The neural correlates of consciousness (NCC) are the minimal set of neural events and mechanisms sufficient for a specific conscious experience. Identifying NCCs is the empirical approach to the "hard problem" of consciousness: how and why do physical brain processes give rise to subjective experience? Research uses contrastive methods, comparing brain activity when a stimulus is consciously perceived versus when an identical stimulus is not perceived.
Major Theories
Global workspace theory (Baars) proposes that consciousness arises when information is broadcast widely via a "global workspace" involving prefrontal and parietal cortex, making it available to multiple cognitive systems. Integrated information theory (Tononi) proposes that consciousness corresponds to integrated information (phi), requiring both differentiation and integration of information in a system. Higher-order theories propose that consciousness requires a representation of one's own mental states. Recurrent processing theory (Lamme) proposes that recurrent (feedback) processing in sensory cortex is sufficient for consciousness.
Key paradigms for studying consciousness include binocular rivalry (two different images presented to the two eyes alternate in awareness), masking (a briefly presented stimulus is rendered invisible by a following stimulus), and attentional manipulations (inattentional blindness). These paradigms hold the physical stimulus constant while consciousness varies, allowing researchers to identify neural activity specifically associated with conscious awareness rather than stimulus processing per se.