Alzheimer's disease brain tissue. Light micrograph of a section of hippocampal brain tissue affected by Alzheimer's disease. Characteristic features of Alzheimer's disease are seen here: a neuritic amyloid plaque (upper left) and nerve cells containing neurofibrillary tangles (black triangles). Tangles in nerve cells lead to the main symptoms of Alzheimer's: memory loss, dementia and death. The tangles are made up mainly of tau protein, which becomes filamentous and pathogenic due to abnormal interactions with sulphated glycosaminoglycans. Stained with anti- heparan sulphate antibody (brown) and anti-tau antibody (black). Magnification: x70 at 35mm size.