Object and Spatial Visual Working Memory Activate Separate Neural Systems in Human Cortex

Human and nonhuman primate visual systems are divided into objectand spatial information processing pathways. In the macaque,it has been shown that these pathways project to separate areasin the frontal lobe and that the ventral and dorsal frontalareas are, respectively, involved in working memory for objectsand spatial locations. A positron emission tomography (PET)study was done to determine if a similar anatomical segregationexists in humans for object and spatial visual working memory.Face working memory demonstrated significant increases in regionalcerebral blood flow (rCBF), relative to location working memory,in fusiform, parahippocampal, inferior frontal, and anteriorcingulate cortices, and in right thalamus and midline cerebellum.Location working memory demonstrated significant increases inrCBF, relative to face working memory, in superior and inferiorparietal cortex, and in the superior frontal sulcus. Our resultsshow that the neural systems involved in working memory forfaces and for spatial location are functionally segregated,with different areas recruited in both extrastriate and frontalcortices for processing the two types of visual information.