The neural dynamics of familiarity representation during cued recall

Face familiarity elicits reliable neural signatures during perception, yet how it is represented when faces are recalled from memory by using visual imagery and how these signals relate to perceptual representations, remains unclear. We combined perceptual and imagery conditions with electroencephalography and multivariate pattern analysis. In a perceptual session we presented of four famous individuals, while in the imagery session we used a cued recall paradigm and presented abstract symbols, associated to them. By using time-resolved multivariate decoding we tested if familiarity information is shared across stimulus categories, and if perceptual face familiarity representations overlap with processing during cued recall, related to imagery. The face perception condition showed typical and robust familiarity information over occipito-temporal electrodes. The symbolic cues also carried similar familiarity information, demonstrating cross-category familiarity processing between symbols and faces. During cued recall, familiarity information emerged over posterior regions and evolved into a prolonged and late information component over right anterior electrodes. Importantly, cross-domain temporal generalization analysis revealed an overlap between perceptual face familiarity patterns and recall/imagery related processing: perceptual face familiarity information mapped onto later processing during cued recall, with a pronounced and prolonged right anterior dominance and a shorter overlap over left posterior channels. Together, these results suggest that familiarity processing, similarly to category representations, is supported by overlapping neural patterns across perception and recall/imagery, transitioning from dynamic posterior representations, consistent with perceptual analysis, to a stable and prolonged representation over right anterior sites, that is compatible with a sustained processing, related to recall and/or imagery.