the cerebral cortex's convex gyri folds whereas the horizontal meridian tends to be represented in their concave sulci folds. Methods Retinotopy mapping in humans is done with functional Magnetic Resonance Imaging (fMRI). The subject inside the fMRI machine focuses on a point. Then the retina is stimulated with a circular image or angled lines about focus point. The radial map displays the distance from the center of vision. The angular map shows angular location using rays angled about the center of vision. Combining the radial and angular maps, you can see the separate regions of the visual cortex and the smaller maps in each region. See also Biological neural network Cortical magnification Frontal eye field Tonotopy Visual space References Visual system