176 research outputs found

    Reading faces: differential lateral gaze bias in processing canine and human facial expressions in dogs and 4-year-old children

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    Sensitivity to the emotions of others provides clear biological advantages. However, in the case of heterospecific relationships, such as that existing between dogs and humans, there are additional challenges since some elements of the expression of emotions are species-specific. Given that faces provide important visual cues for communicating emotional state in both humans and dogs, and that processing of emotions is subject to brain lateralisation, we investigated lateral gaze bias in adult dogs when presented with pictures of expressive human and dog faces. Our analysis revealed clear differences in laterality of eye movements in dogs towards conspecific faces according to the emotional valence of the expressions. Differences were also found towards human faces, but to a lesser extent. For comparative purpose, a similar experiment was also run with 4-year-old children and it was observed that they showed differential processing of facial expressions compared to dogs, suggesting a species-dependent engagement of the right or left hemisphere in processing emotions

    Exclusion Performance in Dwarf Goats (Capra aegagrus hircus) and Sheep (Ovis orientalis aries)

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    Using a comparative approach, we investigated the ability of dwarf goats and sheep to use direct and indirect information about the location of a food reward in an object-choice task. Subjects had to choose between two cups with only one covering a reward. Before making a choice, subjects received information about the baited (direct information) or non-baited cup (indirect information). Both goats and sheep were able to use direct information (presence of food) in the object choice task. After controlling for local enhancement, we found that goats rather than sheep were able to use indirect information (i.e., the absence of food) to find a reward. The actual test setup could not clarify whether individual goats were able to inferentially reason about the content of the baited cup when only shown the content of the non-baited cup or if they simply avoided the empty cup in that situation. As browsing species, feral and wild goats exhibit highly selective feeding behaviour compared to the rather unselective grazing sheep. The potential influence of this species-specific foraging flexibility of goats and sheep for using direct and indirect information to find a food reward is discussed in relation to a higher aversion to losses in food acquisition in goats compared to sheep

    Gestural communication of the gorilla (Gorilla gorilla): repertoire, intentionality and possible origins

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    Social groups of gorillas were observed in three captive facilities and one African field site. Cases of potential gesture use, totalling 9,540, were filtered by strict criteria for intentionality, giving a corpus of 5,250 instances of intentional gesture use. This indicated a repertoire of 102 gesture types. Most repertoire differences between individuals and sites were explicable as a consequence of environmental affordances and sampling effects: overall gesture frequency was a good predictor of universality of occurrence. Only one gesture was idiosyncratic to a single individual, and was given only to humans. Indications of cultural learning were few, though not absent. Six gestures appeared to be traditions within single social groups, but overall concordance in repertoires was almost as high between as within social groups. No support was found for the ontogenetic ritualization hypothesis as the chief means of acquisition of gestures. Many gestures whose form ruled out such an origin, i.e. gestures derived from species-typical displays, were used as intentionally and almost as flexibly as gestures whose form was consistent with learning by ritualization. When using both classes of gesture, gorillas paid specific attention to the attentional state of their audience. Thus, it would be unwarranted to divide ape gestural repertoires into ‘innate, species-typical, inflexible reactions’ and ‘individually learned, intentional, flexible communication’. We conclude that gorilla gestural communication is based on a species-typical repertoire, like those of most other mammalian species but very much larger. Gorilla gestures are not, however, inflexible signals but are employed for intentional communication to specific individuals

    Is caching the key to exclusion in corvids? The case of carrion crows (Corvus corone corone)

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    Recently, two corvid species, food-caching ravens and non-caching jackdaws, have been tested in an exclusion performance (EP) task. While the ravens chose by exclusion, the jackdaws did not. Thus, foraging behaviour may affect EP abilities. To investigate this possibility, another food-caching corvid species, the carrion crow (Corvus corone corone), was tested in the same exclusion task. We hid food under one of two cups and subsequently lifted either both cups, or the baited or the un-baited cup. The crows were significantly above chance when both cups were lifted or when only the baited cup was lifted. When the empty cup was lifted, we found considerable inter-individual variation, with some birds having a significant preference for the un-baited but manipulated cup. In a follow-up task, we always provided the birds with the full information about the food location, but manipulated in which order they saw the hiding or the removal of food. Interestingly, they strongly preferred the cup which was manipulated last, even if it did not contain any food. Therefore, we repeated the first experiment but controlled for the movement of the cups. In this case, more crows found the food reliably in the un-baited condition. We conclude that carrion crows are able to choose by exclusion, but local enhancement has a strong influence on their performance and may overshadow potential inferential abilities. However, these findings support the hypothesis that caching might be a key to exclusion in corvids

    Superior olivary complex organization and cytoarchitecture may be correlated with function and catarrhine primate phylogeny

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    In the mammalian auditory system, the medial nucleus of the trapezoid body and the lateral superior olive (MNTB-LSO system) contribute to binaural intensity processing and lateralization. Localization precision varies with the sound frequencies. As recency of common ancestry with human beings increases, primates have improved low-frequency sensitivity and reduced sensitivity to higher frequencies. The medial part of the MNTB is devoted to higher frequency processing. Thus, its high-frequency-dependent function is nearly lost in humans and its role in binaural processing as part of the contralateral pathway to the LSO remains questionable. Here, Nissl-stained sections of the superior olivary complex of man (Homo sapiens), bonobo (Pan paniscus), chimpanzee (Pan troglodytes), gorilla (Gorilla gorilla), orangutan (Pongo pygmaeus), gibbon (Hylobates lar), and macaque (Macaca fascicularis) were compared to reveal differences and coincidences. From chimpanzees to humans, the size of the LSO decreased, and the MNTB as a compact nucleus nearly disappears. From chimpanzees to humans, the LSO/MNTB ratio increases dramatically too, whereas the LSO/MSO ratio remains 1.1; a finding that probably corresponds to the phylogenetic proximity between the species

    A systematic review of adolescent physiological development and its relationship with health-related behaviour:a protocol

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    BACKGROUND: At any one time, there are one billion people worldwide who are in the second decade of their life, and 1.8 billion in the 10–24 age range. Whilst a great deal of focus has been placed on healthy early years development, the adolescent years are also a unique period of opportunity: exposure to health-influencing behaviours such as alcohol consumption or cigarette smoking, may serve to establish patterns that have significant health consequences in later life. Although there is often an emphasis on risk-taking and detrimental health behaviours during adolescence, these years also provide significant opportunities for behaviour to be shaped in positive ways that may improve longer term health outcomes. However, it is firstly important to understand the complex physiological changes that are taking place within the human body during this period and their relationship with health-related behaviour. Such knowledge can help to inform health policy and intervention development. AIM: The aim of this study is to gain a comprehensive understanding of the relationship between physiological development and health-related behaviours in adolescence. METHODS: The principles of an integrative review will be used. Such reviews are of use where research has emerged in different fields, to combine existing knowledge and produce a more extensive understanding. Studies from a range of different methodological approaches, published or unpublished, will be included. A range of databases and literature depositories will be searched using a pre-defined search strategy. The review will include studies that focus on adolescents (nominally, those aged 10–24 years). We will seek papers that focus on both physiological development and health behaviour, or papers focusing solely on physiological development if there are clear implications for health behaviour. Studies with a focus on participants with specific health conditions will be excluded. Two reviewers will independently screen potential studies for eligibility and quality; members of the project team will act as third reviewers in the case of uncertainty or discrepancy. Further analyses (e.g. meta-analysis, meta-synthesis, meta-summary) will be decided upon, and sub-set analyses carried out. Finally, an integrative summation will be produced, giving a critical analysis of the results and providing conclusions and recommendations. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13643-015-0173-5) contains supplementary material, which is available to authorized users

    Differential response to right unilateral ECT in depressed patients: impact of comorbidity and severity of illness [ISRCTN39974945]

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    BACKGROUND: Recent electroconvulsive therapy (ECT) efficacy studies of right unilateral (RUL) ECT may not apply to real life clinics with a wide range of patients with major depressive episodes. METHODS: The study included two groups of patients. In addition to a homogeneous group of patients with major depression according to DSM-IV criteria with severity of the major depressive episode > 16 scores on 17-item Hamilton Rating Scale for Depression (HDRS) (Group 1, n = 16), we included a heterogeneous group of patients with less severe major depressive episodes or with a variety of comorbid conditions (Group 2, n = 24). We randomly assigned the patients to an RUL ECT treatment dosed at 5 or 2.5 times seizure threshold with an intent-to-treat design. The outcomes measured blindly were HDRS, number of treatments, and Mini-Mental State Examination (MMSE). The patients were considered to have responded to treatment if the improvement in HDRS score was at least 60% and they had a total score of less than ten. RESULTS: The Group 2 patients responded poorer (8% vs. 63%), and had more often simultaneous worsening in their MMSE scores than Group 1 patients. The differences in the outcomes between the two different doses of RUL ECT treatment were not statistically significant. CONCLUSIONS: ECT effectiveness seems to be lower in real-life heterogeneous patient groups than in homogeneous patient samples used in experimental efficacy trials

    Abilities to explicitly and implicitly infer intentions from actions in adults with autism spectrum disorder

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    Previous research suggests that Autism Spectrum Disorder (ASD) might be associated with impairments on implicit but not explicit mentalizing tasks. However, such comparisons are made difficult by the heterogeneity of stimuli and the techniques used to measure mentalizing capabilities. We tested the abilities of 34 individuals (17 with ASD) to derive intentions from others’ actions during both explicit and implicit tasks and tracked their eye-movements. Adults with ASD displayed explicit but not implicit mentalizing deficits. Adults with ASD displayed typical fixation patterns during both implicit and explicit tasks. These results illustrate an explicit mentalizing deficit in adults with ASD, which cannot be attributed to differences in fixation patterns

    HIV-1 gp41 and TCRα Trans-Membrane Domains Share a Motif Exploited by the HIV Virus to Modulate T-Cell Proliferation

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    Viruses have evolved several strategies to modify cellular processes and evade the immune response in order to successfully infect, replicate, and persist in the host. By utilizing in-silico testing of a transmembrane sequence library derived from virus protein sequences, we have pin-pointed a nine amino-acid motif shared by a group of different viruses; this motif resembles the transmembrane domain of the α-subunit of the T-cell receptor (TCRα). The most striking similarity was found within the immunodeficiency virus (SIV and HIV) glycoprotein 41 TMD (gp41 TMD). Previous studies have shown that stable interactions between TCRα and CD3 are localized to this nine amino acid motif within TCRα, and a peptide derived from it (TCRα TMD, GLRILLLKV) interfered and intervened in the TCR function when added exogenously. We now report that the gp41 TMD peptide co-localizes with CD3 within the TCR complex and inhibits T cell proliferation in vitro. However, the inhibitory mechanism of gp41 TMD differs from that of the TCRα TMD and also from the other two known immunosuppressive regions within gp41

    What You See Is What You Get? Exclusion Performances in Ravens and Keas

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    BACKGROUND:Among birds, corvids and parrots are prime candidates for advanced cognitive abilities. Still, hardly anything is known about cognitive similarities and dissimilarities between them. Recently, exclusion has gained increasing interest in comparative cognition. To select the correct option in an exclusion task, one option has to be rejected (or excluded) and the correct option may be inferred, which raises the possibility that causal understanding is involved. However, little is yet known about its evolutionary history, as only few species, and mainly mammals, have been studied. METHODOLOGY/PRINCIPAL FINDINGS:We tested ravens and keas in a choice task requiring the search for food in two differently shaped tubes. We provided the birds with partial information about the content of one of the two tubes and asked whether they could use this information to infer the location of the hidden food and adjust their searching behaviour accordingly. Additionally, this setup allowed us to investigate whether the birds would appreciate the impact of the shape of the tubes on the visibility of food. The keas chose the baited tube more often than the ravens. However, the ravens applied the more efficient strategy, choosing by exclusion more frequently than the keas. An additional experiment confirmed this, indicating that ravens and keas either differ in their cognitive skills or that they apply them differently. CONCLUSION:To our knowledge, this is the first study to demonstrate that corvids and parrots may perform differently in cognitive tasks, highlighting the potential impact of different selection pressures on the cognitive evolution of these large-brained birds
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