Hippocampal structural changes across the menstrual cycle

Magnetic resonance imaging (MRI) in association with Jacobian‐modulated voxel‐based morphometry (VBM) was used to test for regional variation in gray matter over the menstrual cycle. T1‐weighted anatomical images were acquired using a spoiled gradient recalled acquisition sequence in 21 women. Each subject was scanned twice: once during the postmenstrual late‐follicular phase (Days 10–12 after onset of menses), and once during the premenstrual late‐luteal phase (1–5 days before the onset of menses). Gray matter was relatively increased in the right anterior hippocampus and relatively decreased in the right dorsal basal ganglia (globus pallidus/putamen) in the postmenstrual phase. Verbal declarative memory was increased in the postmenstrual vs. premenstrual phase. This first report of human brain structural plasticity associated with the endogenous menstrual cycle extends well‐established animal findings of hormone‐mediated hippocampal plasticity to humans, and has implications for understanding alterations in cognition and behavior across the menstrual cycle. © 2008 Wiley‐Liss, Inc.