Spatiotopic organization in human superior colliculus observed with fMRI

Spatiotopy is a fundamental organizing principle of the visual brain. Using functional magnetic resonance imaging, we have demonstrated reliable data, consistent with spatiotopic organization in the human superior colliculi. Five subjects underwent cardiac-triggered echo-planar image acquisition, during which they viewed alternating left and right visual hemifield stimulation. Intensity variations from the variable TR were removed, and the data were evaluated for correlation with the lateralized stimulus. The data indicate a strongly preferential response of the left superior colliculus to the right side of visual space, and vice versa. This is consistent with previous findings in animal systems and confirms the existence of spatiotopy in the human superior colliculus. (C) 2000 Academic Press.