Estrogen alters hippocampal dendritic spine shape and enhances synaptic protein immunoreactivity and spatial memory in female mice - Chenjian Li; Wayne G. Brake; Russell D. Romeo; John C. Dunlop; Marisa Gordon; Rodica Buzescu; Ana Maria Magarinos; Patrick B. Allen; Paul Greengard; Victoria Luine; Bruce S. McEwen (2004)