FACE ENCODING AND RECOGNITION IN THE HUMAN BRAIN

A dissociation between human neural systems that participate in the en coding and later recognition of new memories for faces was demonstrate d by measuring memory task-related changes in regional cerebral blood flow with positron emission tomography. There was almost no overlap be tween the brain structures associated with these memory functions. A r egion in the right hippocampus and adjacent cortex was activated durin g memory encoding but not during recognition, The most striking findin g in neocortex was the lateralization of prefrontal participation. Enc oding activated left prefrontal cortex, whereas recognition activated right prefrontal cortex. These results indicate that the hippocampus a nd adjacent cortex participate in memory function primarily at the tim e of new memory encoding. Moreover, face recognition is not mediated s imply by recapitulation of operations performed at the time of encodin g but, rather, involves anatomically dissociable operations.