Alzheimer’s disease (AD) involves the deposition of a protein called amyloid β protein (Aβ) in the brain. This protein can build up in both the functional tissues, or “parenchyma”, of the brain, and in the blood vessels. This can lead to AD, causing dementia, or cerebral amyloid angiopathy (CAA), which can lead to cerebral hemorrhage. The reason for Aβ forming deposits in either of these places remains unknown. Now, new research by a team of researchers from Kanazawa University is shedding light on the deposition patterns formed when Aβ is introduced to the brain from external sources.