HEMISPHERIC-ASYMMETRY OF ARTERIAL BLOOD-FLOW VELOCITY CHANGES DURING VERBAL AND VISUOSPATIAL TASKS

Changes in arterial blood flow velocity induced by cognitive activity were measured by simultaneous bilateral transcranial Doppler sonograph y (TCD) of the posterior and the middle cerebral artery. The finding o f a robust left hemisphere dominance for verbal tasks but of an incons istent right hemisphere dominance for visuospatial tasks obtained in a n earlier study [13], in which TCD measurement had been restricted to the middle cerebral arteries, was confirmed. At the same time, it coul d be demonstrated that the failure to find the expected right hemisphe re dominance for tasks of spatial visualization and mental rotation ex tended to the TCD measurement of the posterior cerebral arteries. Copy right (C) 1996 Elsevier Science Ltd