Prioritized Detection of Personally Familiar Faces

We investigated whether personally familiar faces are preferentially processed in conditions of reduced attentional resources and in the absence of conscious awareness. In the first experiment, we used Rapid Serial Visual Presentation (RSVP) to test the susceptibility of familiar faces and faces of strangers to the attentional blink. In the second experiment, we used continuous flash interocular suppression to render stimuli invisible and measured face detection time for personally familiar faces as compared to faces of strangers. In both experiments we found an advantage for detection of personally familiar faces as compared to faces of strangers. Our data suggest that the identity of faces is processed with reduced attentional resources and even in the absence of awareness. Our results show that this facilitated processing of familiar faces cannot be attributed to detection of low-level visual features and that a learned unique configuration of facial features can influence preconscious perceptual processing

Distributed Neural Systems for Face Perception

Face perception plays a central role in social communication and is, arguably, one of the most sophisticated visual perceptual skills in humans. Consequently, face perception has been the subject of intensive investigation and theorizing in both visual and social neuroscience. The organization of neural systems for face perception has stimulated intense debate. Much of this debate has focused on models that posit the existence of a module that is specialized for face perception versus models that propose that face perception is mediated by distributed processing. In our work, we have proposed that face perception is mediated by distributed systems, both in terms of the involvement of multiple brain areas and in terms of locally distributed population codes within these areas. Specifically, we proposed a model for the distributed neural system for face perception that has a Core System of visual extrastriate areas for visual analysis of faces and an Extended System that consists of additional neural systems that work in concert with the Core System to extract various types of information from faces. We also have shown that in visual extrastriate cortices, information that distinguishes faces from other categories of animate and inanimate objects is not restricted to regions that respond maximally to faces, i.e. the fusiform and occipital face areas

Neural response to the visual familiarity of faces

Recognizing personally familiar faces is the result of a spatially distributed process that involves visual perceptual areas and areas that play an essential role in other cognitive and social functions, such as the anterior paracingulate cortex, the precuneus and the amygdala [M.I. Gobbini, E. Leibenluft, N. Santiago, J.V. Haxby, Social and emotional attachment in the neural representation of faces, Neuroimage 22 (2004) 1628–1635; M.I. Gobbini, J.V. Haxby, Neural systems for recognition of familiar faces, Neuropsychologia, in press; E. Leibenluft, M.I. Gobbini, T. Harrison, J.V. Haxby, Mothers’ neural activation in response to pictures of their, and other, children, Biol. Psychiatry 56 (2004) 225–232]. In order to isolate the role of visual familiarity in face recognition, we used fMRI to measure the response to faces characterized by experimentally induced visual familiarity that carried no biographical information or emotional content. The fMRI results showed a stronger response in the precuneus to the visually familiar faces consistent with studies that implicate this region in the retrieval of information from long term memory and imagery. Moreover, this finding supports the hypothesis of a key role of the precuneus in the acquisition of familiarity with faces [H. Kosaka, M. Omori, T. Iidaka, T. Murata, T. Shimoyama, T. Okada, N. Sadato, Y. Yonekura, Y. Wada, Neural substrates participating in acquisition of facial familiarity: an fMRI study, Neuroimage 20 (2003) 1734–1742]. By contrast, the visually familiar faces evoked a weaker response in the fusiform gyrus, which may reflect the development of a sparser encoding, or a reduced attentional load when processing stimuli that are familiar. The visually familiar faces evoked also a weaker response in the amygdala, supporting the proposed role of this structure in mediating the guarded attitude when meeting someone new

Three virtues of similarity based multivariate pattern analysis: an example from the object vision pathway

We present an fMRI investigation of object representation in the human ventral vision pathway highlighting three aspects of similarity analysis that make it especially useful for illuminating the representational content underlying neural activation patterns. First, similarity structures allow for an abstract depiction of representational content in a given brain region. This is demonstrated using hierarchical clustering and multidimensional scaling (MDS) of the dissimilarity matrices defined by our stimulus categories\u2014female and male human faces, dog faces, monkey faces, chairs, shoes, and houses. For example, in ventral temporal (VT) cortex the similarity space was neatly divided into face and non-face regions. Within the face region of the MDS space, male and female human faces were closest to each other, and dog faces were closer to human faces than monkey faces. Within the non-face region of the abstract space, the smaller objects\u2014shoes and chairs\u2014were closer to each other than they were to houses. Second, similarity structures are independent of the data source. Dissimilarities among stimulus categories can be derived from behavioral measures, from stimulus models, or from neural activity patterns in different brain regions and different subjects. The similarity structures from these diverse sources all have the same dimensionality. This source independence allowed for the direct comparison of similarity structures across subjects (n = 16) and across three brain regions representing early, middle, and late stages of the object vision pathway. Finally, similarity structures can change shape in well-ordered ways as the source of the dissimilarities changes\u2014helping to illuminate how representational content is transformed along a neural pathway. By comparing similarity spaces from three regions along the ventral visual pathway, we demonstrate how the similarity structure transforms from an organization based on low-level visual features\u2014as reflected by patterns in early visual cortex\u2014to a more categorical representation in late object vision cortex with intermediate organization at the middle stage

Dorsomedial prefrontal cortex responses to appearance-based and behavior-based person impressions

We explored the neural correlates of learning about people when the affective value of both facial appearance and behavioral information is manipulated. Participants were presented with faces that were either rated as high or low on trustworthiness. Subsequently, we paired these faces with positive, negative, or no behavioral information. Prior to forming face-behavior associations, a cluster in the right amygdala responded more strongly to untrustworthy than to trustworthy faces. During learning, a cluster in the dorsomedial prefrontal cortex (dmPFC) responded more strongly to faces paired with behaviors than faces not paired with behaviors. We also observed that the activity in the dmPFC was correlated with behavioral learning performance assessed after scanning. Interestingly, individual differences in the initial amygdala response to face trustworthiness prior to learning modulated the relationship between dmPFC activity and learning. This finding suggests that the activity of the amygdala can affect the interaction between dmPFC activity and learning