Face processing without awareness in the right fusiform gyrus

Abstract

We investigated brain activity evoked by faces which were not consciously perceived by subjects. Subdural electrophysiological recordings and functional neuroimaging studies have each demonstrated face-specific processing in the fusiform gyrus (FFG) of humans. Using pattern masks, a stimulus can be presented but not consciously perceived, and thus can be used to assay obligatory or automatic processes. Here, using event-related functional magnetic resonance imaging and pattern masking, we observed that masked faces but not masked objects activated the right FFG. Other regions activated by consciously perceived unmasked faces were not activated when faces were masked. These data provide strong evidence for an automatic face processing region in the right FFG.A briefly exposed visual stimulus may not be consciously perceived if it is preceded and followed by a dissimilar visual pattern, or mask. Masked facial expressions have been shown to influence the activation of the amygdala by subsequent visible faces (Whalen et al., 1998) thus demonstrating that some aspects of face processing can occur without conscious awareness. It has been suggested in these studies that the amygdala is responding to a primitive face representation that bypasses processing in extrastriate cortical regions such as the fusiform gyrus (FFG). Functional MRI studies have demonstrated that visible faces selectively activate focal regions of the FFG (e.g., Kanwisher, McDermott, & Chun, 1997;McCarthy, Puce, Gore, & Allison, 1997;Puce, Allison, Gore, & McCarthy, 1995); however, whether masked faces similarly activate these regions has not yet been examined. Here, we compared activation evoked by masked and unmasked faces and non-face objects to determine whether the FFG and other brain regions are activated by faces without a subject's awareness. Methods SubjectsTwenty healthy young adults (10 males) served as subjects in the fMRI study. Two groups of 10 additional healthy young adults (9 male) participated in two separate behavioral

Greater sensitivity of the cortical face processing system to perceptually-equated face detection

“…Thus, the robust responses of FFA and OFA to facial configuration information suggest that these brain areas provide neural substrates for initial processing of global facial signals, in addition to later analysis of local and detailed facial features. Significant activation differences were not found for correct vs. incorrect responses in either region, consistent with the notion that these structures responded automatically to the presence of face regardless of awareness (Morris et al, 2007), a property one may expect of a system tuned to be sensitive to a particular stimulus type.…”

“…Studies of patients with prosopagnosia bolsters this division, as these patients can identify face from non-face but cannot tell the identity of faces (Barton, Cherkasova, Press, Intriligator, & O'Connor, 2003; Behrmann & Avidan, 2005). Further evidence comes from demonstration of face detection without awareness (Morris, Pelphrey, & McCarthy, 2007). It is not entirely clear whether this initial process of face perception is mediated by the same face processing system that is responsible for other aspects of face perception, though involvement of fusiform gyrus has been shown in a previous study (Morris et al, 2007).…”

“…Further evidence comes from demonstration of face detection without awareness (Morris, Pelphrey, & McCarthy, 2007). It is not entirely clear whether this initial process of face perception is mediated by the same face processing system that is responsible for other aspects of face perception, though involvement of fusiform gyrus has been shown in a previous study (Morris et al, 2007). …”

Wanting it Too Much: An Inverse Relation Between Social Motivation and Facial Emotion Recognition in Autism Spectrum Disorder

“…After confirming waveform morphology in the grand average and from each individual participant’s data, ERPs were extracted from electrode sites corresponding to those indicated in previous literature [23, 29]. Specifically, N170 (latency; between 160 and 220 ms) was identified at the right PO4 electrode [10, 27, 61, 62], which was selected based on evidence suggesting greater right hemisphere cortical specialization for faces [63]. Peak N170 latencies across all ‘‘good’’ trials were averaged for each participant and subsequently used in the analyses below.…”

An integrative neural model of social perception, action observation, and theory of mind

“…Among them, the fusiform face area (FFA) selectively responds to face stimuli, whereas the fusiform body area (FBA) selectively responds to body stimuli (Schwarzlose et al, 2005). The FFA is sensitive to the typical pattern of saccades and fixations observed during implicit facial processing (Morris et al, 2007a, 2007b). Furthermore, the FFA is involved in facial identity recognition (Pitcher et al, 2011), and goal-directed action recognition (Gobbini et al, 2007, 2011; Schultz et al, 2003; Shultz and McCarthy, 2012).…”