The prevalence of facial recognition problems appears to have been underestimated in the normal population. Prosopagnosia or """"""""face blindness"""""""" (whether congenital or acquired) causes untold embarrassment and often leads to social isolation. Recent imaging studies in normals have suggested that an area within the fusiform gyrus of the human cortex is active when faces are present, and non-invasive electrophysiological studies have now demonstrated that this activation begins around 140 ms over posterior cortex after presentation of a face (N170 component of the scalp ERP). The amplitude of the N170 is usually larger over the right than left hemisphere for normal upright faces and has been argued to reflect configural processing of faces. There has been some evidence that the response to faces can be modulated by attention. Attention to the configural properties produces more modulation in the right fusiform while attention to parts produces more modulation in the left, reminiscent of the evidence for other global/local hemispheric differences. The studies proposed here concern attention and face perception, including the role of awareness and automaticity (i.e., testing our hypothesis for mandatory priority of faces), some which address questions concerning the level of processing at which faces enter awareness (i.e., testing our hypothesis that all else being equal, attention is drawn to faces reflexively), and others that address the role of executive or top down mechanisms in processing faces under divided and focused conditions. These issues are addressed by combining neuropsychological, cognitive and electrophysiological methods to examine face processing in normal participants, in individuals who suffer from congenital prosopagnosia and in patients with attentional deficits that affect awareness (i.e., hemi-inattention). There are several unique strengths to this proposal: 1) collaboration between the PI and Co-PI with their respective expertise in cognitive neuropsychology of attention and electrophysiology of face perception; 2) the relatively large cohort of congenital prosopagnosic subjects (2 in Israel & 6 in California), some who have already been tested with the same paradigms across our two laboratories; 3) the opportunity for translational training for graduate and post doctoral students who will work on the proposed projects.
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