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All animals can perform certain survival behaviors without prior experience, suggesting a “hard wiring” of underlying neural circuits. Experience, however, can alter the expression of innate behaviors. Where in the brain and how such plasticity occurs remains largely unknown. Previous studies have established the phenomenon of “aggression training,” in which the repeated experience of winning successive aggressive encounters across multiple days leads to increased aggressiveness. Here, we show that this procedure also leads to long-term potentiation (LTP) at an excitatory synapse, derived from the posteromedial part of the amygdalohippocampal area (AHiPM), onto estrogen receptor 1-expressing (Esr1⁺) neurons in the ventrolateral subdivision of the ventromedial hypothalamus (VMHvl). We demonstrate further that the optogenetic induction of such LTP in vivo facilitates, while optogenetic long-term depression (LTD) diminishes, the behavioral effect of aggression training, implying a causal role for potentiation at AHiPM→VMHvlEsr1 synapses in mediating the effect of this training. Interestingly, ∼25% of inbred C57BL/6 mice fail to respond to aggression training. We show that these individual differences are correlated both with lower levels of testosterone, relative to mice that respond to such training, and with a failure to exhibit LTP after aggression training. Administration of exogenous testosterone to such nonaggressive mice restores both behavioral and physiological plasticity. Together, these findings reveal that LTP at a hypothalamic circuit node mediates a form of experience-dependent plasticity in an innate social behavior, and a potential hormone-dependent basis for individual differences in such plasticity among genetically identical mice.

Transnational Actors in War and Peace explores the identities, organization, strategies, and influence of transnational actors involved in contentious politics, armed conflict, and peacemaking over the last one hundred years. While the study of transnational politics has been a rapidly growing field, to date, the disparate array of actors have not been analyzed alongside each other, making it difficult to develop a common theoretical framework or determine their relative influence on international stability, war, and peace. This work seeks to fill this gap by bringing together a diverse set of scholars focused on a range of transnational actors, such as: pirates, foreign fighters, terrorists, private military security companies, criminal networks, religious groups, diasporas, political exiles, NGOs, environmental activists, global news agencies, and feminist advocacy networks. Each chapter examines a different transnational actor and is structured around five components: how the actor is organized; how it interacts with other actors; how it communicates both internally and externally; how it influences conflict/peace; and how it reflects developments in transnationalism.

The study of naturalistic social behavior requires quantification of animals’ interactions. This is generally done through manual annotation—a highly time-consuming and tedious process. Recent advances in computer vision enable tracking the pose (posture) of freely behaving animals. However, automatically and accurately classifying complex social behaviors remains technically challenging. We introduce the Mouse Action Recognition System (MARS), an automated pipeline for pose estimation and behavior quantification in pairs of freely interacting mice. We compare MARS’s annotations to human annotations and find that MARS’s pose estimation and behavior classification achieve human-level performance. We also release the pose and annotation datasets used to train MARS to serve as community benchmarks and resources. Finally, we introduce the Behavior Ensemble and Neural Trajectory Observatory (BENTO), a graphical user interface for analysis of multimodal neuroscience datasets. Together, MARS and BENTO provide an end-to-end pipeline for behavior data extraction and analysis in a package that is user-friendly and easily modifiable.

Spoiling for a fight: an aggression pheromone in Drosophila Pheromones controlling aggression have been identified in insects and in mice, but the nature of the neuronal circuits involved remains unclear. Liming Wang and David Anderson show that the volatile pheromone cVA ( cis -vaccenyl acetate) produced by the male fruitfly promotes male-to-male aggression by activating olfactory sensory neurons expressing a cVA receptor protein, Or67d. This neuronal circuit may regulate male population density on a food resource through cVA-promoted aggression and consequent male fly dispersal, which in turn lowers cVA levels, thereby reducing aggression. This work in the classic genetic model Drosophila — using machine vision technology described in a recent Nature feature ( page 562 in the 3 December issue ) and shown in movie form at go.nature.com/o8sRLs — opens the study of aggressive behaviour to detailed genetic manipulation and investigation. Although aggression is known to be regulated by pheromones in many animal species, in no system have the pheromones, their receptors and corresponding sensory neurons been identified. Here, 11- cis -vaccenyl acetate (cVA), a volatile pheromone produced by male fruitflies, is shown to promote male-to-male aggression through the activation of olfactory sensory neurons expressing the receptor Or67d. Aggression is regulated by pheromones in many animal species 1 , 2 , 3 . However, in no system have aggression pheromones, their cognate receptors and corresponding sensory neurons been identified. Here we show that 11- cis -vaccenyl acetate (cVA), a male-specific volatile pheromone, robustly promotes male–male aggression in the vinegar fly Drosophila melanogaster . The aggression-promoting effect of synthetic cVA requires olfactory sensory neurons (OSNs) expressing the receptor Or67d 4 , 5 , 6 , as well as the receptor itself. Activation of Or67d-expressing OSNs, either by genetic manipulation of their excitability or by exposure to male pheromones in the absence of other classes of OSNs, is sufficient to promote aggression. High densities of male flies can promote aggression by the release of volatile cVA. In turn, cVA-promoted aggression can promote male fly dispersal from a food resource, in a manner dependent on Or67d-expressing OSNs. These data indicate that cVA may mediate negative-feedback control of male population density, through its effect on aggression. Identification of a pheromone–OSN pair controlling aggression in a genetic organism opens the way to unravelling the neurobiology of this evolutionarily conserved behaviour.

Activation of Esr1 + neurons of the mouse ventromedial hypothalamus initiates graded social behavioural responses–weak activation triggers close investigation (sniffing) during a social encounter that often leads, with continued stimulation, to mounting behaviours by males towards either gender; mounting behaviour transitions to aggressive attacks with greater stimulation intensity. Hypothalamus neurons that mediate aggression In the mouse ventromedial hypothalamus, there are intermixed populations of neurons differentiated by the expression of the oestrogen receptor, Esr1. Previous work revealed that Esr1 + neurons can initiate aggressive behaviour when artificially activated. Here, David Anderson and colleagues extend those results to demonstrate a graded behavioural response to the activation of these neurons along a continuum of social behavior. Weaker activation could initiate close inspection during an encounter that could lead to mounting behaviours by males towards either gender with further stimulation. Mounting behaviour transitioned to aggressive attacks with even greater stimulation intensity. Thus, these data reveal a circuit that controls the nature of a set of social behaviors in a scalable manner based on neuronal activity levels. Social behaviours, such as aggression or mating, proceed through a series of appetitive and consummatory phases 1 that are associated with increasing levels of arousal 2 . How such escalation is encoded in the brain, and linked to behavioural action selection, remains an unsolved problem in neuroscience. The ventrolateral subdivision of the murine ventromedial hypothalamus (VMHvl) contains neurons whose activity increases during male–male and male–female social encounters. Non-cell-type-specific optogenetic activation of this region elicited attack behaviour, but not mounting 3 . We have identified a subset of VMHvl neurons marked by the oestrogen receptor 1 (Esr1), and investigated their role in male social behaviour. Optogenetic manipulations indicated that Esr1 + (but not Esr1 − ) neurons are sufficient to initiate attack, and that their activity is continuously required during ongoing agonistic behaviour. Surprisingly, weaker optogenetic activation of these neurons promoted mounting behaviour, rather than attack, towards both males and females, as well as sniffing and close investigation. Increasing photostimulation intensity could promote a transition from close investigation and mounting to attack, within a single social encounter. Importantly, time-resolved optogenetic inhibition experiments revealed requirements for Esr1 + neurons in both the appetitive (investigative) and the consummatory phases of social interactions. Combined optogenetic activation and calcium imaging experiments in vitro , as well as c-Fos analysis in vivo , indicated that increasing photostimulation intensity increases both the number of active neurons and the average level of activity per neuron. These data suggest that Esr1 + neurons in VMHvl control the progression of a social encounter from its appetitive through its consummatory phases, in a scalable manner that reflects the number or type of active neurons in the population.

Clarity and cutting-edge examples have made 'Statistics for Business and Economics' the definitive textbook for students across the United Kingdom, Europe, Middle East, and Africa. This new edition builds on the text's well-respected foundations to deliver a clear, up-to-date and comprehensive revision. All the key concepts, combined with the latest technologies and applications, are introduced with hallmark precision, making this your complete introduction to business statistics.

A lack of automated, quantitative, and accurate assessment of social behaviors in mammalian animal models has limited progress toward understanding mechanisms underlying social interactions and their disorders such as autism. Here we present a new integrated hardware and software system that combines video tracking, depth sensing, and machine learning for automatic detection and quantification of social behaviors involving close and dynamic interactions between two mice of different coat colors in their home cage. We designed a hardware setup that integrates traditional video cameras with a depth camera, developed computer vision tools to extract the body “pose” of individual animals in a social context, and used a supervised learning algorithm to classify several well-described social behaviors. We validated the robustness of the automated classifiers in various experimental settings and used them to examine how genetic background, such as that of Black and Tan Brachyury (BTBR) mice (a previously reported autism model), influences social behavior. Our integrated approach allows for rapid, automated measurement of social behaviors across diverse experimental designs and also affords the ability to develop new, objective behavioral metrics.