High-Resolution FMRI of Visual Stimulation and Attention in Human Superior Colliculus

David Ress^1,2, Sucharit Katyal², Clint Greene¹

We measured the retinotopic organization of superior colliculus to direct visual stimulation using a 90-wedge of moving dots that rotated around fixation. The retinotopy of covert attention was measured using a full-field array of moving dots. Subjects were cued to perform a task within a 90 portion of the stimulus, and only the cue rotated around fixation. FMRI (1.2 mm voxels) data shows retinotopic maps of both visual stimulation and covert attention that are in registration with each other. Visual attention and stimulation produced activity primarily in the superficial and intermediate laminae, but attention activity was more superficial than stimulation.