Histological examination of brain tissue in Alzheimer's patients reveals the presence of amyloid plaques and neurofibrillary tangles. Special staining techniques, such as immunohistochemistry and silver staining, are used to visualize these pathological features. For instance, the Bielschowsky stain is commonly used to highlight neurofibrillary tangles, while the Congo red stain can identify amyloid plaques under polarized light, showing apple-green birefringence.
