Located between the brain stem and the cerebral hemispheres is a region of the brain known as the thalamus. The thalamus is a double lobed mass of gray matter that in humans is approximately the size of a small egg. It is separated from the thalamus by a small groove known as the hypothalamic sulcus and forms part of the lateral wall of the third ventricle. In most people, the lobes of the thalamus are connected by the massa intermedia across the ventricle, but in about one-fifth of the population, they are discrete structures. The thalamus is important as a relay between other regions of the nervous system and is thought to modulate sensory signals.

Myelin basic protein, which is expressed in myelin axon sheaths, and glial fibrillary acidic protein, a type III intermediate filament protein found primarily in astroglia, were immunofluorescently labeled in the rat brain sagittal tissue section presented above by treating the specimen with a cocktail of mouse anti-myelin BP and rabbit anti-GFAP primary antibodies followed by goat anti-mouse and anti-rabbit secondary antibodies conjugated to Alexa Fluor 488 and Alexa Fluor 568, respectively. Hoechst 33342, a dsDNA-interactive agent, was utilized to target cell nuclei. Images were recorded in grayscale with a 12-bit digital camera coupled to a Nikon Eclipse 80i microscope equipped with bandpass emission fluorescence filter optical blocks. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles.