Prosopamnesia: a selective impairment in face learning.

The structures required for new learning, and those required for the representation of what has been learned, are believed to be distinct. This counterintuitive division of labour when considered alongside the localised nature of knowledge representation for at least some stimulus domains, implies that circumscribed new learning impairments should occasionally be found as a result of disconnection between learning mechanisms and domain-specific representations. We describe the most narrowly circumscribed new learning deficit so far reported, consisting of a selective new learning impairment for faces, which we term "prosopamnesia." Logically, a diagnosis of prosopamnesia requires preserved face perception, preserved memory for material other than faces (including visual material), and preserved recognition of faces known premorbidly. We describe a patient who meets these criteria, thus supporting the division of labour between neural systems for learning and neural systems for knowledge representation, as well as providing further support for segregated face representation in cortex.