ALEXANDRA YCAZA HERRERA, PH.D.
Women experience extreme changes in sex hormone profile across the lifespan. With the onset of puberty, women begin experiencing cyclic fluctuations in estradiol and progesterone levels. Many women experience further alterations in hormone profile during the reproductive years through the use of hormonal contraception. Then, in midlife, women experience menopause. During this time, women stop experiencing monthly fluctuations and eventually experience the lowest levels of these hormones than any other point in life. Each of these hormonal states is associated with changes in the physiological response to stress and cognition. My research aims to understand how these changes in hormone profile across the adult female lifespan affect the stress-response system and the subsequent effects of stress on cognition.
In particular, I study the ability of estradiol to modulate the cortisol response in women. To investigate how ovarian hormone levels can affect the adrenal cortisol and progesterone responses to stress, I study post-menopausal women using and not using estradiol therapy, pre-menopausal women not using hormonal contraception during various points of the natural menstrual cycle, and women using hormonal contraception during the different phases of the hormonal contraceptive cycle. In testing these effects, I also examine whether the influence of ovarian hormones on the stress response alters the typical effects of stress on cognition.
I utilize a number of modalities in my research program including behavioral testing, neuroimaging using functional magnetic resonance imaging (fMRI), and enzyme-linked immunosorbent assays (ELISA) for hormone measurements.