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, du ring which they viewed alternating left and right visual hemifield stimulat ion. Intensity variations from the variable TR were removed, and the data w ere evaluated for correlation with the lateralized stimulus. The data indic ate a strongly preferential response of the left superior colliculus to the right side of visual space, and vice versa. This is consistent with previo us findings in animal systems and confirms the existence of spatiotopy in t he human superior colliculus. (C) 2000 Academic Press.