GY, a well-studied human hemianope, is aware of salient visual events in his cortically blind field but does not call this 'vision'. To see whether he has low-level phenomenal vision, or whether instead he has learned to gain conscious access to visual information that is not phenomenally represented, we attempted to image-process a stimulus s presented to the impaired field so that when the transformed stimulus T(s) was presented to the normal hemifield it would cause a sensation similar to that caused by s in the impaired field. An example result of this procedure is shown below. The original stimulus s (a translating bar) is shown right and the transformed stimulus T(s) left. The "motion-only" stimulus T(s) may help us understand the nature of GY's V1-less vision in the impaired field.
To view the moving stimuli click on the image below (with some patience you will see that there is something to see on the left - unless there is a problem with your quicktime player).
This www page is related to the following paper:
P. Stoerig and E. Barth: Phenomenal vision despite unilateral destruction of primary visual cortex. Consciousness and Cognition, 10, 574-587, 2001.
To view the stimuli used in the experiments click here.
Curator: E. Barth
Last update: June 6, 2001