Perceptual and Contextual Awareness

JOAQUIN NAVAJAS; HERNAN G REY; RODRIGO QUIAN QUIROGA

Congreso; 19th Annual meeting of the Association for a Scientific Study of Consciousness (ASSC); 2015

Association for a Scientific Study of Consciousness (ASSC)

In the last decades, vast empirical and theoretical efforts have been yielded to unravel the neural correlates of consciousness (NCCs). However, to date, there is little agreement about the areas, timing, and mechanisms involved in eliciting a conscious percept. We propose that this is partially due to the fact that different studies report the neural correlates of different conscious processes in the brain. As an example, our own work has recently provided dissimilar evidence in terms of modulations by awareness occurring at different times and in different areas: 1) An evoked potential measured from the scalp in the occipito-temporal cortex peaking at ~170 ms that predicts conscious face perception (Navajas et al., 2013); 2) Single-cell firing at ~300-400 ms of highly-selective neurons in the medial temporal lobe (MTL) appearing only upon conscious recognition (Quian Quiroga et al., 2008); and 3) A deflection in the local-field potential (LFP) in the 4-8 Hz band preceding the firing of MTL neurons that is present only in recognized trials (Rey et al., 2014). To put together these results into a coherent framework, we introduce a distinction 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 MTL, triggering a rich representation of the context, associations, and memories linked to the specific stimulus (Navajas et al., 2014).