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Bembenek BM, Meyers-Manor JE, Forbes-Lorman RM. Decrease in ERɑ within the BNST of sexually naïve male rats following an encounter with a novel female. Behav Brain Res 2023; 454:114626. [PMID: 37595756 DOI: 10.1016/j.bbr.2023.114626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 07/27/2023] [Accepted: 08/09/2023] [Indexed: 08/20/2023]
Abstract
Testosterone and its metabolites facilitate male-typical social behaviors in sexually experienced animals. The metabolite estradiol acts on estrogen receptors (ERs) within the bed nucleus of the stria terminalis (BNST) to facilitate socio-sexual behaviors. While circulating testosterone does not increase in naïve males, aromatase-expressing neurons within the BNST of naïve males are necessary for sex recognition, suggesting that local estradiol production may be responsible. In the present study, we examined ERɑ-immunoreactive (ir) cell number within the brain of sexually naïve male rats 24 h after an encounter with a novel animal. As expected, males investigated females more than males. Additionally, males that encountered females had fewer ERɑ-ir cells within both anterior and posterior BNST compared to those who encountered a novel male or a non-social control. There were no changes within the AVPV, MPN, or MeA. The decrease in ERɑ-ir cell number within the posterior BNST only occurred in males that encountered estrus females whereas the decrease in the anterior BNST occurred only in males that encountered non-estrus females. Additionally, anogenital investigations were correlated with fewer ERɑ-ir cells in the posterior BNST, while cage sniffing correlated with the number ERɑ-ir cells in the anterior BNST. There were no differences in serum testosterone 45 min or 24 h after the encounter, suggesting changes in ERɑ were due to local changes in estradiol levels. Our results expand upon previous research regarding the role of estradiol within the subregions of the BNST in naïve male rat socio-sexual behavior.
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Affiliation(s)
- Brianna M Bembenek
- Ripon College, Ripon, WI 54971, USA; Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905, USA
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2
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Liiver K, Imbeault S, Školnaja M, Kaart T, Kanarik M, Laugus K, De Wettinck J, Pulver A, Shimmo R, Harro J. Active vs passive novelty-related strategies: Sex differences in exploratory behaviour and monoaminergic systems. Behav Brain Res 2023; 441:114297. [PMID: 36641084 DOI: 10.1016/j.bbr.2023.114297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 01/02/2023] [Accepted: 01/10/2023] [Indexed: 01/13/2023]
Abstract
Sex differences are apparent in numerous behavioural characteristics. In order to compare and characterise male and female variability of exploratory behaviour, 365 male and 401 female rats were assessed in a task where a bimodal response distribution had previously been established in males. Female rats had significantly higher exploratory activity, and presented normal distribution of the behaviour, very differently from the bimodal distribution of males. No major effect of litter or oestrous cycle was detected. Several differences between male and female rats were found in monoamine metabolism measured ex vivo. Male rats had lower levels of dopamine (DA) in frontal cortex, and higher levels of 3,4-dihydroxyphenylacetic acid (DOPAC) in raphe area; higher levels of serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in dorsal striatum but lower levels of 5-HT and 5-HIAA in locus coeruleus area, 5-HIAA levels were also lower in hippocampus as compared to females. Males had higher noradrenaline (NA) levels in hippocampus and lower normetanephrine (NMN) levels in striatum, in both brain regions male animals had lower NMN/NA ratio. No sex difference was found in accumbens. The only brain region with an interaction between sex and the expression of exploratory activity was raphe: Here 5-HT levels were lower, and DOPAC levels and DOPAC/DA and 5-HIAA/5-HT ratios higher in low exploring male but not female rats. Conclusively, female rats not only display higher levels of exploration but the population distribution of this behaviour is distinct; this may be related to differences in the monoaminergic systems between female and male animals.
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Affiliation(s)
- Kristi Liiver
- School of Natural Sciences and Health, Tallinn University, Narva Road 25, 10120 Tallinn, Estonia
| | - Sophie Imbeault
- School of Natural Sciences and Health, Tallinn University, Narva Road 25, 10120 Tallinn, Estonia
| | - Marianna Školnaja
- School of Natural Sciences and Health, Tallinn University, Narva Road 25, 10120 Tallinn, Estonia; Laboratory Animal Centre, Tallinn University of Technology, Akadeemia Road 15, 12618 Tallinn, Estonia
| | - Tanel Kaart
- Institute of Veterinary Medicine and Animal Science, Estonian University of Life Sciences, 51006 Tartu, Estonia
| | - Margus Kanarik
- Division of Neuropsychopharmacology, Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
| | - Karita Laugus
- Division of Neuropsychopharmacology, Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
| | - Jade De Wettinck
- School of Natural Sciences and Health, Tallinn University, Narva Road 25, 10120 Tallinn, Estonia
| | - Aleksander Pulver
- School of Natural Sciences and Health, Tallinn University, Narva Road 25, 10120 Tallinn, Estonia
| | - Ruth Shimmo
- School of Natural Sciences and Health, Tallinn University, Narva Road 25, 10120 Tallinn, Estonia
| | - Jaanus Harro
- School of Natural Sciences and Health, Tallinn University, Narva Road 25, 10120 Tallinn, Estonia; Division of Neuropsychopharmacology, Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia; Institute of Biotechnology, HiLIFE, University of Helsinki, Viikinkaari 5D, 00014 Helsinki, Finland.
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3
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Hegab IM, Yao B, Qian Z, Tan Y, Pu Q, Wang Z, Wang H, Su J. Examining sex disparities in risk/reward trade-offs in Smith's zokors, Eospalax smithii. Behav Processes 2022; 201:104716. [PMID: 35901938 DOI: 10.1016/j.beproc.2022.104716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/05/2022] [Accepted: 07/23/2022] [Indexed: 11/02/2022]
Abstract
Risk taking is imperative for the survival and fitness of animals since they are constantly facing innumerable threats from various sources. Indeed, the ability of the individual to balance the costs and benefits of various options and adopt a wise decision is critical for the animal well-being. We modified several traditionally used anxiety tests [The modified light-dark box (mLDB), the modified open field test (mOFT) and the modified defensive withdrawal apparatus (mDWA)] by adding a palatable food reward within the anxiogenic zone which granted us to assess the sex differences in risk-taking behavior in Smith's zokors (Eospalax smithii), a typical subterranean rodent species endemic to the Qinghai-Tibetan Plateau. Concomitant with our working hypothesis, female zokors showed strong aversion and avoidance behavioral responses when tested in the mOFT and mDWA while there were no apparent sexually dimorphic behavioral changes when they were tested in the mLDB (Except for the percentage of food consumed and the latency till start feeding). Furthermore, comparison between the three behavioral paradigms revealed that both sexes showed different behavioral responses toward the different behavioral tests. Sex differences in repeatable behaviors were more profound in females than males. This might reflect different degrees of risk perception and emotionality that may differ considerably between the different models of anxiety. Our results highlighted the functional significance of a trade-off between risk and incentives in natural environment that both male and female zokors differ in the processing of risk assessment in the presence of a food reward.
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Affiliation(s)
- Ibrahim M Hegab
- Department of Hygiene, Zoonoses and Animal Behaviour and Management, Faculty of Veterinary Medicine, Suez Canal University, Ismailia 41522, Egypt
| | - Baohui Yao
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China; Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity, Gansu Agricultural University, Lanzhou 730070, China
| | - Zhang Qian
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China; Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity, Gansu Agricultural University, Lanzhou 730070, China
| | - Yuchen Tan
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China; Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity, Gansu Agricultural University, Lanzhou 730070, China
| | - Qiangsheng Pu
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China; Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity, Gansu Agricultural University, Lanzhou 730070, China
| | - Zhicheng Wang
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China; Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity, Gansu Agricultural University, Lanzhou 730070, China
| | - Haifang Wang
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China; Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity, Gansu Agricultural University, Lanzhou 730070, China
| | - Junhu Su
- College of Grassland Science, Key Laboratory of Grassland Ecosystem (Ministry of Education), Gansu Agricultural University, Lanzhou 730070, China; Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity, Gansu Agricultural University, Lanzhou 730070, China.
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4
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Harrison LM, Noble DWA, Jennions MD. A meta-analysis of sex differences in animal personality: no evidence for the greater male variability hypothesis. Biol Rev Camb Philos Soc 2021; 97:679-707. [PMID: 34908228 DOI: 10.1111/brv.12818] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 11/13/2021] [Accepted: 11/17/2021] [Indexed: 12/18/2022]
Abstract
The notion that men are more variable than women has become embedded into scientific thinking. For mental traits like personality, greater male variability has been partly attributed to biology, underpinned by claims that there is generally greater variation among males than females in non-human animals due to stronger sexual selection on males. However, evidence for greater male variability is limited to morphological traits, and there is little information regarding sex differences in personality-like behaviours for non-human animals. Here, we meta-analysed sex differences in means and variances for over 2100 effects (204 studies) from 220 species (covering five broad taxonomic groups) across five personality traits: boldness, aggression, activity, sociality and exploration. We also tested if sexual size dimorphism, a proxy for sex-specific sexual selection, explains variation in the magnitude of sex differences in personality. We found no significant differences in personality between the sexes. In addition, sexual size dimorphism did not explain variation in the magnitude of the observed sex differences in the mean or variance in personality for any taxonomic group. In sum, we find no evidence for widespread sex differences in variability in non-human animal personality.
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Affiliation(s)
- Lauren M Harrison
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Canberra, ACT, 2600, Australia
| | - Daniel W A Noble
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Canberra, ACT, 2600, Australia
| | - Michael D Jennions
- Division of Ecology and Evolution, Research School of Biology, The Australian National University, 46 Sullivans Creek Road, Canberra, ACT, 2600, Australia
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5
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Glenn MJ, Batallán Burrowes AA, Yu W, Blackmer‐Raynolds L, Norchi A, Doak AL. Progression of behavioral deficits during periadolescent development differs in female and male DISC1 knockout rats. GENES, BRAIN, AND BEHAVIOR 2021; 21:e12741. [PMID: 33960643 PMCID: PMC9744521 DOI: 10.1111/gbb.12741] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 05/01/2021] [Accepted: 05/04/2021] [Indexed: 01/02/2023]
Abstract
Mutations in the disrupted in schizophrenia-1 (DISC1) gene are associated with an increased risk of developing psychological disorders including schizophrenia, bipolar disorder, and depression. Assessing the impact of knocking out genes, like DISC1, in animal models provides valuable insights into the relationship between the gene and behavioral outcomes. Previous research has relied on mouse models to assess these impacts, however these may not yield as reliable or rich a behavioral analysis as can be obtained using rats. Thus, the goal of the present study was to characterize the behavioral effects of a biallelic functional deletion of the DISC1 gene in the Sprague Dawley rat. Female and male wild type and DISC1 knockout rats were assessed beginning just prior to weaning and during the post-weaning periadolescent period. The primary outcomes evaluated were activity, anxiety, responses to novel objects and conspecifics, and prepulse inhibition. These behaviors were selected as analogous indices of psychological dysfunction in humans. The DISC1 knockout had significant effects on behavior, although the kind and magnitude of deficits was different for females and males: in females, effects included hyperactivity, aversion to novelty, and a modest prepulse inhibition deficit; in males, effects in anxiety and neophobia were mild but their prepulse inhibition deficit was large. These data confirm that the DISC1 knockout rat model is an excellent way to reproduce and study symptoms of psychological disorders and provides compelling evidence for differential consequences of its dysfunction for females and males in the progression and emergence of specific behavioral deficits.
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Affiliation(s)
| | - Ariel A. Batallán Burrowes
- Department of PsychologyColby CollegeWatervilleMaineUSA,Present address:
Center for Studies in Behavioral Neurobiology, Department of PsychologyConcordia UniversityMontréalQuébecCanada
| | - Waylin Yu
- Department of PsychologyColby CollegeWatervilleMaineUSA,Present address:
Department of Pharmacology, School of MedicineUniversity of North Carolina at Chapel HillChapel HillNorth CarolinaUSA
| | - Lisa Blackmer‐Raynolds
- Department of PsychologyColby CollegeWatervilleMaineUSA,Present address:
Department of PhysiologyEmory University School of MedicineAtlantaGeorgiaUSA
| | - Amanda Norchi
- Department of PsychologyColby CollegeWatervilleMaineUSA
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6
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Delarue EMP, Kerr SE, Rymer TL. Habitat and sex effects on behaviour in fawn-footed mosaic-tailed rats (Melomys cervinipes). AUSTRALIAN MAMMALOGY 2021. [DOI: 10.1071/am19065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Habitat complexity reflects resource availability and predation pressure – both factors that influence behaviour. We investigated whether exploratory behaviour and activity varied in fawn-footed mosaic-tailed rats (Melomys cervinipes) from two habitats that were categorised differently based on vegetation. We conducted vegetation surveys to determine structural complexity and vegetation cover, confirming that an abandoned hoop-pine (Araucaria cunninghami) plantation forest was structurally less complex, with lower vegetation cover than a variable secondary rainforest. We then tested mosaic-tailed rats from both sites in four behavioural tests designed to assess exploratory and activity behaviours (open field, novel object, light-dark box, acoustic startle), predicting that rats from the less structurally complex habitat would be less exploratory, and show lower activity. Our results provide some evidence for a context-specific trade-off between exploratory behaviour and predation risk in rats from the abandoned hoop pine plantation, as rats were less active, and showed a freezing strategy in the light-dark box. We also found context-specific sex differences in behaviour in response to a novel object and sound. Our results suggest that small-scale variation in habitat structure and complexity, as well as sex differences, is associated with variation in behaviour, most likely through effects on resource availability and/or predation risk.
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7
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Seidenbecher SE, Sanders JI, von Philipsborn AC, Kvitsiani D. Reward foraging task and model-based analysis reveal how fruit flies learn value of available options. PLoS One 2020; 15:e0239616. [PMID: 33007023 PMCID: PMC7531776 DOI: 10.1371/journal.pone.0239616] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 09/10/2020] [Indexed: 11/18/2022] Open
Abstract
Foraging animals have to evaluate, compare and select food patches in order to increase their fitness. Understanding what drives foraging decisions requires careful manipulation of the value of alternative options while monitoring animals choices. Value-based decision-making tasks in combination with formal learning models have provided both an experimental and theoretical framework to study foraging decisions in lab settings. While these approaches were successfully used in the past to understand what drives choices in mammals, very little work has been done on fruit flies. This is despite the fact that fruit flies have served as model organism for many complex behavioural paradigms. To fill this gap we developed a single-animal, trial-based decision making task, where freely walking flies experienced optogenetic sugar-receptor neuron stimulation. We controlled the value of available options by manipulating the probabilities of optogenetic stimulation. We show that flies integrate reward history of chosen options and forget value of unchosen options. We further discover that flies assign higher values to rewards experienced early in the behavioural session, consistent with formal reinforcement learning models. Finally, we also show that the probabilistic rewards affect walking trajectories of flies, suggesting that accumulated value is controlling the navigation vector of flies in a graded fashion. These findings establish the fruit fly as a model organism to explore the genetic and circuit basis of reward foraging decisions.
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Affiliation(s)
- Sophie E Seidenbecher
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Aarhus, Denmark.,Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Joshua I Sanders
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Aarhus, Denmark.,Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Anne C von Philipsborn
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Aarhus, Denmark.,Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Duda Kvitsiani
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Aarhus, Denmark.,Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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8
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Diana P, Joksimovic SM, Faisant A, Jevtovic-Todorovic V. Early exposure to general anesthesia impairs social and emotional development in rats. Mol Neurobiol 2020; 57:41-50. [PMID: 31494825 PMCID: PMC6980478 DOI: 10.1007/s12035-019-01755-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 08/29/2019] [Indexed: 11/25/2022]
Abstract
Several animal and emerging human studies suggest an association between an early exposure to general anesthesia (GA) and long-lasting problems with complex social and emotional behaviors such as inattentiveness, impulsivity, anxiogenic tendencies, as well as difficulties engaging in proper social intercourse, with significant increase in attention deficit and hyperactivity-type behaviors. To further investigate these behaviors, and to examine the potential of presently available rodent behavioral models to guide future assessments of long-term socio-emotional impairments in humans, we examined the long-term effects of GA on anxiety/fear and social behaviors. We exposed male and female Sprague-Dawley infant rats at the peak of their synaptogenesis to either GA containing midazolam (9 mg/kg, i.p.), 70% nitrous oxide (N2O) and 0.75% isoflurane (Iso) administered in 29-30% oxygen (experimental), or air (with 30% oxygen) plus the vehicle, 0.1% dimethyl sulfoxide (Sham) for 6 h. Behavioral experiments were conducted at adolescence (the open-field test) and young adulthood (the open-field test, the elevated plus-maze and the social novelty test). We report that an early exposure to GA during critical stages of brain development results in long-lasting increase in risk-taking tendencies and significant changes in the anxiety-related behaviors when tested in young adult rats. In addition, we noted novelty-seeking tendencies/less guarded behavior with changes in social discrimination. We conclude that early exposure to anesthesia may have lasting influences on emotional and social development. Importantly, our results show that currently used rodent behavioral models could be a good correlate to assess long-term socio-emotional GA-induced impairments observed in humans.
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Affiliation(s)
- Paolo Diana
- Department of Medicine, University of Padua, Padua, Italy
| | - Srdjan M Joksimovic
- Department of Anesthesiology, University of Colorado School of Medicine, 12801 E. 17th Avenue, Rm L18-4100, Aurora, CO, USA
| | - Azra Faisant
- School of Nursing, University of Virginia, Charlottesville, VA, USA
| | - Vesna Jevtovic-Todorovic
- Department of Anesthesiology, University of Colorado School of Medicine, 12801 E. 17th Avenue, Rm L18-4100, Aurora, CO, USA.
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9
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Storsberg S, Stryjek R, Modlińska K, Gottswinter K, D'Hanis W, Kröber A, Wernecke KE, Roskoden T, Fendt M. Predator odor induced defensive behavior in wild and laboratory rats: A comparative study. Physiol Behav 2018; 194:341-347. [DOI: 10.1016/j.physbeh.2018.06.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 06/01/2018] [Accepted: 06/08/2018] [Indexed: 01/04/2023]
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10
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Gender difference in unconditioned and conditioned predator fear responses in Smith's zokors (Eospalax smithii). Glob Ecol Conserv 2018. [DOI: 10.1016/j.gecco.2018.e00503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
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11
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Social instability stress in adolescent male rats reduces social interaction and social recognition performance and increases oxytocin receptor binding. Neuroscience 2017; 359:172-182. [DOI: 10.1016/j.neuroscience.2017.07.032] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 07/05/2017] [Accepted: 07/13/2017] [Indexed: 11/21/2022]
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12
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Medial septal GABAergic projection neurons promote object exploration behavior and type 2 theta rhythm. Proc Natl Acad Sci U S A 2016; 113:6550-5. [PMID: 27208094 DOI: 10.1073/pnas.1605019113] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Exploratory drive is one of the most fundamental emotions, of all organisms, that are evoked by novelty stimulation. Exploratory behavior plays a fundamental role in motivation, learning, and well-being of organisms. Diverse exploratory behaviors have been described, although their heterogeneity is not certain because of the lack of solid experimental evidence for their distinction. Here we present results demonstrating that different neural mechanisms underlie different exploratory behaviors. Localized Cav3.1 knockdown in the medial septum (MS) selectively enhanced object exploration, whereas the null mutant (KO) mice showed enhanced-object exploration as well as open-field exploration. In MS knockdown mice, only type 2 hippocampal theta rhythm was enhanced, whereas both type 1 and type 2 theta rhythm were enhanced in KO mice. This selective effect was accompanied by markedly increased excitability of septo-hippocampal GABAergic projection neurons in the MS lacking T-type Ca(2+) channels. Furthermore, optogenetic activation of the septo-hippocampal GABAergic pathway in WT mice also selectively enhanced object exploration behavior and type 2 theta rhythm, whereas inhibition of the same pathway decreased the behavior and the rhythm. These findings define object exploration distinguished from open-field exploration and reveal a critical role of T-type Ca(2+) channels in the medial septal GABAergic projection neurons in this behavior.
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13
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Jolles JW, Boogert NJ, van den Bos R. Sex differences in risk-taking and associative learning in rats. ROYAL SOCIETY OPEN SCIENCE 2015; 2:150485. [PMID: 26716004 PMCID: PMC4680619 DOI: 10.1098/rsos.150485] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 10/08/2015] [Indexed: 05/28/2023]
Abstract
In many species, males tend to have lower parental investment than females and greater variance in their reproductive success. Males might therefore be expected to adopt more high-risk, high-return behaviours than females. Next to risk-taking behaviour itself, sexes might also differ in how they respond to information and learn new associations owing to the fundamental link of these cognitive processes with the risk-reward axis. Here we investigated sex differences in both risk-taking and learned responses to risk by measuring male and female rats' (Rattus norvegicus) behaviour across three contexts in an open field test containing cover. We found that when the environment was novel, males spent more time out of cover than females. Males also hid less when exposed to the test arena containing predator odour. By contrast, females explored more than males when the predator odour was removed (associatively learned risk). These results suggest that males are more risk-prone but behave more in line with previous experiences, while females are more risk-averse and more responsive to changes in their current environment. Our results suggest that male and female rats differ in how they cope with risk and highlight that a general link may exist between risk-taking behaviour and learning style.
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Affiliation(s)
- Jolle Wolter Jolles
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Neeltje J. Boogert
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK
| | - Ruud van den Bos
- Faculty of Science, Department of Organismal Animal Physiology, Radboud University Nijmegen, Nijmegen, The Netherlands
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14
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Kennedy BC, Dimova JG, Siddappa AJM, Tran PV, Gewirtz JC, Georgieff MK. Prenatal choline supplementation ameliorates the long-term neurobehavioral effects of fetal-neonatal iron deficiency in rats. J Nutr 2014; 144:1858-65. [PMID: 25332485 PMCID: PMC4195423 DOI: 10.3945/jn.114.198739] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 07/12/2014] [Accepted: 08/21/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Gestational iron deficiency in humans and rodents produces long-term deficits in cognitive and socioemotional function and alters expression of plasticity genes in the hippocampus that persist despite iron treatment. Prenatal choline supplementation improves cognitive function in other rodent models of developmental insults. OBJECTIVE The objective of this study was to determine whether prenatal choline supplementation prevents the long-term effects of fetal-neonatal iron deficiency on cognitive and social behaviors and hippocampal gene expression. METHODS Pregnant rat dams were administered an iron-deficient (2-6 g/kg iron) or iron-sufficient (IS) (200 g/kg iron) diet from embryonic day (E) 3 to postnatal day (P) 7 with or without choline supplementation (5 g/kg choline chloride, E11-18). Novel object recognition (NOR) in the test vs. acquisition phase, social approach (SA), and hippocampal mRNA expression were compared at P65 in 4 male adult offspring groups: formerly iron deficient (FID), FID with choline supplementation (FID-C), IS, and IS with choline supplementation. RESULTS Relative to the intact NOR in IS rats (acquisition: 47.9%, test: 60.2%, P < 0.005), FID adult rats had impaired recognition memory at the 6-h delay (acquisition: 51.4%, test: 55.1%, NS), accompanied by a 15% reduction in hippocampal expression of brain-derived neurotrophic factor (Bdnf) (P < 0.05) and myelin basic protein (Mbp) (P < 0.05). Prenatal choline supplementation in FID rats restored NOR (acquisition: 48.8%, test: 64.4%, P < 0.0005) and increased hippocampal gene expression (FID-C vs. FID group: Bdnf, Mbp, P < 0.01). SA was also reduced in FID rats (P < 0.05 vs. IS rats) but was only marginally improved by prenatal choline supplementation. CONCLUSIONS Deficits in recognition memory, but not social behavior, resulting from gestational iron deficiency are attenuated by prenatal choline supplementation, potentially through preservation of hippocampal Bdnf and Mbp expression. Prenatal choline supplementation may be a promising adjunct treatment for fetal-neonatal iron deficiency.
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Affiliation(s)
- Bruce C Kennedy
- Graduate Program in Neuroscience, Center for Neurobehavioral Development,
| | | | - Asha J M Siddappa
- Center for Neurobehavioral Development, Department of Pediatrics, and
| | - Phu V Tran
- Center for Neurobehavioral Development, Department of Pediatrics, and
| | - Jonathan C Gewirtz
- Graduate Program in Neuroscience, Center for Neurobehavioral Development, Department of Psychology
| | - Michael K Georgieff
- Graduate Program in Neuroscience, Center for Neurobehavioral Development, Department of Pediatrics, and Institute of Child Development, University of Minnesota, Minneapolis, MN
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Hudson S, Jacobson-Pick S, Anisman H. Sex differences in behavior and pro-inflammatory cytokine mRNA expression following stressor exposure and re-exposure. Neuroscience 2014; 277:239-49. [DOI: 10.1016/j.neuroscience.2014.07.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/16/2014] [Accepted: 07/07/2014] [Indexed: 12/22/2022]
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16
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Ursinus WW, Bolhuis JE, Zonderland JJ, Rodenburg TB, de Souza AS, Koopmanschap RE, Kemp B, Korte-Bouws GAH, Korte SM, van Reenen CG. Relations between peripheral and brain serotonin measures and behavioural responses in a novelty test in pigs. Physiol Behav 2013; 118:88-96. [PMID: 23685231 DOI: 10.1016/j.physbeh.2013.05.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 04/02/2013] [Accepted: 05/06/2013] [Indexed: 11/16/2022]
Abstract
Pigs differ in their behavioural responses towards environmental challenges. Individual variation in maladaptive responses such as tail biting, may partly originate from underlying biological characteristics related to (emotional) reactivity to challenges and serotonergic system functioning. Assessing relations between behavioural responses and brain and blood serotonin parameters may help in understanding susceptibility to the development of maladaptive responses. The objective of the current study was, therefore, to assess the relationship between the pigs' serotonergic parameters measured in both blood and brain, and the behaviour of pigs during a novelty test. Pigs (n=31) were subjected to a novelty test at 11weeks of age, consisting of 5-min novel environment exposure after which a novel object (a bucket) was introduced for 5min. Whole blood serotonin, platelet serotonin level, and platelet serotonin uptake were determined at 13weeks of age. Levels of serotonin, its metabolite and serotonin turnover were determined at 19weeks of age in the frontal cortex, hypothalamus and hippocampus. The behaviour of the pigs was different during exposure to a novel object compared to the novel environment only, with more fear-related behaviours exhibited during novel object exposure. Platelet serotonin level and brain serotonergic parameters in the hippocampus were interrelated. Notably, the time spent exploring the test arena was significantly correlated with both platelet serotonin level and right hippocampal serotonin activity (turnover and concentration). In conclusion, the existence of an underlying biological trait - possibly fearfulness - may be involved in the pig's behavioural responses toward environmental challenges, and this is also reflected in serotonergic parameters.
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Affiliation(s)
- Winanda W Ursinus
- Wageningen University, Department of Animal Sciences, Adaptation Physiology Group, P.O. Box 338, 6700 AH, Wageningen, The Netherlands.
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17
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Green MR, Barnes B, McCormick CM. Social instability stress in adolescence increases anxiety and reduces social interactions in adulthood in male long-evans rats. Dev Psychobiol 2012; 55:849-59. [DOI: 10.1002/dev.21077] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 07/26/2012] [Indexed: 12/27/2022]
Affiliation(s)
- Matthew R. Green
- Department of Psychology; Brock University; 500 Glenridge Ave St. Catharines, Ontario, Canada L2S 3A1
| | - Brittany Barnes
- Centre for Neuroscience; Brock University; 500 Glenridge Ave St. Catharines, Ontario, Canada L2S 3A1
| | - Cheryl M. McCormick
- Department of Psychology; Brock University; 500 Glenridge Ave St. Catharines, Ontario, Canada L2S 3A1
- Centre for Neuroscience; Brock University; 500 Glenridge Ave St. Catharines, Ontario, Canada L2S 3A1
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18
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Lillard AS, Erisir A. Old Dogs Learning New Tricks: Neuroplasticity Beyond the Juvenile Period. DEVELOPMENTAL REVIEW 2011; 31:207-239. [PMID: 24648605 PMCID: PMC3956134 DOI: 10.1016/j.dr.2011.07.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Twenty years ago, the prevalent view in psychology was that although learning and the formation of new memories are lifelong occurrences, the neural changes associated with these events were all in the existing receptors. No new neural hardware, from synapses to neurons, was thought to appear after a protracted period early in life. In the past 20 years, another view has supplanted this one, showing that although the juvenile period is especially suited to neuroplastic adaptation, there is hard neuroplastic change later in life as well. We review a selection of evidence for this view from both animal and human models, showing how it reflects three principles of neuroplasticity: 1) earlier and later experience-induced changes to neuroarchitecture differ in degree more so than in type; 2) the types of experiences that lead to neuroplastic change narrow with age; and 3) differences in the amenability of neural circuitry to change result from basic differences in neuroarchitecture and neuroenvironment in different phases of development.
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