BOLD response in dorsal areas varies with relative disparity level.
Using fMRI, we explored cortical responses to dichoptically presented random-dot (RD) stimuli which formed a checkerboard by means of horizontal disparity (Julesz). Depth reversals occurred every 800 ms by appropriate horizontal shifting of a subset of the RD pattern. We compared cortical blood oxygen level dependent (BOLD) responses of five subjects under conditions with and without binocular disparity. The results indicate that only extrastriate, but not striate, areas responded more to the stimuli with binocular disparity. We further found that the BOLD signal increased with increasing disparity level only in dorsal areas of occipito-parietal and prefrontal cortex. These results suggest that the fMRI BOLD response can reflect the processing of relative binocular disparity in extrastriate cortex.
Rutschmann
Roland Marcus
RM
Cognitive Neurosciences, University of Oldenburg, Ammerländer Heerstrasse 114, 26111 Oldenburg, Germany. Roland.M.Rutschmann@uni-oldenburg.de
Greenlee
Mark W
MW
D001931:Brain Mapping; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D010296:Parietal Lobe / Q000033:anatomy & histology / Q000502:physiology; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D017397:Prefrontal Cortex / Q000033:anatomy & histology / Q000502:physiology; D011930:Reaction Time / Q000502:physiology; D012016:Reference Values; D015357:Vision Disparity / Q000502:physiology*; D014793:Visual Cortex / Q000033:anatomy & histology / Q000502:physiology*; D014795:Visual Pathways / Q000033:anatomy & histology / Q000502:physiology