@article{KarabegGrauthoffKollertetal.2013,
  author    = {Karabeg, Margherita M. and Grauthoff, Sandra and Kollert, Sina Y. and Weidner, Magdalena and Heiming, Rebecca S. and Jansen, Friederike and Popp, Sandy and Kaiser, Sylvia and Lesch, Klaus-Peter and Sachser, Norbert and Schmitt, Angelika G. and Lewejohann, Lars},
  title     = {5-HTT Deficiency Affects Neuroplasticity and Increases Stress Sensitivity Resulting in Altered Spatial Learning Performance in the Morris Water Maze but Not in the Barnes Maze},
  series = {PLoS ONE},
  volume    = {8},
  journal   = {PLoS ONE},
  number    = {10},
  doi       = {10.1371/journal.pone.0078238},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-129978},
  pages     = {e78238},
  year      = {2013},
  abstract  = {The purpose of this study was to evaluate whether spatial hippocampus-dependent learning is affected by the serotonergic system and stress. Therefore, 5-HTT knockout (-/-), heterozygous (+/-) and wildtype (+/+) mice were subjected to the Barnes maze (BM) and the Morris water maze (WM), the latter being discussed as more aversive. Additionally, immediate early gene (IEG) expression, hippocampal adult neurogenesis (aN), and blood plasma corticosterone were analyzed. While the performance of 5-HTT-/- mice in the BM was undistinguishable from both other genotypes, they performed worse in the WM. However, in the course of the repeated WM trials 5-HTT-/- mice advanced to wildtype level. The experience of a single trial of either the WM or the BM resulted in increased plasma corticosterone levels in all genotypes. After several trials 5-HTT-/- mice exhibited higher corticosterone concentrations compared with both other genotypes in both tests. Corticosterone levels were highest in 5-HTT-/- mice tested in the WM indicating greater aversiveness of the WM and a greater stress sensitivity of 5-HTT deficient mice. Quantitative immunohistochemistry in the hippocampus revealed increased cell counts positive for the IEG products cFos and Arc as well as for proliferation marker Ki67 and immature neuron marker NeuroD in 5-HTT-/- mice compared to 5-HTT+/+ mice, irrespective of the test. Most differences were found in the suprapyramidal blade of the dentate gyrus of the septal hippocampus. Ki67-immunohistochemistry revealed a genotype x environment interaction with 5-HTT genotype differences in na{\"i}ve controls and WM experience exclusively yielding more Ki67-positive cells in 5-HTT+/+ mice. Moreover, in 5-HTT-/- mice we demonstrate that learning performance correlates with the extent of aN. Overall, higher baseline IEG expression and increased an in the hippocampus of 5-HTT-/- mice together with increased stress sensitivity may constitute the neurobiological correlate of raised alertness, possibly impeding optimal learning performance in the more stressful WM.},
  language  = {en}
}
@article{PoppSchmittBoehrerLangeretal.2021,
  author    = {Popp, Sandy and Schmitt-B{\"o}hrer, Angelika and Langer, Simon and Hofmann, Ulrich and Hommers, Leif and Schuh, Kai and Frantz, Stefan and Lesch, Klaus-Peter and Frey, Anna},
  title     = {5-HTT Deficiency in Male Mice Affects Healing and Behavior after Myocardial Infarction},
  series = {Journal of Clinical Medicine},
  volume    = {10},
  journal   = {Journal of Clinical Medicine},
  number    = {14},
  issn      = {2077-0383},
  doi       = {10.3390/jcm10143104},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-242739},
  year      = {2021},
  abstract  = {Anxiety disorders and depression are common comorbidities in cardiac patients. Mice lacking the serotonin transporter (5-HTT) exhibit increased anxiety-like behavior. However, the role of 5-HTT deficiency on cardiac aging, and on healing and remodeling processes after myocardial infarction (MI), remains unclear. Cardiological evaluation of experimentally na{\"i}ve male mice revealed a mild cardiac dysfunction in ≥4-month-old 5-HTT knockout (-/-) animals. Following induction of chronic cardiac dysfunction (CCD) by MI vs. sham operation 5-HTT-/- mice with infarct sizes >30\% experienced 100\% mortality, while 50\% of 5-HTT+/- and 37\% of 5-HTT+/+ animals with large MI survived the 8-week observation period. Surviving (sham and MI < 30\%) 5-HTT-/- mutants displayed reduced exploratory activity and increased anxiety-like behavior in different approach-avoidance tasks. However, CCD failed to provoke a depressive-like behavioral response in either 5-Htt genotype. Mechanistic analyses were performed on mice 3 days post-MI. Electrocardiography, histology and FACS of inflammatory cells revealed no abnormalities. However, gene expression of inflammation-related cytokines (TGF-β, TNF-α, IL-6) and MMP-2, a protein involved in the breakdown of extracellular matrix, was significantly increased in 5-HTT-/- mice after MI. This study shows that 5-HTT deficiency leads to age-dependent cardiac dysfunction and disrupted early healing after MI probably due to alterations of inflammatory processes in mice.},
  language  = {en}
}
@article{ZieglerEhlisWeberetal.2021,
  author    = {Ziegler, Georg C. and Ehlis, Ann-Christine and Weber, Heike and Vitale, Maria Rosaria and Z{\"o}ller, Johanna E. M. and Ku, Hsing-Ping and Schiele, Miriam A. and K{\"u}rbitz, Laura I. and Romanos, Marcel and Pauli, Paul and Kalisch, Raffael and Zwanzger, Peter and Domschke, Katharina and Fallgatter, Andreas J. and Reif, Andreas and Lesch, Klaus-Peter},
  title     = {A Common CDH13 Variant is Associated with Low Agreeableness and Neural Responses to Working Memory Tasks in ADHD},
  series = {Genes},
  volume    = {12},
  journal   = {Genes},
  number    = {9},
  issn      = {2073-4425},
  doi       = {10.3390/genes12091356},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-245220},
  year      = {2021},
  abstract  = {The cell—cell signaling gene CDH13 is associated with a wide spectrum of neuropsychiatric disorders, including attention-deficit/hyperactivity disorder (ADHD), autism, and major depression. CDH13 regulates axonal outgrowth and synapse formation, substantiating its relevance for neurodevelopmental processes. Several studies support the influence of CDH13 on personality traits, behavior, and executive functions. However, evidence for functional effects of common gene variation in the CDH13 gene in humans is sparse. Therefore, we tested for association of a functional intronic CDH13 SNP rs2199430 with ADHD in a sample of 998 adult patients and 884 healthy controls. The Big Five personality traits were assessed by the NEO-PI-R questionnaire. Assuming that altered neural correlates of working memory and cognitive response inhibition show genotype-dependent alterations, task performance and electroencephalographic event-related potentials were measured by n-back and continuous performance (Go/NoGo) tasks. The rs2199430 genotype was not associated with adult ADHD on the categorical diagnosis level. However, rs2199430 was significantly associated with agreeableness, with minor G allele homozygotes scoring lower than A allele carriers. Whereas task performance was not affected by genotype, a significant heterosis effect limited to the ADHD group was identified for the n-back task. Heterozygotes (AG) exhibited significantly higher N200 amplitudes during both the 1-back and 2-back condition in the central electrode position Cz. Consequently, the common genetic variation of CDH13 is associated with personality traits and impacts neural processing during working memory tasks. Thus, CDH13 might contribute to symptomatic core dysfunctions of social and cognitive impairment in ADHD.},
  language  = {en}
}
@article{ConzelmannReifJacobetal.2012,
  author    = {Conzelmann, Annette and Reif, Andreas and Jacob, Christian and Weyers, Peter and Lesch, Klaus-Peter and Lutz, Beat and Pauli, Paul},
  title     = {A polymorphism in the gene of the endocannabinoid-degrading enzyme FAAH (FAAH C385A) is associated with emotional-motivational reactivity},
  series = {Psychopharmacology},
  volume    = {224},
  journal   = {Psychopharmacology},
  number    = {4},
  doi       = {10.1007/s00213-012-2785-y},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-126845},
  pages     = {573-579},
  year      = {2012},
  abstract  = {RATIONALE: The endocannabinoid (eCB) system is implicated in several psychiatric disorders. Investigating emotional-motivational dysfunctions as underlying mechanisms, a study in humans revealed that in the C385A polymorphism of the fatty acid amide hydrolase (FAAH), the degrading enzyme of the eCB anandamide (AEA), A carriers, who are characterized by increased signaling of AEA as compared to C/C carriers, exhibited reduced brain reactivity towards unpleasant faces and enhanced reactivity towards reward. However, the association of eCB system with emotional-motivational reactivity is complex and bidirectional due to upcoming compensatory processes. OBJECTIVES: Therefore, we further investigated the relationship of the FAAH polymorphism and emotional-motivational reactivity in humans. METHODS: We assessed the affect-modulated startle, and ratings of valence and arousal in response to higher arousing pleasant, neutral, and unpleasant pictures in 67 FAAH C385A C/C carriers and 45 A carriers. RESULTS: Contrarily to the previous functional MRI study, A carriers compared to C/C carriers exhibited an increased startle potentiation and therefore emotional responsiveness towards unpleasant picture stimuli and reduced startle inhibition indicating reduced emotional reactivity in response to pleasant pictures, while both groups did not differ in ratings of arousal and valence. CONCLUSIONS: Our findings emphasize the bidirectionality and thorough examination of the eCB system's impact on emotional reactivity as a central endophenotype underlying various psychiatric disorders.},
  language  = {en}
}
@article{ConzelmannReifJacobetal.2012,
  author    = {Conzelmann, Annette and Reif, Andreas and Jacob, Christian and Weyers, Peter and Lesch, Klaus-Peter and Lutz, Beat and Pauli, Paul},
  title     = {A polymorphism in the gene of the endocannabinoid-degrading enzyme FAAH (FAAH C385A) is associated with emotional-motivational reactivity},
  series = {Psychopharmacology},
  volume    = {224},
  journal   = {Psychopharmacology},
  number    = {4},
  doi       = {10.1007/s00213-012-2785-y},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-129936},
  pages     = {573-579},
  year      = {2012},
  abstract  = {Rationale The endocannabinoid (eCB) system is implicated in several psychiatric disorders. Investigating emotional-motivational dysfunctions as underlying mechanisms, a study in humans revealed that in the C385A polymorphism of the fatty acid amide hydrolase (FAAH), the degrading enzyme of the eCB anandamide (AEA), A carriers, who are characterized by increased signaling of AEA as compared to C/C carriers, exhibited reduced brain reactivity towards unpleasant faces and enhanced reactivity towards reward. However, the association of eCB system with emotional-motivational reactivity is complex and bidirectional due to upcoming compensatory processes. Objectives Therefore, we further investigated the relationship of the FAAH polymorphism and emotional-motivational reactivity in humans. Methods We assessed the affect-modulated startle, and ratings of valence and arousal in response to higher arousing pleasant, neutral, and unpleasant pictures in 67 FAAH C385A C/C carriers and 45 A carriers. Results Contrarily to the previous functional MRI study, A carriers compared to C/C carriers exhibited an increased startle potentiation and therefore emotional responsiveness towards unpleasant picture stimuli and reduced startle inhibition indicating reduced emotional reactivity in response to pleasant pictures, while both groups did not differ in ratings of arousal and valence. Conclusions Our findings emphasize the bidirectionality and thorough examination of the eCB system's impact on emotional reactivity as a central endophenotype underlying various psychiatric disorders.},
  language  = {en}
}
@article{PostemaHoogmanAmbrosinoetal.2021,
  author    = {Postema, Merel C. and Hoogman, Martine and Ambrosino, Sara and Asherson, Philip and Banaschewski, Tobias and Bandeira, Cibele E. and Baranov, Alexandr and Bau, Claiton H.D. and Baumeister, Sarah and Baur-Streubel, Ramona and Bellgrove, Mark A. and Biederman, Joseph and Bralten, Janita and Brandeis, Daniel and Brem, Silvia and Buitelaar, Jan K. and Busatto, Geraldo F. and Castellanos, Francisco X. and Cercignani, Mara and Chaim-Avancini, Tiffany M. and Chantiluke, Kaylita C. and Christakou, Anastasia and Coghill, David and Conzelmann, Annette and Cubillo, Ana I. and Cupertino, Renata B. and de Zeeuw, Patrick and Doyle, Alysa E. and Durston, Sarah and Earl, Eric A. and Epstein, Jeffery N. and Ethofer, Thomas and Fair, Damien A. and Fallgatter, Andreas J. and Faraone, Stephen V. and Frodl, Thomas and Gabel, Matt C. and Gogberashvili, Tinatin and Grevet, Eugenio H. and Haavik, Jan and Harrison, Neil A. and Hartman, Catharina A. and Heslenfeld, Dirk J. and Hoekstra, Pieter J. and Hohmann, Sarah and H{\o}vik, Marie F. and Jernigan, Terry L. and Kardatzki, Bernd and Karkashadze, Georgii and Kelly, Clare and Kohls, Gregor and Konrad, Kerstin and Kuntsi, Jonna and Lazaro, Luisa and Lera-Miguel, Sara and Lesch, Klaus-Peter and Louza, Mario R. and Lundervold, Astri J. and Malpas, Charles B and Mattos, Paulo and McCarthy, Hazel and Namazova-Baranova, Leyla and Nicolau, Rosa and Nigg, Joel T. and Novotny, Stephanie E. and Oberwelland Weiss, Eileen and O'Gorman Tuura, Ruth L. and Oosterlaan, Jaap and Oranje, Bob and Paloyelis, Yannis and Pauli, Paul and Picon, Felipe A. and Plessen, Kerstin J. and Ramos-Quiroga, J. Antoni and Reif, Andreas and Reneman, Liesbeth and Rosa, Pedro G.P. and Rubia, Katya and Schrantee, Anouk and Schweren, Lizanne J.S. and Seitz, Jochen and Shaw, Philip and Silk, Tim J. and Skokauskas, Norbert and Soliva Vila, Juan C. and Stevens, Michael C. and Sudre, Gustavo and Tamm, Leanne and Tovar-Moll, Fernanda and van Erp, Theo G.M. and Vance, Alasdair and Vilarroya, Oscar and Vives-Gilabert, Yolanda and von Polier, Georg G. and Walitza, Susanne and Yoncheva, Yuliya N. and Zanetti, Marcus V. and Ziegler, Georg C. and Glahn, David C. and Jahanshad, Neda and Medland, Sarah E. and Thompson, Paul M. and Fisher, Simon E. and Franke, Barbara and Francks, Clyde},
  title     = {Analysis of structural brain asymmetries in attention-deficit/hyperactivity disorder in 39 datasets},
  series = {Journal of Child Psychology and Psychiatry},
  volume    = {62},
  journal   = {Journal of Child Psychology and Psychiatry},
  number    = {10},
  doi       = {10.1111/jcpp.13396},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-239968},
  pages     = {1202 -- 1219},
  year      = {2021},
  abstract  = {Objective Some studies have suggested alterations of structural brain asymmetry in attention-deficit/hyperactivity disorder (ADHD), but findings have been contradictory and based on small samples. Here, we performed the largest ever analysis of brain left-right asymmetry in ADHD, using 39 datasets of the ENIGMA consortium. Methods We analyzed asymmetry of subcortical and cerebral cortical structures in up to 1,933 people with ADHD and 1,829 unaffected controls. Asymmetry Indexes (AIs) were calculated per participant for each bilaterally paired measure, and linear mixed effects modeling was applied separately in children, adolescents, adults, and the total sample, to test exhaustively for potential associations of ADHD with structural brain asymmetries. Results There was no evidence for altered caudate nucleus asymmetry in ADHD, in contrast to prior literature. In children, there was less rightward asymmetry of the total hemispheric surface area compared to controls (t = 2.1, p = .04). Lower rightward asymmetry of medial orbitofrontal cortex surface area in ADHD (t = 2.7, p = .01) was similar to a recent finding for autism spectrum disorder. There were also some differences in cortical thickness asymmetry across age groups. In adults with ADHD, globus pallidus asymmetry was altered compared to those without ADHD. However, all effects were small (Cohen's d from -0.18 to 0.18) and would not survive study-wide correction for multiple testing. Conclusion Prior studies of altered structural brain asymmetry in ADHD were likely underpowered to detect the small effects reported here. Altered structural asymmetry is unlikely to provide a useful biomarker for ADHD, but may provide neurobiological insights into the trait.},
  language  = {en}
}
@article{RantamaekiVesaAntilaetal.2011,
  author    = {Rantam{\"a}ki, Tomi and Vesa, Liisa and Antila, Hanna and Di Lieto, Antonio and Tammela, P{\"a}ivi and Schmitt, Angelika and Lesch, Klaus-Peter and Rios, Maribel and Castr{\´e}n, Eero},
  title     = {Antidepressant Drugs Transactivate TrkB Neurotrophin Receptors in the Adult Rodent Brain Independently of BDNF and Monoamine Transporter Blockade},
  series = {PLoS ONE},
  volume    = {6},
  journal   = {PLoS ONE},
  number    = {6},
  doi       = {10.1371/journal.pone.0020567},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-133746},
  pages     = {e20567},
  year      = {2011},
  abstract  = {Background: Antidepressant drugs (ADs) have been shown to activate BDNF (brain-derived neurotrophic factor) receptor TrkB in the rodent brain but the mechanism underlying this phenomenon remains unclear. ADs act as monoamine reuptake inhibitors and after prolonged treatments regulate brain bdnf mRNA levels indicating that monoamine-BDNF signaling regulate AD-induced TrkB activation in vivo. However, recent findings demonstrate that Trk receptors can be transactivated independently of their neurotrophin ligands. Methodology: In this study we examined the role of BDNF, TrkB kinase activity and monoamine reuptake in the AD-induced TrkB activation in vivo and in vitro by employing several transgenic mouse models, cultured neurons and TrkB-expressing cell lines. Principal Findings: Using a chemical-genetic TrkB(F616A) mutant and TrkB overexpressing mice, we demonstrate that ADs specifically activate both the maturely and immaturely glycosylated forms of TrkB receptors in the brain in a TrkB kinase dependent manner. However, the tricyclic AD imipramine readily induced the phosphorylation of TrkB receptors in conditional bdnf(-/-) knock-out mice (132.4+/-8.5\% of control; P = 0.01), indicating that BDNF is not required for the TrkB activation. Moreover, using serotonin transporter (SERT) deficient mice and chemical lesions of monoaminergic neurons we show that neither a functional SERT nor monoamines are required for the TrkB phosphorylation response induced by the serotonin selective reuptake inhibitors fluoxetine or citalopram, or norepinephrine selective reuptake inhibitor reboxetine. However, neither ADs nor monoamine transmitters activated TrkB in cultured neurons or cell lines expressing TrkB receptors, arguing that ADs do not directly bind to TrkB. Conclusions: The present findings suggest that ADs transactivate brain TrkB receptors independently of BDNF and monoamine reuptake blockade and emphasize the need of an intact tissue context for the ability of ADs to induce TrkB activity in brain.},
  language  = {en}
}
@article{VeniaminovaCespuglioCheungetal.2017,
  author    = {Veniaminova, Ekaterina and Cespuglio, Raymond and Cheung, Chi Wai and Umriukhin, Alexei and Markova, Nataliia and Shevtsova, Elena and Lesch, Klaus-Peter and Anthony, Daniel C. and Strekalova, Tatyana},
  title     = {Autism-like behaviours and memory deficits result from a Western Diet in mice},
  series = {Neural Plasticity},
  journal   = {Neural Plasticity},
  doi       = {10.1155/2017/9498247},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158211},
  pages     = {9498247},
  year      = {2017},
  abstract  = {Nonalcoholic fatty liver disease, induced by a Western diet (WD), evokes central and peripheral inflammation that is accompanied by altered emotionality. These changes can be associated with abnormalities in social behaviour, hippocampus-dependent cognitive functions, and metabolism. Female C57BL/6J mice were fed with a regular chow or with a WD containing 0.2\% of cholesterol and 21\% of saturated fat for three weeks. WD-treated mice exhibited increased social avoidance, crawl-over and digging behaviours, decreased body-body contacts, and hyperlocomotion. The WD-fed group also displayed deficits in hippocampal-dependent performance such as contextual memory in a fear conditioning and pellet displacement paradigms. A reduction in glucose tolerance and elevated levels of serum cholesterol and leptin were also associated with the WD. The peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1a) mRNA, a marker of mitochondrial activity, was decreased in the prefrontal cortex, hippocampus, hypothalamus, and dorsal raphe, suggesting suppressed brain mitochondrial functions, but not in the liver. This is the first report to show that a WD can profoundly suppress social interactions and induce dominant-like behaviours in na{\"i}ve adult mice. The spectrum of behaviours that were found to be induced are reminiscent of symptoms associated with autism, and, if paralleled in humans, suggest that a WD might exacerbate autism spectrum disorder.},
  language  = {en}
}
@article{BoddenRichterSchreiberetal.2015,
  author    = {Bodden, Carina and Richter, S. Helene and Schreiber, Rebecca S. and Kloke, Vanessa and Gerß, Joachim and Palme, Rupert and Lesch, Klaus-Peter and Lewejohann, Lars and Kaiser, Sylvia and Sachser, Norbert},
  title     = {Benefits of adversity?! How life history affects the behavioral profile of mice varying in serotonin transporter genotype},
  series = {Frontiers in Behavioral Neuroscience},
  volume    = {9},
  journal   = {Frontiers in Behavioral Neuroscience},
  number    = {47},
  doi       = {10.3389/fnbeh.2015.00047},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-143723},
  year      = {2015},
  abstract  = {Behavioral profiles are influenced by both positive and negative experiences as well as the genetic disposition. Traditionally, accumulating adversity over lifetime is considered to predict increased anxiety like behavior ("allostatic load"). The alternative "mismatch hypothesis" suggests increased levels of anxiety if the early environment differs from the later-life environment. Thus, there is a need for a whole-life history approach to gain a deeper understanding of how behavioral profiles are shaped. The aim of this study was to elucidate the effects of life history on the behavioral profile of mice varying in serotonin transporter (5-HIT) genotype, an established mouse model of increased anxiety-like behavior. For this purpose, mice grew up under either adverse or beneficial conditions during early phases of life. In adulthood, they were further subdivided so as to face a situation that either matched or mismatched the condition experienced so far, resulting in four different life histories. Subsequently, mice were tested for their anxiety-like and exploratory behavior. The main results were: (1) Life history profoundly modulated the behavioral profile. Surprisingly, mice that experienced early beneficial and later escapable adverse conditions showed less anxiety-like and more exploratory behavior compared to mice of other life histories. (2) Genotype significantly influenced the behavioral profile, with homozygous 5-HTT knockout mice displaying highest levels of anxiety-like and lowest levels of exploratory behavior. Our findings concerning life history indicate that the absence of adversity does not necessarily cause lower levels of anxiety than accumulating adversity. Rather, some adversity may be beneficial, particularly when following positive events. Altogether, we conclude that for an understanding of behavioral profiles, it is not sufficient to look at experiences during single phases of life, but the whole life history has to be considered.},
  language  = {en}
}
@article{KaestnerRichterUrbaniketal.2019,
  author    = {K{\"a}stner, Niklas and Richter, S. Helene and Urbanik, Sarah and Kunert, Joachim and Waider, Jonas and Lesch, Klaus-Peter and Kaiser, Sylvia and Sachser, Norbert},
  title     = {Brain serotonin deficiency affects female aggression},
  series = {Scientific Reports},
  volume    = {9},
  journal   = {Scientific Reports},
  doi       = {10.1038/s41598-018-37613-4},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-325386},
  year      = {2019},
  abstract  = {The neurotransmitter serotonin plays a key role in the control of aggressive behaviour. While so far most studies have investigated variation in serotonin levels, a recently created tryptophan hydroxylase 2 (Tph2) knockout mouse model allows studying effects of complete brain serotonin deficiency. First studies revealed increased aggressiveness in homozygous Tph2 knockout mice in the context of a resident-intruder paradigm. Focussing on females, this study aimed to elucidate effects of serotonin deficiency on aggressive and non-aggressive social behaviours not in a test situation but a natural setting. For this purpose, female Tph2 wildtype (n = 40) and homozygous knockout mice (n = 40) were housed with a same-sex conspecific of either the same or the other genotype in large terraria. The main findings were: knockout females displayed untypically high levels of aggressive behaviour even after several days of co-housing. Notably, in response to aggressive knockout partners, they showed increased levels of defensive behaviours. While most studies on aggression in rodents have focussed on males, this study suggests a significant involvement of serotonin also in the control of female aggression. Future research will show, whether the observed behavioural effects are directly caused by the lack of serotonin or by potential compensatory mechanisms.},
  language  = {en}
}