Psyb51- chapter 3 spatial vision: from stars to stripes| page1. Lateral section of the brain, illustrating early visual areas and showing the putative where (dorsal) and what" (ventral) streams. The basic organization of the pirmary visual pathway from eyeball to striate cortex, in coronal section. The angle subtended by an object at the retina. To calculate the visual angle of your resolution acuity: (size of cycle / distance where orientation is barely seen)arc tan. Light intensity in such gratings varies smoothly and continuously across each cycle. If the receptors are spaced such that the whitest and blackest parts of the gratings fall on separate cones, we can make out the cones. Falls on single cone = see nothing (grayfield) aka aliasing. Cones in the fovea have a center to center separation of about 0. 5 minute of arch (0. 008 degree) Mispreception of a grating due to under sampling.