As far as we know, a living being without a brain cannot have conscious experiences. But are certain parts of the brain more critical for conscious awareness than others? More specifically, how might disorders of perceptual consciousness after damage to the human brain inform the scientific world about relationships between neural systems and conscious perceptual awareness? In many cases, the loss of awareness is accompanied by indications that “invisible” information is nevertheless still being processed by the visual cortex. Studies of neuropsychological disorders of perceptual consciousness have shown that the primary visual cortex is neither necessary nor sufficient to account for perceptual awareness. This entry describes blindsight, unilateral visual neglect, Bálint's syndrome, visual agnosia, and further issues relating to consciousness disorders.