Browsing by Author "Nunes, Ana Rita"
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- Genetic variation in the social environment affects behavioral phenotypes of oxytocin receptor mutants in zebrafishPublication . Ribeiro, Diogo; Nunes, Ana Rita; Teles, Magda C; Anbalagan, Savani; Blechman, Janna; Levkowitz, Gil; Oliveira, Rui FilipeOxytocin-like peptides have been implicated in the regulation of a wide range of social behaviors across taxa. On the other hand, the social environment, which is composed of conspecifics that may vary in their genotypes, also influences social behavior, creating the possibility for indirect genetic effects. Here, we used a zebrafish oxytocin receptor knockout line to investigate how the genotypic composition of the social environment (Gs) interacts with the oxytocin genotype of the focal individual (Gi) in the regulation of its social behavior. For this purpose, we have raised wild-type or knock-out zebrafish in either wild-type or knock-out shoals and tested different components of social behavior in adults. GixGs effects were detected in some behaviors, highlighting the need to control for GixGs effects when interpreting results of experiments using genetically modified animals, since the genotypic composition of the social environment can either rescue or promote phenotypes associated with specific genes.
- Genetic variation in the social environment affects behavioral phenotypes of oxytocin receptor mutants in zebrafishPublication . Ribeiro, Diogo; Nunes, Ana Rita; Teles, Magda C; Anbalagan, Savani; Blechman, Janna; Levkowitz, Gil; Oliveira, Rui FilipeOxytocin-like peptides have been implicated in the regulation of a wide range of social behaviors across taxa. On the other hand, the social environment, which is composed of conspecifics that may vary in their genotypes, also influences social behavior, creating the possibility for indirect genetic effects. Here, we used a zebrafish oxytocin receptor knockout line to investigate how the genotypic composition of the social environment (Gs) interacts with the oxytocin genotype of the focal individual (Gi) in the regulation of its social behavior. For this purpose, we have raised wild-type or knock-out zebrafish in either wild-type or knock-out shoals and tested different components of social behavior in adults. GixGs effects were detected in some behaviors, highlighting the need to control for GixGs effects when interpreting results of experiments using genetically modified animals, since the genotypic composition of the social environment can either rescue or promote phenotypes associated with specific genes.
- Homeodomain protein Otp affects developmental neuropeptide switching in oxytocin neurons associated with a long-term effect on social behaviorPublication . Wircer, Einav; Blechman, Janna; Borodovsky, Nataliya; Tsoory, Michael; Nunes, Ana Rita; Oliveira, Rui Filipe; Levkowitz, GilProper response to stress and social stimuli depends on orchestrated development of hypothalamic neuronal circuits. Here we address the effects of the developmental transcription factor orthopedia (Otp) on hypothalamic development and function. We show that developmental mutations in the zebrafish paralogous gene otpa but not otpb affect both stress response and social preference. These behavioral phenotypes were associated with developmental alterations in oxytocinergic (OXT) neurons. Thus, otpa and otpb differentially regulate neuropeptide switching in a newly identified subset of OXT neurons that co-express the corticotropin-releasing hormone (CRH). Single-cell analysis revealed that these neurons project mostly to the hindbrain and spinal cord. Ablation of this neuronal subset specifically reduced adult social preference without affecting stress behavior, thereby uncoupling the contribution of a specific OXT cluster to social behavior from the general otpa(-/-) deficits. Our findings reveal a new role for Otp in controlling developmental neuropeptide balance in a discrete OXT circuit whose disrupted development affects social behavior.
- Oxytocin receptor signaling modulates novelty recognition but not social preference in zebrafishPublication . Ribeiro, Diogo; Nunes, Ana Rita; Gligsberg, Michael; Anbalagan, Savani; Levkowitz, Gil; Oliveira, RuiSociality is a complex phenomenon that involves the individual's motivation to approach their conspecifics, along with social cognitive functions that enable individuals to interact and survive. The nonapeptide oxytocin (OXT) is known to regulate sociality in many species. However, the role of OXT in specific aspects of sociality is still not well understood. In the present study we investigated the contribution of the OXT receptor (OXTR) signaling in two different aspects of zebrafish social behavior: social preference, by measuring their motivation to approach a shoal of conspecifics, and social recognition, by measuring their ability to discriminate between a novel and familiar fish, using a mutant zebrafish lacking a functional OXTR. Although oxtr mutant zebrafish displayed normal attraction to a shoal of conspecifics, they exhibited reduced social recognition. We further investigated if this effect would be social-domain specific by replacing conspecific fish by objects. Although no differences were observed in object approach, oxtr mutant fish also exhibited impaired object recognition. Our findings suggest that OXTR signaling regulates a more general memory recognition of familiar vs. novel entities, not only in social but also in a non-social domain, in zebrafish.
- Perceptual mechanisms of social affiliation in zebrafishPublication . Nunes, Ana Rita; Carreira, Leonor; Anbalagan, Savani; Blechman, Janna; Levkowitz, Gil; Oliveira, Rui FilipeSocial living animals need to recognize the presence of conspecifics in the environment in order to engage in adaptive social interactions. Social cues can be detected through different sensory modalities, including vision. Two main visual features can convey information about the presence of conspecifics: body form and biological motion (BM). Given the role that oxytocin plays in social behavior regulation across vertebrates, particularly in the salience and reward values of social stimuli, we hypothesized that it may also be involved in the modulation of perceptual mechanisms for conspecific detection. Here, using videoplaybacks, we assessed the role of conspecific form and BM in zebrafish social affiliation, and how oxytocin regulates the perception of these cues. We demonstrated that while each visual cue is important for social attraction, BM promotes a higher fish engagement than the static conspecific form alone. Moreover, using a mutant line for one of the two oxytocin receptors, we show that oxytocin signaling is involved in the regulation of BM detection but not conspecific form recognition. In summary, our results indicate that, apart from oxytocin role in the regulation of social behaviors through its effect on higher-order cognitive mechanisms, it may regulate social behavior by modulating very basic perceptual mechanisms underlying the detection of socially-relevant cues.
- Social phenotypes in ZebrafishPublication . Nunes, Ana Rita; Ruhl, Nathan; Winberg, Svante; Oliveira, Rui FilipeZebrafish are an established model organism in developmental and behavioral neuroscience, also recently emerging as an excellent model to study social behavior. Zebrafish are highly social, forming groups (shoals) with structured social relationships, dominance hierarchies and overt territoriality. Moreover, social behavior in zebrafish exhibits considerable plasticity both within- (i.e., as a context-dependent behavior) and between individuals (e.g., sex-differences, personality and coping styles) of the same strain, as well as between strains. This richness and plasticity of social behavior, together with the genetic tools available to visualize and manipulate neural circuits in zebrafish places it in the forefront of studying the neurobiological mechanisms underlying complex social behavior. Here, we review the cognitive abilities involved in social behavior, as well as the different functional classes of social behavior present in zebrafish and their variation. We also highlight recent ground-breaking methodological developments in the field, including automated image-based tracking and classification of behavior coupled with video-animated social stimuli, which collectively foster the development of future high-throughput screens of zebrafish social phenotypes.
- Social zebrafish: Danio rerio as an emerging model in social neuroendocrinologyPublication . Kareklas, Kyriacos; Teles, Magda C; Nunes, Ana Rita; F. Oliveira, RuiThe fitness benefits of social life depend on the ability of animals to affiliate with others and form groups, on dominance hierarchies within groups that determine resource distribution, and on cognitive capacities for recognition, learning and information transfer. The evolution of these phenotypes is coupled with that of neuroendocrine mechanisms, but the causal link between the two remains underexplored. Growing evidence from our research group and others demonstrates that the tools available in zebrafish, Danio rerio, can markedly facilitate progress in this field. Here, we review this evidence and provide a synthesis of the state-of-the-art in this model system. We discuss the involvement of generalized motivation and cognitive components, neuroplasticity and functional connectivity across social decision-making brain areas, and how these are modulated chiefly by the oxytocin-vasopressin neuroendocrine system, but also by reward-pathway monoamine signaling and the effects of sex-hormones and stress physiology.