduction in the contralesional left ventral pathway. Remarkably, posterior parts of the dorsal pathway bilaterally also evinced a reduction in shape sensitivity. These findings were similar over a two-year interval, revealing that a focal cortical lesion can lead to persistent large-scale alterations of the two visual pathways. These alterations are consistent with the view that a distributed network of regions contributes to shape perception.