In a double immunofluorescence experiment, the coronal rat cerebral cortex section featured in this confocal image was fixed, permeabilized, blocked with 10-percent normal goat serum, and then treated with a cocktail of mouse anti-beta-III-tubulin (microtubules in neurons) and chicken anti-NF-H (neurofilaments) primary antibodies followed by goat anti-mouse and anti-chicken secondary antibodies (IgG) conjugated to Alexa Fluor 488 and Alexa Fluor 568, respectively. The specimen was counterstained for nuclei with DRAQ5, a far-red fluorescent DNA probe. Images were recorded with a 40x oil immersion objective using a zoom factor of 1.8 and sequential scanning with the 488-nanometer spectral line of an argon-ion laser, the 543-nanometer line from a green helium-neon laser, and the 633-nanometer line of a red helium-neon laser. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles, with the exception of DRAQ5, which was pseudocolored blue.