Compact neuritic plaques exhibit a core of AD beta protein amyloid, surrounded by distended silver positive neuritic swellings filled with neurofibrillary tangles, also referred as paired helical filaments (PHF), reactive microglia, and reactive astrocytes. Immunoglobulin and complement can be demonstrated in plaques. Similar tangles involve the neuronal soma shown in the next silver stained section of cerebral cortex, note the black fibrillary cytoplasmic "inclusion". These tangles contain abnormal hyperphosphorylated tau protein and ubiquitin.