The concept of 'consciousness' in the search for neural correlates of consciousness (NCC) is problematic, and the term 'correlates' is also confused. Brain events that covary with conscious experience can be neural substrates of the experience, but they can also be neural prerequisites or neural consequences. This work disentangles these different sorts of brain processes conceptually and proposes a concrete multi-pronged research program to distinguish them empirically in near-future consciousness research.
Neural correlates of consciousness (NCCs) include three distinct components: neural substrates that directly represent conscious experience, neural prerequisites that must occur before an experience, and neural consequences that follow it. In standard correlative studies, these three types are indistinguishable. A multi-pronged research approach could help separate them. The authors integrate their ideas with other recent work on NCC components and propose strategies to address the empirical-epistemological challenges posed by the problem of three NCCs. They conclude that while the problem is important and difficult, it is not destructive, and the NCC research program still has much to contribute.
Subliminal priming—behavioral changes caused by an unseen stimulus—is a form of unconscious visual processing. Theories of recurrent processing propose that consciousness arises from non-hierarchical feedback loops in the brain, while unconscious subliminal priming relies on the initial feedforward sweep of visual information. Evidence increasingly supports the necessity of recurrent connectivity for visual awareness, though whether global or local recurrence is required remains unclear. Recurrent processing alone is not sufficient for consciousness. The neural correlates of subliminal priming deserve more attention because understanding them can explain why people exhibit certain behaviors, even without awareness.