DISSOCIATION OF PATHWAYS FOR OBJECT AND SPATIAL VISION - A PET STUDY IN HUMANS

A positron emission tomography (PET) study was conducted to determine which brain regions are differentially involved in visual object ident ification and object localization Subjects engaged in a spatial task i n which they matched the location of common objects, and an object tas k in which they matched the identity of common objects. In both tasks the stimulus arrangements used were of the same kind. Regional cerebra l blood Bow data showed that a right-sided region in the inferior pari etal lobule was more activated during spatial than during object match ing. In contrast, bilateral occipitotemporal regions, with the left mo re predominant, were more activated during object than spatial matchin g. These results provide support for Ungerleider and Mishkin's dual pa thway model of vision and indicate important patterns of lateralizatio n in the human visual system.