Recognition memory of newly learned faces.

We used event-related fMRI to study recognition memory of newly learned faces. Caucasian subjects memorized unfamiliar, neutral and happy South Korean faces and 4 days later performed a memory retrieval task in the MR scanner. We predicted that previously seen faces would be recognized faster and more accurately and would elicit stronger neural activation than novel faces. Consistent with our hypothesis, novel faces were recognized more slowly and less accurately than previously seen faces. We found activation in a distributed cortical network that included face-responsive regions in the visual cortex, parietal and prefrontal regions, and the hippocampus. Within all regions, correctly recognized, previously seen faces evoked stronger activation than novel faces. Additionally, in parietal and prefrontal cortices, stronger activation was observed during correct than incorrect trials. Finally, in the hippocampus, false alarms to happy faces elicited stronger responses than false alarms to neutral faces. Our findings suggest that face recognition memory is mediated by stimulus-specific representations stored in extrastriate regions; parietal and prefrontal regions where old and new items are classified; and the hippocampus where veridical memory traces are recovered.