the plaques are formed when beta-secretase snips the app molecule at one end of the beta-amyloid peptide, releasing sappβ from the cell. gamma-secretase then cuts the pieces of app that is left and, still sticking out of the neuron’s membrane, at the other end of the beta-amyloid peptide. after this snipping the beta-amyloid peptide is released into the space outside the neuron and begins to stick to other beta-amyloid peptides. these pieces stick together to form "oligomers". different oligomers of various sizes are now floating around in the spaces between the neurons, which may be responsible for reacting with receptors on neighboring cells and synapses, affecting their ability to function.