Cortical networks for working memory and executive functions sustain the conscious resting state in man

The cortical anatomy of the conscious resting state (REST) was investigated using a meta-analysis of nine positron emission tomography (PET) activatio n protocols that dealt with different cognitive tasks but shared REST as a common control state. During REST, subjects were in darkness and silence, a nd were instructed to relax, refrain from moving, and avoid systematic thou ghts. Each protocol contrasted REST to a different cognitive task consistin g either of language, mental imagery, mental calculation, reasoning, finger movement, or spatial working memory, using either auditory, visual car no stimulus delivery, and requiring either vocal, motor or no output. A total of 63 subjects and 370 spatially normalized PET scans were entered in the m eta-analysis. Conjunction analysis revealed a network of brain areas jointl y activated during conscious REST as compared to the nine cognitive tasks, including the bilateral angular gyrus, the left anterior precuneus and post erior cingulate cortex, the left medial frontal and anterior cingulate cort ex, the left superior and medial frontal sulcus, and the left inferior fron tal cortex. These results suggest that brain activity during conscious REST is sustained by a large scale network of heteromodal associative parietal and frontal cortical areas, that can be further hierarchically organized in an episodic working memory parieto-frontal network, driven in part by emot ions, working under the supervision of an executive left prefrontal network . (C) 2001 Elsevier Science Inc.