Dynamics of plaque formation in Alzheimer's disease

Plaques that form in the brains of Alzheimer patients are made of deposits of the amyloid-beta peptide. We analyze the time evolution of amyloid-beta deposition in immunostained brain slices from transgenic mice. We find that amyloid-beta deposits appear in clusters whose characteristic size increas es from 14 mu m in 8-month-old mice to 22 mu m in 12-month-old mice. We sho w that the clustering has implications for the biological growth of amyloid -beta by presenting a growth model that accounts for the experimentally obs erved structure of individual deposits and predicts the formation of cluste rs of deposits and their time evolution.