ABSTRACT
It is widely accepted that the human parietal cortex is concerned with visuospatial representation and attention. In the case of the macaque monkey, however, anatomical, neurophysiological and lesion data suggest that only limited regions of parietal cortex are involved in visuospatial representation and attention, while other areas are more concerned with the control of limb and hand movements. Recent imaging and transcranial magnetic stimulation data have suggested possible homologues of the different parietal regions in the human brain and have raised the possibility that there are different attentional systems within the parietal lobe. A posterior, possibly lateral, intraparietal area may be concerned with (1) visuospatial attentional selection and (2) orienting covert, preparatory visuospatial attention prior to an overt eye movement. Other parietal areas, one in the posterior, superior parietal lobule and adjacent medial intraparietal sulcus and one in the anterior inferior parietal cortex and adjacent anterior intraparietal sulcus, are concerned with (1) motor intentional selection and (2) directing covert, preparatory motor attention prior to an overt arm movement.
