Temporal properties of spatial channel of processing in hemianopia

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26 Citations (Scopus)

Abstract

The term blindsight, coined by Larry Weiskrantz, describes those discrimination abilities that can be elicited with visual stimuli restricted to the blindfield of a patient with occipital brain lesion or damaged optic radiation. Over the past 3 decades, many aspects of blindsight have been investigated including detection of basic stimulus attributes such as structure, colour and movement as well as more complex tasks such as discrimination of facial expressions and semantic processing. The neuronal mechanisms mediating blindsight rely on processing in subcortical and/or extrastriate areas. It appears that following the occipital brain damage, there is a restricted "window of processing" and stimulus parameters mainly outside this window may not lead to blindsight performance. Here we report how the restricted "window of processing" appears to have a specific spatio-temporal response profile, mainly tuned to low spatial frequencies and intermediate temporal frequencies. In addition, in a group of blindsight patients, we demonstrate that above chance detection performance is related to the target size. The findings have implications both for the reported incidence of blindsight and development of rehabilitation strategies. (c) 2007 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)879-885
Number of pages7
JournalNeuropsychologia
Volume46
Issue number3
Early online date19 Nov 2007
DOIs
Publication statusPublished - 12 Feb 2008

Keywords

  • blindsight
  • temporal processing
  • forced choice detection
  • contrast sensitivity
  • contrast-sensitivity
  • motion perception
  • residual vision
  • visual-field
  • discrimination
  • responses
  • lesions
  • humans
  • damage

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