Dissociation between goal-directed and discrete response localization in a patient with bilateral cortical blindness

J Cogn Neurosci. 2013 Oct;25(10):1769-75. doi: 10.1162/jocn_a_00404. Epub 2013 Apr 22.

Abstract

We investigated localization performance of simple targets in patient TN, who suffered bilateral damage of his primary visual cortex and shows complete cortical blindness. Using a two-alternative forced-choice paradigm, TN was asked to guess the position of left-right targets with goal-directed and discrete manual responses. The results indicate a clear dissociation between goal-directed and discrete responses. TN pointed toward the correct target location in approximately 75% of the trials but was at chance level with discrete responses. This indicates that the residual ability to localize an unseen stimulus depends critically on the possibility to translate a visual signal into a goal-directed motor output at least in certain forms of blindsight.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blindness, Cortical / physiopathology*
  • Brain Mapping*
  • Choice Behavior / physiology
  • Functional Laterality / physiology
  • Goals*
  • Humans
  • Image Processing, Computer-Assisted
  • Magnetic Resonance Imaging
  • Movement
  • Orientation / physiology*
  • Oxygen / blood
  • Photic Stimulation
  • Psychomotor Performance / physiology
  • Reaction Time / physiology
  • Visual Cortex / blood supply
  • Visual Cortex / physiopathology*
  • Visual Fields / physiology*

Substances

  • Oxygen