A dissociation between spatial and identity matching in callosotomy patients

ALTHOUGH they are structurally similar, the two hemispheres of the human br ain have many functional asymmetries. Some of these, such as language and m otor control, have been well characterized. Others, such as visuospatial as ymmetries, are less well understood. Many researchers have noted that the r ight hemisphere appears to be specialized for visuospatial processing. We i nvestigated the abilities of the divided cerebral hemispheres of two callos otomy patients to perform discriminations based on spatial or identity info rmation. The data revealed a robust right-hemisphere superiority for spatia l judgments. In contrast, the left hemisphere was somewhat better than the right at making identity judgments. These results suggest that the right he misphere is specialized for spatial processing, and the left is specialized for pattern recognition. NeuroReport 10:2183-2187 (C) 1999 Lippincott Will iams & Wilkins.