The Attentional Role of the Left Parietal Cortex: The Distinct Lateralization and Localization of Motor Attention in the

& It is widely agreed that visuospatial orienting attention depends on a network of frontal and parietal areas in the right hemisphere. It is thought that the visuospatial orienting role of the right parietal lobe is related to its role in the production of overt eye movements. The experiments reported here test the possibility that other parietal regions may be important for directing attention in relation to response modalities other than eye movement. Specifically, we used positron emission tomography (PET) to test the hypothesis that a ’left ’ parietal area, the supramarginal gyrus, is important for attention in relation to limb movements (Rushworth et al., 1997; Rush-worth, Ellison, & Walsh, in press). We have referred to this process as ’motor attention ’ to distinguish it from orienting attention. In one condition subjects spent most of the scannin