The neural correlates of person familiarity - A functional magnetic resonance imaging study with clinical implications

Neural activity was measured in 10 healthy volunteers by functional MRI whi le they viewed familiar and unfamiliar faces and listened to familiar and u nfamiliar voices. The familiar faces and voices were those of people person ally known to the subjects; they were not people who are more widely famous in the media. Changes in neural activity associated with stimulus modality irrespective of familiarity were observed in modules previously demonstrat ed to be activated by faces (fusiform gyrus bilaterally) and voices (superi or temporal gyrus bilaterally), Irrespective of stimulus modality, familiar ity of faces and voices (relative to unfamiliar faces and voices) was assoc iated with increased neural activity in the posterior cingulate cortex, inc luding the retrosplenial cortex, Our results suggest that recognizing a per son involves information flow from modality-specific modules in the tempora l cortex to the retrosplenial cortex. The latter area has recently been imp licated in episodic memory and emotional salience, and now seems to be a ke y area involved in assessing the familiarity of a person. We propose that d isturbances in the information flow described may underlie neurological and psychiatric disorders of the recognition of familiar faces, voices and per sons (prosopagnosia, phonagnosia and Capgras delusion, respectively).