NEURAL SUBSTRATES OF FACIAL RECOGNITION

Seventeen healthy normal volunteers performed three facial recognition tasks while their cerebral bloodflow was measured with PET: categoriz ing faces according to gender, recognizing new faces, and recognizing familiar faces. These tasks activated three different pathways: respec tively, the le;ft inferior temporal lobe and left frontal cortex; a pr edominantly right frontal-right parietal-left cerebellar network; and left lingual and left and right fusiform gyri. These results suggest t hat humans use different brain regions in performing these three routi ne daily activities. The results are consistent with previous observat ions concerning organization of extrastriate visual cortex in human an d nonhuman primate lesion studies, including studies of the unusual sy ndrome of prosopagnosia (loss of the ability to recognize familiar fac es with intact ability to recognize a face as a face).