Behavioural and neural dynamics of category learning across the menstrual cycle

Hormonal changes across the menstrual cycle have extensive effects on the brain yet resulting impacts on human cognition are yet to be elucidated. The current work provides a comprehensive, multimodal account of menstrual cycle effects on category learning – a core cognitive process that requires careful coordination of learning, memory and attention. Study 1 outlines a novel method for studying cognition across the menstrual cycle, and leverages it to demonstrate that category learning varies across the cycle in a non-linear fashion that parallels the typical rise and fall of ovarian hormone estradiol (N=171). Study 2 (N=183), provides a conceptual replication using a separate cognitive task that relies on similar pattern separation processes as category learning and further demonstrates the utility of the method developed in Study 1. Study 4 (N=64) takes the analysis a step further by examining hormone-gene interactions in participants tested twice, at low- and high-estradiol points in the menstrual cycle. Results demonstrate that BDNF genotype, which affects neuroplasticity, modulates participants’ sensitivity to estradiol fluctuations across the menstrual cycle as reflected in category learning performance. Finally, Study 5 (N = 41), directly replicates the initial behavioural effect and identifies its neural correlates, confirming that activation in brain regions supporting category learning varies across the menstrual cycle and with ovarian hormone levels. Not only does this body of work provide the first evidence of menstrual cycle effects on category learning and details their behavioural and neural dynamics, it is also the first to report an interaction between BDNF genotype and the menstrual cycle phase in affecting cognition – something that has previously been done only in animal model analogues. Overall, the current work bridges neuroscience, behavioral genetics and neuroendocrinology to provide a comprehensive account of learning and memory across the menstrual cycle, while also providing new methodological directions for the broader study of menstrual cycle effects on cognition.

Department dc:contributor.department

Psychology

Year dc:date.issued

2025

Author dc:creator

• Perovic, Mateja

Advisor dc:contributor.advisor

• Mack, Michael

• BDNF
• cognitive neuroscience
• concept formation
• estradiol
• learning and memory
• menstrual cycle

Handle dc:identifier.uri

https://hdl.handle.net/1807/150051

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/150051