Related Experiment Video
Updated: Jul 16, 2026
Assessing Primary Motor Cortex Excitability and Excitability Modulation by Pairing Transcranial Magnetic Stimulation with Electromyography
Published on: October 7, 2025
Excitability of the motor cortex during ovulatory and anovulatory cycles: a transcranial magnetic stimulation study
Katja Hattemer1, Susanne Knake, Janine Reis
1Department of Neurology, University of Marburg, Germany. hattemer@med.uni-marburg.de
Objective:
The pathophysiology of catamenial diseases such as epilepsy is unclear. Therefore, we investigated changes in cortical excitability during anovulatory and ovulatory cycles.
Patients And Methods:
Using transcranial magnetic stimulation (TMS), eight healthy women were investigated during anovulatory and 12 during ovulatory cycles. On days 8, -14, -7 and 2 of the cycle, resting motor threshold (RMT), cortical silent period (CSP), intracortical inhibition (ICI) and intracortical facilitation (ICF) were investigated. Repeated-measures analysis of variance (anova) and nonparametric methods were used for statistical analysis.
Results:
A trend was seen for group by phase interaction regarding ICI (F = 2.5, P = 0.10). ICI varied during anovulatory cycles (median: 51.0% on day 8; 45.3% on day -14, 51.0% on day -7, and 28.6% on day 2; P = 0.040), mainly because of an increased inhibition on day 2. ICI was more pronounced in anovulatory cycles on day -14 (P = 0.021), -7 (P = 0.048) and 2 (P = 0.018) compared to ovulatory women who did not show intraindividual changes (P = 0.56). RMT, CSP and ICF showed no significant changes during anovulatory or ovulatory cycles.
Conclusions:
The results suggest fluctuations in cortical excitability during anovulatory cycles, possibly due to the withdrawal of 'excitatory' oestrogens that initiate menses in anovulatory cycles.
