3D-topography of cell nuclei in a vertebrate retina--a confocal and two-photon microscopic study

We demonstrate methods to simultaneously acquire and evaluate the pattern of cell nuclei in the three cell layers of the vertebrate retina as an aspect of its functional morphology. 3D-position, shape and quantity of fluorescence-labelled cell nuclei are measured using laser scanning microscopy at several retinal locations, the pros and cons of single and two-photon excitation are compared. Subsequently topographies of all discriminable morphotypes are calculated via linear interpolation of local countings. In addition derived maps are calculated correlating density- and layer thickness-distributions to demonstrate the potential of 3D-morphometry in the retina. In the European anchovy Engraulis encrasicolus L. (Engraulididae, Teleostei) the angular density of all involved cell types varies considerably with the location in the hemispherical coordinate system. All cells belonging to the photopic system show a density peak in the ventro-temporal quadrant, suggesting acute vision in the frontal binocular visual field. A second, less pronounced maximum is found nasally.