ABSTRACT
This chapter explores the early studies on selective attention that used nontomographic regional cerebral blood-Flow (rCBF) methods. These methods permitted rCBF determination only at the cortical level. The chapter reviews that related positron emission tomography (PET) and single photon emission computed tomography (SPECT) work, which made it possible to measure rCBF and regional metabolic changes in the entire brain. The normal rCBF resting pattern is "hyperfrontal". The prefrontal and frontal regions, as well as the posterior Sylvian region, appear to be relatively active, whereas the temporal, parietal, and postcentral Rolandic regions are less active. In an early study on task-specific rCBF, J. Risberg and D. H. Ingvar found that in problem solving using Raven matrices or a backward digit-span memory test, the flow increased in premotor and frontal regions. The attention-dependent rCBF foci corresponded to regions of extrastriate visual cortex that appear to be specialized for processing sensory information corresponding to the attended attribute.
