We propose to investigate the organization of directed spatial attention based on a model that relates different behavioral components to different sectors of a distributed neuroanatomical network. The behavioral and anatomical mechanisms related to overt and covert attentional processes will be examined in subjects who have had a unilateral cerebral stroke and in non-brain-injured, age-matched controls. Variables to measure include reaction time to visual stimuli in the right and left hemispaces, numbers of targets detected, visual dwell times, etc.