Abstract
Faces and places are ubiquitous in our environment and recognition of both is crucial for everyday life functioning. Magnetoencephalography (MEG) studies have shown that the perception of faces generates specific MEG components including one at 100 ms and 170 ms post stimulus onset, whereas the perception of places generates an MEG component between 200 and 300 ms post stimulus onset. Given that humans grasp the “gist” of a scene within a small fraction of a second, we aimed to investigate the existence of a potential MEG component associated with place perception occurring earlier than that previously described in literature (between 200 and 300 ms post stimulus onset). MEG activity was recorded while 11 participants were presented with pairs of face and place stimuli (S1 followed by S2), that were either the same (repeated condition) or different (unrepeated condition). Fifty percent of the stimuli were famous and fifty percent unfamiliar. MEG activity associated with S1 was used to define regions of interest (ROIs) for faces and places in both hemispheres. Subsequently, the timecourse of MEG activity associated with S2 was examined within the ROIs. Our results showed that the MEG activity associated with face and place perception differed across hemispheres. In right occipito-temporal ROIs we found that the amplitude of MEG activity at 100 ms post stimulus onset was significantly higher for faces compared to places, in line with the previously described M100 for faces. In contrast, in left occipito-temporal ROIs we found the opposite pattern, namely a significantly higher MEG activity at 100 ms post stimulus onset for places compared to faces, a novel component we referred to as M100p. Neither the M100 nor the M100p were affected by familiarity or by repetition, and are therefore likely to be associated with face/place categorization.