A common view is that visual processing within the ventral visual stream is modulated by attention and awareness. We used fMRI adaptation to investigate whether activation in a network of brain regions involved with face recognition--the fusiform face area (FFA), occipital face area (OFA), and right superior temporal sulcus (rSTS)--was modulated by physical changes to face stimuli or by observers' awareness of the changes. We sequentially presented two matrices of four faces. In two-thirds of the trials one of the faces changed. We compared activations generated in three conditions (i) change-detected trials, (ii) change-blind trials, and (iii) no-change trials. We found that FFA and rSTS recovered from adaptation when subjects were aware of changes; whereas OFA was modulated by the physical changes to a face but not to awareness. These results suggest that, within the face network, OFA is involved in representing information that has not yet entered awareness and that consciousness is not an all-or-none phenomenon throughout the ventral stream.
Large, M. (2007). The fate of unseen faces: an fMRI investigation of awareness in the face perception network. Perception, 36(ECVP Abstract Supplement), 110 - 110