PASAT PERFORMANCE AND THE PATTERN OF UPTAKE OF TC-99M-EXAMETAZIME IN BRAIN ESTIMATED WITH SINGLE-PHOTON EMISSION TOMOGRAPHY

The effect of the paced auditory serial addition test (PASAT) on the r egional uptake of Tc-99m-exametazime was determined by single photon e mission computed tomography. Twenty insulin-treated diabetic outpatien ts were scanned at rest and during the performance of the PASAT task u sing split-dose injection of tracer. When resting and activation scans were compared there were significant decreases in tracer uptake in th e right anterior cingulate and left posterior cingulate areas during P ASAT activation. The findings are compared with previous studies which had implicated the anterior cingulate area in the mechanisms of atten tion in humans and other animals. The potentially confounding role of anxiety during attentional tasks is discussed.