Locating and fractionating working memory using functional neuroimaging: storage, maintenance, and executive functions.

Working memory encompasses the short-term store of information and operations on that information. We review functional neuroimaging studies that have attempted to determine cortical areas involved in working memory functions. Current research suggests distinct systems for verbal information, visual objects, and spatial locations. Passive storage buffers appear to be located in posterior brain areas, whereas active maintenance of the information involves ventrolateral prefrontal areas. More complex, executive operations appear to recruit dorsolateral prefrontal cortex and anterior cingulate cortex. The possible involvement of reciprocal circuits including frontal cortex, basal ganglia, and thalamus is also discussed. Copyright 2000 Wiley-Liss, Inc.