BRAIN-REGIONS ASSOCIATED WITH RETRIEVAL OF STRUCTURALLY COHERENT VISUAL INFORMATION

AN object's global, three-dimensional structure may be represented by a specialized brain system involving regions of inferior temporal cort ex(1-3). This system's role in object representation can be understood by experiments in which people study drawings of novel objects with p ossible or impossible three-dimensional structures, and later make eit her possible/impossible object decisions or old/new recognition decisi ons about briefly flashed studied and nonstudied objects. Although obj ect decisions about possible objects are facilitated by prior study, t here is no corresponding facilitation for impossible objects, thereby implicating a system that is specifically involved in the representati on of structurally coherent visual objects(4). Here we show, by positr on emission tomography (PET), that increases in blood flow in inferior temporal regions are associated with object decisions about possible but not impossible objects, and that there are increases in the vicini ty of the hippocampal formation associated with episodic recognition o f possible objects.