The 'correlates' in neural correlates of consciousness

In the search for neural correlates of consciousness (NCC), the concept of 'consciousness' remains problematic. We suggest that not only the 'consciousness' in neural correlates of consciousness is a confused term, but 'correlates' is as well. When brain events are found to covary with conscious experience, these brain events can be the neural substrates of the experience, as is often (implicitly) suggested, but they can also be neural prerequisites or neural consequences of the experience. We here disentangle these different sorts of brain processes conceptually. But we also propose a concrete multi-pronged research program that may, in near-future consciousness research, distinguish these brain processes empirically. (C) 2011 Elsevier Ltd. All rights reserved.