Frequency-specific neural abnormalities in congenital prosopagnosia revealed by magnetoencephalography during face perception.

Congenital prosopagnosia (CP) is characterized by lifelong impairment in face recognition despite intact basic visual processing. While previous studies have demonstrated preserved "core" face processing with disrupted information propagation to "extended" regions, the temporal dynamics of these deficits remain unclear. Here, we used magnetoencephalography (MEG) during a seeing-as-face task to investigate frequency-specific neural mechanisms in three individuals with CP compared to seventeen healthy controls. By presenting identical visual stimuli perceived either as abstract patterns (Non-Face condition) or schematic faces (Face condition), we isolated face-specific cognitive processes while controlling for low-level visual processing. CP showed preserved early face detection (M120) but exhibited enhanced alpha-band (8-13 Hz) activity in right anterior temporal sensors in the 300-450 ms time window (p = 0.046, cluster-corrected) during face processing - the sole finding surviving rigorous statistical correction. This abnormality was specific to Face conditions and suggests disrupted information integration between core and extended face processing networks. The temporal dissociation between preserved early detection and impaired later processing supports conceptualizing CP as a disconnection syndrome. Our preliminary findings suggest potential frequency-specific neural patterns of face processing deficits in CP, providing neural signatures that may warrant investigation in larger studies.