Distilling the neural correlates of consciousness

Identifying the neural correlates of consciousness (NCC) is a major goal in neuroscience, typically pursued by comparing brain activity when a person is conscious of a stimulus versus when they are not. This review argues that such contrastive analyses are problematic because they can capture not only the true NCC but also neural prerequisites for conscious processing and consequences that follow it. Previous findings may therefore be ambiguous. The authors propose experimental strategies to isolate the NCC from these confounds, aiming to refine the contrastive approach.

Study at a glance

Abstract

Solving the problem of consciousness remains one of the biggest challenges in modern science. One key step towards understanding consciousness is to empirically narrow down neural processes associated with the subjective experience of a particular content. To unravel these neural correlates of consciousness (NCC) a common scientific strategy is to compare perceptual conditions in which consciousness of a particular content is present with those in which it is absent, and to determine differences in measures of brain activity (the so called "contrastive analysis"). However, this comparison appears not to reveal exclusively the NCC, as the NCC proper can be confounded with prerequisites for and consequences of conscious processing of the particular content. This implies that previous results cannot be unequivocally interpreted as reflecting the neural correlates of conscious experience. Here we review evidence supporting this conjecture and suggest experimental strategies to untangle the NCC from the prerequisites and consequences of conscious experience in order to further develop the otherwise valid and valuable contrastive methodology.