Functional neuroanatomy of memory for 'old' and 'new' faces: A functional magneticresonance imaging study

Human animal and lesion models of memory have suggested that there is a double dissociation between the neural system involved in retrieving old and new memory. Lesions to medial temporal lobe structures (e.g., hippocampus, parahippocampal gyrus, entorhinal cortex) impair the ability to acquire new declarative memories, but the ability to recall remote memories is relatively preserved. Conversely, lesions to anterior temporal cortical areas selectively disrupt the ability to disrupt the ability to recall remote memories. We tested the notion that the recognition of remote and recent memories are dissociable using whole brain functional magnetic resonance imaging (FMRI) in 11 healthy, right-handed volunteers. Activation associated with the recognition of famous faces, newly learned unfamiliar faces, and recognition foils were averaged and compared using ANOVA. Compared with the recognition of newly learned faces, famous face recognition activated bilateral regions in the frontal and anterior temporal lobe. Famous face recognition also produced greater activation of medial temporal lobe structures than recently learned face recognition. The pattern of activation was similar when famous face recognition was compared to foil rejection. No differences between new unfamiliar faces and foils were observed at the level of the medial temporal lobe. These findings corroborate current models suggesting a fronto-temporal system underlying remote memory retrieval. They do not provide strong evidence that the medial temporal lobe is differentially involved in the retrieval of recent and remote memory in the intact brain.