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Sensory processing is influenced by neuromodulators such as serotonin, thought to relay behavioural state. Recent work has shown that the modulatory effect of serotonin itself differs with the animal's behavioural state. In primates, including humans, the serotonin system is anatomically important in the primary visual cortex (V1). We previously reported that in awake fixating macaques, serotonin reduces the spiking activity by decreasing response gain in V1. But the effect of serotonin on the local network is unknown. Here, we simultaneously recorded single‐unit activity and local field potentials (LFPs) while iontophoretically applying serotonin in V1 of alert monkeys fixating on a video screen for juice rewards. The reduction in spiking response we observed previously is the opposite of the known increase of spiking activity with spatial attention. Conversely, in the local network (LFP), the application of serotonin resulted in changes mirroring the local network effects of previous reports in macaques directing spatial attention to the receptive field. It reduced the LFP power and the spike–field coherence, and the LFP became less predictive of spiking activity, consistent with reduced functional connectivity. We speculate that together, these effects may reflect the sensory side of a serotonergic contribution to quiet vigilance: The lower gain reduces the salience of stimuli to suppress an orienting reflex to novel stimuli, whereas at the network level, visual processing is in a state comparable to that of spatial attention. [ABSTRACT FROM AUTHOR]

Aim: Rapid advances in technology have created tools able to explore how animals differ in their use of the environment based on behaviour, which can provide insights into the ecology of endangered animals and the threats they face. Though threatened, we know little of vultures' spatial ecology. We examine the external variables that affect vultures' decisions regarding space use, specifically during foraging and feeding when they are at greatest risk for encountering threats, and use this to inform effective conservation interventions. Location: Tanzania, specifically Southern Tanzanian protected area networks. Taxon: Gyps africanus. Methods: We tracked 26 African white‐backed vultures between 2015 and 2019 in Southern Tanzania. Using hidden Markov models to identify behaviour from raw GPS points and point process models to spatially analyse these behaviours, we tested resource selection decisions in vultures during foraging and feeding, when they are at greatest risk of poisoning. Results: African white‐backed vultures are most likely to forage early in the day outside National Parks, specifically in Game Reserves and Wildlife Management Areas, but avoid areas with high livestock numbers to feed. Eastern and Western populations showed slight differences in preferences, highlighting the need for population level considerations. When not selecting for behaviour, closeness to rivers and habitat openness were more important than protected area status for predicting vulture use. Main conclusions Through combining complex analyses, we identified results which simple statistical analyses could not offer. Hidden Markov models and point process models are complementary and can be used to define specific behaviours and associated resource selection. These results provide insight into how animals use their habitat explicitly rather than describing where they spend most of their time. This adds to the growing evidence that although National Parks are important, the management of surrounding areas must be included in conservation efforts. [ABSTRACT FROM AUTHOR]

Neuronal responses to similar stimuli change dynamically over time, raising the question of how internal representations can provide a stable substrate for neural coding. Recent work has suggested a large degree of drift in neural representations even in sensory cortices, which are believed to store stable representations of the external world. While the drift of these representations is mostly characterized in relation to external stimuli, the behavioural state of the animal (for instance, the level of arousal) is also known to strongly modulate the neural activity. We therefore asked how the variability of such modulatory mechanisms can contribute to representational changes. We analysed large-scale recording of neural activity from the Allen Brain Observatory, which was used before to document representational drift in the mouse visual cortex. We found that, within these datasets, behavioural variability significantly contributes to representational changes. This effect was broadcasted across various cortical areas in the mouse, including the primary visual cortex, higher order visual areas, and even regions not primarily linked to vision like hippocampus. Our computational modelling suggests that these results are consistent with independent modulation of neural activity by behaviour over slower timescales. Importantly, our analysis suggests that reliable but variable modulation of neural representations by behaviour can be misinterpreted as representational drift if neuronal representations are only characterized in the stimulus space and marginalized over behavioural parameters.

Abstract Background Movements and habitat selection of predators shape ecological communities by determining the spatiotemporal distribution of predation risk. Although intraspecific interactions associated to territoriality and parental care are involved in predator habitat selection, few studies have addressed their effects simultaneously with those of prey and habitat distribution. Moreover, individuals require behavioural and temporal flexibility in their movement decisions to meet various motivations in a heterogeneous environment. To untangle the relative importance of ecological determinants of predator fine-scale habitat selection, we studied simultaneously several spatial, temporal, and behavioural predictors of habitat selection in territorial arctic foxes (Vulpes lagopus) living within a Greater snow goose (Anser caerulescens atlantica) colony during the reproductive season. Methods Using GPS locations collected at 4-min intervals and behavioural state classification (active and resting), we quantified how foxes modulate state-specific habitat selection in response to territory edges, den proximity, prey distribution, and habitats. We also assessed whether foxes varied their habitat selection in response to an important phenological transition marked by decreasing prey availability (goose egg hatching) and decreasing den dependency (emancipation of cubs). Results Multiple factors simultaneously played a key role in driving habitat selection, and their relative strength differed with respect to the behavioural state and study period. Foxes avoided territory edges, and reproductive individuals selected den proximity before the phenological transition. Higher goose nest density was selected when foxes were active but avoided when resting, and was less selected after egg hatching. Selection for tundra habitats also varied through the summer, but effects were not consistent. Conclusions We conclude that constraints imposed by intraspecific interactions can play, relative to prey distribution and habitat characteristics, an important role in the habitat selection of a keystone predator. Our results highlight the benefits of considering behavioural state and seasonal phenology when assessing the flexibility of predator habitat selection. Our findings indicate that considering intraspecific interactions is essential to understand predator space use, and suggest that using predator habitat selection to advance community ecology requires an explicit assessment of the social context in which movements occur.

Post‐release monitoring of translocated animals is often used to inform future translocation protocols. Quantifying habitat selection of translocated individuals may help identify features that characterize good settlement habitat and thus inform the choice of future release sites. However, translocated animals often undergo post‐release behavioural modification, and their habitat selection may vary depending on the underlying behavioural state.To investigate this, we analysed behavioural state‐dependent habitat selection in female greater sage‐grouse Centrocercus urophasianus translocated from Wyoming to North Dakota, USA, using Hidden Markov Models combined with Integrated Step Selection Analysis. We segmented individual trajectories into behavioural phases corresponding to an exploratory state, characterized by broad and directed movements, and a restricted state, characterized by short and tortuous movements. Then, we quantified habitat selection in each state while accounting for seasonality and individual reproductive status.While in the exploratory state, sage‐grouse exhibited natal habitat preference induction by selecting for high sagebrush cover, which is typical of their natal area in Wyoming but not of the release area in North Dakota.In the restricted state, sage‐grouse selected for gentle topography and also adjusted their habitat selection to constraints imposed by seasonality and reproductive needs by selecting for high herbaceous cover during brood rearing.Synthesis and applications. Habitat selection of translocated sage‐grouse differed between the post‐release exploration and the settlement phase. Features selected after settling, not during exploration, are likely indicative of suitable settlement habitat. Our results suggest that areas characterized by gentle topography and high herbaceous cover are well‐suited as release sites for sage‐grouse translocated during the summer, especially brood‐rearing females, and that sagebrush cover may not be a critical factor in determining the appropriateness of release sites for sage‐grouse in North Dakota. Our findings highlight the need to consider behaviour when using habitat selection estimates to inform the choice of future release sites. [ABSTRACT FROM AUTHOR]

Understanding animal movement often relies upon telemetry and biologging devices. These data are frequently used to estimate latent behavioural states to help understand why animals move across the landscape. While there are a variety of methods that make behavioural inferences from biotelemetry data, some features of these methods (e.g. analysis of a single data stream, use of parametric distributions) may limit their generality to reliably discriminate among behavioural states.To address some of the limitations of existing behavioural state estimation models, we introduce a nonparametric Bayesian framework called the mixed‐membership method for movement (M4), which is available within the open‐source bayesmove R package. This framework can analyse multiple data streams (e.g. step length, turning angle, acceleration) without relying on parametric distributions, which may capture complex behaviours more successfully than current methods. We tested our Bayesian framework using simulated trajectories and compared model performance against two segmentation methods (behavioural change point analysis (BCPA) and segclust2d), one machine learning method [expectation‐maximization binary clustering (EMbC)] and one type of state‐space model [hidden Markov model (HMM)]. We also illustrated this Bayesian framework using movements of juvenile snail kites Rostrhamus sociabilis in Florida, USA.The Bayesian framework estimated breakpoints more accurately than the other segmentation methods for tracks of different lengths. Likewise, the Bayesian framework provided more accurate estimates of behaviour than the other state estimation methods when simulations were generated from less frequently considered distributions (e.g. truncated normal, beta, uniform). Three behavioural states were estimated from snail kite movements, which were labelled as 'encamped', 'area‐restricted search' and 'transit'. Changes in these behaviours over time were associated with known dispersal events from the nest site, as well as movements to and from possible breeding locations.Our nonparametric Bayesian framework estimated behavioural states with comparable or superior accuracy compared to the other methods when step lengths and turning angles of simulations were generated from less frequently considered distributions. Since the most appropriate parametric distributions may not be obvious a priori, methods (such as M4) that are agnostic to the underlying distributions can provide powerful alternatives to address questions in movement ecology. [ABSTRACT FROM AUTHOR]

Background: Movements and habitat selection of predators shape ecological communities by determining the spatiotemporal distribution of predation risk. Although intraspecific interactions associated to territoriality and parental care are involved in predator habitat selection, few studies have addressed their effects simultaneously with those of prey and habitat distribution. Moreover, individuals require behavioural and temporal flexibility in their movement decisions to meet various motivations in a heterogeneous environment. To untangle the relative importance of ecological determinants of predator fine-scale habitat selection, we studied simultaneously several spatial, temporal, and behavioural predictors of habitat selection in territorial arctic foxes (Vulpes lagopus) living within a Greater snow goose (Anser caerulescens atlantica) colony during the reproductive season. Methods: Using GPS locations collected at 4-min intervals and behavioural state classification (active and resting), we quantified how foxes modulate state-specific habitat selection in response to territory edges, den proximity, prey distribution, and habitats. We also assessed whether foxes varied their habitat selection in response to an important phenological transition marked by decreasing prey availability (goose egg hatching) and decreasing den dependency (emancipation of cubs). Results: Multiple factors simultaneously played a key role in driving habitat selection, and their relative strength differed with respect to the behavioural state and study period. Foxes avoided territory edges, and reproductive individuals selected den proximity before the phenological transition. Higher goose nest density was selected when foxes were active but avoided when resting, and was less selected after egg hatching. Selection for tundra habitats also varied through the summer, but effects were not consistent. Conclusions: We conclude that constraints imposed by intraspecific interactions can play, relative to prey distribution and habitat characteristics, an important role in the habitat selection of a keystone predator. Our results highlight the benefits of considering behavioural state and seasonal phenology when assessing the flexibility of predator habitat selection. Our findings indicate that considering intraspecific interactions is essential to understand predator space use, and suggest that using predator habitat selection to advance community ecology requires an explicit assessment of the social context in which movements occur. [ABSTRACT FROM AUTHOR]

Aim: Little is known about infant-directed speech addressed to preterm infants. The current study investigated the association between changes in preterm infant behavioural states and acoustical qualities of both maternal and paternal infant-directed speech.Methods: The mothers and fathers of 11 preterm infants participated in the study. Parents in turn were asked to talk freely to their infant over a 5-minute period. A total of 72 audio sequences were selected and analysed as a function of the behavioural states.Results: Acoustic analysis showed that the vocal qualities of both fathers' and mothers' speech were influenced by infant behaviour. Parental infant-directed speech was characterised by higher loudness and spectral related parameters when preterm infants were sleeping, or transiting from one state to another, than when they were awake. Furthermore, loudness and spectral flux were higher in maternal speech than in paternal speech and fathers used higher pitch, jitter and shimmer when they saw their preterm infant in an awake state, demonstrating that alertness in infants modulates the father's voice.Conclusion: More research is needed to know whether other social partners' vocal qualities may also be related to infant behavioural state as such findings would have implications for clinical practice. [ABSTRACT FROM AUTHOR]

Groups of animals possess phenotypes such as collective behaviour, which may determine the fitness of group members. However, the stability and robustness to perturbations of collective phenotypes in natural conditions is not established. Furthermore, whether group phenotypes are transmitted from parent to offspring groups with fidelity is required for understanding how selection on group phenotypes contributes to evolution, but parent–offspring resemblance at the group level is rarely estimated. We evaluated the repeatability, robustness to perturbation and parent–offspring resemblance of collective foraging aggressiveness in colonies of the social spider Anelosimus eximius. Among‐colony differences in foraging aggressiveness were consistent over time but changed if the colony was perturbed through the removal of individuals or via individuals' removal and subsequent return. Offspring and parent colony behaviour were correlated at the phenotypic level, but only once the offspring colony had settled after being translocated, and the correlation overlapped with zero at the among‐colony level. The parent–offspring resemblance was not driven by a shared elevation but could be due to other environmental factors. The behaviour of offspring colonies in a common garden laboratory setting was not correlated with the behaviour of the parent colony nor with the same colony's behaviour once it was returned to the field. The phenotypes of groups represent a potentially important tier of biological organization, and assessing the stability and heritability of such phenotypes helps us better understand their role in evolution. [ABSTRACT FROM AUTHOR]

The honey bee Apis mellifera is a model organism for studying learning and memory in insects. Although much work has been done to study olfactory learning using the proboscis extension reflex paradigm, we currently lack a high throughput method to study spatial learning and memory under controlled conditions. Here we outline a new paradigm to study spatial learning and memory in honey bees based on a food search task adopted from the vertebrate literature. After establishing that honey bees are able to learn and recall the location of artificial flowers inside the testing arena, we used the procedure to compare the performance of young nurse bees, who stay in the colony and nurse the brood, and old forager bees who forage outside. We also compared the spatial learning and memory of age-staged bees that were experimentally treated with cyclic guanosine monophosphate (cGMP), which causes precocious foraging, and cyclic adenosine monophosphate (cAMP), which does not alter behavioural state. Although foragers and nurses from typical colonies had similar learning curves, we found that foragers were significantly more accurate when recalling the location of previously rewarding artificial flowers inside the testing arena. This effect was also observed when comparing age-staged bees that have been chronically exposed to cGMP vs. those chronically exposed to cAMP. The Food Search Box paradigm is a simple and effective way to study spatial learning and memory in honey bees. [ABSTRACT FROM AUTHOR]

Most animals rely on visual information for a variety of everyday tasks. The information available to a visual system depends in part on its spatial resolving power and contrast sensitivity. Because of their competing demands for physical space within an eye, these traits cannot simultaneously be improved without increasing overall eye size. The contrast sensitivity function is an integrated measure of visual performance that measures both resolution and contrast sensitivity. Its measurement helps us identify how different species have made a trade-off between contrast sensitivity and spatial resolution. It further allows us to identify the evolutionary drivers of sensory processing and visually mediated behaviour. Here, we measured the contrast sensitivity function of the fiddler crab Gelasimus dampieri using its optokinetic responses to wide-field moving sinusoidal intensity gratings of different orientations, spatial frequencies, contrasts and speeds. We further tested whether the behavioural state of the crabs (i.e. whether crabs are actively walking or not) affects their optokinetic gain and contrast sensitivity. Our results from a group of five crabs suggest a minimum perceived contrast of 6% and a horizontal and vertical visual acuity of 0.4 cyc deg-1 and 0.28 cyc deg-1, respectively, in the crabs' region of maximum optomotor sensitivity. Optokinetic gain increased in moving crabs compared with restrained crabs, adding another example of the importance of naturalistic approaches when studying the performance of animals., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2023. Published by The Company of Biologists Ltd.)

The dynamic nature of animal societies often hides multiple layers of complexity. The field of animal behaviour is rapidly advancing with the development of increasingly sophisticated analytical methods that allow scientists to identify complex and nuanced drivers of social patterns. The resurgent interest in giraffe sociality illustrates this by challenging the early view that individuals interact at random; it became clear that, instead, giraffes can be organized into multilevel societies, apparently founded on preferred associations. However, it is unclear whether such enduring associations result from active choice for specific individuals. The extent to which other social and asocial factors can contribute to an individual's inclusion in groups remains underexplored. Here we assess how context affects social preferences at the individual level by evaluating grouping patterns of giraffes in different behavioural states, habitats and levels of disturbance. When we controlled for potential class-based (as opposed to individual-based) assortment of individuals by sex, age and gregariousness, we found that giraffes only exhibited individual social preferences when foraging, with minor influence of habitat complexity or level of disturbance. Our results indicate that behavioural context is a major driver of giraffe social association. This strengthens recent evidence of complex social systems in giraffes and suggests that classic metrics of social relationships (such as association indices) may be too coarse, concealing true social preferences in wild populations. Highlights • Behavioural context is a major driver of social associations in giraffes. • Giraffes only exhibit social preferences when foraging. • Habitat complexity and predation risk had minor influences on association patterns. • Social preferences may be driven by females' selection of foraging companions. • Accounting for behavioural context can reveal true social preferences among animals. [ABSTRACT FROM AUTHOR]

Abstract: Electronic tagging of marine fishes is commonly achieved with archival tags that rely on light levels and sea surface temperatures to retrospectively estimate movements. However, methodological issues associated with light‐level geolocation have constrained meaningful inference to species where it is possible to accurately estimate time of sunrise and sunset. Most studies have largely ignored the oceanographic profiles collected by the tag as a potential way to refine light‐level geolocation estimates. Open‐source oceanographic measurements and outputs from high‐resolution models are increasingly available and accessible. Temperature and depth profiles recorded by electronic tags can be integrated with these empirical data and model outputs to construct likelihoods and improve geolocation estimates. The R package HMMoce leverages available tag and oceanographic data to improve position estimates derived from electronic tags using a hidden Markov approach. We illustrate the use of the model and test its performance using example blue and mako shark archival tag data. Model results were validated using independent, known tracks and compared to results from other geolocation approaches. HMMoce exhibited as much as six‐fold improvement in pointwise error as compared to traditional light‐level geolocation approaches. The results demonstrated the general applicability of HMMoce to marine animals, particularly those that do not frequent surface waters during crepuscular periods. [ABSTRACT FROM AUTHOR]

Aim: Our aim was to study the development of the cutaneous flexion withdrawal reflex among premature infants admitted to the neonatal intensive care unit of the Children's Hospital, University of Cologne, in 2013.Methodology: This longitudinal cohort study explored the development of spinal cord excitability of 19 premature infants born at 22-26 weeks of gestation. We performed five investigations per subject and studied changes in the reflex threshold with increasing postnatal age at different behavioural states. The premature infants were stimulated with von Frey filaments on the plantar surface of the foot near the first metatarsophalangeal joint during the first 3 days of life and at postnatal ages of 10-14 days, 21-28 days, 49-59 days and a corrected gestational age of 37-40 weeks.Results: The mean gestational age of the premature infants included in the study was 24 weeks. Premature infants with a gestational age of less than 26 weeks presented a flexion withdrawal reflex with a low threshold (0.5-2.85 milli-Newton) in the first 72 hours of life.Conclusion: The flexion withdrawal reflex among premature infants born at less than 26 weeks showed a continuous threshold increase with increasing postnatal age, reflecting changes in spinal cord excitability. [ABSTRACT FROM AUTHOR]

Evaluating landscape connectivity and identifying and protecting corridors for animal movement have become central challenges in applied ecology and conservation. Currently, resource selection analyses are widely used to focus corridor planning where animal movement is predicted to occur. An animal's behavioural state (e.g. foraging, dispersing) is a significant determinant of resource selection patterns, yet has largely been ignored in connectivity assessments., We review 16 years of connectivity studies employing resource selection analysis to evaluate how researchers have incorporated animal behaviour into corridor planning, and highlight promising new approaches for identifying wildlife corridors. To illustrate the importance of behavioural information in such analyses, we present an empirical case study to test behaviour-specific predictions of connectivity with long-distance dispersal movements of African wild dogs Lycaon pictus. We conclude by recommending strategies for developing more realistic connectivity models for future conservation efforts., Our review indicates that most connectivity studies conflate resource selection with connectivity requirements, which may result in misleading estimates of landscape resistance, and lack validation of proposed connectivity models with movement data., Our case study shows that including only directed movement behaviour when measuring resource selection reveals markedly different, and more accurate, connectivity estimates than a model measuring resource selection independent of behavioural state., Synthesis and applications. Our results, using African wild dogs as a case study, suggest that resource selection analyses that fail to consider an animal's behavioural state may be insufficient in targeting movement pathways and corridors for protection. This failure may result in misidentification of wildlife corridors and misallocation of limited conservation resources. Our findings underscore the need for considering patterns of animal movement in appropriate behavioural contexts to ensure the effective application of resource selection analyses for corridor planning. [ABSTRACT FROM AUTHOR]

Due to the substantial progress in tracking technology, recent years have seen an explosion in the amount of movement data being collected. This has led to a huge demand for statistical tools that allow ecologists to draw meaningful inference from large tracking data sets., The class of hidden Markov models (HMMs) matches the intuitive understanding that animal movement is driven by underlying behavioural modes and has proven to be very useful for analysing movement data. For data that involve a regular sampling unit and negligible measurement error, these models usually are sufficiently flexible to capture the complex correlation structure found in movement data, yet are computationally inexpensive compared to alternative methods., The R package moveHMM allows ecologists to process GPS tracking data into series of step lengths and turning angles, and to fit an HMM to these data, allowing, in particular, for the incorporation of environmental covariates. The package includes assessment and visualization tools for the fitted model., We illustrate the use of moveHMM using (simulated) movement of the legendary wild haggis Haggis scoticus. Our findings illustrate the role our software, and movement modelling in general, can play in conservation and management by illuminating environmental constraints. [ABSTRACT FROM AUTHOR]

Aims. To assess the use of skin conductance as an objective measure of pain in infants of different gestational age. A second aim was to investigate the relationship between skin conductivity and selected physiological and behavioural variables (oxygen saturation, heart rate and behavioural state). Methods. Infants were divided according to gestational age into the following 3 groups; group A: 25+0 - 31+6 weeks (13 infants), group B: 32+0 - 35+6 weeks (25 infants), group C: 36+0 - 41+6 weeks (19 infants). The pain stimulus was blood sampling. Results. The most sensitive parameter for describing changes in skin conductance related to pain was peak per second. No other parameter correlated with the physiological variables chosen. The results showed that the inability to determine basal skin conductance is a crucial disadvantage to practical application. The lack of correlation between conductance parameters and gestational age is surprising. Conclusion. We conclude that the Peak per Second is the best parameter for evaluating skin conductance in infants and it is not influenced by gestational age. Peaks per Second correlate only with Prechtl's Scale of behavioural state and not with the physiological parameters chosen. [ABSTRACT FROM AUTHOR]

Group dynamics are a fundamental aspect of many species' movements. The need to adequately model individuals' interactions with other group members has been recognized, particularly in order to differentiate the role of social forces in individual movement from environmental factors. However, to date, practical statistical methods, which can include group dynamics in animal movement models, have been lacking., We consider a flexible modelling framework that distinguishes a group-level model, describing the movement of the group's centre, and an individual-level model, such that each individual makes its movement decisions relative to the group centroid. The basic idea is framed within the flexible class of hidden Markov models, extending previous work on modelling animal movement by means of multistate random walks., While in simulation experiments parameter estimators exhibit some bias in non-ideal scenarios, we show that generally the estimation of models of this type is both feasible and ecologically informative., We illustrate the approach using real movement data from 11 reindeer ( Rangifer tarandus). Results indicate a directional bias towards a group centroid for reindeer in an encamped state. Though the attraction to the group centroid is relatively weak, our model successfully captures group-influenced movement dynamics. Specifically, as compared to a regular mixture of correlated random walks, the group dynamic model more accurately predicts the non-diffusive behaviour of a cohesive mobile group., As technology continues to develop, it will become easier and less expensive to tag multiple individuals within a group in order to follow their movements. Our work provides a first inferential framework for understanding the relative influences of individual versus group-level movement decisions. This framework can be extended to include covariates corresponding to environmental influences or body condition. As such, this framework allows for a broader understanding of the many internal and external factors that can influence an individual's movement. [ABSTRACT FROM AUTHOR]

Neuronal responses to similar stimuli change dynamically over time, raising the question of how internal representations can provide a stable substrate for neural coding. Recent work has suggested a large degree of drift in neural representations even in sensory cortices, which are believed to store stable representations of the external world. While the drift of these representations is mostly characterized in relation to external stimuli, the behavioural state of the animal (for instance, the level of arousal) is also known to strongly modulate the neural activity. We therefore asked how the variability of such modulatory mechanisms can contribute to representational changes. We analysed large-scale recording of neural activity from the Allen Brain Observatory, which was used before to document representational drift in the mouse visual cortex. We found that, within these datasets, behavioural variability significantly contributes to representational changes. This effect was broadcasted across various cortical areas in the mouse, including the primary visual cortex, higher order visual areas, and even regions not primarily linked to vision like hippocampus. Our computational modelling suggests that these results are consistent with independent modulation of neural activity by behaviour over slower timescales. Importantly, our analysis suggests that reliable but variable modulation of neural representations by behaviour can be misinterpreted as representational drift if neuronal representations are only characterized in the stimulus space and marginalized over behavioural parameters., Competing Interests: SS, CC No competing interests declared, (© 2022, Sadeh and Clopath.)

Locomotor activity like walking or flying has recently been shown to alter visual processing in several species. In insects, the neuromodulator octopamine is thought to play an important role in mediating state changes during locomotion of the animal [K.D. Longden & H.G. Krapp (2009) J. Neurophysiol., 102, 3606-3618; (2010) Front. Syst. Neurosci., 4, 153; S.N. Jung et al. (2011) J. Neurosci., 31, 9231-9237]. Here, we used the octopamine agonist chlordimeform (CDM) to mimic effects of behavioural state changes on visual motion processing. We recorded from identified motion-sensitive visual interneurons in the lobula plate of the blowfly Calliphora vicina. In these neurons, which are thought to be involved in visual guidance of locomotion, motion adaptation leads to a prominent attenuation of contrast sensitivity. Following CDM application, the neurons maintained high contrast sensitivity in the adapted state. This modulation of contrast gain adaptation was independent of the activity of the recorded neurons, because it was also present after stimulation with visual motion that did not result in deviations from the neurons' resting activity. We conclude that CDM affects presynaptic inputs of the recorded neurons. Accordingly, the effect of CDM was weak when adapting and test stimuli were presented in different parts of the receptive field, stimulating separate populations of local presynaptic neurons. In the peripheral visual system adaptation depends on the temporal frequency of the stimulus pattern and is therefore related to pattern velocity. Contrast gain adaptation could therefore be the basis for a shift in the velocity tuning that was previously suggested to contribute to state-dependent processing of visual motion information in the lobula plate interneurons. [ABSTRACT FROM AUTHOR]

Abstract: We have designed an automated method for analyzing electrocortical (ECoG) activity in the near-term ovine fetus to process and quantitatively classify large amounts of data rapidly and objectively. Seven chronically catheterized fetal sheep were studied for 8h each at ~0.9 of gestation with continuous recording of ECoG activity using a computerized data acquisition system. Multiple ECoG amplitude and frequency parameters were scored from which we established animal specific parameter cut-off values as well as population based duration cut-off values to distinguish low-voltage/high frequency (LV/HF) and high-voltage/low frequency (HV/LF) state epochs, and indeterminate voltage/frequency (IV/F) and transition period activities. We have shown that the incidence of the predominant LV/HF and HV/LF activity states at 45% and 36% of the time, respectively, is comparable to that previously reported using semi-quantitative techniques with visual analysis. However, the duration of these state epochs is considerably shorter due to the detection of brief periods of IV/F activity which would be difficult to capture using visual analysis. Importantly, our findings in the healthy ovine fetus near-term using this automated ECoG scoring methodology now provide a framework from which to study maturational events in younger animals, and under adverse pregnancy conditions. [Copyright &y& Elsevier]

Interference can be defined as the reduction of intake rate caused by the presence of congeneric individuals. However, surrounding congeneric individuals may also accelerate food depletion. Therefore, it is difficult to quantify interference (contest) and exploitative (scramble) competition separately, particularly in the field. In an individual-based model, where food was immediately replenished in patches after a foraging bout, we isolated the effect of interference competition. In this way, we investigated how interference shapes the intake rates of flocking Bewick’s swans, Cygnus bewickii, consuming tubers of fennel pondweed, Potamogeton pectinatus. The model predicted that intake rate declines with increasing swan density, and that the rate of decline is greater in subordinate birds than in dominant birds. Subordinate birds suffered a large reduction in intake rate at high densities because they spent a large proportion of the time avoiding more dominant individuals. A major decline in intake rate of subordinates occurred close to the maximum swan densities observed in the field. We expected subordinates to leave high-density flocks and look for another foraging location: interference competition seemed to regulate the maximum swan flock density in the field. Hence, the mean population intake rate at realized densities was only slightly lower than in the absence of interference. As interference occurred mainly as avoidance behaviour, which is difficult to observe in the field, it might commonly remain cryptic for the observer. Our results may explain other field studies where interference competition seemed to be of lesser importance. [ABSTRACT FROM AUTHOR]

The strength of stimulus-induced responses at the neuronal and the behavioural level often depends on the internal state of an animal. Within pathways processing sensory information and eventually controlling behavioural responses, such gain changes can originate at several sites. Using motion-sensitive lobula plate tangential cells (LPTCs) of blowflies, we address whether and in which way information processing changes for two different states of motor activity. We distinguish between the two states on the basis of haltere movements. Halteres are the evolutionarily transformed hindwings of flies. They oscillate when the animals walk or fly. LPTCs mediate, amongst other behaviours, head optomotor responses. These are either of large or small amplitude depending on the state of motor activity. Here we find that LPTC responses also depend on the motor activity of flies. In particular, LPTC responses are enhanced when halteres oscillate. Nevertheless, the response changes of LPTCs do not account for the corresponding large gain changes of head movements. Moreover, haltere activity itself does not change the activity of LPTCs. Instead, we propose that a central signal associated with motor activity changes the gain of head optomotor responses and the response properties of LPTCs. [ABSTRACT FROM AUTHOR]