Retinotopic organization of lateral eye input to Limulus brain

1. The retinotopic organization of retinal inputs from the lateral eye of Limulus to the optic ganglia of the brain was determined from microelectrode recordings of nerve impulses. 2. The central connections of the natural subunits of the lateral optic nerve were determined using cobalt impregnation of cut axons. 3. Complete retinal maps exist in both the lamina and medulla. The laminar map is a simple rotation and folding of the retinal array. The medullar map is more complex as a result of the combined effects of the chiasma and the basic subunit structure of the optic nerve, which is preserved in the lamina and medulla. 4. The chiasma between the lamina and medulla reverses the anterior-posterior axis of the retinal map. There is no corresponding reversal in the dorsal-ventral axis.