Research master thesis | Psychology (research) (MSc)
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Menstrual cycle-related fluctuations in the hormones estradiol and progesterone affect brain function and structure, leading to changes in behavior and cognition. Low or falling estradiol,...Show moreMenstrual cycle-related fluctuations in the hormones estradiol and progesterone affect brain function and structure, leading to changes in behavior and cognition. Low or falling estradiol, especially with high or increasing progesterone, may impair cognition, while estradiol may enhance it. However, the precise interaction between these hormones and cognitive processes remains unclear, with inconsistent study results. Recent neuroimaging findings suggest using dense-sampling designs to track hormonal and cognitive fluctuations intensively. This study used such a design to examine the effects of progesterone/estradiol on cognitive performance and the theta/beta ratio (TBR), a marker of attentional control. We expected high estradiol to enhance cognitive performance. Additionally, we anticipated that TBR would mediate the relationship between progesterone and cognitive performance, with high progesterone levels leading to decreased TBR, indicating enhanced attentional control. Daily hormone levels and quasi-daily cognitive performance and TBR measures were collected from a healthy, naturally-cycling woman. We used a Flanker task to capture response conflict and an N-Back task with three levels of complexity to capture response sensitivity. For our analyses we used generalized additive models (GAMs). Increased progesterone/estradiol ratio was associated with improved response inhibition accuracy (but not speed) and working memory. Furthermore, decreased progesterone/estradiol ratio was additionally associated with improved working memory. Higher progesterone/estradiol levels were associated with increased N-Back sensitivity, and this was mediated by attentional control. Higher progesterone relative to estradiol also correlated with increased allocation of attentional control resources, suggesting enhanced cognitive processing capacity during high progesterone phases. This aligns with an idea of more flexible cognitive strategies during these phases to compensate for low estradiol. These findings, though needing replication, are the first to combine dense-sampling with electroencephalography, enhancing our understanding of how menstrual cycle hormones impact cognition. This knowledge can inform workplace and educational policies to create more supportive environments for women. Future studies are encouraged to include baseline dopamine levels and time-lagged models.Show less
Steroid hormones are frequently highlighted as an important modulator of women’s susceptibility for developing mood and anxiety disorders. One of the often-considered influences is the effect of...Show moreSteroid hormones are frequently highlighted as an important modulator of women’s susceptibility for developing mood and anxiety disorders. One of the often-considered influences is the effect of estradiol on the dopaminergic activity in the prefrontal cortex. Given this association it was investigated if natural levels of estradiol might affect women’s executive functions. The focus of measurement was the participant’s performance on the flanker task. It was hypothesised that women in a menstrual cycle phase marked by high estradiol show enhanced interference control and post-error adjustment. The study was conducted as an observational, natural group design and executed in an online format. Self-reports on the menstrual cycle were used for an approximation of the women’s current estradiol levels based on which two groups of women, either high or low in estradiol, were created. Main comparisons were made between 29 naturally cycling women in total and 48 men. The outcomes suggest that the cycle phase of women and the assumed levels of estradiol may not have influenced the processes of interference control or post-error adjustment. To interpret the obtained results, the measured constructs, interference control, error monitoring, and the menstrual cycle are discussed, and possible uncontrolled variables outlined. Future research is needed to further explore women’s executive processes and related neural correlates in the context of the menstrual cycle. Research in this field may provide better understanding of possible influences on women’s cognitive and emotional circuits in the brain, which will help to achieve a clearer picture of women’s psychological wellbeing throughout their life span.Show less
