Does localisation blindsight extend to two-dimensional targets?

David P. Carey, Arash Sahraie, Ceri Tamsin Trevethan, Larry Weiskrantz

Research output: Contribution to journalArticle

7 Citations (Scopus)


Residual sensorimotor skills which survive compromise of the geniculostriate visual system may depend on activity of the dorsal stream of extrastriate occipitoparietal cortex. These circuits are crucial for controlling hand and eye movements to targets in a three-dimensional world. Remarkably, demonstrations of above chance localisation by hand and by eye in blindsight patients have used luminous targets that were only varied in one spatial dimension. These limitations result in experimental confounds. in the present study we examined saccadic and manual localisation in a well-studied patient (DB) to positions that were varied in 1 or 2 dimensions, using targets which control for luminance artefacts. We found that his good manual localisation without awareness in 1 D conditions was relatively preserved when the targets were varied in 2D. In stark contrast, saccadic performance was completely attenuated with 2D targets. These paradoxical results are difficult to reconcile with feedforward models of eye-hand coordination and with accounts of localisation that depend on intact multidimensional representations of the visual fields in non-geniculostriate systems. (c) 2008 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)3053-3060
Number of pages8
Issue number13
Early online date26 Jun 2008
Publication statusPublished - Nov 2008


  • blindsight
  • localisation
  • saccades
  • reaching
  • dorsal stream
  • visual-field defects
  • striate cortex
  • superior colliculus
  • residual vision
  • test score
  • area MT
  • macaque
  • pulvinar
  • monkeys
  • dissociation


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