An alternative staining method to demonstrate the substance stained black in the image is which of the following?

• A. Luxol Fast Blue
• B. Congo red
• C. Sudan Black
• D. Toluidine Blue

Answer: (A)

The main idea is recognizing a stain that specifically highlights myelin in nervous tissue. Luxol Fast Blue binds to the lipid components of myelin sheaths, coloring white matter blue. In many micrographs this blue can appear very dark, even black, which makes it a natural alternative to demonstrate the same substance that’s shown as black in the image. Since the goal is to visualize myelin, Luxol Fast Blue is the most direct and reliable choice.

Congo red targets amyloid proteins, not myelin, so it wouldn’t reveal the same structure. Sudan Black also stains lipids and can highlight myelin, but it’s less specific for myelin architecture and is typically used for general lipid visualization. Toluidine Blue is a general stain that isn’t specific for myelin.