Which staining technique uses copper in its impregnating solution to increase differentiation between neural and connective tissues?

• A. Bodian
• B. Weil
• C. Luxol fast blue
• D. PTAH

Answer: (A)

The main idea is that copper in the impregnation step helps silver-based neural stains distinguish nerve tissue from surrounding connective tissue. In the Bodian method, sections are impregnated with a copper-containing silver solution so that neural elements—axons, dendrites, and neurofibrils—deposit silver more readily. When developed, these neural structures appear dark (often black) while connective tissue remains comparatively pale, giving a sharp contrast that highlights neural architecture. This selective enhancement is what makes Bodian particularly useful for tracing nerve fibers in brain and peripheral nerves.