Perceptual and contextual awareness: Methodological considerations in the search for the neural correlates of consciousness

A review of studies on the neural correlates of consciousness (NCCs) argues that disagreements in the field arise because different studies capture different conscious processes. The authors advocate for paradigms that produce different perceptual outputs from identical visual inputs. They distinguish perceptual awareness, linked to a boost in object-selective neural assemblies, from contextual awareness, reflected in the firing of concept neurons in the medial temporal lobe that trigger rich representations of context, associations, and memories.

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Abstract

In the last decades, the neural correlates of consciousness (NCCs) have been explored using both invasive and non-invasive recordings by comparing the brain activity elicited by seen versus unseen visual stimuli (i.e., the contrastive analysis). Here, we review a selection of these studies and discuss a set of considerations to improve the search for the NCCs using the contrastive analysis. In particular, we first argue in favour of implementing paradigms where different perceptual outputs are obtained using identical visual inputs. Second, we propose that the large disagreement in the field -in terms of the dissimilar neural patterns proposed as NCCs- is partially explained by the fact that different studies report the neural correlates of different conscious processes in the brain. More specifically, we distinguish between the perceptual awareness of a visual stimulus, associated to a boost in object-selective neural assemblies, and a more elaborate process (contextual awareness) that we argue is reflected in the firing of concept neurons in the medial temporal lobe, triggering a rich representation of the context, associations, and memories linked to the specific stimulus.