Figure 5. Comparison of the inner regions of the retina. A: Without a fluorescent nuclear dye (ethidium bromide homodimer; EthD-1) counterstain. B: With nuclear fluorescent dye. Panels A and B show the ganglion cell layer imaged with third harmonic generation (THG) and two-photon autofluorescence (TPAF). The EthD-1 nuclear staining (Panel B, x), coincides with the THG signal from the ganglion cell nuclei (Panel A, *). Panel C shows an adjacent histological section stained with hematoxylin and eosin. The scale bar represents 20 µm.