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Social animals make behavioural decisions based on local habitat and conspecifics, as well as memorized past experience (i.e. 'familiarity') with habitat and conspecifics. Here, we develop a conceptual and empirical understanding of how spatial and social familiarity fit within the spatial–social interface—a novel framework integrating the spatial and social components of animal behaviour. We conducted a multi-scale analysis of the movements of GPS-collared plains bison (Bison bison, n = 66) residing in and around Yellowstone National Park, USA. We found that both spatial and social familiarity mediate how individuals respond to their spatial and social environments. For instance, individuals with high spatial familiarity rely on their own knowledge as opposed to their conspecifics, and individuals with high social familiarity rely more strongly on the movement of conspecifics to guide their own movement. We also found that fine-scale spatial and social phenotypes often scale up to broad-scale phenotypes. For instance, bison that select more strongly to align with their nearest neighbour have larger home ranges. By integrating spatial and social familiarity into the spatial–social interface, we demonstrate the utility of the interface for testing hypotheses, while also highlighting the pervasive importance of cognitive mechanisms in animal behaviour. This article is part of the theme issue 'The spatial–social interface: a theoretical and empirical integration'. [ABSTRACT FROM AUTHOR]

Human disturbance is contributing to widespread, global changes in the distributions and densities of wild animals. These anthropogenic impacts on wildlife arise from multiple bottom-up and top-down pathways, including habitat loss, resource provisioning, climate change, pollution, infrastructure development, hunting and our direct presence. Animal behaviour is an important mechanism linking these disturbances to population outcomes, although these behavioural pathways are often complex and can remain obscured when different aspects of behaviour are studied in isolation from one another. The spatial–social interface provides a lens for understanding how an animal's spatial and social environments interact to determine its spatial and social phenotype (i.e. measurable characteristics of an individual), and how these phenotypes interact and feed back to reshape environments. Here, we review studies of animal behaviour at the spatial–social interface to understand and predict how human disturbance affects animal movement, distribution and intraspecific interactions, with consequences for the conservation of populations and ecosystems. By understanding the spatial–social mechanisms linking human disturbance to conservation outcomes, we can better design management interventions to mitigate undesired consequences of disturbance. This article is part of the theme issue 'The spatial–social interface: a theoretical and empirical integration'. [ABSTRACT FROM AUTHOR]

Background: MK-801 is a drug widely used in preclinical studies to model schizophrenia in animals. Its distinctive feature is the ability to mimic pathological changes in social interactions. Unlike humans, rodents rely heavily on their sense of smell for social interaction. Since, as previously demonstrated, it also impairs neurogenesis, we set out to determine whether olfactory impairment is associated with chronic administration of the drug. Methods: The mice were divided into two groups, of which one was administered the drug for 3 weeks, and the other only once. Olfaction and social transfer of food preferences were tested after the drug administration period. At the end of the experiment, an immunofluorescence study was performed to determine differences in neurogenesis in the olfactory bulbs. Results: An olfactory deficit was observed in animals that received the drug for 3 weeks. These changes were also accompanied by an abnormal lack of food preference in the social transmission test. As a result of a morphological study, a pronounced decrease in the number of new neurons was found in the olfactory bulbs of the animals that had received the drug. Conclusion: Our results indicate that at least some of the impairments in social behavior of the animals exposed to NMDA receptor antagonists are likely caused by changes in the sense of smell. These changes are associated with disruptions of neurogenesis. [ABSTRACT FROM AUTHOR]

The weather poses challenges for wildlife. Environmental challenges can be responded to at the group level by social animals, but the influence of weather on group behavior is poorly understood. We investigated how weather affects behavior in a gregarious species by monitoring common waxbills (Estrilda astrild) in a large mesocosm during 5 yr. We found seasonal patterns in collective foraging, aggressiveness, and the structure of the social network, usually showing 2 cycles per year: one peaking in Spring and a smaller one peaking in late Summer. Controlling for seasonality, we found behavioral changes related to increased energy demands in colder and/or cloudier days, such as more frequent and larger foraging groups that resulted in less-structured social networks. Rain and wind disturb movement, and we found that, on rainy days, foraging group journeys became briefer and more synchronous, resulting in stronger associations between individuals and less-structured networks, and that on windy days foraging groups were less frequent, larger, and with more within-group aggression. The results show that the weather has more varied effects than anticipated on ecologically relevant group behavior. We discuss how such weather-related effects can improve predictions of how social animals will react to environmental changes. [ABSTRACT FROM AUTHOR]

Oxytocin (OXT) is a peptide hormone and a neuropeptide that regulates various peripheral physiological processes and modulates behavioral responses in the central nervous system. While the humoral release occurs from the axons arriving at the median eminence, the neuropeptide is also released from oxytocinergic cell axons in various brain structures that contain its receptor, and from their dendrites in hypothalamic nuclei and potentially into the cerebrospinal fluid (CSF). Understanding oxytocin's complex functions requires the knowledge on patterns of oxytocinergic projections in relationship to its receptor (OXTR). This study provides the first comprehensive examination of the oxytocinergic system in the prairie vole (Microtus ochrogaster), an animal exhibiting social behaviors that mirror human social behaviors linked to oxytocinergic functioning. Using light and electron microscopy, we characterized the neuroanatomy of the oxytocinergic system in this species. OXT+ cell bodies were found primarily in the hypothalamus, and axons were densest in subcortical regions. Examination of the OXT+ fibers and their relationship to oxytocin receptor transcripts (Oxtr) revealed that except for some subcortical structures, the presence of axons was not correlated with the amount of Oxtr across the brain. Of particular interest, the cerebral cortex that had high expression of Oxtr transcripts contained little to no fibers. Electron microscopy is used to quantify dense cored vesicles (DCV) in OXT+ axons and to identify potential axonal release sites. The ependymal cells that line the ventricles were frequently permissive of DCV-containing OXT+ dendrites reaching the third ventricle. Our results highlight a mechanism in which oxytocin is released directly into the ventricles and circulates throughout the ventricular system, may serve as the primary source for oxytocin that binds to OXTR in the cerebral cortex. [ABSTRACT FROM AUTHOR]

Neuropeptide Y (NPY) increases resilience and buffers behavioral stress responses in male rats in part through decreasing the excitability of principal output neurons in the basolateral amygdala (BLA). Intra-BLA administration of NPY acutely increases social interaction (SI) through activation of either Y1 or Y5 receptors, whereas repeated NPY (rpNPY) injections (once daily for 5 d) produce persistent increases in SI through Y5 receptor-mediated neuroplasticity in the BLA. In this series of studies, we characterized the neural circuits from the BLA that underlie these behavioral responses to NPY. Using neuronal tract tracing, NPY Y1 and Y5 receptor immunoreactivity was identified on subpopulations of BLA neurons projecting to the bed nucleus of the stria terminalis (BNST) and the central nucleus of the amygdala (CeA). Inhibition of BLA→BNST, but not BLA→CeA, neurons using projection-restricted, cre-driven designer receptors exclusively activated by designer drug-Gi expression increased SI and prevented stress-induced decreases in SI produced by a 30 min restraint stress. This behavioral profile was similar to that seen after both acute and rpNPY injections into the BLA. Intracellular recordings of BLA→BNST neurons demonstrated NPY-mediated inhibition via suppression of H currents, as seen previously. Repeated intra-BLA injections of NPY, which are associated with the induction of BLA neuroplasticity, decreased the activity of BLA→BNST neurons and decreased their dendritic complexity. These results demonstrate that NPY modulates the activity of BNST-projecting BLA neurons, suggesting that this pathway contributes to the stress-buffering actions of NPY and provides a novel substrate for the proresilient effects of NPY. [ABSTRACT FROM AUTHOR]

Community organisation permeates both social and biological complex systems. To study its interplay with behaviour emergence, we model mobile structured populations with multiplayer interactions. We derive general analytical methods for evolutionary dynamics under high home fidelity when populations self-organise into networks of asymptotically isolated communities. In this limit, community organisation dominates over the network structure and emerging behaviour is independent of network topology. We obtain the rules of multiplayer cooperation in networks of communities for different types of social dilemmas. The success of cooperation is a result of the benefits shared among communal cooperators outperforming the benefits reaped by defectors in mixed communities. Under weak selection, cooperation can evolve and be stable for any size (Q) and number (M) of communities if the reward-to-cost ratio (V/K) of public goods is higher than a critical value. Community organisation is a solid mechanism for sustaining the evolution of cooperation under public goods dilemmas, particularly when populations are organised into a higher number of smaller communities. Contrary to public goods dilemmas relating to production, the multiplayer Hawk-Dove (HD) dilemma is a commons dilemma focusing on the fair consumption of preexisting resources. This game yields mixed results but tends to favour cooperation under larger communities, highlighting that the two types of social dilemmas might lead to solid differences in the behaviour adopted under community structure. Author summary: Human and animal behaviour is strongly influenced by the structure of their social interactions. The interaction networks that characterise these social systems are diverse, but among them community structure can be often found. This work focuses on the impact of community organisation on the evolution of cooperative behaviour in the face of collective social dilemmas. The work shows that community organisation is a solid mechanism for sustaining the evolution of cooperation under public goods dilemmas, particularly when populations are organised into a larger number of smaller communities. However, cooperation can evolve for any size and number of communities under all public goods dilemmas considered. The success of cooperation is a result of the benefits shared among communal cooperators outperforming the benefits reaped by defectors in mixed communities. The size and number of communities is much more important in determining the evolution of cooperation than the way they are connected to other communities. These results have significant implications for the study of animal and human social behaviour, metapopulation dynamics, and general dynamics on social interaction networks. [ABSTRACT FROM AUTHOR]

A large body of evidence implies the involvement of brain-derived neurotrophic factor (BDNF) in the pathogenesis of autism spectrum disorders (ASDs). A deficiency of BDNF in the hippocampus and frontal cortex of BTBR mice (a model of autism) has been noted in a number of studies. Earlier, we showed that induction of BDNF overexpression in the hippocampus of BTBR mice reduced anxiety and severity of stereotyped behavior, but did not affect social interest. Here, we induced BDNF overexpression in the frontal cortex neurons of BTBR mice using an adeno-associated viral vector, which resulted in a significant increase in the social interest in the three-chamber social test. At the same time, the stereotypy, exploratory behavior, anxiety-like behavior, and novel object recognition were not affected. Therefore, we have shown for the first time that the presence of BDNF in the frontal cortex is critical for the expression of social interest in BTBR mice, since compensation for its deficiency in this structure eliminated the autism-like deficiencies in the social behavior characteristic for these animals. [ABSTRACT FROM AUTHOR]

This document is a compilation of scientific articles that explore the historical treatment of rodents in scientific research and the growing recognition of their cognitive abilities and welfare. It emphasizes the importance of considering animal suffering and the need for animal-friendly methods in rodent behavioral testing. The articles discuss various approaches and technologies, such as mirror-based tests and automated monitoring systems, that prioritize animal welfare while providing valid results. The research presented in these articles sheds light on the complex behaviors and capabilities of rodents, highlighting their similarities to humans and the potential for further study in this field. [Extracted from the article]

Background: Social behaviour plays a key role in mental health and wellbeing, and developing greater understanding of mechanisms underlying social interaction—particularly social motivation—holds substantial transdiagnostic impact. Common rodent behavioural assays used to assess social behaviour are limited in their assessment of social motivation, whereas the social operant conditioning model can provide unique and valuable insights into social motivation. Further characterisation of common experimental parameters that may influence social motivation within the social operant model, as well as complementary methodological and analytical approaches, are warranted. Methods: This study investigated the effects of biological sex, housing condition, and time-of-day, on social motivation using the social operant model. This involved training rats to lever press (FR1) for 60-s access to a social reward (same-sex conspecific stimulus). Subjects were male and female Wistar rats, housed under individual or paired conditions, and sessions were conducted either in the mid-late light phase (ZT6-10) or early-mid dark phase (ZT13-17). A behavioural economics approach was implemented to measure social demand and the influence of stimulus partner sex (same- vs. opposite-sex stimulus) on social operant responding. Additionally, video tracking analyses were conducted to assess the degree of convergence between social appetitive and consummatory behaviours. Results: Biological sex, housing conditions, the interaction between sex and housing, and stimulus partner sex potently influenced social motivation, whereas time-of-day did not. Behavioural economics demonstrated that sex, housing, and their interaction influence both the hedonic set-point and elasticity of social demand. Video analysis of social interaction during social operant sessions revealed that social appetitive and consummatory behaviours are not necessarily convergent, and indicate potential social satiety. Lastly, oestrus phase of female experimental and stimulus rats did not impact social motivation within the model. Conclusions: Social isolation-dependent sex differences exist in social motivation for rats, as assessed by social operant conditioning. The social operant model represents an optimal preclinical assay that comprehensively evaluates social motivation and offers a platform for future investigations of neurobiological mechanisms underlying sex differences in social motivation. These findings highlight the importance of continued consideration and inclusion of sex as a biological variable in future social operant conditioning studies. Plain English summary: Humans are social creatures—our everyday interactions with others and the support this provides play a key role in our wellbeing. For those experiencing mental health conditions, people's motivation to engage with others can wane, which can lead them to withdraw from those who support them. Therefore, to develop better treatment strategies for these conditions, we need to gain a deeper understanding of social motivation. Studying social behaviour in animals can facilitate this investigation of social motivation as it allows for a causal understanding of underlying neurobiology that is not possible in human experiments. An optimal way to study social motivation in animals is using the social operant conditioning model, where rats learn to press a lever that opens a door and allows them to interact with another rat for a short time. This study characterised the social operant model by testing whether sex, housing conditions, time-of-day, and the sex of the stimulus partner influence rats' motivation to seek interaction with another rat. We found that female rats were more socially motivated than males, and that rats living alone were more motivated than those living with another rat; interestingly, this effect of housing affected females more than males. Regardless of sex, rats were more motivated to interact with a rat of the opposite sex. These findings provide insights into sex differences in social motivation in rats and new insights into the social operant model which will help guide future research into social motivation and other mental health conditions. Highlights: Female Wistar rats exhibited greater social motivation than male rats in the social operant conditioning model. Isolated housing produced higher social motivation than paired housing, but this isolation-induced increase was either more marked for, or only present in, female rats. Both female and male rats demonstrate higher motivation for opposite-sex than same-sex stimulus conspecifics. Time-of-day and oestrus phase (of female experimental and stimulus rats) did not appear to impact social motivatio. Both between- and within-session behavioural economics in conjunction with video tracking analyses can be applied to better assess social motivation and interaction during social operant conditioning. [ABSTRACT FROM AUTHOR]

Computer vision models such as You Only Look Once (YOLO) excel at tracking general objects, yet they often struggle to accurately track multiple animals. In this study, we aimed to verify the improvement of animal tracking performance using YOLO by fine-tuning. We obtained videos of multiple domestic cats by ourselves and annotated the videos, and performed fine-tuning with this video dataset. Results of this study show that even training with less than one hundred images improves accuracy and enables tracking of individual animals. This result suggests that our method is promising for the realization of animal social behavior analysis. [ABSTRACT FROM AUTHOR]

Many group-living animals coordinate social behaviours using contact calls, which can be produced for all group members or targeted at specific individuals. In the disc-winged bat, Thyroptera tricolor, group members use 'inquiry' and 'response' calls to coordinate daily movements into new roosts (furled leaves). Rates of both calls show consistent among-individual variation, but causes of within-individual variation remain unknown. Here, we tested whether disc-winged bats produce more contact calls towards group members with higher kinship or association. In 446 experimental trials, we recorded 139 random within-group pairs of one flying bat (producing inquiry calls for roost searching) and one roosting bat (producing response calls for roost advertising). Using generalized linear mixed-effect models (GLMM), we assessed how response and inquiry calling rates varied by sender, receiver, genetic kinship and co-roosting association rate. Calling rates varied consistently across senders but not by receiver. Response calling was influenced by inquiry calling rates, but neither calling rate was higher when the interacting pair had higher kinship or association. Rather than dyadic calling rates indicating within-group relationships, our findings are consistent with the hypothesis that bats produce contact calls to maintain contact with any or all individuals within a group while collectively searching for a new roost site. This article is part of the theme issue 'The power of sound: unravelling how acoustic communication shapes group dynamics'. [ABSTRACT FROM AUTHOR]

Post-Traumatic Stress Disorder (PTSD) is a chronic mental disorder characterized by symptoms of panic and anxiety, depression, impaired cognitive functioning, and difficulty in social interactions. While the effect of the traditional Chinese medicine artemisinin (AR) on PTSD is unknown, its therapeutic benefits have been demonstrated by studies on models of multiple neurological disorders. This study aimed to extend such findings by investigating the effects of AR administration on a rat model of PTSD induced by a regimen of single prolonged stress (SPS). After rats were subjected to the SPS protocol, AR was administered and its impact on PTSD-like behaviors was evaluated. In the present study, rats were subjected to a multitude of behavioral tests to evaluate behaviors related to anxiety, memory function, and social interactions. The expression of hippocampal synaptic plasticity-related proteins was detected using Western blot and immunofluorescence. The ultrastructure of synapses was observed under transmission electron microscopy. The apoptosis of hippocampal neurons was examined with Western blot, TUNEL staining, and HE staining. The results showed that AR administration alleviated the PTSD-like phenotypes in SPS rats, including behavior indicative of anxiety, cognitive deficits, and diminished sociability. AR administration was further observed to improve synaptic plasticity and inhibit neuronal apoptosis in SPS rats. These findings suggest that administering AR after the onset of severe traumatic events may alleviate anxiety, cognitive deficits, and impaired social interaction, improve synaptic plasticity, and diminish neuronal apoptosis. Hence, the present study provides evidence for AR's potential as a multi-target agent in the treatment of PTSD. [ABSTRACT FROM AUTHOR]

Extracellular ATP (eATP) signaling through the P2X7 receptor pathway is widely believed to trigger NLRP3 inflammasome assembly in microglia, potentially contributing to depression. However, the cellular stress responses of microglia to both eATP and stress itself remain largely unexplored. Mitochondria-associated membranes (MAMs) is a platform facilitating calcium transport between the endoplasmic reticulum (ER) and mitochondria, regulating ER stress responses and mitochondrial homeostasis. This study aims to investigate how MAMs influence microglial reaction and their involvement in the development of depression-like symptoms in response to chronic social defeat stress (CSDS). CSDS induced ER stress, MAMs' modifications, mitochondrial damage, and the formation of the IP3R3-GRP75-VDAC1 complex at the ER-mitochondria interface in hippocampal microglia, all concomitant with depression-like behaviors. Additionally, exposing microglia to eATP to mimic CSDS conditions resulted in analogous outcomes. Furthermore, knocking down GRP75 in BV2 cells impeded ER-mitochondria contact, calcium transfer, ER stress, mitochondrial damage, mitochondrial superoxide production, and NLRP3 inflammasome aggregation induced by eATP. In addition, reduced GRP75 expression in microglia of Cx3cr1CreER/+Hspa9f/+ mice lead to reduce depressive behaviors, decreased NLRP3 inflammasome aggregation, and fewer ER-mitochondria contacts in hippocampal microglia during CSDS. Here, we show the role of MAMs, particularly the formation of a tripartite complex involving IP3R3, GRP75, and VDAC1 within MAMs, in facilitating communication between the ER and mitochondria in microglia, thereby contributing to the development of depression-like phenotypes in male mice. Malfunctioning of cellular organelles, such as the endoplasmic reticulum (ER) and mitochondria, can have a role in stress-induced pathophysiological changes. Here, the authors show that increased mitochondria‐associated endoplasmic reticulum membranes contacts related to ATP-P2X7 receptor signaling contribute to stress responses in microglia and the development of depression-like behavior in male mice. [ABSTRACT FROM AUTHOR]

Identifying the factors that favor group living is central to studies of animal social behavior. One demographic parameter that is expected to substantially shape spatial and social relationships is population density. Specifically, high population densities may favor group living by constraining opportunities to live alone. In contrast, low densities may allow individuals to spread out within the habitat, leading to a reduction in the prevalence or size of social groups. Abrupt changes in density following natural catastrophic events provide important opportunities to evaluate the effects of population density on patterns of spatial and social organization. As part of long-term studies of the behavioral ecology of a population of highland tuco-tucos (Ctenomys opimus) at Monumento Natural Laguna de los Pozuelos, Jujuy Province, Argentina, we monitored the demographic and behavioral consequences of a flood that inundated our study site during December 2012. Unlike most species of Ctenomys studied to date, highland tuco-tucos are group living, meaning that multiple adults share burrow systems and nest sites. Despite a post-flood reduction in population density of ~75%, animals present on the study site during the 2013 breeding season continued to live in multi-adult social units (groups). No differences between pre- and post-flood home range sizes were detected and although between-unit spatial overlap was reduced in 2013, overlap within social units did not differ from that in pre-flood years. Animals assigned to the same social unit in 2013 had not lived together during 2012, indicating that post-flood groups were not simply the remnants of those present prior to the flood. Collectively, these findings indicate that group living in highland tuco-tucos is not driven by the density of conspecifics in the habitat. In addition to enhancing understanding of the adaptive bases for group living in Ctenomys, our analyses underscore the power of catastrophic events to generate insights into fundamental aspects of social behavior. [ABSTRACT FROM AUTHOR]

A new study leads the way to a more ethical and ethologically meaningful way of investigating brain functions of complex behaviors in social animals. [ABSTRACT FROM AUTHOR]

Erving Goffman is one of sociology's most influential thinkers. Scholars debate the extent to which he worked in competing theoretical traditions (e.g., interactionist or structuralist), yet few acknowledge his intellectual indebtedness to animal ethology. This article traces how naturalistic studies of paralinguistic animal communication influenced Goffman's corpus and specifies the ideas he built on from that field, especially territoriality and ritualized display. Goffman's comparative approach to animal and human interaction reveals the shortcomings of sociologists' lingua-centric approach to interaction; elevates animals to social actors, capable of metacommunication, reading others' intentions, and adjusting their behavior accordingly; and humbles humans, who he finds enacting rituals of civility for the same reason animals engage in ritualized display: to manage threats and facilitate bonding. Goffman's thesis on the similarities between animal and human social behavior compels sociology to consider animal studies, and his use of ethology helps reconcile his interactionist and Durkheimian tendencies. [ABSTRACT FROM AUTHOR]

The article discusses the concept of collective behavior in the context of ecology and evolution. It draws parallels between the synchronized freezing of actors in a musical theater production and the coordinated fleeing of ground squirrels in response to a predator. The author argues that collective behavior is heavily influenced by the environment and that studying social networks within their natural contexts is crucial for understanding how these networks function. The article also highlights the need for field-based research and proposes hypotheses related to resource distribution, feedback systems, and network modularity. Overall, the article encourages researchers to shift towards a more holistic approach to studying collective behavior. [Extracted from the article]

Autism spectrum disorders (ASDs) are known to present sex-specific differences. At the same time, understanding how maternal behaviours are affected by pathogenic mutations is crucial to translate research efforts since rearing may recursively modulate neurodevelopment phenotype of the progeny. In this work, we focused on the effects of Gprasp2 deletion in females and its impact in progeny care and development. Female mice, wild-type (WT), Gprasp2+/− (HET) or Gprasp2−/− (KO) mutants and their progeny were used and behavioural paradigms targeting anxiety, memory, maternal care, and other social behaviours were performed. Analysis of communication was carried out through daily recordings of ultrasonic vocalizations in isolated pups and cross-fostering experiments were performed to understand the effect of maternal genotype in pup development. We found that Gprasp2−/− females presented striking impairments in social and working memory. Females also showed disruptions in maternal care, as well as physiological and molecular alterations in the reproductive system and hypothalamus, such as the structure of the mammary gland and the expression levels of oxytocin receptor (OxtR) in nulliparous versus primiparous females. We observed alterations in pup communication, particularly a reduced number of calls in Gprasp2 KO pups, which resulted from an interaction effect of the dam and pup genotype. Cross-fostering mutant pups with wild-type dams rescued some of the early defects shown in vocalizations, however, this effect was not bidirectional, as rearing WT pups with Gprasp2−/− dams was not sufficient to induce significant phenotypical alterations. Our results suggest Gprasp2 mutations perturb social and working memory in a sex-independent manner, but impact female-specific behaviours towards progeny care, female physiology, and gene expression. These changes in mutant dams contribute to a disruption in early stages of progeny development. More generally, our results highlight the need to better understand GxE interactions in the context of ASDs, when female behaviour may present a contributing factor in postnatal neurodevelopmental trajectory. [ABSTRACT FROM AUTHOR]

Social play behaviour is a rewarding activity that can entail risks, thus allowing young individuals to test the limits of their capacities and to train their cognitive and emotional adaptability to challenges. Here, we tested in rats how opportunities for risk‐taking during play affect the development of cognitive and emotional capacities and medial prefrontal cortex (mPFC) function, a brain structure important for risk‐based decision making. Male and female rats were housed socially or social play‐deprived (SPD) between postnatal day (P)21 and P42. During this period, half of both groups were daily exposed to a high‐risk play environment. Around P85, all rats were tested for cognitive performance and emotional behaviour after which inhibitory currents were recorded in layer 5 pyramidal neurons in mPFC slices. We show that playing in a high‐risk environment altered cognitive flexibility in both sexes and improved behavioural inhibition in males. High‐risk play altered anxiety‐like behaviour in the elevated plus maze in males and in the open field in females, respectively. SPD affected cognitive flexibility in both sexes and decreased anxiety‐like behaviour in the elevated plus maze in females. We found that synaptic inhibitory currents in the mPFC were increased in male, but not female, rats after high‐risk play, while SPD lowered prefrontal cortex (PFC) synaptic inhibition in both sexes. Together, our data show that exposure to risks during play affects the development of cognition, emotional behaviour and inhibition in the mPFC. Furthermore, our study suggests that the opportunity to take risks during play cannot substitute for social play behaviour. [ABSTRACT FROM AUTHOR]

Perinatal exposure to valproic acid is commonly used for autism spectrum disorder (ASD) animal model development. The inhibition of histone deacetylases by VPA has been proposed to induce epigenetic changes during neurodevelopment, but the specific alterations in genetic expression underlying ASD-like behavioral changes remain unclear. We used qPCR-based gene expression and epigenetics tools and Western blotting in the hippocampi of neonatal valproic acid-exposed animals at 4 weeks of age and conducted the social interaction test to detect behavioral changes. Significant alterations in gene expression were observed in males, particularly concerning mRNA expression of Foxo3, which was significantly associated with behavioral changes. Moreover, notable differences were observed in H3K27ac chromatin immunoprecipitation, quantitative PCR (ChIP-qPCR), and methylation-sensitive restriction enzyme-based qPCR targeting the Foxo3 gene promoter region. These findings provide evidence that epigenetically regulated hippocampal Foxo3 expression may influence social interaction-related behavioral changes. Furthermore, identifying sex-specific gene expression and epigenetic changes in this model may elucidate the sex disparity observed in autism spectrum disorder prevalence. [ABSTRACT FROM AUTHOR]

The Slitrk family consists of six synaptic adhesion molecules, some of which are associated with neuropsychiatric disorders. In this study, we aimed to investigate the physiological role of Slitrk4 by analyzing Slitrk4 knockout (KO) mice. The Slitrk4 protein was widely detected in the brain and was abundant in the olfactory bulb and amygdala. In a systematic behavioral analysis, male Slitrk4 KO mice exhibited an enhanced fear memory acquisition in a cued test for classical fear conditioning, and social behavior deficits in reciprocal social interaction tests. In an electrophysiological analysis using amygdala slices, Slitrk4 KO mice showed enhanced long-term potentiation in the thalamo-amygdala afferents and reduced feedback inhibition. In the molecular marker analysis of Slitrk4 KO brains, the number of calretinin (CR)-positive interneurons was decreased in the anterior part of the lateral amygdala nuclei at the adult stage. In in vitro experiments for neuronal differentiation, Slitrk4-deficient embryonic stem cells were defective in inducing GABAergic interneurons with an altered response to sonic hedgehog signaling activation that was involved in the generation of GABAergic interneuron subsets. These results indicate that Slitrk4 function is related to the development of inhibitory neurons in the fear memory circuit and would contribute to a better understanding of osttraumatic stress disorder, in which an altered expression of Slitrk4 has been reported. [ABSTRACT FROM AUTHOR]

Recent studies have emphasized that there is a strong link between the gut microbiome and the brain that affects social behavior and personality in animals. However, the interface between personality and the gut microbiome in wild primates remains poorly understood. Here, we used high-throughput sequencing and ethological methods in primate behavioral ecology to investigate the relationship between gut microbiome and personality in Tibetan macaques (Macaca thibetana). The behavioral assessment results indicated three personality dimensions including socialization, shyness, and anxiety. There was significant variation in alpha diversity only for shyness, with a significantly lower alpha diversity indices (including Shannon, Chao1, and PD) for bold individuals than for shy individuals. Using regression models to control for possible confounding factors, we found that the relative abundance of three genera, Akkermansia, Dialister, and Asteroleplasma, was significantly and positively correlated with the sociability scores in the macaques. In addition, Oscillospiraceae exhibited a positive correlation with scores for Shy Dimension. Furthermore, we found that the predicted functional genes for propionate and pyruvate, porphyrin and chlorophyll metabolic pathways related to animal behavior, were significant enriched in shyness group. We propose that the gut microbiome may play an important role in the formation of personality of Tibetan macaques. [ABSTRACT FROM AUTHOR]

Social aggregative behaviour may have evolved in marine isopods to aid hunting, and help the animals protect themselves from predation. This social behaviour could have assisted some isopod species to make the evolutionary transition from marine to terrestrial environments, as aggregative huddling of isopods on land reduces desiccation when out of water. To determine if the common pill-bug Armadillidium vulgare demonstrates social behaviour, groups of animals were filmed for 60 min in an arena that contained a binary choice of two shelters. This experiment was directly repeated with the same specimens three more times in the same day and this series of four experimental runs was replicated a total of 10 times with a different group of animals for each of the 10 series. In most cases, the majority of specimens chose one of the two identical shelters at random, and congregated under this winning shelter. The amount of animals that congregated under the winning shelter, however, significantly decreased over the four consecutive runs, whereas the amount of animals that congregated under the losing shelter significantly increased with prior experience. These data indicate that A. vulgare is a social animal but this social behaviour can decrease with exposure to the novel environment. This attenuation in social behaviour may serve to decrease the drive to join the larger of the two groups in an area where a danger from predation has not been encountered and allow experienced animals to explore new terrain. [ABSTRACT FROM AUTHOR]

Circular RNAs are highly enriched in the synapses of the mammalian brain and play important roles in neurological function by acting as molecular sponges of microRNAs. circAnk3 is derived from the 11th intron of the ankyrin-3 gene, Ank3 , a strong genetic risk factor for neuropsychiatric disorders; however, the function of circAnk3 remains elusive. In this study, we investigated the function of circAnk3 and its downstream regulatory network for target genes in the hippocampus of mice. The DNA sequence from which circAnk3 is generated was modified using CRISPR/Cas9 (clustered regularly interspaced short palindromic repeats/Cas9) technology, and neurobehavioral tests (anxiety and depression-like behaviors, social behaviors) were performed in circAnk3+/− mice. A series of molecular and biochemical assays were used to investigate the function of circAnk3 as a microRNA sponge and its downstream regulatory network for target genes. circAnk3+/− mice exhibited both anxiety-like behaviors and social deficits. circAnk3 was predominantly located in the cytoplasm of neuronal cells and functioned as a miR-7080-3p sponge to regulate the expression of Iqgap1. Inhibition of miR-7080-3p or restoration of Iqgap1 in the hippocampus ameliorated the behavioral deficits of circAnk3+/− mice. Furthermore, circAnk3 deficiency decreased the expression of the NMDA receptor subunit GluN2a and impaired the structural plasticity of dendritic synapses in the hippocampus. Our results reveal an important role of the circAnk3/miR-7080-3p/IQGAP1 axis in maintaining the structural plasticity of hippocampal synapses. circAnk3 might offer new insights into the involvement of circular RNAs in neuropsychiatric disorders. [ABSTRACT FROM AUTHOR]

Fluorene-9-bisphenol (BHPF) is widely used in the manufacture of plastic products and potentially disrupts several physiological processes, but its biological effects on social behavior remain unknown. In this study, we investigated the effects of BHPF exposure on anxiety-like and social behavior in female mice and the potential mechanisms, thereby proposing a potential therapy strategy. We exposed female Balb/c mice to BHPF by oral gavage at different doses (0.5, 50 mg/kg bw/2-day) for 28 days, which were found BHPF (50 mg/kg) exposure affected motor activity in the open field test (OFT) and elevated cross maze (EPM), resulting in anxiety-like behaviors, as well as abnormal social behavioral deficits in the Social Interaction Test (SIT). Analysis of histopathological staining results showed that BHPF exposure caused damage to hippocampal neurons in the CA1/CA3/DG region and decreased Nissl pyramidal neurons in the CA1/CA3 regions of the hippocampus, as well as a decrease in parvalbumin neuron expression. In addition, BHPF exposure upregulated the expression of excitatory and inhibitory (E/I) vesicle transporter genes (Vglut1, Vglut2, VGAT, GAD67, Gabra) and axon growth gene (Dcc) in the mouse hippocampus. Interestingly, behavioral disturbances and E/I balance could be alleviated by exogenous melatonin (15 mg/kg bw/2-day) therapy. Our findings suggest that exogenous melatonin may be a potential therapy with protective potential for ameliorating or preventing BHPF-induced hippocampal neuronal damage and behavioral disturbances. This study provided new insight into the neurotoxicological effects on organisms exposed to endocrine-disrupting chemicals and aroused our vigilance in current environmental safety about chemical use. [ABSTRACT FROM AUTHOR]

The article discusses various scientific studies published in the Proceedings of the National Academy of Sciences of the United States of America. The studies cover a range of topics, including preserved magnetism in meteorites, group formation among solitary animals, expansion and recession of human populations, mismatch between plant green-up and bird migration, genomics of Tasmanian devil cancer, elderly populations and energy consumption, and fluctuations in the Patagonian ice sheet. The studies provide valuable insights into these subjects and contribute to our understanding of the natural world. [Extracted from the article]

Human communities teem with a variety of social norms. In order to change unjust and harmful social norms, it is crucial to identify the psychological processes that give rise to them. Most researchers take it for granted that social norms are uniquely human. By contrast, we approach this matter from a comparative perspective, leveraging recent research on animal social behaviour. While there is currently only suggestive evidence for norms in nonhuman communities, we argue that human social norms are likely produced by a wide range of mechanisms, many of which we share with nonhuman animals. Approaching this variability from a comparative perspective can help norm researchers expand and reframe the range of hypotheses they test when attempting to understand the causes of socially normative behaviours in humans. First, we diagnose some of the theoretical obstacles to developing a comparative science of social norms, and offer a few basic constructs and distinctions to help norm researchers overcome these obstacles. Then we develop a six-dimensional model of the psychological and social factors that contribute to variability in both human and potential nonhuman norms. This article is part of the theme issue 'Social norm change: drivers and consequences'. [ABSTRACT FROM AUTHOR]

Simple Summary: Phonotaxis is the movement of an animal towards an acoustic signal. In crickets, males generate the calling signals, thereby attracting females and other males. The calling signal is the only means of distant communication in crickets. Reception of the calling signal by the female may occur during flight, and flight often precedes copulation. We had previously found that a prior flight significantly enhanced subsequent terrestrial phonotaxis in female crickets. It is clear that some neurochemical mechanisms are responsible for the enhancement of phonotaxis after a flight. The purpose of our research was to elucidate these mechanisms. The most likely targets to test were the octopaminergic and serotonergic systems. It is known that the concentration of octopamine in the cricket hemolymph increases during flight, and that serotonin is involved in the modulation of social behavior in many animals, including insects. Using pharmacological manipulations, we show that the increase in the serotonin synthesis enhances phonotaxis. The 5-HT content in thoracic ganglia was significantly higher in flyers in comparison to the control group. The role of octopamine in phonotactic behavior is more complex and controversial. We demonstrate that octopamine suppresses rather than activates the central mechanisms associated with phonotaxis. We make suggestions about why serotonin may enhance phonotaxis and examine possible reasons for the ambiguous role of the octopaminergic system in phonotactic behavior. We have recently shown that experience of flight remarkably enhanced subsequent terrestrial phonotaxis in females in response to the male calling song. Here, we elucidated the possible roles of octopamine and serotonin in the enhancing effect of flying on phonotactic behavior. Octopamine is known to be released into the hemolymph during flight in insects; however, the octopamine receptor antagonist epinastine did not abolish the effects of flight in our study. On the contrary, the drug significantly potentiated the influence of flying on phonotactic behavior. The octopamine receptor agonist chlordimeform, at a concentration of 2 mM, which was previously found to activate aggression in crickets, dramatically reduced the phonotactic response. However, at a 10-times-lower dose, chlordimeform produced a light but significant decrease in the time that females took to reach the source of the calling song. A similar effect was produced by octopamine itself, which hardly passes the blood–brain barrier in insects. The effect of flight was completely abolished in female crickets treated with alpha-methyl tryptophan (AMTP). AMPT suppresses the synthesis of serotonin, decreasing its content in the nervous systems of insects, including crickets. An activation of the serotonin synthesis with 5-hydroxytryptophan mimicked the effect of flight by increasing the number of visits to and the time spent in the zone near the source of the calling song. The 5-HT content in the third thoracic ganglion was significantly higher in flyers compared to the control group. In contrast, no changes in the octopamine level were observed in the third thoracic ganglion, which is known to play a crucial role in decision-making involved in intraspecific interactions. Therefore, the results suggest that although octopamine is known to be released into the hemolymph during flight, it is likely to inhibit rather than activate the central mechanisms related to phonotaxis. The weak facilitating effect of a low dose of chlordimeform can be attributed to the activation of peripheral octopaminergic receptors. Our results suggest that the serotoninergic system may contribute to the facilitation of female phonotactic behavior by flying. We suggest that both flying and serotonin enhance sexual motivation in females and, by these means, impact their behavioral response to the male calling song. [ABSTRACT FROM AUTHOR]

Background: Behaviors in captive animals, including changes in appetite, activity level, and social interaction, are often seen as adaptive responses. However, these behaviors may become progressively maladaptive, leading to stress, anxiety, depression, and other negative reactions in animals. Results: In this study, we investigated the whole-genome sequencing data of 39 giant panda individuals, including 11 in captivity and 28 in the wild. To eliminate the mountain range effect and focus on the factor of captivity only, we first performed a principal component analysis. We then enumerated the 21,474,180 combinations of wild giant pandas (11 chosen from 28) and calculated their distances from the 11 captive individuals. The 11 wild individuals with the closest distances were used for the subsequent analysis. The linkage disequilibrium (LD) patterns demonstrated that the population was almost eliminated. We identified 505 robust selected genomic regions harboring at least one SNP, and the absolute frequency difference was greater than 0.6 between the two populations. GO analysis revealed that genes in these regions were mainly involved in nerve-related pathways. Furthermore, we identified 22 GO terms for which the selection strength significantly differed between the two populations, and there were 10 nerve-related pathways among them. Genes in the differentially abundant regions were involved in nerve-related pathways, indicating that giant pandas in captivity underwent minor genomic selection. Additionally, we investigated the relationship between genetic variation and chromatin conformation structures. We found that nucleotide diversity (θπ) in the captive population was correlated with chromatin conformation structures, which included A/B compartments, topologically associated domains (TADs) and TAD-cliques. For each GO term, we then compared the expression level of genes regulated by the above four factors (AB index, TAD intactness, TAD clique and PEI) with the corresponding genomic background. The retained 10 GO terms were all coordinately regulated by the four factors, and three of them were associated with nerve-related pathways. Conclusions: This study revealed that giant pandas in captivity undergo short-term adaptation in nerve-related pathways. Furthermore, it provides new insights into the molecular mechanism of gene expression regulation under short-term adaptation to environmental change. [ABSTRACT FROM AUTHOR]

Kinase D-interacting substrate of 220 kDa (Kidins220) is a transmembrane protein that participates in neural cell survival, maturation, and plasticity. Mutations in the human KIDINS220 gene are associated with a neurodevelopmental disorder ('SINO' syndrome) characterized by spastic paraplegia, intellectual disability, and in some cases, autism spectrum disorder. To better understand the pathophysiology of KIDINS220-linked pathologies, in this study, we assessed the sensory processing and social behavior of transgenic mouse lines with reduced Kidins220 expression: the CaMKII-driven conditional knockout (cKO) line, lacking Kidins220 in adult forebrain excitatory neurons, and the Kidins220floxed line, expressing constitutively lower protein levels. We show that alterations in Kidins220 expression levels and its splicing pattern cause impaired response to both auditory and olfactory stimuli. Both transgenic lines show impaired startle response to high intensity sounds, with preserved pre-pulsed inhibition, and strongly reduced social odor recognition. In the Kidins220floxed line, olfactory alterations are associated with deficits in social memory and increased aggressive behavior. Our results broaden our knowledge of the SINO syndrome; understanding sensory information processing and its deviations under neuropathological conditions is crucial for devising future therapeutic strategies to enhance the quality of life of affected individuals. [ABSTRACT FROM AUTHOR]

Animal social and spatial behaviours are inextricably linked. Animal movements are driven by environmental factors and social interactions. Habitat structure and changing patterns of animal space use can also shape social interactions.Animals adjust their social and spatial behaviours to reduce the risk of offspring mortality. In territorial infanticidal species, two strategies are possible for males: they can stay close to offspring to protect them against rivals (infant‐defence hypothesis) or patrol the territory more intensively to prevent rival intrusions (territorial‐defence hypothesis). Here, we tested these hypotheses in African lions (Panthera leo) by investigating how males and females adjust their social and spatial behaviours in the presence of offspring.We combined datasets on the demography and movement of lions, collected between 2002 and 2016 in Hwange National Park (Zimbabwe), to document the presence of cubs (field observations) and the simultaneous movements of groupmates and competitors (GPS tracking).We showed a spatial response of lions to the presence of offspring, with females with cubs less likely to select areas close to waterholes or in the periphery of the territory than females without cubs. In contrast, these areas were more selected by males when there were cubs in the pride. We also found social responses. Males spent more time with females as habitat openness increased but the presence of cubs in the pride did not influence the average likelihood of observing males with females. Furthermore, rival males relocated further after an encounter with pride males when cubs were present in the prides, suggesting that the presence of cubs leads to a more vigorous repulsion of competitors. Males with cubs in their pride were more likely to interact with male competitors on the edge of the pride's home range and far from the waterholes, suggesting that they are particularly assiduous in detecting and repelling rival males during these periods.In general, the strategies to avoid infanticide exhibited by male lions supported the territorial‐defence hypothesis. Our study contributes to answer the recent call for a behavioural ecology at the spatial‐social interface. [ABSTRACT FROM AUTHOR]

• ERα and ERβ were differently distributed and rarely co-localized in the same cells in the lateral septum (LS). • The overall number of ERβ-expressing cells was significantly higher compared to ERα-expressing cells in the LS. • Site-specific ERβ gene knockdown in the LS increased the levels of social anxiety. • ERβ-positive LS neurons send neuronal projections to the brain areas known to be related to anxiety modulation. 17β-estradiol (E2) regulates various forms of social behavior through the activation of two types of estrogen receptors, ERα and ERβ. The lateral septum (LS) is thought to be one of the potential target sites of E2, but the role played by ERα and ERβ in this brain area remains largely unknown. In the present study, we first analyzed the distribution of ERα and ERβ with double fluorescent immunohistochemistry in a transgenic mouse line in which red fluorescent protein (RFP) signal has been a reliable marker of ERβ expression. The overall number of ERβ-RFP-expressing cells was significantly higher (about 2.5 times) compared to ERα-expressing cells. The distribution of the two types of ERs was different, with co-expression only seen in about 1.2% of total ER-positive cells. Given these distinctive distribution patterns, we examined the behavioral effects of site-specific knockdown of each ER using viral vector-mediated small interference RNA (siRNA) techniques in male mice. We found ERβ-specific behavioral alterations during a social interaction test, suggesting involvement of ERβ-expressing LS neurons in the regulation of social anxiety and social interest. Further, we investigated the neuronal projections of ERα- and ERβ-expressing LS cells by injecting an anterograde viral tracer in ERα-Cre and ERβ-iCre mice. Dense expression of green fluorescence protein (GFP) in synaptic terminals was observed in ERβ-iCre mice in areas known to be related to the modulation of anxiety. These findings collectively suggest that ERβ expressed in the LS plays a major role in the estrogenic control of social anxiety-like behavior. [ABSTRACT FROM AUTHOR]

Introduction: Autism spectrum disorder (ASD) is a complex neurodevelopmental condition. Maternal separation (MS) stress is an early-life stress factor associated with behaviors resembling Autism. Both MECP2 and oxidative stress are implicated in the pathophysiology of Autism. Umbelliprenin (UMB) is a coumarin compound with various pharmacological properties. Our study aimed to investigate the potential effects of UMB in mitigating autistic-like behaviors in a mouse model subjected to MS stress, focusing on probable alterations in MECP2 gene expression in the hippocampus. Methods: MS paradigm was performed, and mice were treated with saline or UMB. Behavioral tests consisting of the three-chamber test (evaluating social interaction), shuttle box (assessing passive avoidance memory), elevated plus-maze (measuring anxiety-like behaviors), and marble-burying test (evaluating repetitive behaviors) were conducted. Gene expression of MECP2 and measurements of total antioxidant capacity (TAC), nitrite level, and malondialdehyde (MDA) level were assessed in the hippocampus. Results: The findings demonstrated that MS-induced behaviors resembling Autism, accompanied by decreased MECP2 gene expression, elevated nitrite, MDA levels, and reduced TAC in the hippocampus. UMB mitigated these autistic-like behaviors induced by MS and attenuated the adverse effects of MS on oxidative stress and MECP2 gene expression in the hippocampus. Conclusion: In conclusion, UMB likely attenuated autistic-like behaviors caused by MS stress, probably, through the reduction of oxidative stress and an increase in MECP2 gene expression. [ABSTRACT FROM AUTHOR]

Deficient social interactions are a hallmark of major neuropsychiatric disorders, and accumulating evidence points to altered social reward and motivation as key underlying mechanisms of these pathologies. In the present study, we further explored the role of the balance of activity between D 1 and D 2 receptor–expressing striatal projection neurons (D1R- and D2R-SPNs) in the control of social behavior, challenging the hypothesis that excessive D2R-SPN activity, rather than deficient D1R-SPN activity, compromises social behavior. We selectively ablated D1R- and D2R-SPNs using an inducible diphtheria toxin receptor–mediated cell targeting strategy and assessed social behavior as well as repetitive/perseverative behavior, motor function, and anxiety levels. We tested the effects of optogenetic stimulation of D2R-SPNs in the nucleus accumbens (NAc) and pharmacological compounds repressing D2R-SPN. Targeted deletion of D1R-SPNs in the NAc blunted social behavior in mice, facilitated motor skill learning, and increased anxiety levels. These behaviors were normalized by pharmacological inhibition of D2R-SPN, which also repressed transcription in the efferent nucleus, the ventral pallidum. Ablation of D1R-SPNs in the dorsal striatum had no impact on social behavior but impaired motor skill learning and decreased anxiety levels. Deletion of D2R-SPNs in the NAc produced motor stereotypies but facilitated social behavior and impaired motor skill learning. We mimicked excessive D2R-SPN activity by optically stimulating D2R-SPNs in the NAc and observed a severe deficit in social interaction that was prevented by D2R-SPN pharmacological inhibition. Repressing D2R-SPN activity may represent a promising therapeutic strategy to relieve social deficits in neuropsychiatric disorders. [ABSTRACT FROM AUTHOR]

Whether fibril formation increases or decreases cytotoxicity remains unclear. Aggregation of human islet amyloid polypeptide (hIAPP), a pivotal regulator of glucose homeostasis, impairs the function and viability of pancreatic β cells. Evidence suggests that low-order oligomers of hIAPP are more toxic to β cells than fibril. However, it remains unclear whether non-fibril form of hIAPP specifically alters brain functions. This study produced fibril and non-fibril forms from a single hIAPP 8–20 peptide. The non-fibril form-injected mice showed changes in spontaneous motor activities, preference for location in the open field and social behavior. In contrast, the fibril-injected mice showed no changes in these behavioral tests. In line with the behavioral changes, the non-fibril form led to impaired neurite outgrowth of cultured neuron-like cells and the loss of neurons in the mouse hippocampus. These findings suggest that non-fibril form but not fibril form of hIAPP changes brain functions. [ABSTRACT FROM AUTHOR]

Curiosity, or novelty seeking, is a fundamental mechanism motivating animals to explore and exploit environments to improve survival, and is also positively associated with cognitive, intrapersonal and interpersonal well-being in humans. However, curiosity declines as humans age, and the decline even positively predicts the extent of cognitive decline in Alzheimer's disease patients. Therefore, determining the underlying mechanism, which is currently unknown, is an urgent task for the present aging society that is growing at an unprecedented rate. This study finds that seeking behaviors for both social and inanimate novelties are compromised in aged mice, suggesting that the aging-related decline in curiosity and novelty-seeking is a biological process. This study further identifies an aging-related reduction in the activity (manifesting as a reduction in spontaneous firing) of dopaminergic neurons in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). Finally, this study establishes that this reduction in activity causally underlies the aging-related decline in novelty-seeking behaviors. This study potentially provides an interventional strategy for maintaining high curiosity in the aged population, i.e., compensating for the reduced activity of VTA/SNc dopaminergic neurons, enabling the aged population to cope more smoothly with the present growing aging society, physically, cognitively and socioeconomically. Behavioral tests together with specific neuronal recordings and manipulation suggest that aging-related decline in social and inanimate novelty seeking is caused by a reduction in the spontaneous firing of midbrain VTA/SNc dopaminergic neurons. [ABSTRACT FROM AUTHOR]

In separate chambers, responding by two pairs of pigeons was reinforced under concurrent random‐ratio schedules of reinforcement. For each pair, the birds' schedules were coupled in such a manner that left‐ and right‐key reinforcement probabilities were determined by the key being pecked by the other pigeon of the pair. In this way, a reinforcement matrix, like that of the popular Prisoner's Dilemma game of game theory, was created. The responding of all subjects soon gravitated to the choice combination identified by the mathematician John Nash as the equilibrium of the Prisoner's Dilemma game. This was found both before and after reversal of contingencies on the keys. In a second experiment, with a single pair of pigeons, stimuli signaling the choice of the paired pigeon had little lasting effect: responding again gravitated to the game's equilibrium. The results affirm earlier findings, demonstrating that Skinner's principle of positive reinforcement, together with Nashian mathematics, entirely accounts for iterative game‐theoretic behavior. They extend these findings to the so‐called free operant: to schedules of reinforcement in which responding is not constrained by stimulus–response sequencing (i.e., a trials procedure). The coupled schedule of reinforcement introduced here offers significant promise for the experimental analysis of economic and social behaviors. [ABSTRACT FROM AUTHOR]

Social behaviors in animals such as bees, ants, and birds have shown high levels of intelligence from a multi-agent system perspective. They present viable solutions to real-world problems, particularly in navigating constrained environments with simple robotic platforms. Among these behaviors is swarm flocking, which has been extensively studied for this purpose. Flocking algorithms have been developed from basic behavioral rules, which often require parameter tuning for specific applications. However, the lack of a general formulation for tuning has made these strategies difficult to implement in various real conditions, and even to replicate laboratory behaviors. In this paper, we propose a flocking scheme for small autonomous robots that can self-learn in dynamic environments, derived from a deep reinforcement learning process. Our approach achieves flocking independently of population size and environmental characteristics, with minimal external intervention. Our multi-agent system model considers each agent’s action as a linear function dynamically adjusting the motion according to interactions with other agents and the environment. Our strategy is an important contribution toward real-world flocking implementation. We demonstrate that our approach allows for autonomous flocking in the system without requiring specific parameter tuning, making it ideal for applications where there [ABSTRACT FROM AUTHOR]

The study aimed to analyse the spatial structure of moose (Alces alces) in central-eastern Poland, taking into account sex structure and preferences regarding the composition of social groups. The density of animals in forest and swamp areas was analysed. Moose were shown to strongly prefer forest areas. Females moving with fawns and single females and males were most often observed. Statistical analysis confirmed that the biotope preference of this species does not depend on the type of social group in which the animals migrate. In the territory of the Regional Directorate of State Forests in Lublin, the moose density per 1000 ha of forest and swamp averaged 5.9 individuals. Reproductive success and the number of young born were typical of the species. In 73% of cases, they moved in three dominant types of social groups, i.e. a hind with fawns, solitary stags and solitary hinds. The animals were found mainly in forest areas (65.1%). It should be remembered that in European forests it is very rarely possible to maintain Cervidae populations at a level that guarantees the absence of foraging effects on forest regeneration and the maintenance of its sustainability. Therefore, continuous monitoring of the species' population size is recommended. [ABSTRACT FROM AUTHOR]

Background: Harmful social behaviours, such as injurious feather pecking in poultry and tail biting in swine, reduce animal welfare and production efficiency. While these behaviours are heritable, selective breeding is still limited due to a lack of individual phenotyping methods for large groups and proper genetic models. In the near future, large-scale longitudinal data on social behaviours will become available, e.g. through computer vision techniques, and appropriate genetic models will be needed to analyse such data. In this paper, we investigated prospects for genetic improvement of social traits recorded in large groups by (1) developing models to simulate and analyse large-scale longitudinal data on social behaviours, and (2) investigating required sample sizes to obtain reasonable accuracies of estimated genetic parameters and breeding values (EBV). Results: Latent traits were defined as representing tendencies of individuals to be engaged in social interactions by distinguishing between performer and recipient effects. Animal movement was assumed random and without genetic variation, and performer and recipient interaction effects were assumed constant over time. Based on the literature, observed-scale heritabilities ( h o 2 ) of performer and recipient effects were both set to 0.05, 0.1, or 0.2, and the genetic correlation ( r A ) between those effects was set to – 0.5, 0, or 0.5. Using agent-based modelling, we simulated ~ 200,000 interactions for 2000 animals (~ 1000 interactions per animal) with a half-sib family structure. Variance components and breeding values were estimated with a general linear mixed model. The estimated genetic parameters did not differ significantly from the true values. When all individuals and interactions were included in the analysis, the accuracy of EBV was 0.61, 0.70, and 0.76 for h o 2 = 0.05, 0.1, and 0.2, respectively (for r A = 0). Including 2000 individuals each with only ~ 100 interactions, already yielded promising accuracies of 0.47, 0.60, and 0.71 for h o 2 = 0.05, 0.1, and 0.2, respectively (with r A = 0). Similar results were found with r A of – 0.5 or 0.5. Conclusions: We developed models to simulate and genetically analyse social behaviours for animals that are kept in large groups, anticipating the availability of large-scale longitudinal data in the near future. We obtained promising accuracies of EBV with ~ 100 interactions per individual, which would correspond to a few weeks of recording. Therefore, we conclude that animal breeding can be a promising strategy to improve social behaviours in livestock. [ABSTRACT FROM AUTHOR]

Simple Summary: As animals age, exposure to additional environmental stressors such as noise pollution might be more detrimental at the physiological and behavioural levels, but such an effect is not yet clear. In this study, we tested the effects of noise exposure for 24 h on young adults and old zebrafish. Based on different behavioural tests, we found that both noise and ageing caused anxiety responses when the animals were introduced to a novel environment as well as a tendency for social proximity. Such anxiety responses decreased when the animals were tested in groups. Since the old zebrafish already showed anxiety-like behaviour with a preference for bottom dwelling, noise treatment induced the opposite effect in these individuals, increasing their vertical exploration. This work is a first attempt to investigate the effects of noise and ageing on zebrafish, a reference model in hearing and ecotoxicology research. Overall, we suggest that old individuals may have distinct physiological and behavioural mechanisms for dealing with noisy environments. Noise pollution is creating a wide range of health problems related to physiological stress and anxiety that impact the social life of vertebrates, including humans. Ageing is known to be associated with changes in susceptibility to acoustic stimuli; however, the interaction between noise effects and senescence is not well understood. We tested the effects of 24 h continuous white noise (150 dB re 1 Pa) on both young adults and old zebrafish in terms of anxiety (novel tank diving test), social interactions (with mirror/conspecific attraction), and shoaling behaviour. Both noise and ageing induced higher anxiety responses in a novel environment. Since the old zebrafish showed longer bottom dwelling, acoustic treatment induced the opposite pattern with an initial increase in vertical exploration in the aged individuals. Both noise- and age-related anxiety responses were lowered when individuals were tested within a group. Regarding social interactions, both noise and ageing seemed to cause an increase in their proximity to a mirror. Although the results were not statistically significant, noise exposure seemed to further enhance conspecific attraction. Moreover, the interindividual distance within a shoal decreased with noise treatment in the aged individuals. This study is a first attempt to investigate the effects of both noise and ageing on zebrafish behaviour, suggesting the age-dependent physiological coping mechanisms associated with environmental stress. [ABSTRACT FROM AUTHOR]

In many mammalian species, females exhibit higher sociability and gregariousness than males, presumably due to the benefit of group living for maternal care. We have previously reported that adult female mice exhibit contact-seeking behaviors upon acute social isolation via amylin-calcitonin receptor (Calcr) signaling in the medial preoptic area (MPOA). In this study, we examined the sex differences in the behavioral responses to acute social isolation and reunion, and the levels of amylin and Calcr expression in the MPOA. We found that male mice exhibited significantly less contact-seeking upon social isolation. Upon reunion, male mice contacted each other to a similar extent as females, but their interactions were more aggressive and less affiliative compared with females. While Calcr-expressing neurons were activated during social contacts in males as in females, the amylin and Calcr expression were significantly lower in males than in females. Together with our previous findings, these findings suggested that the lower expression of both amylin and Calcr may explain the lower contact-seeking and social affiliation of male mice. • Male mice exhibited less contact-seeking behaviors after acute social isolation than female mice. • Expression of amylin and Calcr was lower in male mice than female mice. • Results suggest that the lower expression of amylin and Calcr may explain the lower contact-seeking behaviors in male mice. [ABSTRACT FROM AUTHOR]

Stresses in early ontogenesis can influence anxiety-depressive, defensive and social behavior, as well as the immune and hormonal reactivity of adult animals. The model of early pro-inflammatory stress assumes activation of the immune system by the introduction of bacterial lipopolysaccharide (LPS) in early ontogenesis. Whether neonatal LPS stress impacts aggressive behavior or sexual motivation is still unknown. Pathological aggressiveness and disorders in sexual behavior are characteristic of many neuropsychiatric diseases, therefore, the study of the prerequisites for their occurrence is highly relevant. On the 3rd and 5th day after birth, the rats were injected with either LPS at a dose of 50 µg/kg (LPS group) or saline solution (SAL group, control). The aggressive behavior of adult rats in the resident-intruder test after a week of social isolation was analyzed, as well as the sexual preference of males or females in a three-chamber test. The behavior of rats was compared with baseline levels of corticosterone and interleukin 1-beta in blood serum. The males of the LPS group compared with the control had more attacks on the intruder in the resident-intruder test, and the number of attacks did not decrease by the end of the experiment. The males of the LPS group had an increased interaction time with the female at the diestrus stage in the social preference test of males and females. There were no changes in aggressive behavior in females after the administration of LPS in early ontogenesis. The baseline level of interleukin-1-beta was higher in males, and corticosterone was higher in females, there were no differences between the LPS and SAL groups in biochemical parameters. The results obtained indicate an increase in aggressiveness provoked by social isolation, as well as sexual motivation in adult males after early pro-inflammatory stress, i.e., a change in the motivational and emotional component in social behavior. [ABSTRACT FROM AUTHOR]

The ability to discriminate between different individuals based on identity cues, which is important to support the social behaviour of many animal species, has mostly been investigated in conspecific contexts. A rare example of individual heterospecific discrimination is found in domestic dogs, who are capable of recognising their owners' voices. Here, we test whether grey wolves, the nearest wild relative of dogs, also have the ability to distinguish familiar human voices, which would indicate that dogs' ability is not a consequence of domestication. Using the habituation–dishabituation paradigm, we presented captive wolves with playback recordings of their keepers' and strangers' voices producing either familiar or unfamiliar phrases. The duration of their response was significantly longer when presented with keepers' voices than with strangers' voices, demonstrating that wolves discriminated between familiar and unfamiliar speakers. This suggests that dogs' ability to discriminate between human voices was probably present in their common ancestor and may support the idea that this is a general ability of vertebrates to recognise heterospecific individuals. Our study also provides further evidence for familiar voice discrimination in a wild animal in captivity, indicating that this ability may be widespread across vertebrate species. [ABSTRACT FROM AUTHOR]