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Analysis of pathways mediating preserved vision after striate cortex lesions
Author(s) -
Schoenfeld Mircea Ariel,
Noesselt Toemme,
Poggel Dorothe,
Tempelmann Claus,
Hopf JensMax,
Woldorff Martin G.,
Heinze HansJochen,
Hillyard Steven A.
Publication year - 2002
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.10394
Subject(s) - psychology , visual cortex , lesion , neuroscience , extrastriate cortex , blindsight , functional magnetic resonance imaging , visual field , cortex (anatomy) , audiology , perception , visual perception , medicine , psychiatry
This study investigated the neural substrates of preserved visual functioning in a patient with homonymous hemianopsia and Riddoch syndrome after a posterior cerebral artery stroke affecting the primary visual cortex (area V1). The limited visual abilities of this patient included above‐chance verbal reports of movement and color change as well as discrimination of movement direction in the hemianopic field. Functional magnetic resonance imaging showed that motion and color‐change stimuli presented to the hemianopic field produced activation in several extrastriate areas of the lesioned hemisphere that were defined using retinotopic mapping. Magnetoencephalographic recordings indicated that evoked activity occurred earlier in the higher‐tier visual areas V4/V8 and V5 than in the lower‐tier areas V2/V3 adjacent to the lesion. In addition, the functional magnetic resonance imaging analysis showed an increased functional connectivity between areas V4/V8 and V5 of the lesioned hemisphere in comparison with the same areas in the intact hemisphere during the presentation of color changes. These results suggest that visual perception after the V1 lesion in Riddoch syndrome is mediated by subcortical pathways that bypass V1 and project first to higher‐tier visual areas V5 and V4/V8 and subsequently to lower‐tier areas V2/V3.