title: Low-level phenomenal vision despite unilateral destruction of primary visual cortex.
abstract: GY, an extensively studied human hemianope, is aware of salient visual events in his cortically blind field but does not call this "vision." To learn whether he has low-level conscious visual sensations or whether instead he has gained conscious knowledge about, or access to, visual information that does not produce a conscious phenomenal sensation, 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. While degradation of contrast, spatio-temporal filtering, contrast reversal, and addition of smear and random blobs all failed to match the response to a flashed bar s(f), moving textures of low contrast were accepted to match the response to a moving contrast-defined bar, s(m). Orientation and motion direction discrimination of the perceptually matched stimuli [s(m) and T(s(m))] was closely similar. We suggest that the existence of a satisfactory match indicates that GY has phenomenal vision.
authors.affiliation: Institute of Experimental Psychology II, Universitätstrasse1, Bldg. 23.03, Düsseldorf, D-40225, Germany. petra.stoerig@uni-duesseldorf.de
authors.forename: P
authors.initials: P
authors.lastname: Stoerig
authors.forename: E
authors.initials: E
authors.lastname: Barth
mesh_terms: D000328:Adult; D006423:Hemianopsia / Q000175:diagnosis / Q000503:physiopathology; D006801:Humans; D008297:Male; D012720:Severity of Illness Index; D014785:Vision, Ocular / Q000502:physiology*; D014793:Visual Cortex / Q000473:pathology* / Q000503:physiopathology*