<P> A highly debated model for the origin of orientation maps is Moiré interference from retinal ganglion cells (RGCs). The ideal case takes two layers of perfect hexagonal lattices of the on - center and off - center receptive fields of the RGCs . These two layers are superimposed on each other with an angled offset that produces a periodic interference pattern . This pattern produces dipoles of these RGCs that have a preferred orientation scattered throughout the visual field . This mosaic produces periodic map of preferred orientation that fulfills all orientations with regularity . Cortical inputs from this mosaic of RGCs through the LGN can explain the origin of the orientation maps in the visual cortex . </P> <P> The theory of Moire interference patterns governing the orientation map predicts the existence of orientation scotomas . This is because the lattice of the RGCs are not perfectly hexagonal and therefore, at some locations, representation of specific orientations will be missing . Currently there is research that is testing this hypothesis by "mapping human orientation discrimination thresholds of very small stimuli in the far periphery ." </P> <Ul> <Li> Eye, Brain and Vision By Hubel </Li> <Li> Nobel Lecture 1981 By David Hubel </Li> </Ul> <Li> Eye, Brain and Vision By Hubel </Li>

Cells in striate cortex (area v1) have a preferred