title: Excitability of the motor cortex during ovulatory and anovulatory cycles: a transcranial magnetic stimulation study.
abstract: OBJECTIVE
  The pathophysiology of catamenial diseases such as epilepsy is unclear. Therefore, we investigated changes in cortical excitability during anovulatory and ovulatory cycles.
  
  
  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.
authors.affiliation: Department of Neurology, University of Marburg, Germany. hattemer@med.uni-marburg.de
authors.forename: Katja
authors.initials: K
authors.lastname: Hattemer
authors.forename: Susanne
authors.initials: S
authors.lastname: Knake
authors.forename: Janine
authors.initials: J
authors.lastname: Reis
authors.forename: Justine
authors.initials: J
authors.lastname: Rochon
authors.forename: Wolfgang H
authors.initials: WH
authors.lastname: Oertel
authors.forename: Felix
authors.initials: F
authors.lastname: Rosenow
authors.forename: Hajo M
authors.initials: HM
authors.lastname: Hamer
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000858:Anovulation / Q000097:blood / Q000503:physiopathology*; D001927:Brain Diseases / Q000097:blood / Q000503:physiopathology; D016022:Case-Control Studies; D004958:Estradiol / Q000097:blood; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D008597:Menstrual Cycle / Q000502:physiology; D009044:Motor Cortex / Q000503:physiopathology*; D011374:Progesterone / Q000097:blood; D018709:Statistics, Nonparametric; D050781:Transcranial Magnetic Stimulation
chemical_list: D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone