872 research outputs found

    Anchoring effects in the development of false childhood memories

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    When people receive descriptions or doctored photos of events that never happened, they often come to remember those events. But if people receive both a description and a doctored photo, does the order in which they receive the information matter? We asked people to consider a description and a doctored photograph of a childhood hot air balloon ride, and we varied which medium they saw first. People who saw a description first reported more false images and memories than people who saw a photo first, a result that fits with an anchoring account of false childhood memories

    Salt Bridges and Gating in the COOH-terminal Region of HCN2 and CNGA1 Channels

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    Hyperpolarization-activated cyclic nucleotide-modulated (HCN) channels and cyclic nucleotide-gated (CNG) channels are activated by the direct binding of cyclic nucleotides. The intracellular COOH-terminal regions exhibit high sequence similarity in all HCN and CNG channels. This region contains the cyclic nucleotide-binding domain (CNBD) and the C-linker region, which connects the CNBD to the pore. Recently, the structure of the HCN2 COOH-terminal region was solved and shown to contain intersubunit interactions between C-linker regions. To explore the role of these intersubunit interactions in intact channels, we studied two salt bridges in the C-linker region: an intersubunit interaction between C-linkers of neighboring subunits, and an intrasubunit interaction between the C-linker and its CNBD. We show that breaking these salt bridges in both HCN2 and CNGA1 channels through mutation causes an increase in the favorability of channel opening. The wild-type behavior of both HCN2 and CNGA1 channels is rescued by switching the position of the positive and negative residues, thus restoring the salt bridges. These results suggest that the salt bridges seen in the HCN2 COOH-terminal crystal structure are also present in the intact HCN2 channel. Furthermore, the similar effects of the mutations on HCN2 and CNGA1 channels suggest that these salt bridge interactions are also present in the intact CNGA1 channel. As disrupting the interactions leads to channels with more favorable opening transitions, the salt bridges appear to stabilize a closed conformation in both the HCN2 and CNGA1 channels. These results suggest that the HCN2 COOH-terminal crystal structure contains the C-linker regions in the resting configuration even though the CNBD is ligand bound, and channel opening involves a rearrangement of the C-linkers and, thus, disruption of the salt bridges. Discovering that one portion of the COOH terminus, the CNBD, can be in the activated configuration while the other portion, the C-linker, is not activated has lead us to suggest a novel modular gating scheme for HCN and CNG channels

    The bullying of autistic children: A review of anti-bullying interventions, and a feasibility study examining the relationship between bullying victimisation and psychosis-like experiences.

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    Bullying of autistic children by their peers is prevalent. This is a significant concern given research linking childhood bullying with adverse mental health outcomes, in both autistic and neurotypical groups. The first section of this thesis is a scoping review, which aimed to establish what interventions have been developed to reduce the bullying of autistic children. The second section reports an investigation of the feasibility of examining the relationship between bullying victimisation and psychosis-like experiences (PLEs) in autistic children. Following a systematic literature search 10 studies were identified for inclusion in the scoping review. Broadly, interventions focussed either upon skills-development for autistic children, or the promotion of contact between autistic children and neurotypical peers. There was heterogeneity in the research designs used and outcome measures employed. Overall, the evidence base is in its infancy and there is a need to develop and evaluate multicomponent interventions involving autistic children, neurotypical peers, staff and schools. A quantitative cross-sectional design was used to investigate the feasibility of testing the relationship between bullying victimisation and PLEs in autistic children, and to test the preliminary hypothesis of association between these variables. Parents completed a battery of online questionnaires about their children (N=53). Hierarchical multiple regression was used to test the relationship between the variables of interest, while controlling for: age, sex, family history of psychosis and internalising difficulties. It was found that there is a lack of suitable questionnaires for measuring PLEs in autistic children, and that recruiting a large sample via a clinical service may not be feasible. Preliminary hypothesis testing failed to establish a statistically significant relationship between bullying victimisation and PLEs in autistic children. However, this should not preclude future work in this area

    Near to One's Heart: The Intimate Relationship Between the Placenta and Fetal Heart.

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    The development of the fetal heart is exquisitely controlled by a multitude of factors, ranging from humoral to mechanical forces. The gatekeeper regulating many of these factors is the placenta, an external fetal organ. As such, resistance within the placental vascular bed has a direct influence on the fetal circulation and therefore, the developing heart. In addition, the placenta serves as the interface between the mother and fetus, controlling substrate exchange and release of hormones into both circulations. The intricate relationship between the placenta and fetal heart is appreciated in instances of clinical placental pathology. Abnormal umbilical cord insertion is associated with congenital heart defects. Likewise, twin-to-twin transfusion syndrome, where monochorionic twins have unequal sharing of their placenta due to inter-twin vascular anastomoses, can result in cardiac remodeling and dysfunction in both fetuses. Moreover, epidemiological studies have suggested a link between placental phenotypic traits and increased risk of cardiovascular disease in adult life. To date, the mechanistic basis of the relationships between the placenta, fetal heart development and later risk of cardiac dysfunction have not been fully elucidated. However, studies using environmental exposures and gene manipulations in experimental animals are providing insights into the pathways involved. Likewise, surgical instrumentation of the maternal and fetal circulations in large animal species has enabled the manipulation of specific humoral and mechanical factors to investigate their roles in fetal cardiac development. This review will focus on such studies and what is known to date about the link between the placenta and heart development

    Take the Monkey and Run

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    The common marmoset (Callithrix jacchus) is a small, New World primate that is used extensively in biomedical and behavioral research. This short-lived primate, with its small body size, ease of handling, and docile temperament, has emerged as a valuable model for aging and neurodegenerative research. A growing body of research has indicated exercise, aerobic exercise especially, imparts beneficial effects to normal aging. Understanding the mechanisms underlying these positive effects of exercise, and the degree to which exercise has neurotherapeutic effects, is an important research focus. Thus, developing techniques to engage marmosets in aerobic exercise would have great advantages

    Quantification of Hair Cortisol Concentration in Common Marmosets (\u3cem\u3eCallithrix jacchus\u3c/em\u3e) and Tufted Capuchins (\u3cem\u3eCebus apella\u3c/em\u3e)

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    Quantifying cortisol concentration in hair is a non-invasive biomarker of long-term hypothalamic-pituitary-adrenal (HPA) activation, and thus can provide important information on laboratory animal health. Marmosets (Callithrix jacchus) and capuchins (Cebus apella) are New World primates increasingly used in biomedical and neuroscience research, yet published hair cortisol concentrations for these species are limited. Review of the existing published hair cortisol values from marmosets reveals highly discrepant values and the use of variable techniques for hair collection, processing, and cortisol extraction. In this investigation we utilized a well-established, standardized protocol to extract and quantify cortisol from marmoset (n = 12) and capuchin (n = 4) hair. Shaved hair samples were collected from the upper thigh during scheduled exams and analyzed via methanol extraction and enzyme immunoassay. In marmosets, hair cortisol concentration ranged from 2710 – 6267 pg/mg and averaged 4070 ± 304 pg/mg. In capuchins, hair cortisol concentration ranged from 621 – 2089 pg/mg and averaged 1092 ± 338 pg/mg. Hair cortisol concentration was significantly different between marmosets and capuchins, with marmosets having higher concentrations than capuchins. The incorporation of hair cortisol analysis into research protocols provides a non-invasive measure of HPA axis activity over time, which offers insight into animal health. Utilization of standard protocols across laboratories is essential to obtaining valid measurements and allowing for valuable future cross-species comparisons

    Evolution of the Cerebellar Cortex: The Selective Expansion of Prefrontal-Projecting Cerebellar Lobules

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    It has been suggested that interconnected brain areas evolve in tandem because evolutionary pressures act on complete functional systems rather than on individual brain areas. The cerebellar cortex has reciprocal connections with both the prefrontal cortex and motor cortex, forming independent loops with each. Specifically, in capuchin monkeys cerebellar cortical lobules Crus I and Crus II connect with prefrontal cortex, whereas the primary motor cortex connects with cerebellar lobules V, VI, VIIb, and VIIIa. Comparisons of extant primate species suggest that the prefrontal cortex has expanded more than cortical motor areas in human evolution. Given the enlargement of the prefrontal cortex relative to motor cortex in humans, our hypothesis would predict corresponding volumetric increases in the parts of the cerebellum connected to the prefrontal cortex, relative to cerebellar lobules connected to the motor cortex. We tested the hypothesis by comparing the volumes of cerebellar lobules in structural MRI scans in capuchins, chimpanzees and humans. The fractions of cerebellar volume occupied by Crus I and Crus II were significantly larger in humans compared to chimpanzees and capuchins. Our results therefore support the hypothesis that in the cortico-cerebellar system, functionally related structures evolve in concert with each other. The evolutionary expansion of these prefrontal-projecting cerebellar territories might contribute to the evolution of the higher cognitive functions of humans

    Age-Related Changes in Myelin of Axons of the Corpus Callosum and Cognitive Decline in Common Marmosets

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    Executive control is a higher‐level cognitive function that involves a range of different processes that are involved in the planning, coordination, execution, and inhibition of responses. Many of the processes associated with executive control, such as response inhibition and mental flexibility, decline with age. Degeneration of white matter architecture is considered to be the one of the key factors underlying cognitive decline associated with aging. Here we investigated how white matter changes of the corpus callosum were related to cognitive aging in common marmosets (Callithrix jacchus). We hypothesized that reduction in myelin thickness, myelin density, and myelin fraction of axonal fibers in the corpus callosum would be associated with performance on a task of executive function in a small sample of geriatric marmosets (n = 4) and young adult marmosets (n = 2). Our results indicated declines in myelin thickness, density, and myelin fraction with age. Considerable variability was detected on these characteristics of myelin and cognitive performance assessed via the detoured reach task. Age‐related changes in myelin in Region II of the corpus callosum were predictive of cognitive performance on the detoured reach task. Thus the detoured reach task appears to also measure aspects of corticostriatal function in addition to prefrontal cortical function

    The State of Capacity Development Evaluation in Biodiversity Conservation and Natural Resource Management

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    Capacity development is critical to long-term conservation success, yet we lack a robust and rigorous understanding of how well its effects are being evaluated. A comprehensive summary of who is monitoring and evaluating capacity development interventions, what is being evaluated and how, would help in the development of evidence-based guidance to inform design and implementation decisions for future capacity development interventions and evaluations of their effectiveness. We built an evidence map by reviewing peer-reviewed and grey literature published since 2000, to identify case studies evaluating capacity development interventions in biodiversity conservation and natural resource management. We used inductive and deductive approaches to develop a coding strategy for studies that met our criteria, extracting data on the type of capacity development intervention, evaluation methods, data and analysis types, categories of outputs and outcomes assessed, and whether the study had a clear causal model and/or used a systems approach. We found that almost all studies assessed multiple outcome types: most frequent was change in knowledge, followed by behaviour, then attitude. Few studies evaluated conservation outcomes. Less than half included an explicit causal model linking interventions to expected outcomes. Half of the studies considered external factors that could influence the efficacy of the capacity development intervention, and few used an explicit systems approach. We used framework synthesis to situate our evidence map within the broader literature on capacity development evaluation. Our evidence map (including a visual heat map) highlights areas of low and high representation in investment in research on the evaluation of capacity development
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