Pii: S0010-0277(00)00125-6

Neural correlates of perceptual awareness, until very recently an elusive quarry, are now almost commonplace ®ndings. This article ®rst describes a variety of neural correlates of perceptual awareness based on fMRI, ERPs, and single-unit recordings. It is then argued that our quest should ultimately focus not on mere correlates of awareness, but rather on the neural events that are both necessary and suf®cient for perceptual awareness. Indeed, preliminary evidence suggests that although many of the neural correlates already reported may be necessary for the corresponding state of awareness, it is unlikely that they are suf®cient for it. The ®nal section considers three hypotheses concerning the possible suf®ciency conditions for perceptual awareness. q 2001 Elsevier Science B.V. All rights reserved.