3-DIMENSIONAL RECONSTITUTION OF CONE ARRANGEMENT ON THE SPHERICAL SURFACE OF THE RETINA IN THE MEDAKA EYES

In the retina of the medaka four kinds of retinal cone photoreceptor c ells are arranged in a simple, repeating organizational pattern known as a square mosaic. We found that the distribution of cones in the ret ina could be easily detected by autofluorescence-emission from the pho toreceptor cells without any staining. In tangential sections of the r etina, cones were located at a specific position in a crystalline latt ice as follows: Double cone pairs display a zigzagging appearance, ori ented roughly 90-120 degrees to one another, and single cones were in the center of the square consisting of four double cone pairs. In orde r to determine the continuity of this regular arrangement on the spher ical surface, the distribution of this cone mosaic pattern was examine d in central, dorsal, ventral, nasal and caudal areas of the retina. T he regular arrangement of cones was confirmed in the whole retina. Dou ble cones and single cones are in their respective lines and these lin es form a lattice-work. As a result of reconstructing these arrangemen ts on the retinal hemisphere, the lines of this lattice-work of cones were found to be orthogonal to the retinal margin, radiating from the center of the retina-like meridians, and parallel to the retinal margi n forming concentric circles that is reminiscent of a longitudinal and a latitudinal lines of a terrestrial globe. This construction of the cone arrangement in whole retina of the medaka was consistent with mai ntaining a rectangular mosaic in growing retina with newly produced ce lls only in a marginal cell proliferating zone.