Corpora amylacea. Light micrograph of a section through the choroid plexus of brain, showing two corpora amylacea (purple, bottom). These small masses are a normal find in ageing brains. Their function is unknown. The choroid plexus is a network of capillary blood vessels that is found in each of the four ventricles (fluid-filled cavities) of the brain. Magnification: x200 when printed at 10 centimetres wide.