The thriving field of comparative cognition examines the behaviour of diverse animals in cognitive terms. Comparative cognition research has primarily focused on the abilities of animals - what tasks ...they can do - rather than on the limits of their cognition - tasks that exceed an animal's cognitive abilities. We propose that understanding and identifying cognitive limits is as important as demonstrating the capacities of animal minds. Here, we identify challenges that have deterred the study of cognitive limits related to epistemic, practical and publication problems. The epistemic problem is concerned with how we can confidently infer a cognitive limit from null or negative results. The practical problem is how can we be certain our research has identified a cognitive limit rather than failures in tasks due to methodological or experimental design issues. The publication problem outlines the publication bias toward positive and exciting results over negative or null results in animal cognition. We propose solutions to these three challenges and examples of how to conduct research to confidently identify and confirm cognitive limits in animals. We believe a refocus on the cognitive limits of animals is the next step in the field of comparative cognition. Knowing the limits to the intelligence of different animals will aid us in appreciating the diversity of animal intelligence, and will resolve outstanding questions of how cognition evolves.
Teleost fishes show an extraordinary diversity of sexual patterns, social structures, and sociosexual behaviors. Sex steroid hormones are key modulators of social behaviors in teleosts as in other ...vertebrates and act on sex steroid receptor-containing brain nuclei that form the evolutionarily conserved vertebrate social behavior network (SBN). Fishes also display important differences relative to tetrapod vertebrates that make them particularly well-suited to study the physiological mechanisms modulating social behavior. Specifically, fishes exhibit high levels of brain aromatization and have what has been proposed to be a lifelong, steroid hormone dependent plasticity in the neural substrates mediating sociosexual behavior. In this review, we examine how estrogenic signaling modulates sociosexual behaviors in teleosts with a particular focus on agonistic behavior. Estrogens have been shown to mediate agonistic behaviors in a broad range of fishes, from sexually monomorphic gonochoristic species to highly dimorphic sex changers with alternate reproductive phenotypes. These similarities across such diverse taxa contribute to a growing body of evidence that estrogens play a crucial role in the modulation of aggression in vertebrates. As analytical techniques and genomic tools rapidly advance, methods such as LC-MS/MS, snRNAseq, and CRISPR-based mutagenesis show great promise to further elucidate the mechanistic basis of estrogenic effects on social behavior in the diverse teleost lineage.
•Estrogens influence agonistic behavior across vertebrates including teleost fishes.•Teleosts provide powerful models to test estrogen effects on agonistic behavior.•Accessibility of genomic tools has expanded for non-model study systems.•Applying genomic tools to fishes will expand our understanding of estrogen actions.
Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that inhibits gonadotropin secretion and socio-sexual behaviours. Oestrogen (neuroestrogen) synthesized in the brain from ...androgen by aromatase regulates male socio-sexual behaviours. Here we show that GnIH directly activates aromatase and increases neuroestrogen synthesis in the preoptic area (POA) and inhibits socio-sexual behaviours of male quail. Aromatase activity and neuroestrogen concentration in the POA are low in the morning when the birds are active, but neuroestrogen synthesis gradually increases until the evening when the birds become inactive. Centrally administered GnIH in the morning increases neuroestrogen synthesis in the POA and decreases socio-sexual behaviours. Centrally administered 17β-oestradiol at higher doses also inhibits socio-sexual behaviours in the morning. These results suggest that GnIH inhibits male socio-sexual behaviours by increasing neuroestrogen synthesis beyond its optimum concentration for the expression of socio-sexual behaviours. This is the first demonstration of any hypothalamic neuropeptide that directly regulates neuroestrogen synthesis.
Here, we characterized behavioral abnormalities induced by prolonged social isolation in adult rodents. Social isolation induced both anxiety- and anhedonia-like symptoms and decreased cAMP response ...element-binding protein (CREB) activity in the nucleus accumbens shell (NAcSh). All of these abnormalities were reversed by chronic, but not acute, antidepressant treatment. However, although the anxiety phenotype and its reversal by antidepressant treatment were CREB-dependent, the anhedonia-like symptoms were not mediated by CREB in NAcSh. We found that decreased CREB activity in NAcSh correlated with increased expression of certain K(+) channels and reduced electrical excitability of NAcSh neurons, which was sufficient to induce anxiety-like behaviors and was reversed by chronic antidepressant treatment. Together, our results describe a model that distinguishes anxiety- and depression-like behavioral phenotypes, establish a selective role of decreased CREB activity in NAcSh in anxiety-like behavior, and provide a mechanism by which antidepressant treatment alleviates anxiety symptoms after social isolation.
Animal Behavior Case of the Month Hauser, Hagar
Journal of the American Veterinary Medical Association,
05/2022, Letnik:
260, Številka:
8
Journal Article
Some insects have a frustrating knack for avoiding a swatter. A new study shows that mosquitos not only evade the visual image of the looming threat, they also surf the wave of air the swatter ...creates.
Aromatase-expressing neuroendocrine neurons in the vertebrate male brain synthesize estradiol from circulating testosterone. This locally produced estradiol controls neural circuits underlying ...courtship vocalization, mating, aggression, and territory marking in male mice. How aromatase-expressing neuronal populations control these diverse estrogen-dependent male behaviors is poorly understood, and the function, if any, of aromatase-expressing neurons in females is unclear. Using targeted genetic approaches, we show that aromatase-expressing neurons within the male posterodorsal medial amygdala (MeApd) regulate components of aggression, but not other estrogen-dependent male-typical behaviors. Remarkably, aromatase-expressing MeApd neurons in females are specifically required for components of maternal aggression, which we show is distinct from intermale aggression in pattern and execution. Thus, aromatase-expressing MeApd neurons control distinct forms of aggression in the two sexes. Moreover, our findings indicate that complex social behaviors are separable in a modular manner at the level of genetically identified neuronal populations.
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•MeApd aromatase neurons regulate male aggression, but not marking, singing, or mating•MeApd aromatase neurons regulate maternal aggression, but not female sexual behavior•MeApd aromatase neurons regulate specific components of aggression in both sexes•MeApd aromatase neurons control aggression in a modular manner
Aromatase controls sexually dimorphic social behaviors in both sexes. Unger et al. show that the small population of aromatase-expressing neurons in the medial amygdala is required for intermale and maternal aggression, but not other sexually dimorphic behaviors. Thus, aromatase-expressing medial amygdalar neurons control complex social behaviors in a modular manner.
The medial amygdala (MeA) plays a critical role in processing species- and sex-specific signals that trigger social and defensive behaviors. However, the principles by which this deep brain structure ...encodes social information is poorly understood. We used a miniature microscope to image the Ca2+ dynamics of large neural ensembles in awake behaving mice and tracked the responses of MeA neurons over several months. These recordings revealed spatially intermingled subsets of MeA neurons with distinct temporal dynamics. The encoding of social information in the MeA differed between males and females and relied on information from both individual cells and neuronal populations. By performing long-term Ca2+ imaging across different social contexts, we found that sexual experience triggers lasting and sex-specific changes in MeA activity, which, in males, involve signaling by oxytocin. These findings reveal basic principles underlying the brain’s representation of social information and its modulation by intrinsic and extrinsic factors.
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•Ca2+ imaging in freely behaving mice reveals sex-specific differences in the encoding of social stimuli•MeA depiction of social information relies on population and individual neuron responses•Sexual experience triggers lasting and sex-specific changes in MeApd activity•Changes in the MeApd of sexually experienced males involve the neuropeptide oxytocin
Imaging of the neuronal activity during social encounters over the span of several months reveals sex-specific differences in response to social cues, as well as long-lasting changes in social representation following sexual experience.
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