title: Estradiol concentrations and working memory performance in women of reproductive age.
abstract: OBJECTIVE
  Estrogen has been proposed to exert a regulatory influence on the working memory system via actions in the female prefrontal cortex. Tests of this hypothesis have been limited almost exclusively to postmenopausal women and pharmacological interventions. We explored whether estradiol discernibly influences working memory within the natural range of variation in concentrations characteristic of the menstrual cycle.
  
  
  METHODS
  The performance of healthy women (n=39) not using hormonal contraceptives, and a control group of age- and education-matched men (n=31), was compared on a spatial working memory task. Cognitive testing was done blind to ovarian status. Women were retrospectively classified into low- or high-estradiol groups based on the results of radioimmunoassays of saliva collected immediately before and after the cognitive testing.
  
  
  RESULTS
  Women with higher levels of circulating estradiol made significantly fewer errors on the working memory task than women tested under low estradiol. Pearson's correlations showed that the level of salivary estradiol but not progesterone was correlated inversely with the number of working memory errors produced. Women tested at high levels of circulating estradiol tended to be more accurate than men. Superior performance by the high estradiol group was seen on the working memory task but not on two control tasks, indicating selectivity of the effects.
  
  
  CONCLUSIONS
  Consistent with previous studies of postmenopausal women, higher levels of circulating estradiol were associated with better working memory performance. These results add further support to the hypothesis that the working memory system is modulated by estradiol in women, and show that the effects can be observed under non-pharmacological conditions.
authors.affiliation: Department of Psychology, University of Western Ontario, London, ON, Canada; Graduate Program in Neuroscience, University of Western Ontario, London, ON, Canada. Electronic address: ehampson@uwo.ca.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Hampson
authors.forename: Erin E
authors.initials: EE
authors.lastname: Morley
mesh_terms: D000293:Adolescent; D000328:Adult; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007092:Imagination / Q000502:physiology; D007361:Intelligence Tests; D008570:Memory, Short-Term / Q000502:physiology*; D009483:Neuropsychological Tests; D011374:Progesterone / Q000378:metabolism; D011597:Psychomotor Performance / Q000502:physiology*; D011863:Radioimmunoassay; D012399:Rotation; D012463:Saliva / Q000378:metabolism; D014825:Vocabulary; D055815:Young Adult
chemical_list: D011374:Progesterone; D004958:Estradiol; D006854:Hydrocortisone
keywords: Cognitive; Estradiol; Estrogen; Menstrual cycle; Mental rotation; Working memory