Protein filaments in Alzheimer's disease. Coloured Transmission Electron Micrograph (TEM) of beta protein filaments which occur in brain tissue in Alzheimer's disease. The filaments here have been purified in the laboratory. Alzheimer's disease is a form of senile dementia. The brain is affected by degenerative changes in frontal and temporal lobes, and brain tissue shrinks in size. Senile plaques are produced which consist, as seen here, of tangled masses of filaments and granules which are often centred around an area of amyloid. Masses of thickened filaments also form in the cytoplasm of nerve cells, called neurofibrillary tangles. Magnification: x7,000 at 35mm size.