Dissociation between goal-directed and discrete response localization in a patient with bilateral cortical blindness.
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.
University of Illinois at Urbana-Champaign, USA.
Simona
S
Buetti
Marco
M
Tamietto
Alexis
A
Hervais-Adelman
Dirk
D
Kerzel
Beatrice
B
de Gelder
Alan J
AJ
Pegna
D019575:Blindness, Cortical / Q000503:physiopathology*; D001931:Brain Mapping; D002755:Choice Behavior / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006040:Goals; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D009068:Movement; D009949:Orientation / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D014793:Visual Cortex / Q000098:blood supply / Q000503:physiopathology*; D014794:Visual Fields / Q000502:physiology*
D010100:Oxygen