Visual perception is not instantaneous. It takes a few milliseconds for light to be transduced in photoreceptors and tens of milliseconds more for neuronal spikes to occur at successive levels of the visual hierarchy. Moreover, the latency of responses varies across the visual field and the cortical hierarchy. In peripheral compared to central vision, the impulse response of primates' ganglion cells has a higher peak occurring at shorter latency [1], and yet humans' primary visual cortex is activated later [2]. The diversity of these physiological results makes it difficult to predict when is the perceived present [3], especially when events are presented across the visual field. This question cannot be directly addressed with paradigms traditionally used to investigate perceptual latencies. In particular, response times are not suitable because they are influenced by decisional mechanisms, motor-related processing or compensatory mechanisms [4,5]. Likewise, temporal order judgements between foveal and peripheral stimuli are not suitable because humans overweigh foveal information when making perceptual decisions [6]. Here we explicitly asked participants to estimate when a stimulus is perceived within a fixed duration temporal interval, rather than relative to another stimulus presented in its near temporal proximity. We show that the perceived time of a visual event depends on its position in the visual field. We find a large bias to report events earlier when they were presented in the periphery.Climate change is regarded as a major threat to global biodiversity [1]. However, another key driver of declines in biodiversity during the last century has been, and still is, the devastating impact of anthropogenic habitat destruction [2]. Human degradation of natural habitats has resulted in large, formerly homogeneous areas becoming exceedingly isolated and fragmented, resulting in reduced genetic diversity and a concomitant increased vulnerability to pathogens [3] and increased risk of inbreeding [4]. In order to restore genetic diversity in small isolated or fragmented populations, genetic rescue - that is, an intervention in which unrelated individuals are brought into a population, leading to introduction of novel alleles - has been shown to reduce the deleterious effects of inbreeding [4,5].Iron is an essential micronutrient for microorganisms, plants, animals, and humans. However, iron overload can damage the organism through a variety of mechanisms, including the induction of cell death. Ferroptosis is defined as an iron-dependent form of regulated cell death caused by unrestricted lipid peroxidation and subsequent membrane damage. Ferroptosis can be triggered through either the extrinsic or the intrinsic pathway. The extrinsic pathway is initiated through the regulation of transporters (e.g., inhibition of the amino acid antiporter system xc- or activation of the iron transporters transferrin and lactotransferrin), whereas the intrinsic pathway is mainly induced by blocking the expression or activity of intracellular antioxidant enzymes, such as glutathione peroxidase 4 (GPX4). In addition to small-molecule compounds and drugs, certain stresses (e.g., high temperature, low temperature, hypoxia, and radiation) induce ferroptotic cell death. The abnormal regulation of this process, which is connected to protein degradation pathways, such as autophagy and the ubiquitin-proteasome system, is associated with various pathological conditions, including acute tissue damage, infection, cancer, and neurodegeneration. Here, we discuss the core process and regulation of ferroptosis in mammalian cells, as well as its therapeutic implications in disease.Rohan Brooker and Bob Wong introduce the ways animals conceal themselves using non-visual sensory stimuli.A consistent finding from contemporary Western societies is that women outlive men. However, what is unclear is whether sex differences in survival are constant across varying socio-ecological conditions. We test the universality of the female survival advantage with mortality data from a nineteenth century population in the Baja California peninsula of Mexico. When examined simply, we find evidence for a male-biased survival advantage. However, results from Cox regression clearly show the importance of age intervals for variable survival patterns by sex. Our key findings are that males (i) experience significantly lower mortality risk than females during the ages 15-30 (RR = 0.69), (ii) are at a significantly increased risk of dying in the 61+ category (RR = 1.30) and (iii) do not experience significantly different mortality risk at any other age interval (0-14, 31-45, 46-60). We interpret our results to stem from differing intrinsic and extrinsic risk factors for sex-biased mortality across age intervals, highlighting the relevance of a lifecourse approach to the study of survival advantage. Ultimately, our results make clear the need to more broadly consider variability in mortality risk factors across time and place to allow for a clearer understanding of human survival differences.The Upper Triassic tetrapod fossil record of North America features a pronounced discrepancy between the assemblages of present-day Virginia and North Carolina relative to those of the American Southwest. While both are typified by large-bodied archosaurian reptiles like phytosaurs and aetosaurs, the latter notably lacks substantial representation of mammal relatives, including cynodonts. Recently collected non-mammalian eucynodontian jaws from the middle Norian Blue Mesa Member of the Chinle Formation in northeastern Arizona shed light on the Triassic cynodont record from western equatorial Pangaea. Importantly, they reveal new biogeographic connections to eastern equatorial Pangaea as well as southern portions of the supercontinent. This discovery indicates that the faunal dissimilarity previously recognized between the western and eastern portions of equatorial Pangaea is overstated and possibly reflects longstanding sampling biases, rather than a true biogeographic pattern.Recent research in mammals supports a link between cognitive ability and the gut microbiome, but little is known about this relationship in other taxa. In a captive population of 38 zebra finch(es) (Taeniopygia guttata), we quantified performance on cognitive tasks measuring learning and memory. https://www.selleckchem.com/products/LBH-589.html We sampled the gut microbiome via cloacal swab and quantified bacterial alpha and beta diversity. Performance on cognitive tasks related to beta diversity but not alpha diversity. We then identified differentially abundant genera influential in the beta diversity differences among cognitive performance categories. Though correlational, this study provides some of the first evidence of an avian microbiota-gut-brain axis, building foundations for future microbiome research in wild populations and during host development.
Visual perception is not instantaneous. It takes a few milliseconds for light to be transduced in photoreceptors and tens of milliseconds more for neuronal spikes to occur at successive levels of the visual hierarchy. Moreover, the latency of responses varies across the visual field and the cortical hierarchy. In peripheral compared to central vision, the impulse response of primates' ganglion cells has a higher peak occurring at shorter latency [1], and yet humans' primary visual cortex is activated later [2]. The diversity of these physiological results makes it difficult to predict when is the perceived present [3], especially when events are presented across the visual field. This question cannot be directly addressed with paradigms traditionally used to investigate perceptual latencies. In particular, response times are not suitable because they are influenced by decisional mechanisms, motor-related processing or compensatory mechanisms [4,5]. Likewise, temporal order judgements between foveal and peripheral stimuli are not suitable because humans overweigh foveal information when making perceptual decisions [6]. Here we explicitly asked participants to estimate when a stimulus is perceived within a fixed duration temporal interval, rather than relative to another stimulus presented in its near temporal proximity. We show that the perceived time of a visual event depends on its position in the visual field. We find a large bias to report events earlier when they were presented in the periphery.Climate change is regarded as a major threat to global biodiversity [1]. However, another key driver of declines in biodiversity during the last century has been, and still is, the devastating impact of anthropogenic habitat destruction [2]. Human degradation of natural habitats has resulted in large, formerly homogeneous areas becoming exceedingly isolated and fragmented, resulting in reduced genetic diversity and a concomitant increased vulnerability to pathogens [3] and increased risk of inbreeding [4]. In order to restore genetic diversity in small isolated or fragmented populations, genetic rescue - that is, an intervention in which unrelated individuals are brought into a population, leading to introduction of novel alleles - has been shown to reduce the deleterious effects of inbreeding [4,5].Iron is an essential micronutrient for microorganisms, plants, animals, and humans. However, iron overload can damage the organism through a variety of mechanisms, including the induction of cell death. Ferroptosis is defined as an iron-dependent form of regulated cell death caused by unrestricted lipid peroxidation and subsequent membrane damage. Ferroptosis can be triggered through either the extrinsic or the intrinsic pathway. The extrinsic pathway is initiated through the regulation of transporters (e.g., inhibition of the amino acid antiporter system xc- or activation of the iron transporters transferrin and lactotransferrin), whereas the intrinsic pathway is mainly induced by blocking the expression or activity of intracellular antioxidant enzymes, such as glutathione peroxidase 4 (GPX4). In addition to small-molecule compounds and drugs, certain stresses (e.g., high temperature, low temperature, hypoxia, and radiation) induce ferroptotic cell death. The abnormal regulation of this process, which is connected to protein degradation pathways, such as autophagy and the ubiquitin-proteasome system, is associated with various pathological conditions, including acute tissue damage, infection, cancer, and neurodegeneration. Here, we discuss the core process and regulation of ferroptosis in mammalian cells, as well as its therapeutic implications in disease.Rohan Brooker and Bob Wong introduce the ways animals conceal themselves using non-visual sensory stimuli.A consistent finding from contemporary Western societies is that women outlive men. However, what is unclear is whether sex differences in survival are constant across varying socio-ecological conditions. We test the universality of the female survival advantage with mortality data from a nineteenth century population in the Baja California peninsula of Mexico. When examined simply, we find evidence for a male-biased survival advantage. However, results from Cox regression clearly show the importance of age intervals for variable survival patterns by sex. Our key findings are that males (i) experience significantly lower mortality risk than females during the ages 15-30 (RR = 0.69), (ii) are at a significantly increased risk of dying in the 61+ category (RR = 1.30) and (iii) do not experience significantly different mortality risk at any other age interval (0-14, 31-45, 46-60). We interpret our results to stem from differing intrinsic and extrinsic risk factors for sex-biased mortality across age intervals, highlighting the relevance of a lifecourse approach to the study of survival advantage. Ultimately, our results make clear the need to more broadly consider variability in mortality risk factors across time and place to allow for a clearer understanding of human survival differences.The Upper Triassic tetrapod fossil record of North America features a pronounced discrepancy between the assemblages of present-day Virginia and North Carolina relative to those of the American Southwest. While both are typified by large-bodied archosaurian reptiles like phytosaurs and aetosaurs, the latter notably lacks substantial representation of mammal relatives, including cynodonts. Recently collected non-mammalian eucynodontian jaws from the middle Norian Blue Mesa Member of the Chinle Formation in northeastern Arizona shed light on the Triassic cynodont record from western equatorial Pangaea. Importantly, they reveal new biogeographic connections to eastern equatorial Pangaea as well as southern portions of the supercontinent. This discovery indicates that the faunal dissimilarity previously recognized between the western and eastern portions of equatorial Pangaea is overstated and possibly reflects longstanding sampling biases, rather than a true biogeographic pattern.Recent research in mammals supports a link between cognitive ability and the gut microbiome, but little is known about this relationship in other taxa. In a captive population of 38 zebra finch(es) (Taeniopygia guttata), we quantified performance on cognitive tasks measuring learning and memory. https://www.selleckchem.com/products/LBH-589.html We sampled the gut microbiome via cloacal swab and quantified bacterial alpha and beta diversity. Performance on cognitive tasks related to beta diversity but not alpha diversity. We then identified differentially abundant genera influential in the beta diversity differences among cognitive performance categories. Though correlational, this study provides some of the first evidence of an avian microbiota-gut-brain axis, building foundations for future microbiome research in wild populations and during host development.
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