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

TLDR

Visual systems in primates separate object and spatial processing into distinct pathways that project to different frontal lobe areas. The study aimed to test whether humans show anatomical segregation of object and spatial visual working memory. The authors used positron emission tomography to measure regional cerebral blood flow during face and location working memory tasks. Face and location working memory recruit distinct neural networks, with face memory activating ventral temporal and frontal regions and location memory engaging dorsal parietal and frontal areas.

Abstract

Human and nonhuman primate visual systems are divided into object and spatial information processing pathways. In the macaque, it has been shown that these pathways project to separate areas in the frontal lobe and that the ventral and dorsal frontal areas are, respectively, involved in working memory for objects and spatial locations. A positron emission tomography (PET) study was done to determine if a similar anatomical segregation exists in humans for object and spatial visual working memory. Face working memory demonstrated significant increases in regional cerebral blood flow (rCBF), relative to location working memory, in fusiform, parahippocampal, inferior frontal, and anterior cingulate cortices, and in right thalamus and midline cerebellum. Location working memory demonstrated significant increases in cRBF, relative to face working memory, in superior and inferior parietal cortex, and in the superior frontal sulcus. Our results show that the neural systems involved in working memory for faces and for spatial location are functionally segregated, with different areas recruited in both extrastriate and frontal cortices for processing the two types of visual information.