Through menopause the brain rebuilds, and memory holds

After menopause, women had less grey matter in the temporal cortex than women with regular cycles, and their temporal and parietal regions burned less glucose. In perimenopause the dip was in the precuneus, a patch of cortex, where women had less grey matter even than those past menopause. Comparing them with men of the same age, the authors concluded that the differences followed the hormonal transition rather than age.

After menopause most measures had levelled off. Seventeen postmenopausal women were scanned again two years later, and their precuneus had gained grey matter. Twelve men of the same age showed no such gain. The more of it a woman had, the higher her memory scores. And tests of memory and thinking showed no clear difference between the three stages, or between women and men.

The gain shows up in just 17 women and one brain region, and over the same two years glucose use in the parietal cortex kept falling. Everything else compares different women at different stages, which cannot prove cause, as the authors themselves write. Many volunteered because they worried about their memory, and on average they had 17 years of schooling, so this was not a random sample. The authors tentatively read the findings as adaptation: a brain learning to run on less oestrogen. While it rebuilds, memory, by this evidence, keeps up.