Some evidence links estrogen, which enhances cortical dopamine activity, to improving working memory function in postmenopausal women on estrogen replacement. Other evidence suggests that working memory fluctuates throughout the estrogen cycle and varies greatly from woman to woman, depending on their baseline.
To determine estrogen’s impact on cognition, this study enrolled young healthy females and tracked their menstrual cycles for four months. The subjects were seen on three occasions—the first for an introductory neurophysical exam. The second and third were timed to each woman’s menstrual cycle—one when estrogen levels were low and the other when levels were high.
On initial testing, the women did not differ significantly. During high and low estrogen test sessions, women completed a verbal working memory test during MRI scanning and were assessed for mood and motor speed. Some women performed poorly at the start of their cycle when estrogen was low and improved when it was high. Other women showed the opposite pattern.
“Although estrogen, considered in isolation, may have unpredictable effects on cognition, its influence is clarified when considered within a larger neuromodulatory framework. A man and woman’s milieu differ; until we understand how, we cannot fully understand neural processes as they unfold in the healthy state, much less in the diseased state,” the authors conclude.