title: Sex and estrous cycle differences in immediate early gene activation in the hippocampus and the dorsal striatum after the cue competition task.
abstract: The hippocampus and dorsal striatum are important structures involved in place and response learning strategies respectively. Both sex and estrous cycle phase differences in learning strategy preference exist following cue competition paradigms. Furthermore, significant effects of sex and learning strategy on hippocampal neural plasticity have been reported. However, associations between learning strategy and immediate early gene (IEG) expression in the hippocampus and dorsal striatum are not completely understood. In the current study we investigated the effects of sex and estrous cycle phase on strategy choice and IEG expression in the hippocampus and dorsal striatum of rats following cue competition training in the Morris water maze. We found that proestrous rats were more likely to choose a place strategy than non-proestrous or male rats. Although male cue strategy users travelled greater distances than the other groups on the first day of training, there were no other sex or strategy differences in the ability to reach a hidden or a visible platform. Female place strategy users exhibited greater zif268 expression and male place strategy users exhibited greater cFos expression compared to all other groups in CA3. Furthermore, cue strategy users had greater expression of cFos in the dorsal striatum than place strategy users. Shorter distances to reach a visible platform were associated with less activation of cFos in CA3 and CA1 of male place strategy users. Our findings indicate multiple differences in brain activation with sex and strategy use, despite limited behavioral differences between the sexes on this cue competition paradigm.
authors.affiliation: Graduate Program in Neuroscience, University of British Columbia, Vancouver, Canada.
authors.forename: Shunya
authors.initials: S
authors.lastname: Yagi
authors.affiliation: Department of Psychology, University of British Columbia, Vancouver, Canada.
authors.forename: Dimka
authors.initials: D
authors.lastname: Drewczynski
authors.affiliation: Graduate Program in Neuroscience, University of British Columbia, Vancouver, Canada.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Wainwright
authors.affiliation: Department of Psychology, University of British Columbia, Vancouver, Canada.
authors.forename: Cindy K
authors.initials: CK
authors.lastname: Barha
authors.affiliation: Department of Psychology, University of British Columbia, Vancouver, Canada.
authors.forename: Olivia
authors.initials: O
authors.lastname: Hershorn
authors.affiliation: Graduate Program in Neuroscience, University of British Columbia, Vancouver, Canada; Department of Psychology, University of British Columbia, Vancouver, Canada; Centre for Brain Health, University of British Columbia, Vancouver, Canada. Electronic address: lgalea@psych.ubc.ca.
authors.forename: Liisa A M
authors.initials: LAM
authors.lastname: Galea
mesh_terms: D000818:Animals; D002755:Choice Behavior / Q000502:physiology; D003163:Competitive Behavior / Q000502:physiology*; D003463:Cues; D018891:Dentate Gyrus / Q000378:metabolism; D030762:Estrous Cycle / Q000502:physiology*; D005260:Female; D017781:Genes, Immediate-Early / Q000235:genetics*; D006624:Hippocampus / Q000378:metabolism*; D008297:Male; D018782:Maze Learning / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012727:Sex Characteristics; D012725:Sexual Behavior / Q000502:physiology; D015533:Transcriptional Activation
keywords: Adult neurogenesis; Cue competition; Dentate gyrus; Estrous cycle; Hippocampus; Immediate early genes; Learning strategy; Sex differences; c-Fos; zif268