Plaques form when protein pieces called beta-amyloid (BAY-tuh AM-uh-loyd) clump together. Beta-amyloid
comes from a larger protein found in the fatty membrane
surrounding nerve cells.
Beta-amyloid is chemically "sticky" and gradually builds
up into plaques.
The most damaging form of beta-amyloid may be groups
of a few pieces rather than the plaques themselves.
The small clumps may block cell-to-cell signaling at
synapses. They may also activate immune system cells
that trigger inflammation and devour disabled cells.