FUNCTIONAL NEUROANATOMY OF THE HUMAN VISUAL FIXATION SYSTEM

The regional cerebral blood flow correlates of the active fixation of an imagined target were studied in five healthy humans using the posit ron emission tomography activation paradigm. The fixation task was con trasted to a passive control condition, both tasks being performed in total darkness. Blood flow increases were observed in the frontal eye fields and supplementary eye fields and in the median cingulate gyrus. We suggest that the network of these activated regions mediates the i nteractions between ocular fixation, eye movements and directed visual attention.