Topographic Organization of Human Visual Areas in the Absence of Input from Primary Cortex

• DOI: 10.1523/jneurosci.19-07-02619.1999
• Publication Date: 2018-04-04T18:05:55Z
• Authors: Heidi A. Baseler; Antony B. Morland; Brian A. Wandell
• Keywords: Extrastriate cortex; Orientation column; Retinotopy; Meridian (astronomy)

Recently, there has been evidence for considerable plasticity in primary sensory areas of adult cortex. In this study, we asked to what extent topographical maps human extrastriate reorganize after damage a portion visual (striate) cortex, V1. Functional magnetic resonance imaging signals were measured subject (G.Y.) with large calcarine lesion that includes most cortex but spares the foveal representation. When stimulation was present, intact lesioned occipital lobe exhibited conventional retinotopic organization. Several could be identified (V1, V2, V3, V3 accessory, and V4 ventral). However, when stimuli restricted blind field, responses found primarily dorsal areas. Furthermore, had formerly shown normal topography now represented only field around lower vertical meridian. possible sources reorganized activity are considered, including transcallosal connections, direct subcortical projections residual inputs from V1 near margin lesion. A scheme is described explain how occur based on changes local neural connections.