Cover Image
QR Code

Reflections on Blindsight: Neuroimaging and Behavioural Explorations Clarify a Case of Reversed Localisation in the Blind Field of a Patient With Hemianopia.

Blindsight refers to residual visual abilities of patients with primary visual cortex lesions. Most of this research uses single case studies, most famously patient GY. We examined a patient (DC) after surgical resection of V1 who demonstrated robust but reversed blind field target localisation, mis...

Full description

Published in:Canadian Journal of Experimental Psychology Vol. 64; no. 2; pp. 86 - 102
Main Authors: Danckert, James, Culham, C.
Format: Article
Published: Canadian Psychological Association June 2010
Subjects:
Visual cortex
Visual fields
Vision disorders
Online Access:View this record in EBSCOhost
fields @attributes:
  recordID: 1
pdfLink:
plink: https://search.ebscohost.com/login.aspx?direct=true&db=ssf&AN=511039806&site=ehost-live
header:
  @attributes:
    shortDbName: ssf
    uiTerm: 511039806
    longDbName: Social Sciences Full Text (H.W. Wilson)
    uiTag: AN
  controlInfo:
    bkinfo:
    jinfo:
      jid:
        11961961
        CJX
      jtl: Canadian Journal of Experimental Psychology
      issn: 11961961
      maglogo: N
    pubinfo:
      dt: June 2010
      vid: 64
      iid: 2
      pid: 98
      pub: Canadian Psychological Association
    artinfo:
      ui:
        511039806
        10.1037/a0017426
      ppf: 86
      ppct: 16
      formats:
        fmt:
          – @attributes:
              type: T
          – @attributes:
              type: C
          – @attributes:
              type: P
              size: 21.3MB
      tig:
        atl: Reflections on Blindsight: Neuroimaging and Behavioural Explorations Clarify a Case of Reversed Localisation in the Blind Field of a Patient With Hemianopia.
      aug:
        au:
          Danckert, James
          Culham, C.
      su:
        Visual cortex
        Visual fields
        Vision disorders
      sug:
        subj:
          Visual cortex
          Visual fields
          Vision disorders
      keyword: Blindsight
      ab: Blindsight refers to residual visual abilities of patients with primary visual cortex lesions. Most of this research uses single case studies, most famously patient GY. We examined a patient (DC) after surgical resection of V1 who demonstrated robust but reversed blind field target localisation, mislocalising midline blind field targets to the periphery and vice versa. This pattern was reliable across multiple sessions and was not because of extraocular light scatter. We then used functional magnetic resonance imaging to examine neural responses to blind field motion stimuli with no evidence of motion-selective activation in DC's extrastriate cortex in the damaged hemisphere, in stark contrast to GY who showed robust bilateral activation in response to blind field stimuli. This suggests that DC's blind field performance may not represent true blindsight. Follow-up testing with the target—background contrast reversed (i.e., black targets/white background), eliminated DC's reversed localisation, strongly suggesting that she was employing an unusual decision criterion based on intraocular light scatter. DC's failure to demonstrate true blindsight may be related to the age at which she acquired her lesion—much later in life than GY.
      pubtype: Academic Journal
      doctype: Article
      src: R
    language: English
    refInfo:
    copyright:
      @attributes:
        flag: N
    holdings:
      @attributes:
        islocal: N