FIGURE 14-25 Hormones and Neuroplasticity Sections of dendrites from hippocampal cells during times of high and low estrogen levels during the rat’s 4-day estrous cycle reveal many more dendritic spines when estrogen levels are high.

Information from C. S. Woolley, E. Gould, M. Frankfurt, & B. S. McEwen (1990). Naturally occurring fluctuation in dendritic spine density on adult hippocampal pyramidal neurons. Journal of Neuroscience, 10, p. 4038.