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Hyper-vision in a patient with central and paracentral vision loss reflects cortical reorganization

  • CLARA CASCO (a1), GIANLUCA CAMPANA (a1) (a2), ALBA GRIECO (a1), SILVANA MUSETTI (a1) and SALVATORE PERRONE (a3)...
Abstract

SM, a 21-year-old female, presents an extensive central scotoma (30 deg) with dense absolute scotoma (visual acuity = 10/100) in the macular area (10 deg) due to Stargardt's disease. We provide behavioral evidence of cortical plastic reorganization since the patient could perform several visual tasks with her poor-vision eyes better than controls, although high spatial frequency sensitivity and visual acuity are severely impaired. Between 2.5-deg and 12-deg eccentricities, SM presented (1) normal acuity for crowded letters, provided stimulus size is above acuity thresholds for single letters; (2) a two-fold sensitivity increase (d-prime) with respect to controls in a simple search task; and (3) largely above-threshold performance in a lexical decision task carried out randomly by controls. SM's hyper-vision may reflect a long-term sensory gain specific for unimpaired low spatial-frequency mechanisms, which may result from modifications in response properties due to practice-dependent changes in excitatory/inhibitory intracortical connections.

Copyright
Corresponding author
Address correspondence and reprint requests to: Professor Clara Casco, Dipartimento di Psicologia Generale, Universita' di Padova, Via Venezia, 8, 35131 Padova, Italy. E-mail: clara.casco@unipd.it
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Visual Neuroscience
  • ISSN: 0952-5238
  • EISSN: 1469-8714
  • URL: /core/journals/visual-neuroscience
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