Dissociating person-specific from general semantic knowledge: roles of the left and right temporal lobes.

The cognitive architecture and neural underpinnings of different semantic domains remains highly controversial. We report two patients with focal temporal lobe atrophy who presented with contrasting and theoretically informative dissociations of person-specific versus general semantic knowledge. Subject J.P. showed severely impaired person-specific semantics, with relative preservation of knowledge about objects and animals, while subject M.A. exhibited the opposite pattern of performance (good knowledge of people in the context of impoverished general semantics). Voxel-based morphometric analysis of MR images in the two cases established predominantly right temporal atrophy associated with J.P.'s deficit for person knowledge and predominantly left temporal atrophy in M.A. who was impaired in general conceptual knowledge.