title: Changes in brain size during the menstrual cycle.
abstract: BACKGROUND
  There is increasing evidence for hormone-dependent modification of function and behavior during the menstrual cycle, but little is known about associated short-term structural alterations of the brain. Preliminary studies suggest that a hormone-dependent decline in brain volume occurs in postmenopausal, or women receiving antiestrogens, long term. Advances in serial MR-volumetry have allowed for the accurate detection of small volume changes of the brain. Recently, activity-induced short-term structural plasticity of the brain was demonstrated, challenging the view that the brain is as rigid as formerly believed.
  
  
  RESULTS
  We used MR-volumetry to investigate short-term brain volume changes across the menstrual cycle in women or a parallel 4 week period in men, respectively. We found a significant grey matter volume peak and CSF loss at the time of ovulation in females. This volume peak did not correlate with estradiol or progesterone hormone levels. Men did not show any significant brain volume alterations.
  
  
  CONCLUSIONS
  These data give evidence of short-term hormone-dependent structural brain changes during the menstrual cycle, which need to be correlated with functional states and have to be considered in structure-associated functional brain research.
authors.affiliation: Hans Berger Clinic for Neurology, University Hospital Jena, Jena, Germany. georg.hagemann@helios-kliniken.de
authors.forename: Georg
authors.initials: G
authors.lastname: Hagemann
authors.forename: Tarik
authors.initials: T
authors.lastname: Ugur
authors.forename: Ekkehard
authors.initials: E
authors.lastname: Schleussner
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Mentzel
authors.forename: Clemens
authors.initials: C
authors.lastname: Fitzek
authors.forename: Otto W
authors.initials: OW
authors.lastname: Witte
authors.forename: Christian
authors.initials: C
authors.lastname: Gaser
mesh_terms: D000328:Adult; D001826:Body Fluids / Q000378:metabolism / Q000502:physiology; D001921:Brain / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D004958:Estradiol / Q000032:analysis / Q000097:blood; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008597:Menstrual Cycle / Q000097:blood / Q000134:cerebrospinal fluid / Q000502:physiology*; D009929:Organ Size / Q000502:physiology; D010060:Ovulation / Q000097:blood / Q000134:cerebrospinal fluid / Q000502:physiology; D011374:Progesterone / Q000032:analysis / Q000097:blood; D011859:Radiography; D012727:Sex Characteristics; D055815:Young Adult
chemical_list: D011374:Progesterone; D004958:Estradiol