Psychophysiology. 2018;55:e13268. wileyonlinelibrary.com/journal/psyp | 1 of 10 https://doi.org/10.1111/psyp.13268 © 2018 Society for Psychophysiological Research 1 | INTRODUCTION The menstrual cycle has long been associated with psycho- logical changes: mood and neurocognitive processes are impacted, and females often experience increases in psychi- atric symptoms that include depression and anxiety (Farage, Osborn, & Maclean, 2008; Kiesner, 2009). Specific hor- mones that vary across the menstrual cycle, including pro- gesterone and estradiol, have been shown to impact emotion and cognition (Andreano & Cahill, 2010; Sakaki & Mather, 2012), and could therefore play a role in mood and cogni- tive variability across the menstrual cycle. Progesterone and estradiol have also been shown to impact neural and sub- jective measures of responsivity to reward (Dreher et al., 2007; Evans & Foltin, 2006; Evans, Haney, & Foltin, 2002; Ossewaarde et al., 2010; Sakaki & Mather, 2012), a construct that plays a central role in depression and risk for depression (Bress, Foti, Kotov, Klein, & Hajcak, 2013; Nelson, Perlman, Klein, Kotov, & Hajcak, 2016). Given these links, it stands to reason that reward function could be a mechanism by which ovarian hormones influence mood. Therefore, the current study utilized a within‐subject design to examine the asso- ciation between ovarian hormones, neural indices of reward sensitivity, and depressive symptoms at multiple points in the menstrual cycle. The menstrual cycle is a biological phenomenon that can be divided into three phases that are characterized by distinct fluctuations in endogenous hormones (Farage et al., 2008). Received: 29 January 2018 | Revised: 1 June 2018 | Accepted: 13 June 2018 DOI: 10.1111/psyp.13268 ORIGINAL ARTICLE Effects of menstrual cycle phase on electrocortical response to reward and depressive symptoms in women Elizabeth M. Mulligan 1 | Brady D. Nelson 2 | Zachary P. Infantolino 2 | Katherine R. Luking 1 | Radhika Sharma 2 | Greg Hajcak 1,3 1 Department of Psychology, Florida State University, Tallahassee, Florida 2 Department of Psychology, Stony Brook University, Stony Brook, New York 3 Department of Biomedical Sciences, Florida State University, Tallahassee, Florida Correspondence Elizabeth Mulligan, Department of Psychology, Florida State University, 1107 West Call Street, Tallahassee, FL 32304. Email: Mulligan@psy.fsu.edu Abstract The menstrual cycle impacts mood and neural response to reward—phenomena that may be related to natural fluctuations in ovarian hormones. Using a within‐subject design, the present study examined ovarian hormones (i.e., estradiol and progester- one) and ERPs in response to feedback indicating gains and losses in both the follicu- lar and luteal phases of the menstrual cycle. We examined whether hormone levels and variation in neural response to reward and loss across menstrual cycle phases were associated with depressive symptoms. Participants high in depressive symp- toms showed a reduced reward positivity (RewP) to monetary gains during the luteal phase of the menstrual cycle as compared to the follicular phase, while those low in depressive symptoms showed no change in the RewP to monetary gains between phases. Thus, increased fluctuation in the neural response to gains (but not losses) across menstrual cycle phases was associated with greater depression symptoms. Overall, findings indicate that hormonal fluctuations associated with the menstrual cycle may relate to depressive symptoms by altering reward sensitivity. Furthermore, fluctuation in the neural response to rewards over the menstrual cycle may play an important role in the expression of depressive symptoms. KEYWORDS depression, ERPs, estradiol, menstrual cycle, progesterone, reward positivity