Fig. 2.

A shows the psychophysical task performed by the patients with unilateral homonymous hemianopia (n = 8) and patient SBR who has bilateral cortical blindness. The patients were required to determine which of the two intervals contained the Gabor patch. The upper row shows a high contrast Gabor patch, while the lower row shows a low contrast Gabor patch. In each case the Gabor patch is only presented for 500 ms rather than the entire trial. B shows the performance of each of the unilateral patients at the different contrast levels. Only one patient (grey line) was unable to perform this task above chance when the stimulus was at 100% contrast. C shows the performance of SBR in the two hemifields, and indicates his ability to perform above chance at the higher two contrasts.