title: Different brain activation patterns to pain and pain-related unpleasantness during the menstrual cycle.
abstract: BACKGROUND
  The changes in the functional magnetic resonance imaging signal during anticipation, pain stimulation, and the poststimulation periods were investigated to determine whether changes in sex hormones affect brain activity.
  
  
  METHODS
  Eighteen participants were examined twice, once in the follicular phase and once in the luteal phase. Half the participants were tested first during the follicular phase, and the other half were tested first in the luteal phase.
  
  
  RESULTS
  The pain and unpleasantness ratings were significantly higher in the luteal phase than in the follicular. During the anticipation of pain, the prefrontal cortices were activated during the follicular phase, whereas the parahippocampal gyrus and amygdala were activated during the luteal phase. During the pain stimulation, putamen and cerebellum and precentral gyrus involving motor preparation and defense mechanism related to antinociceptive behavior were activated during the follicular phase, whereas the thalamus was activated during the luteal phase. During the poststimulation periods, the prefrontal cortices were activated during the follicular phase, whereas parahippocampal gyrus was activated during the luteal phase. The temporal pole was activated during the anticipation, pain stimulation, and poststimulation periods of the luteal phase.
  
  
  CONCLUSIONS
  During surgical and medical procedures, requirements of anesthetic and analgesic and anxiolytic drugs may be reduced during the follicular phase and increased during the luteal phase. These results highlight the need to consider the effects of the sex hormones in women when designing clinical or neuroimaging studies or when treating patients for pain and pain-related unpleasantness.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Yonsei University Wonju College of Medicine, Kwangwon-Do, South Korea. jaechan@yonsei.ac.kr
authors.forename: Jae Chan
authors.initials: JC
authors.lastname: Choi
authors.forename: Sang Kyu
authors.initials: SK
authors.lastname: Park
authors.forename: Yun-Hee
authors.initials: YH
authors.lastname: Kim
authors.forename: Yong-Wook
authors.initials: YW
authors.lastname: Shin
authors.forename: Jun Soo
authors.initials: JS
authors.lastname: Kwon
authors.forename: Jin Soo
authors.initials: JS
authors.lastname: Kim
authors.forename: Ji-Woong
authors.initials: JW
authors.lastname: Kim
authors.forename: Soon Yul
authors.initials: SY
authors.lastname: Kim
authors.forename: Sang Gyu
authors.initials: SG
authors.lastname: Lee
authors.forename: Moo Sam
authors.initials: MS
authors.lastname: Lee
mesh_terms: D000328:Adult; D001921:Brain / Q000378:metabolism*; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008597:Menstrual Cycle / Q000097:blood*; D010146:Pain / Q000097:blood*; D010147:Pain Measurement / Q000379:methods
chemical_list: D012739:Gonadal Steroid Hormones