Psychophysical and pupillometric study of spatial channels of visual processing in blindsight

Arash Sahraie, Ceri T Trevethan, R. Cruce, Alison Dorothy Murray, L. Weiskrantz

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)


To date no systematic method has been used for characterising the residual capacity of blindsight subjects that would allow comparison and generalisation across all subjects. The detection of isoluminant gratings of varying spatial and temporal frequencies commends itself for detailed between-subject comparison, and for mapping results onto physiological properties in relation to neuronal circuitry. We report the ability of a blindsight subject (CS) to detect suprathreshold sine-wave gratings over a range of spatial and temporal frequencies using psychophysical techniques. A band-pass spatial channel with an upper cutoff below 3.5 cycles/deg is specified. The data also have been analysed to compare differences between two types of blindsight performances, type I and type II. Spatial gratings were also used to elicit a pupillary grating response, offering an objective method that is free of verbal nuances and response bias, and the resulting band-pass channel can be used both for clinical screening and for prediction and comparisons with psychophysical profiles. Finally, we have compared our results with those reported in studies of a well-known subject, GY, which demonstrate remarkable similarities. Implications are discussed in relation to blindsight research.

Original languageEnglish
Pages (from-to)249-256
Number of pages7
JournalExperimental Brain Research
Issue number2
Publication statusPublished - 2002


  • blindsight
  • residual vision
  • cortical blindness
  • spatial vision
  • pupil


Dive into the research topics of 'Psychophysical and pupillometric study of spatial channels of visual processing in blindsight'. Together they form a unique fingerprint.

Cite this