393 research outputs found

    The hand of Homo naledi

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    A nearly complete right hand of an adult hominin was recovered from the Rising Star cave system, South Africa. Based on associated hominin material, the bones of this hand are attributed to Homo naledi. This hand reveals a long, robust thumb and derived wrist morphology that is shared with Neandertals and modern humans, and considered adaptive for intensified manual manipulation. However, the finger bones are longer and more curved than in most australopiths, indicating frequent use of the hand during life for strong grasping during locomotor climbing and suspension. These markedly curved digits in combination with an otherwise human-like wrist and palm indicate a significant degree of climbing, despite the derived nature of many aspects of the hand and other regions of the postcranial skeleton in H. naledi

    Localized microstimulation of primate pregenual cingulate cortex induces negative decision-making

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    The pregenual anterior cingulate cortex (pACC) has been implicated in human anxiety disorders and depression, but the circuit-level mechanisms underlying these disorders are unclear. In healthy individuals, the pACC is involved in cost-benefit evaluation. We developed a macaque version of an approach-avoidance decision task used to evaluate anxiety and depression in humans and, with multi-electrode recording and cortical microstimulation, we probed pACC function as monkeys performed this task. We found that the macaque pACC has an opponent process-like organization of neurons representing motivationally positive and negative subjective value. Spatial distribution of these two neuronal populations overlapped in the pACC, except in one subzone, where neurons with negative coding were more numerous. Notably, microstimulation in this subzone, but not elsewhere in the pACC, increased negative decision-making, and this negative biasing was blocked by anti-anxiety drug treatment. This cortical zone could be critical for regulating negative emotional valence and anxiety in decision-making.National Institutes of Health (U.S.) (Javits Merit Grant R01 NS025529)United States. Office of Naval Research (N000140710903)National Parkinson Foundation (U.S.) (Lynn Diamond Fellowship

    Dual coding with STDP in a spiking recurrent neural network model of the hippocampus.

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    The firing rate of single neurons in the mammalian hippocampus has been demonstrated to encode for a range of spatial and non-spatial stimuli. It has also been demonstrated that phase of firing, with respect to the theta oscillation that dominates the hippocampal EEG during stereotype learning behaviour, correlates with an animal's spatial location. These findings have led to the hypothesis that the hippocampus operates using a dual (rate and temporal) coding system. To investigate the phenomenon of dual coding in the hippocampus, we examine a spiking recurrent network model with theta coded neural dynamics and an STDP rule that mediates rate-coded Hebbian learning when pre- and post-synaptic firing is stochastic. We demonstrate that this plasticity rule can generate both symmetric and asymmetric connections between neurons that fire at concurrent or successive theta phase, respectively, and subsequently produce both pattern completion and sequence prediction from partial cues. This unifies previously disparate auto- and hetero-associative network models of hippocampal function and provides them with a firmer basis in modern neurobiology. Furthermore, the encoding and reactivation of activity in mutually exciting Hebbian cell assemblies demonstrated here is believed to represent a fundamental mechanism of cognitive processing in the brain

    Inclusive education for Internally Displaced Children in Kenya::Children perceptions of their learning and development needs in post-conflict schooling

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    Abstract The Kenyan society has been characterised by tribal-political-instigated violence since the declaration of multiparty democracy in 1991. The 2007/8 post-election violence (PEV) particularly saw the scattering of families where some children lost months or years of schooling; others were permanently excluded from education, while the participation and achievement of those arriving in school were characterised by complex needs and experiences. This paper aims to analyse literature and report on findings from creative activities with 16 conflict-affected children (9–12 years) regarding their experiences and understandings of inclusive education during their post-conflict school-life. I conducted an intrinsic case study with aspects of ethnography in a post-conflict community primary school in Kenya whose majority (71%) pupil population was attributed to internal displacement following the 2007/8 PEV. Children perceived inclusive education in regard to their own learning and development needs as involving access and acceptance in the new school community, social-emotional development, ‘peer-keeping’ and community-consciousness. Whilst valuing their teachers’ pursuit for inclusion-sensitive practices, children’s understanding of their own circumstances resulted in group-made strategies like ‘peer-keeping’ and peer-constructed rules of interaction, helping them negotiate systemic constrains and distortion of values. This study underscores the fundamental role of children in social integration in post-conflict circumstances

    Molecular psychiatry of zebrafish

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    Due to their well-characterized neural development and high genetic homology to mammals, zebrafish (Danio rerio) have emerged as a powerful model organism in the field of biological psychiatry. Here, we discuss the molecular psychiatry of zebrafish, and its implications for translational neuroscience research and modeling central nervous system (CNS) disorders. In particular, we outline recent genetic and technological developments allowing for in vivo examinations, high-throughput screening and whole-brain analyses in larval and adult zebrafish. We also summarize the application of these molecular techniques to the understanding of neuropsychiatric disease, outlining the potential of zebrafish for modeling complex brain disorders, including attention-deficit/hyperactivity disorder (ADHD), aggression, post-traumatic stress and substance abuse. Critically evaluating the advantages and limitations of larval and adult fish tests, we suggest that zebrafish models become a rapidly emerging new field in modern molecular psychiatry research

    Violence and vulnerability:Children’s strategies and the logic of violence in Burundi

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    This study explores how children in conflict-affected Burundi deal with violence in their everyday lives. Focusing on schools as a context in which children are prepared for further roles in society, child-centred, qualitative and mixed-methods research was conducted at 36 primary schools throughout Burundi. Findings reveal that children use a variety of strategies to deal with violence they encounter. These strategies reflect a learned 'logic of violence', matching dynamics of violence and vulnerability in society at large. Children's strategies are ultimately aimed at reducing vulnerability to (future) violence and indicative of the omnipresence of violence and uncertainty in Burundi. (C) 2019 The Authors. Children & Society published by National Children's Bureau and John Wiley & Sons LtdPublic Health and primary car

    Processing of inconsistent emotional information: an fMRI study

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    Previous studies investigating the anterior cingulate cortex (ACC) have relied on a number of tasks which involved cognitive control and attentional demands. In this fMRI study, we tested the model that ACC functions as an attentional network in the processing of language. We employed a paradigm that requires the processing of concurrent linguistic information predicting that the cognitive costs imposed by competing trials would engender the activation of ACC. Subjects were confronted with sentences where the semantic content conflicted with the prosodic intonation (CONF condition) randomly interspaced with sentences which conveyed coherent discourse components (NOCONF condition). We observed the activation of the rostral ACC and the middle frontal gyrus when the NOCONF condition was subtracted from the CONF condition. Our findings provide evidence for the involvement of the rostral ACC in the processing of complex competing linguistic stimuli, supporting theories that claim its relevance as a part of the cortical attentional circuit. The processing of emotional prosody involved a bilateral network encompassing the superior and medial temporal cortices. This evidence confirms previous research investigating the neuronal network that supports the processing of emotional information

    Decreased morbidity following long saphenous vein harvesting using a minimally invasive technique: a randomised controlled trial comparing two techniques for long saphenous vein harvest

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    OBJECTIVES: The objective of this study was to compare the morbidity associated with long saphenous vein harvesting using the traditional open technique (A) against a minimally invasive technique using the Mayo vein stripper (B) that involves multiple short incisions. DESIGN: We conducted a prospective randomized controlled study in 80 patients undergoing first time coronary artery bypass grafting. Pain and healing was assessed on each postoperative day. Rings of long saphenous vein were subjected to organ-bath evaluation of endothelium-dependent and endothelium-independent relaxation. RESULTS: Three patients were excluded from the study, leaving 38 patients in Group A and 39 in Group B. With respect to operative procedure, Group A had a greater length of vein harvested than Group B. There was no statistical difference in pain scores and endothelium-dependent or endothelium-independent relaxation between the two groups. However there were significantly more infections in Group A compared with Group B. CONCLUSION: Harvesting vein through multiple incisions using the Mayo vein stripper is quicker, results in fewer infections and has no deleterious effect on endothelial function compared to open technique
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