An attempt to explain the differences between the upper and lower halves of the striate cortical map of the cat's field of view.

Cowey and Rolls have shown that the magnification factor with which the retina is imaged onto the striate cortex is proportional to visual acuity. Schwartz has used this to derive how visual peripheral acuity in the human varies with distance from the fovea, in good agreement with experiment. The same reasoning applied to the map of the lower half of the field of view as imaged onto the striate cortex of the cat indicates that the cat fixating a point up to about 100 cm in front of him sees the foreground portion of the horizontal surface on which he is standing approximately uniformly blurred.