The brain is one of the main targets of sex hormones. Estradiol and progesterone act on neurons, glia and neurotransmitter systems, supporting synaptic plasticity, neuroprotection and the regulation of mood, cognition and stress responses. Across the female lifespan, puberty, the menstrual cycle, pregnancy and the menopausal transition bring marked hormonal changes that are increasingly recognised as periods of brain reorganisation. Yet women's hormonal state is still rarely treated as a source of variability in EEG and psychophysiological research.

In this talk, I will first give an overview of what we know about brain–hormone interactions, drawing on neuroimaging and electrophysiological evidence from the menstrual cycle, pregnancy and menopause. I will then illustrate these principles with a few examples from our own published work on hormonal contraception, using EEG/ERPs, eye tracking and pupillometry: while resting-state EEG and working memory appear robust to hormonal status, emotional reactivity and attention to affective stimuli differ between naturally cycling women and hormonal contraceptive users. Finally, I will outline where we are heading: our ongoing studies of premenstrual dysphoric disorder and the menopausal transition, in which we combine psychophysiological, hormonal and other biological measures to search for biomarkers that could support earlier recognition and more personalised care. I will close with practical recommendations for considering hormonal status in EEG research.