Prosopamnesia: A selective impairment in face learning

The structures required for new learning, and those required for the repres entation of what has been learned, are believed to be distinct. This counte rintuitive division of labour when considered alongside the localised natur e of knowledge representation for at least some stimulus domains, implies t hat circumscribed new learning impairments should occasionally be found as a result of disconnection between learning mechanisms and domain-specific r epresentations. We describe the most narrowly circumscribed new learning de ficit so far reported, consisting of a selective new learning impairment fo r faces, which we term "prosopamnesia." Logically, a diagnosis of prosopamn esia requires preserved face perception, preserved memory for material othe r than faces (including visual material), and preserved recognition of face s known premorbidly. We describe a patient who meets these criteria, thus s upporting the division of labour between neural systems for learning and ne ural systems for knowledge representation, as well as providing further sup port for segregated face representation in cortex.