Abstract
Background: Prosopagnosia following right anterior temporal lesions alone has rarely been described, though functional imaging has suggested that face processing involves regions like aIT, anterior to the core face processing network (the fusiform face area, FFA, occipital face area, OFA, and superior temporal sulcus, STS). Prior work has hypothesized that anterior temporal lesions could cause an associative or amnestic variant of prosopagnosia, though it has been questioned whether this can be independent of a multimodal semantic deficit for people. Objective: Our goal was to determine the type of face recognition deficit after lesions limited to the right anterior temporal lobe. Method: We evaluated face recognition, perception and imagery as well as semantic knowledge about people in two subjects with prosopagnosia following herpes encephalitis causing right temporal pole lesions, in whom fMRI confirmed the integrity of FFA, OFA, and STS. Results: Both subjects performed normally on nearly all tests of perception of facial configuration and features, discrimination of face gender, and face detection. Subject R-AT2 was mildly impaired in discriminating changes in identity when expression also varied, and vice versa, suggesting some difficulty with invariant representations. Subject R-AT3 had mild impairments in discriminating eye shape and mouth changes, but far less severe than in subjects with FFA/OFA damage. In contrast, both subjects had markedly impaired face imagery. Finally, both subjects performed well on identifying famous names and linking semantic data such as occupation to names, in contrast to another subject with bilateral anterior temporal lesions. Conclusion: The right anterior temporal variant of prosopagnosia is characterized by impaired access to facial memories with relatively preserved face perception and semantic knowledge about people, consistent with an amnestic or associative functional subtype of prosopagnosia.
TB was supported by Chargé de recherches, Les Fonds de la Recherche Scientifique, Belge. The work was supported by ESRC grant RES 061-23-0040 and CIHR grant MOP-102567.