Fig. 1.

Aβ assembly pathways: oAβ on or off pathways for amyloid plaque deposition. A: Via the on pathway, oAβs can be pathogenic, but are structural precursors for the formation of the traditional insoluble fibrils that continue to assemble into the parallel β-sheet structure of amyloid plaques, also considered to be pathogenic. B: Via the off pathway assembly process, Aβ can proceed via two separate processes, the pathogenic formation of oAβ or formation of the traditional insoluble fibrils that continue to assemble into amyloid plaques, considered to be benign [reproduced from (86)].