title: Sex differences in learned fear expression and extinction involve altered gamma oscillations in medial prefrontal cortex.
abstract: Sex differences in learned fear expression and extinction involve the medial prefrontal cortex (mPFC). We recently demonstrated that enhanced learned fear expression during auditory fear extinction and its recall is linked to persistent theta activation in the prelimbic (PL) but not infralimbic (IL) cortex of female rats. Emerging evidence indicates that gamma oscillations in mPFC are also implicated in the expression and extinction of learned fear. Therefore we re-examined our in vivo electrophysiology data and found that females showed persistent PL gamma activation during extinction and a failure of IL gamma activation during extinction recall. Altered prefrontal gamma oscillations thus accompany sex differences in learned fear expression and its extinction. These findings are relevant for understanding the neural basis of post-traumatic stress disorder, which is more prevalent in women and involves impaired extinction and mPFC dysfunction.
authors.affiliation: School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK. Electronic address: gef8@leicester.ac.uk.
authors.forename: Georgina E
authors.initials: GE
authors.lastname: Fenton
authors.affiliation: Department of Electronics, University of York, Heslington, York YO10 5DD, UK.
authors.forename: David M
authors.initials: DM
authors.lastname: Halliday
authors.affiliation: School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH, UK.
authors.forename: Rob
authors.initials: R
authors.lastname: Mason
authors.affiliation: Queensland Brain Institute, University of Queensland, Brisbane, Queensland 4072, Australia; Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, United States.
authors.forename: Timothy W
authors.initials: TW
authors.lastname: Bredy
authors.affiliation: School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK. Electronic address: carl.stevenson@nottingham.ac.uk.
authors.forename: Carl W
authors.initials: CW
authors.lastname: Stevenson
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D003214:Conditioning, Classical / Q000502:physiology*; D005108:Extinction, Psychological / Q000502:physiology*; D005239:Fear / Q000502:physiology*; D005260:Female; D065818:Gamma Rhythm / Q000502:physiology*; D008297:Male; D017397:Prefrontal Cortex / Q000502:physiology*; D051381:Rats; D012727:Sex Characteristics
keywords: Extinction; Fear conditioning; Gamma oscillations; Infralimbic; Prelimbic; Sex differences