New brain synapses form when a postsynaptic structure, the dendritic spine, interacts with a
presynaptic terminal. Brain synapses and dendritic spines, membrane-rich structures, are
depleted in Alzheimer's disease, as are some circulating compounds needed for
synthesizing phosphatides, the major constituents of synaptic membranes. Animals given
three of these compounds, all nutrients—uridine, the omega-3 polyunsaturated fatty acid
docosahexaenoic acid, and choline—develop increased levels of brain phosphatides and of …