Biology subjects

O'Connell, L. A.

Publications and source records attributed to O'Connell, L. A..

At least 19 recordsLinked to original sources

bioRxiv2026

Social isolation is associated with microRNA expression changes in the visual system of poison frog tadpoles

Brain microRNA (miRNA) expression can shift in response to the social environment, translating external cues into regulatory action that can influence brain structure, neural activity, and behavior. miRNAs are key drivers of behavioral flexibility, regulating gene networks involved in neuroplasticity. We manipulated social rearing conditions of brilliant-thighed poison frog tadpoles (Allobates femoralis) to test whether isolation-linked behavioral changes are associated with altered miRNA expression in the midbrain and eyes, tissues linked by the retinotectal tract, a known connection for trafficked precursor miRNAs. We asked whether isolation alters visually guided behavior using a light/dark preference assay and found that isolated tadpoles spent less of the trial on the dark side than did group-housed tadpoles. In a social place preference assay, group-housed tadpoles preferred a zone near a conspecific over an object control when provided with multimodal sensory access, but not when access was restricted to vision alone. We next tested whether social rearing conditions influenced miRNA expression and found that isolated tadpoles exhibited upregulation of miR-15-P1c_3p*, the canonically non-dominant arm of an understudied miRNA, in the midbrain and eyes. We detected a shift in arm dosing for miR-124, a miRNA with conserved roles in neural differentiation and plasticity. Finally, social isolation during development was associated with downregulation of parathyroid hormone 2 (pth2), a peptide associated with social isolation and mechanosensation in other aquatic larvae. This work contributes to a growing body of literature implicating miRNAs in developmental neuroplasticity, presenting precedented and novel signatures of the transcriptional and regulatory response to isolation.

neuroscience↗

bioRxiv2026

Neural correlates of place learning in the cane toad, Rhinella marina

Learning locations by integrating external reference points, or place learning, is a form of navigation strongly associated with the mammalian hippocampus and its homologs in other vertebrates. In contrast, cue learning relies on individual environmental features and can occur independently of the hippocampus. Despite growing interest in amphibian spatial cognition and association of spatial functions with the medial pallium brain region, how amphibian brains support different spatial learning strategies remains unknown. We designed a four-arm maze to test place, cue, and turn-direction learning in the cane toad (Rhinella marina), and paired maze trials with visualization of brain activity through pS6 immunohistochemistry. Toads improved performance over time only in the place task but exhibited consistently faster exit times in the cue task. Place task toads displayed elevated brain activity only in the dorsal and lateral palliums. These observations demonstrate that amphibians can acquire spatial navigation strategies through distinct behavioral paradigms and reveal the diverse pallial contributions underlying vertebrate spatial cognition.

animal behavior and cognition↗

bioRxiv2026

Hypothalamic Cell Type Evolution across Vertebrates

The hypothalamus regulates vital functions and is highly conserved among vertebrates occupying diverse niches, but little is known about the evolution of its cell types. Using comparative single-cell transcriptomics across major vertebrate classes, we identified deeply conserved and clade-specific cell types. While homologous cell types express conserved transcription factors and neuropeptides, their regulatory linkages are often rewired across evolution. The paraventricular nucleus largely retains its neuropeptide expression and responds to dehydration with fine cellular resolution from amphibians to mammals, whereas lamina terminalis neurons are specific to terrestrial vertebrates and exhibit gene expression divergence in cell types activated by dehydration and heat. We propose that a conserved set of keystone cell types sustain essential functions across vertebrates, while flexible gene regulatory programs alongside numerous clade-specific cell types offer evolutionary fluidity.

evolutionary biology↗

bioRxiv2026

Aquatic respiratory rates in red devil vampire crabs (Geosesarma hagen) are dependent on interactions between temperature, sex, and body size

The shift to terrestrial environments in ancestrally aquatic animals is often associated with key physiological and physical changes, including shifts in respiratory physiology and in some cases, even the evolution of completely novel respiratory structures. Examining how respiration operates across a gradient of submersion states in ancestrally aquatic terrestrial animals may shed light on how complex biological traits shift under different selective regimes. In this work, we begin exploring respiration in terrestrially-adapted land crabs that still use their gills to respire while underwater. We tested the relationship between aquatic respiratory rates, body size, and sex in red devil vampire crabs (Geosesarma hagen) at two ecologically-relevant temperatures. We found small females respire more than small males at 28{degrees}C, while large females respire more than large males at 21{degrees}C. Additionally, body size is a significant factor affecting respiratory rates of both sexes at 21{degrees}C and warmer temperatures significantly increase respiration in small crabs of both sexes. Interactions between these factors also led to emerging trends that can be explained by both physiological rules, such as reproductive investment and surface-to-volume ratios and heat transfer. We also report a temperature coefficient (Q10) of 1.52 for this species, showing an expected 52% change in respiratory and metabolic rate for every 10{degrees}C increase. This work also demonstrates the importance of understanding how and to what extent biological variables like sex and body size interact with abiotic environmental factors when measuring physiological traits in ectothermic invertebrate animals. What is already knownAs crabs colonize terrestrial environments, they undergo adaptive physical and physiological changes in their respiratory abilities. Few studies have examined these respiratory shifts in individual terrestrial crab species using modern respirometry tools and techniques and across different submersion states and biotic and abiotic factors. We quantify how temperature, body size, and sex affect aquatic respiratory rates in adult terrestrial vampire crabs. What this study addsWe found small females respire more than small males at 28{degrees}C, while large females respire more than large males at 21{degrees}C. Additionally, body size is a significant factor affecting respiratory rates of both sexes at 21{degrees}C and warmer temperatures significantly increase respiration in small crabs of both sexes. Interactions between these factors also led to emerging trends that can be explained by both physiological rules, such as reproductive investment and surface-to-volume ratios and heat transfer. We also report a temperature coefficient (Q10) of 1.52 for this species, showing an expected 52% change in respiratory and metabolic rate for every 10{degrees}C increase.

physiology↗

bioRxiv2026

Diet quality shapes development and feeding circuits in poison frog tadpoles

From birth, offspring must balance internal energy state with the costs of signaling need to caregivers to secure nutrition for growth and healthy development. How diet during this period shapes the developing brain and behavior is a central question in biology, with growing relevance for understanding the developmental origins of metabolic disorders such as obesity. Yet the effects of early nutrition on growth, neural development, and behavior are rarely examined together within a single system. Here, we use poison frog tadpoles as a vertebrate model in which offspring develop outside a womb, can be reared independently under precisely controlled dietary conditions, and display diverse behaviors at a young age. By independently manipulating dietary quantity and quality, we link early nutrition to growth, brain development, and social behavior during ontogeny. Diet quantity increased body size, whereas diet quality accelerated development. Diet quality, but not quantity, shaped behavior: tadpoles fed a natural diet showed increased affiliation during food solicitation and reduced feeding, while aggression and risk avoidance remained unchanged. Diet also affected body and brain development differently, with artificial diets producing larger tadpoles but reduced volume in some brain regions, including areas associated with begging behavior. Anorexigenic urocortin-1 neurons were active during begging behavior and, together with another anorexigenic midbrain population, decreased in abundance under an artificial diet. Functionally, urocortin-1 reduced feeding without directly increasing begging, suggesting it gates socio-positive behavior by suppressing a competing drive rather than initiating it. Together, this work shows that dietary quantity and quality act on distinct developmental processes, with diet quality programming the brain circuits that permit begging behavior while growth is determined by food quantity.

neuroscience↗

bioRxiv2026

Behavioral, hormonal, and chemical responses to seasonality in poison frogs with divergent reproductive strategies

Seasonal rainfall shapes biological responses in tropical ecosystems, yet how tropical organisms integrate behavioral and physiological responses to cope with seasonality remains poorly understood. We assessed how four poison frog species with contrasting reproductive strategies respond to dry and wet season environmental conditions. We quantified spatial behavior, microhabitat use, hormone release rates, and chemical defenses in two seasonal breeders (Allobates femoralis and Ameerega trivittata) and two year-round breeders (Ameerega macero and Ameerega shihuemoy). Seasonal breeders exhibited pronounced sex-specific shifts in space use, where males expanded their space use during the wet season, likely to track reproductive opportunities, while A. femoralis females increased their spatial use during the dry season, likely responding to foraging demands when prey resources are sparse. Year-round breeders maintained similar space use across seasons, likely reflecting their ability to access key resources within the same space to reproduce year-round. Microhabitat use was flexible, as seasonal breeders shifted toward humid refugia during the dry season and reproduction-associated microhabitats during the wet season, whereas year-round breeders selected microhabitats that facilitate continuous reproduction across seasons. Despite these behavioral responses, water-borne corticosterone and testosterone, as well as chemical defenses, showed no consistent seasonal variation, suggesting that behavioral responses may be partially decoupled from shifts in endocrine and chemical defenses. These results support a role for behavioral buffering in mediating responses to seasonal environmental variation. However, given the increasing unpredictability in rainfall timing and intensity as a result of climate change, how these coping strategies will function in the long term is uncertain.

animal behavior and cognition↗

bioRxiv2024

Chronic recording of brain activity in awake toads

BackgroundAmphibians represent an important evolutionary transition from aquatic to terrestrial environments and they display a large variety of complex behaviors despite a relatively simple brain. However, their brain activity is not as well characterized as that of many other vertebrates, partially due to physiological traits that have made electrophysiology recordings difficult to perform in awake and moving animals. New methodWe implanted flexible mesh electronics in the cane toad (Rhinella marina) and performed extracellular recordings in the telencephalon of anesthetized toads and partially restrained, awake toads over multiple days. ResultsWe recorded brain activity over five consecutive days in awake toads and over a 15 week period in a toad that was anesthetized during recordings. We were able to perform spike sorting and identified single- and multi-unit activity in all toads. Comparison with existing methodsTo our knowledge, this is the first report of a modern method to perform electrophysiology in non-paralyzed toads over multiple days, though there are historical references to short term recordings in the past. ConclusionsImplementing flexible mesh electronics in amphibian species will allow for advanced studies of the neural basis of amphibian behaviors.

neuroscience↗

bioRxiv2024

Effects of parental care on skin microbial community composition in poison frogs

Parent-offspring interactions constitute the first contact of many newborns with their environment, priming community assembly of microbes through priority effects. Early exposure to microbes can have lasting influences on the assembly and functionality of the hosts microbiota, leaving a life-long imprint on host health and disease. Studies of the role played by parental care in microbial acquisition have primarily focused on humans and hosts with agricultural relevance. Anuran vertebrates offer the opportunity to examine microbial community composition across life stages as a function of parental investment. In this study, we investigate vertical transmission of microbiota during parental care in a poison frog (Family Dendrobatidae), where fathers transport their offspring piggyback-style from terrestrial clutches to aquatic nurseries. We found that substantial bacterial colonization of the embryo begins after hatching from the vitelline envelope, emphasizing its potential role as microbial barrier during early development. Using a laboratory cross-foster experiment, we demonstrated that poison frogs performing tadpole transport serve as a source of skin microbes for tadpoles on their back. To study how transport impacts the microbial skin communities of tadpoles in an ecologically relevant setting, we sampled frogs and tadpoles of sympatric species that do or do not exhibit tadpole transport in their natural habitat. We found more diverse microbial communities associated with tadpoles of transporting species compared to a non-transporting frog. However, we detected no difference in the degree of similarity between adult and tadpole skin microbiotas, based on whether the frog species exhibits transporting behavior or not. Using a field experiment, we confirmed that tadpole transport can result in the persistent colonization of tadpoles by isolated microbial taxa associated with the caregivers skin, albeit often at low prevalence. This is the first study to describe vertical transmission of skin microbes in anuran amphibians, showing that offspring transport may serve as a mechanism for transmission of parental skin microbes. Overall, these findings provide a foundation for further research on how vertical transmission in this order impacts host-associated microbiota and physiology.

microbiology↗

bioRxiv2024

Neural and sensory basis of homing behavior in the invasive cane toad, Rhinella marina

The behavioral, sensory, and neural bases of vertebrate navigation are primarily described in mammals and birds. While many studies have explored amphibian navigation, none have characterized brain activity associated with navigation in the wild. To address this knowledge gap, we conducted a study on navigation in the cane toad, Rhinella marina. First, we performed a translocation experiment to describe how invasive cane toads in Hawaii navigate home and observed homing following displacements of up to one kilometer. Next, we tested the effect of olfactory and magnetosensory manipulations on homing, as these senses are most commonly associated with amphibian navigation. We found that neither ablation alone prevents homing, further supporting that toad navigation is multimodal. Finally, we tested the hypothesis that the medial pallium, the amphibian homolog to the hippocampus, is involved in homing. Our comparisons of neural activity revealed evidence supporting a conservation of neural structures associated with navigation across vertebrates consistent with neural models of amphibian spatial cognition from recent laboratory studies. Our work furthers our evolutionary understanding of spatial behavior and cognition in vertebrates and lays a foundation for studying the behavioral, sensory, and neural bases of navigation in an invasive amphibian.

animal behavior and cognition↗

bioRxiv2024

Androgenic shifts and external cues mediate parental care versus infanticide in mimic poison frogs

Infanticide is widespread across the animal kingdom, but the physiological drivers of infanticide versus care or neglect are relatively unexplored. Here, we identified salient environmental and physiological antecedents of infanticide in the mimic poison frog (Ranitomeya imitator), a biparental amphibian in which female parents feed their tadpoles unfertilized eggs. Specifically, we explored potential environmental cues influencing infant- directed behavior by evaluating changes in the frequency of food provisioning and tadpole mortality after either cross-fostering tadpoles between family units or displacing tadpoles within the terraria of their parents. We found that changes in offspring location reduce care and increase infanticide. Specifically, parents fed their displaced offspring less and, in some instances, tadpole mortality increased. We also investigated whether care and infanticide were related to changes in steroid hormone concentrations in an unfamiliar setting. Infanticide of fertilized eggs and hatchlings in the new territory included cannibalism and was associated with lower testosterone concentrations, but not with changes in corticosterone. Overall, our results support earlier findings that familiarity with offspring location drives parental investment in poison frogs, while indicating an association between low androgen levels and infanticidal behavior in an amphibian. HighlightsO_LIOffspring location drives parental decisions of care vs. infanticide. C_LIO_LIIn novel territories, adults cannibalize conspecific, unrelated young. C_LIO_LILower circulating testosterone in novel territory is associated with infanticide. C_LI

animal behavior and cognition↗

bioRxiv2024

A toxic environment selects for specialist microbiome in poison frogs

Shifts in microbiome community composition can have large effects on host health. It is therefore important to understand how perturbations, like those caused by the introduction of exogenous chemicals, modulate microbiome community composition. In poison frogs within the family Dendrobatidae, the skin microbiome is exposed to the alkaloids that the frogs sequester from their diet and use for defense. Given the demonstrated antimicrobial effects of these poison frog alkaloids, these compounds may be structuring the skin microbial community. To test this, we first characterized microbial communities from chemically defended and closely related non-defended frogs from Ecuador. Then we conducted a laboratory experiment to monitor the effect of the alkaloid decahydroquinoline (DHQ) on the microbiome of a single frog species. In both the field and lab experiments, we found that alkaloid-exposed microbiomes are more species rich and phylogenetically diverse, with an increase in rare taxa. To better understand the strain-specific behavior in response to alkaloids, we cultured microbial strains from poison frog skin and found the majority of strains exhibited either enhanced growth or were not impacted by the addition of DHQ. Additionally, stable isotope tracing coupled to nanoSIMS suggests that some of these strains are able to metabolize DHQ. Taken together, these data suggest that poison frog chemical defenses open new niches for skin-associated microbes with specific adaptations, including the likely metabolism of alkaloids, that enable their survival in this toxic environment. This work helps expand our understanding of how exposure to exogenous compounds like alkaloids can impact host microbiomes.

microbiology↗

bioRxiv2023

Genome assembly of the dyeing poison frog provides insights into the dynamics of transposable element and genome-size evolution

Genome size varies greatly across the tree of life and transposable elements are an important contributor to this variation. Among vertebrates, amphibians display the greatest variation in genome size, making them ideal models to explore the causes and consequences of genome size variation. However, high-quality genome assemblies for amphibians have, until recently, been rare. Here, we generate a high-quality genome assembly for the dyeing poison frog, Dendrobates tinctorius. We compare this assembly to publicly-available frog genomes and find evidence for both large-scale conserved synteny and widespread rearrangements between frog lineages. Comparing conserved orthologs annotated in these genomes revealed a strong correlation between genome size and gene size. To explore the cause of gene-size variation, we quantified the location of transposable elements relative to gene features and find that the accumulation of transposable elements in introns has played an important role in the evolution of gene size in D. tinctorius, while estimates of insertion times suggest that many insertion events are recent and species-specific. Finally, we show that the diversity and abundance of transposable elements in poison frog genomes can complicate genotyping efforts that rely on repetitive elements as sequence anchors. Our results show that transposable elements have clearly played an important role in the evolution of large genome size in D. tinctorius. Future studies are needed to fully understand the dynamics of transposable element evolution and to optimise primer or bait design for cost-effective population-level genotyping in species with large, repetitive genomes. SignificanceAmphibians display more variation in genome size than any other vertebrate lineage. Complexities associated with large genomes frequently hamper genome assembly and population genetic studies. Here we use long-read HiFi sequences to generate a high-quality 6.3 Gbp genome assembly of the poison frog Dendrobates tinctorius. We use this genome and leverage comparative genomics and de novo annotations to quantify aspects of genome evolution driven by repetitive transposable genetic elements. Our results provide support for the dynamic role that transposable elements play in driving the evolution of "genomic gigantism" in amphibians. We also show how transposable elements can be leveraged for cost-efficient population genetic studies using limited input material.

genetics↗

bioRxiv2023

Diet and chemical defenses of the Sonoran Desert toads

The Sonoran Desert Toad (Incilius alvarius) is the only animal known to secrete the psychedelic compound 5-MeO-DMT as a chemical defense, but the source of 5-MeO-DMT in I. alvarius remains unknown. Some amphibians endogenously produce chemical defenses while others acquire them from specialized diets. In this study we analyzed toxin gland secretions and diet profiles from wild I. alvarius and sympatric anurans from native and urban habitats around Tucson, Arizona to explore possible links between diet and 5-MeO-DMT production. All I. alvarius secreted high concentrations of 5-MeO-DMT, whereas other sympatric toads did not. The diet of I. alvarius was similar to that of sympatric anurans, indicating that I. alvarius does not exhibit relative dietary specialization. Slight dietary differences between I. alvarius in native and urbanized habitats were observed. Taken together, these lines of evidence suggest that diet is not directly linked to 5-MeO-DMT production, and support the alternative hypotheses that Sonoran Desert toads synthesize 5-MeO-DMT endogenously or via a microbial symbiont.

ecology↗

bioRxiv2023

Activity of FoxP2-positive neurons correlates with begging behavior in a social tadpole

Motor function is a critical aspect of social behavior in a wide range of taxa. The transcription factor FoxP2 is well studied in the context of vocal communication in humans, mice, and songbirds, but its role in regulating social behavior in other vertebrate taxa is unclear. We examined the distribution and activity of FoxP2-positive neurons in tadpoles of the mimic poison frog (Ranitomeya imitator). In this species, tadpoles are reared in isolated plant nurseries and are aggressive to other tadpoles. Mothers provide unfertilized egg meals to tadpoles that perform a begging display by vigorously vibrating back and forth. We found that FoxP2 is widely distributed in the tadpole brain and parallels the brain distribution in mammals, birds, and fishes. We then tested the hypothesis that FoxP2-positive neurons would have differential activity levels in begging or aggression contexts compared to non-social controls. We found that FoxP2-positive neurons showed increased activation in the striatum and cerebellum during begging and in the nucleus accumbens during aggression. Overall, these findings lay a foundation for testing the hypothesis that FoxP2 has a generalizable role in social behavior beyond vocal communication across terrestrial vertebrates.

animal behavior and cognition↗

bioRxiv2023

Home security cameras as a tool for behavior observations and science equity

Reliably capturing transient animal behavior in the field and laboratory remains a logistical and financial challenge, especially for small ectotherms. Here, we present home camera systems as affordable, accessible, and suitable alternatives for monitoring small, cold-blooded animals historically overlooked by commercial camera traps. Home security cameras are often weather-resistant, operate offline or online, and allow collection of time-sensitive behavioral data in laboratory and field conditions with continuous data storage for up to four weeks. These lightweight cameras can also utilize phone notifications over Wi-Fi, alerting users when animals enter a space of interest and enabling sample collection at proper time periods. We present our findings, both technological and scientific, in an effort to elevate tools that enable researchers to maximize use of their research budgets. We discuss the relative affordability of our system for researchers in South America, home to the largest ectotherm diversity.

animal behavior and cognition↗

bioRxiv2023

Dopamine neurons govern olfactory-gated infant begging behavior

Altricial young of many species beg parents for the nutrients required for healthy development. From human crying to begging chicks, young expend precious energy reserves to communicate their hunger. Despite repeated independent evolutionary origins, the neural basis of parent-directed communication by infants is unknown. Here, we examined the sensory and neural basis of begging behavior in tadpoles of the monogamous and biparental Mimetic poison frog (Ranitomeya imitator). In this species, tadpoles beg parents for egg meals by dancing. We used this robust motor display to determine that tadpoles use multimodal cues for caregiver recognition, where olfactory cues are necessary for caregiver recognition while visual cues provide an orientation goal. We found that dopamine related brain regions have higher neural activity in begging tadpoles and that dopamine signaling had opposing modulatory effects through D1 and D2 family receptors, similar to swimming behavior in other tadpole species. We then identified caudal posterior tuberculum dopamine neurons as more active during begging behavior and sensitive to caregiver olfactory cues. Projections of these dopaminergic neurons to the spinal accessory motor nucleus are required for begging displays. These findings support the idea that dopamine regulates olfactory-guided parental recognition in young and opens many avenues for studying how new communication behaviors can evolve from ancestral motor circuits.

neuroscience↗

bioRxiv2023

Comparative analysis of amphibian genomes: an emerging resource for basic and applied research

Amphibians are the most threatened group of vertebrates and are in dire need of conservation intervention to ensure their continued survival. They exhibit unique features including a high diversity of reproductive strategies, permeable and specialized skin capable of producing toxins and antimicrobial compounds, multiple genetic mechanisms of sex determination, and in some lineages, the ability to regenerate limbs and organs. Although genomics approaches would shed light on these unique traits and aid conservation, sequencing and assembly of amphibian genomes has lagged behind other taxa due to their comparatively large genome sizes. Fortunately, the development of long-read sequencing technologies and initiatives has led to a recent burst of new amphibian genome assemblies. Although growing, the field of amphibian genomics suffers from the lack of annotation resources, tools for working with challenging genomes, and lack of high-quality assemblies in multiple clades of amphibians. Here we analyze 51 publicly available amphibian genomes to evaluate their usefulness for functional genomics research. We report considerable variation in genome assembly quality and completeness, and report some of the highest transposable element and repeat contents of any vertebrate. Additionally, we detected an association between transposable element content and climatic variables. Our analysis provides evidence of conserved genome synteny despite the long divergence times of this group, but we also highlight inconsistencies in chromosome naming and orientation across genome assemblies. We discuss sequencing gaps in the phylogeny and suggest key targets for future sequencing endeavors. Finally, we propose increased investment in amphibian genomics research to promote their conservation.

genomics↗

bioRxiv2022

Proopiomelanocortin (POMC) is a negative regulator of tadpole aggression through opioid receptor signaling

Aggression is a common behavioral response to limited environmental resources. Most research on the neural basis of aggression in vertebrates focuses on adult males, where sex steroid hormones and the ventromedial hypothalamus are important regulators of aggressive behavior. However, the young of many species also display aggression, although the neural basis of juvenile aggression is not well understood. Here we examine juvenile aggression in Mimic poison frog (Ranitomeya imitator) tadpoles, who live in small isolated pools with limited resources and display aggressive behaviors towards intruder tadpoles. We first conducted a longitudinal study of dyadic behavior and found aggressive behavior increases with tadpole age. We next evaluated which brain regions may be important for tadpole aggression by quantifying pS6-positive cells as a proxy for neural activity. We found more pS6-positive cells in the ventral hypothalamus of aggressive tadpoles compared to controls, similar to findings in adult mammals. We then quantified colocalization of pS6 with vasopressin and oxytocin cells and found no difference across behavior groups. Based on this information, we hypothesized that similar brain regions, but different neuromodulators, may promote aggression in juvenile tadpoles compared to the literature in adult animals. We then used an untargeted approach to molecularly profile pS6-positive neurons and found enrichment of the proopiomelanocortin (POMC) gene in aggressive tadpoles. As POMC is cleaved into several signaling peptides, we used pharmacology to target each pathway and discovered that blocking opioid receptors increases aggressive behavior. Together, this work suggests that POMC-derived B-endorphin is a negative regulator of juvenile aggression through the opioid receptor signaling. More broadly, this work suggests that similar brain regions, but different signaling molecules may be used to regulate aggression in adult and juvenile animals.

animal behavior and cognition↗