281 research outputs found

    Lesions of the paraventricular nucleus of the thalamus differentially affect sign‐ and goal‐tracking conditioned responses

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    Recently, evidence has emerged suggesting a role for the paraventricular nucleus of the thalamus (PVT) in the processing of reward‐associated cues. However, the specific role of the PVT in these processes has yet to be elucidated. Here we use an animal model that captures individual variation in response to discrete reward‐associated cues to further assess the role of the PVT in stimulus–reward learning. When rats are exposed to a Pavlovian conditioning paradigm, wherein a discrete cue predicts food reward, two distinct conditioned responses emerge. Some rats, termed sign‐trackers, approach and manipulate the cue, whereas others, termed goal‐trackers, approach the location of reward delivery upon cue presentation. For both sign‐ and goal‐trackers the cue is a predictor, but only for sign‐trackers is it also an incentive stimulus. We investigated the role of the PVT in the acquisition and expression of these conditioned responses using an excitotoxic lesion. Results indicate that PVT lesions prior to acquisition amplify the differences between phenotypes – increasing sign‐tracking and attenuating goal‐tracking behavior. Lesions of the PVT after rats had acquired their respective conditioned responses also attenuated the expression of the goal‐tracking response, and increased the sign‐tracking response, but did so selectively in goal‐trackers. These results suggest that the PVT acts to suppress the attribution of incentive salience to reward cues, as disruption of the functional activity within this structure enhances the tendency to sign‐track.Here we utilized animal models that capture individual differences in the propensity to attribute incentive salience to reward cues (i.e. sign‐trackers vs. goal‐trackers) to further elucidate the role of the PVT in cue‐motivated behaviors. We report that lesions of this structure increase the tendency for individuals to attribute incentive motivational value to reward cues. These findings suggest that the PVT is a critical part of the circuitry underlying maladaptive behavior, such as addiction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/115973/1/ejn13031-sup-0001-TableS1-FigureS1-S5.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/115973/2/ejn13031.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/115973/3/ejn13031_am.pd

    PENINGKATAN KETERAMPILAN MENULIS TEKS EKSPOSISI MELALUI PENGGUNAAN STRATEGI PEMBELAJARAN THINK TALK WRITE DAN MEDIA AUDIO VISUAL ( Penelitian Tindakan Kelas pada Siswa Kelas X IPS 2 SMA N 1 Surakarta Tahun Pelajaran 2017/2018)

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    Yustina Dwinuryati.2017. Peningkatan Keterampilan menulis Teks Eksposisi melalui Penggunaan Strategi Pembelajaran Think, Talk, Write dan Media Audio Visual (Penelitian Tindakan Kelas pada Siswa Kelas X IPS 2 SMA N 1 Surakarta Tahun Pelajaran 2017/2018). Tesis. Pembimbing: Prof. Dr. Andayani, M.Pd. Kopembimbing: Prof. Dr. Retno Winarni, M.Pd. Program Studi Magister Pendidikan Bahasa Indonesia, Fakultas Keguruan dan Ilmu Pendidikan, Universitas Sebelas Maret Surakarta. ABSTRAK Keterampilan menulis merupakan keterampilan berbahasa tingkat tinggi dan harus diajarkan kepada siswa di Sekolah Menengah Atas. Salah satu keterampilan menulis yang harus diajarkan kepada siswa kelas X sesuai Kurikulum 2013 Revisi adalah menulis teks eksposisi. Pembelajaran keterampilan menulis teks eksposisi di kelas X IPS2 SMA N 1 Surakarta mengalami permasalahan baik dari sisi motivasi belajar maupun keterampilan menulis siswa. Penelitian ini bertujuan untuk meningkatkan: (1) motivasi belajar menulis teks eksposisi siswa kelas X IPS 2 SMA Negeri 1 Surakarta dengan strategi pembelajaran think talk write dan penggunaan media audio visual dan (2) keterampilan menulis teks eksposisi siswa kelas X IPS 2 SMA Negeri 1 Surakarta dengan strategi pembelajaran think talk write dan media audio visual. Strategi penelitian berupa Penelitian Tindakan Kelas. Data penelitian bersumber dari proses pembelajaran, informan, hasil tes menulis teks eksposisi, dan dokumen. Teknik pengumpulan data dengan pengamatan, kajian dokumen, wawancara, dan tes. Uji validitas data menggunakan teknik triangulasi sumber data dan triangulasi metode. Teknik analisis data menggunakan teknik deskriptif komparatif dan analisis kritis. Hasil penelitian menunjukkan bahwa penerapan strategi pembelajaran think, talk, write dan penggunaan media audio visual pada siswa kelas X IPS2 SMA N I Surakarta dapat meningkatkan motivasi belajar dan keterampilan menulis teks eksposisi dari siklus 1 ke siklus 2. Hal itu dibuktikan adanya perubahan dan peningkatan motivasi belajar dan keterampilan menulis teks eksposisi siswa: (1) motivasi siswa meningkat dari siklus 1 sebesar 68% menjadi 82% pada siklus 2 dan (2) keterampilan menulis teks eksposisi meningkat dari siklus 1 sebesar 76% meningkat menjadi 88% pada siklus 2. Kata kunci: teks eksposisi, motivasi, strategi think talk write, audio visua

    Genetic characterization of outbred Sprague Dawley rats and utility for genome-wide association studies

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    Sprague Dawley (SD) rats are among the most widely used outbred laboratory rat populations. Despite this, the genetic characteristics of SD rats have not been clearly described, and SD rats are rarely used for experiments aimed at exploring genotype-phenotype relationships. In order to use SD rats to perform a genome-wide association study (GWAS), we collected behavioral data from 4,625 SD rats that were predominantly obtained from two commercial vendors, Charles River Laboratories and Harlan Sprague Dawley Inc. Using double-digest genotyping-by-sequencing (ddGBS), we obtained dense, high-quality genotypes at 291,438 SNPs across 4,061 rats. This genetic data allowed us to characterize the variation present in Charles River vs. Harlan SD rats. We found that the two populations are highly diverged (FST > 0.4). Furthermore, even for rats obtained from the same vendor, there was strong population structure across breeding facilities and even between rooms at the same facility. We performed multiple separate GWAS by fitting a linear mixed model that accounted for population structure and using meta-analysis to jointly analyze all cohorts. Our study examined Pavlovian conditioned approach (PavCA) behavior, which assesses the propensity for rats to attribute incentive salience to reward-associated cues. We identified 46 significant associations for the various metrics used to define PavCA. The surprising degree of population structure among SD rats from different sources has important implications for their use in both genetic and non-genetic studies

    Hepatitis B virus infected physicians and disclosure of transmission risks to patients: A critical analysis

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    BACKGROUND: The potential for transmission of blood-borne pathogens such as hepatitis B virus from infected healthcare workers to patients is an important and difficult issue facing healthcare policymakers internationally. Law and policy on the subject is still in its infancy, and subject to a great degree of uncertainty and controversy. Policymakers have made few recommendations regarding the specifics of practice restriction for health care workers who are hepatitis B seropositive. Generally, they have deferred this work to vaguely defined "expert panels" which will have the power to dictate the conditions under which infected health care workers may continue to practice. DISCUSSION: In this paper we use recent Canadian policy statements as a critical departure point to propose more specific recommendations regarding disclosure of transmission risks in a way that minimizes practice restriction of hepatitis B seropositive health care workers without compromising patient safety. The range of arguments proposed in the literature are critically examined from the perspective of ethical analysis. SUMMARY: A process for considering the ethical implications of the disclosure of the sero-status of health care workers is advanced that considers the varied perspectives of different stakeholders

    High locomotor reactivity to novelty is associated with an increased propensity to choose saccharin over cocaine: new insights into the vulnerability to addiction.

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    Drug addiction is associated with a relative devaluation of natural or socially-valued reinforcers that are unable to divert addicts from seeking and consuming the drug. Before protracted drug exposure, most rats prefer natural rewards, such as saccharin, over cocaine. However, a subpopulation of animals prefer cocaine over natural rewards and are thought to be vulnerable to addiction. Specific behavioral traits have been associated with different dimensions of drug addiction. For example, anxiety predicts loss of control over drug intake whereas sensation seeking and sign-tracking are markers of a greater sensitivity to the rewarding properties of the drug. However, how these behavioral traits predict the disinterest for natural reinforcers remains unknown. In a population of rats, we identified sensation seekers (HR) on the basis of elevated novelty-induced locomotor reactivity, high anxious rats (HA) based on the propensity to avoid open arms in an elevated-plus maze and sign-trackers (ST) that are prone to approach, and interaction with, reward-associated stimuli. Rats were then tested on their preference for saccharin over cocaine in a discrete-trial choice procedure. We show that HR rats display a greater preference for saccharin over cocaine compared with ST and HA whereas the motivation for the drug was comparable between the three groups. The present data suggest that high locomotor reactivity to novelty, or sensation seeking, by predisposing to an increased choice toward non-drug rewards at early stages of drug use history, may prevent the establishment of chronic cocaine use.This work was funded by an INSERM AVENIR and Agence Nationale de la Recherche (ANR) ANR12 SAMA00201 grant to DB, the rĂ©gion Poitou-Charentes, an AXA research fund fellowship to ABR, and a MinistĂšre de la Recherche et de la Technologie grant to NV. AM was supported by the Behavioural and Clinical Neuroscience Institute of Cambridge.This is the accepted manuscript of a paper published in Neuropsychopharmacology (2015) 40, 577–589; doi:10.1038/npp.2014.204; published online 17 September 2014

    Variance component estimates, phenotypic characterization, and genetic evaluation of bovine congestive heart failure in commercial feeder cattle

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    The increasing incidence of bovine congestive heart failure (BCHF) in feedlot cattle poses a significant challenge to the beef industry from economic loss, reduced performance, and reduced animal welfare attributed to cardiac insufficiency. Changes to cardiac morphology as well as abnormal pulmonary arterial pressure (PAP) in cattle of mostly Angus ancestry have been recently characterized. However, congestive heart failure affecting cattle late in the feeding period has been an increasing problem and tools are needed for the industry to address the rate of mortality in the feedlot for multiple breeds. At harvest, a population of 32,763 commercial fed cattle were phenotyped for cardiac morphology with associated production data collected from feedlot processing to harvest at a single feedlot and packing plant in the Pacific Northwest. A sub-population of 5,001 individuals were selected for low-pass genotyping to estimate variance components and genetic correlations between heart score and the production traits observed during the feeding period. At harvest, the incidence of a heart score of 4 or 5 in this population was approximately 4.14%, indicating a significant proportion of feeder cattle are at risk of cardiac mortality before harvest. Heart scores were also significantly and positively correlated with the percentage Angus ancestry observed by genomic breed percentage analysis. The heritability of heart score measured as a binary (scores 1 and 2 = 0, scores 4 and 5 = 1) trait was 0.356 in this population, which indicates development of a selection tool to reduce the risk of congestive heart failure as an EPD (expected progeny difference) is feasible. Genetic correlations of heart score with growth traits and feed intake were moderate and positive (0.289–0.460). Genetic correlations between heart score and backfat and marbling score were −0.120 and −0.108, respectively. Significant genetic correlation to traits of high economic importance in existing selection indexes explain the increased rate of congestive heart failure observed over time. These results indicate potential to implement heart score observed at harvest as a phenotype under selection in genetic evaluation in order to reduce feedlot mortality due to cardiac insufficiency and improve overall cardiopulmonary health in feeder cattle

    Discovery and population genomics of structural variation in a songbird genus

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    Structural variation (SV) constitutes an important type of genetic mutations providing the raw material for evolution. Here, we uncover the genome-wide spectrum of intra- and interspecific SV segregating in natural populations of seven songbird species in the genus Corvus. Combining short-read (N = 127) and long-read re-sequencing (N = 31), as well as optical mapping (N = 16), we apply both assembly- and read mapping approaches to detect SV and characterize a total of 220,452 insertions, deletions and inversions. We exploit sampling across wide phylogenetic timescales to validate SV genotypes and assess the contribution of SV to evolutionary processes in an avian model of incipient speciation. We reveal an evolutionary young (~530,000 years) cis-acting 2.25-kb LTR retrotransposon insertion reducing expression of the NDP gene with consequences for premating isolation. Our results attest to the wealth and evolutionary significance of SV segregating in natural populations and highlight the need for reliable SV genotyping

    Genetic dissection of fruit quality traits in the octoploid cultivated strawberry highlights the role of homoeo-QTL in their control

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    Fruit quality traits are major breeding targets in the Rosaceae. Several of the major Rosaceae species are current or ancient polyploids. To dissect the inheritance of fruit quality traits in polyploid fleshy fruit species, we used a cultivated strawberry segregating population comprising a 213 full-sibling F1 progeny from a cross between the variety ‘Capitola’ and the genotype ‘CF1116’. We previously developed the most comprehensive strawberry linkage map, which displays seven homoeology groups (HG), including each four homoeology linkage groups (Genetics 179:2045–2060, 2008). The map was used to identify quantitative trait loci (QTL) for 19 fruit traits related to fruit development, texture, colour, anthocyanin, sugar and organic acid contents. Analyses were carried out over two or three successive years on field-grown plants. QTL were detected for all the analysed traits. Because strawberry is an octopolyploid species, QTL controlling a given trait and located at orthologous positions on different homoeologous linkage groups within one HG are considered as homoeo-QTL. We found that, for various traits, about one-fourth of QTL were putative homoeo-QTL and were localised on two linkage groups. Several homoeo-QTL could be detected the same year, suggesting that several copies of the gene underlying the QTL are functional. The detection of some other homoeo-QTL was year-dependent. Therefore, changes in allelic expression could take place in response to environmental changes. We believe that, in strawberry as in other polyploid fruit species, the mechanisms unravelled in the present study may play a crucial role in the variations of fruit quality
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