Which stain is used for the demonstration of neurofibrillary tangles?

• A. Bielschowsky
• B. Bodian
• C. Holzer
• D. Cresyl echt Violet

Answer: (A)

Neurofibrillary tangles are best visualized with a silver impregnation stain because silver methods selectively deposit silver on the neurofibrils inside neurons, making the tangles appear as dark, thread-like structures against a lighter background. The Bielschowsky stain is a classic silver stain specifically developed to highlight neurofibrillary tangles and neuritic plaques, providing sharp contrast and clear visualization that neuropathology relies on for diagnosing Alzheimer’s disease. Other stains in the list have different primary targets: Cresyl echt Violet stains Nissl substance in neuronal cell bodies and doesn’t reveal tangles; Bodian stains are more general for nerve fibers and neuropil; Holzer is another silver method but not the standard for NFTs.