Neurobiological studies of risk assessment: A comparison of expected utility and mean-variance approaches

When modeling valuation under uncertainty, economists generally prefer expected utility because it has an axiomatic foundation, meaning that the resulting choices will satisfy a number of rationality requirements. In expected utility theory, values are computed by multiplying probabilities of each possible state of nature by the payoff in that state and summing the results. The drawback of this approach is that all state probabilities need to be dealt with separately, which becomes extremely cumbersome when it comes to learning. Finance academics and professionals, however, prefer to value risky prospects in terms of a trade-off between expected reward and risk, where the latter is usually measured in terms of reward variance. This mean-variance approach is fast and simple and greatly facilitates learning, but it impedes assigning values to new gambles on the basis of those of known ones. To date, it is unclear whether the human brain computes values in accordance with expected utility theory or with mean-variance analysis. In this article, we discuss the theoretical and empirical arguments that favor one or the other theory. We also propose a new experimental paradigm that could determine whether the human brain follows the expected utility or the mean-variance approach. Behavioral results of implementation of the paradigm are discussed

Neurobiological studies of risk assessment: A comparison of expected utility and mean-variance approaches

When modeling valuation under uncertainty, economists generally prefer expected utility because it has an axiomatic foundation, meaning that the resulting choices will satisfy a number of rationality requirements. In expected utility theory, values are computed by multiplying probabilities of each possible state of nature by the payoff in that state and summing the results. The drawback of this approach is that all state probabilities need to be dealt with separately, which becomes extremely cumbersome when it comes to learning. Finance academics and professionals, however, prefer to value risky prospects in terms of a trade-off between expected reward and risk, where the latter is usually measured in terms of reward variance. This mean-variance approach is fast and simple and greatly facilitates learning, but it impedes assigning values to new gambles on the basis of those of known ones. To date, it is unclear whether the human brain computes values in accordance with expected utility theory or with mean-variance analysis. In this article, we discuss the theoretical and empirical arguments that favor one or the other theory. We also propose a new experimental paradigm that could determine whether the human brain follows the expected utility or the mean-variance approach. Behavioral results of implementation of the paradigm are discusse

Adolescent Impulsivity: Findings From a Community Sample

Impulsivity is central to several psychopathological states in adolescence. However, there is little consensus concerning the definition of impulsivity and its core dimensions. In response to this lack of consensus, Whiteside and Lynam (2001, Pers. Individ. Differ. 30, 669-689) have developed the UPPS Impulsive Behavior Scale, which is able to distinguish 4 dimensions of impulsivity in adults: Urgency, lack of Premeditation, lack of Perseverance, and Sensation seeking. The question arises of whether these 4 dimensions also exist in adolescents and also of whether gender differences can be observed. A sample of teenagers (314 girls and 314 boys) completed a French version of the scale (Van der Linden et al., Eur. J. Psychol. Assess., 2005). Based on exploratory and confirmatory analyses, the 4-factor model is replicated in girls, boys, and the whole sample. Concerning gender differences, girls have a higher score for Urgency and boys a higher score for Sensation seeking. Overall, this study suggests that the UPPS is a promising tool for studying impulsivity in adolescenc

Neural Mechanisms Behind Identification of Leptokurtic Noise and Adaptive Behavioral Response

Large-scale human interaction through, for example, financial markets causes ceaseless random changes in outcome variability, producing frequent and salient outliers that render the outcome distribution more peaked than the Gaussian distribution, and with longer tails. Here, we study how humans cope with this evolutionary novel leptokurtic noise, focusing on the neurobiological mechanisms that allow the brain, 1) to recognize the outliers as noise and 2) to regulate the control necessary for adaptive response. We used functional magnetic resonance imaging, while participants tracked a target whose movements were affected by leptokurtic noise. After initial overreaction and insufficient subsequent correction, participants improved performance significantly. Yet, persistently long reaction times pointed to continued need for vigilance and control. We ran a contrasting treatment where outliers reflected permanent moves of the target, as in traditional mean-shift paradigms. Importantly, outliers were equally frequent and salient. There, control was superior and reaction time was faster. We present a novel reinforcement learning model that fits observed choices better than the Bayes-optimal model. Only anterior insula discriminated between the 2 types of outliers. In both treatments, outliers initially activated an extensive bottom-up attention and belief network, followed by sustained engagement of the fronto-parietal control network

Memory for Angry Faces, Impulsivity, and Problematic Behavior in Adolescence

Research has shown that cognitive processes like the attribution of hostile intention or angry emotion to others contribute to the development and maintenance of conduct problems. However, the role of memory has been understudied in comparison with attribution biases. The aim of this study was thus to test if a memory bias for angry faces was related to conduct problems in youth. Adolescents from a junior secondary school were presented with angry and happy faces and were later asked to recognize the same faces with a neutral expression. They also completed an impulsivity questionnaire. A teacher assessed their behavior. The results showed that a better recognition of angry faces than happy faces predicted conduct problems and hyperactivity/inattention as reported by the teacher. The memory bias effect was more pronounced for impulsive adolescents. It is suggested that a memory bias for angry faces favors disruptive behavior but that a good ability to control impulses may moderate the negative impact of this bia

www.fevertravel.ch: an online study prototype to evaluate the safety and feasibility of computerized guidelines for fever in returning travellers and migrants

Following the paper publication of practice guidelines for the management of febrile patients returning from the tropics, we constructed a consultation website that comprises a decision chart and specific diagnostic features providing medical diagnostic assistance to primary care physicians. We then integrated a research component to evaluate the implementation of these computerized guidelines. This study website has the same interface as the consultation website. In addition, one is able to record: (i) the pathway followed by the physician through the decision chart, (ii) the diagnostic tests performed, (iii) the initial and final diagnoses as well as outcome and (iv) reasons for non-adherence when the physician diverges from the proposed attitude. We believe that Internet technology is a powerful medium to reach physicians of different horizons in their own environment, and could prove to be an effective research tool to disseminate practice guidelines and evaluate their appropriateness. Here we describe the design, content, architecture and system implementation of this interactive study prototype aimed at integrating operational research in primary care practice. [Authors]]]> Emigration and Immigration; Fever; Guidelines as Topic; Internet; Travel eng oai:serval.unil.ch:BIB_4BBC99034368 2022-05-07T01:17:24Z ehelvetica openaire documents phdthesis urnserval <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_4BBC99034368 Usage conditionnel et inconditionnel des droits humains dans la vie quotidienne Anex, Emmanuelle Université de Lausanne, Faculté des sciences sociales et politiques info:eu-repo/semantics/doctoralThesis phdthesis 2018 fre https://serval.unil.ch/resource/serval:BIB_4BBC99034368.P001/REF.pdf http://nbn-resolving.org/urn/resolver.pl?urn=urn:nbn:ch:serval-BIB_4BBC990343683 info:eu-repo/semantics/altIdentifier/urn/urn:nbn:ch:serval-BIB_4BBC990343683 info:eu-repo/semantics/openAccess Copying allowed only for non-profit organizations https://serval.unil.ch/disclaimer application/pdf oai:serval.unil.ch:BIB_4BA5F44A285D 2022-05-07T01:17:24Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_4BA5F44A285D A double-blind, placebo-controlled study of citalopram with and without lithium in the treatment of therapy-resistant depressive patients: a clinical, pharmacokinetic, and pharmacogenetic investigation Baumann, Pierre Nil, Rico Souche, Alain Montaldi, Stefano Baettig, Dominique Lambert, Susanne Uehlinger, Claude Kasas, Anton Amey, Marlyse Jonzier-Perey, Michèle info:eu-repo/semantics/article article 1996 Journal of Clinical Psychopharmacology, vol. 16, pp. 307-314 one$; TBOK eng oai:serval.unil.ch:BIB_4BA60F08CDFC 2022-05-07T01:17:24Z <oai_dc:dc xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:oai_dc="http://www.openarchives.org/OAI/2.0/oai_dc/" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/oai_dc/ http://www.openarchives.org/OAI/2.0/oai_dc.xsd"> https://serval.unil.ch/notice/serval:BIB_4BA60F08CDFC Busulfan Pharmacokinetics in Adenosine Deaminase-Deficient Severe Combined Immunodeficiency Gene Therapy. info:doi:10.1016/j.bbmt.2020.07.004 info:eu-repo/semantics/altIdentifier/doi/10.1016/j.bbmt.2020.07.004 info:eu-repo/semantics/altIdentifier/pmid/32653625 Bradford, K.L. Liu, S. Krajinovic, M. Ansari, M. Garabedian, E. Tse, J. Wang, X. Shaw, K.L. Gaspar, H.B. Candotti, F. Kohn, D.B. info:eu-repo/semantics/article article 2020-10 Biology of blood and marrow transplantation, vol. 26, no. 10, pp. 1819-1827 info:eu-repo/semantics/altIdentifier/eissn/1523-6536 urn:issn:1083-8791 <![CDATA[The pharmacokinetics of low-dose busulfan (BU) were investigated as a nonmyeloablative conditioning regimen for autologous gene therapy (GT) in pediatric subjects with adenosine deaminase-deficient severe combined immunodeficiency disease (ADA SCID). In 3 successive clinical trials, which included either γ-retroviral (γ-RV) or lentiviral (LV) vectors, subjects were conditioned with BU using different dosing nomograms. The first cohort received BU doses based on body surface area (BSA), the second cohort received doses based on actual body weight (ABW), and in the third cohort, therapeutic drug monitoring (TDM) was used to target a specific area under the concentration-time curve (AUC). Neither BSA-based nor ABW-based dosing achieved a consistent cumulative BU AUC; in contrast, TDM-based dosing led to more consistent AUC. BU clearance increased as subject age increased from birth to 18 months. However, weight and age alone were insufficient to accurately predict the dose that would consistently achieve a target AUC. Furthermore, various clinical, laboratory, and genetic factors (eg, genotypes for glutathione-S-transferase isozymes known to participate in BU metabolism) were analyzed, but no single finding predicted subjects with rapid versus slow clearance. Analysis of BU AUC and the postengraftment vector copy number (VCN) in granulocytes, a surrogate marker of the level of engrafted gene-modified hematopoietic stem and progenitor cells (HSPCs), demonstrated gene marking at levels sufficient for therapeutic benefit in the subjects who had achieved the target BU AUC. Although many factors determine the ultimate engraftment following GT, this work demonstrates that the BU AUC correlated with the eventual level of engrafted gene-modified HSPCs within a vector group (γ-RV versus LV), with significantly higher levels of granulocyte VCN in the recipients of LV-modified grafts compared to recipients of γ-RV-transduced grafts. Taken together, these findings provide insight into low-dose BU pharmacokinetics in the unique setting of autologous GT for ADA SCID, and these dosing principles may be applied to future GT trials using low-dose BU to open the bone marrow niche

Feasibility and clinical outcomes when using practice guidelines for evaluation of fever in returning travelers and migrants : a validation study.

BACKGROUND: Practice guidelines for examining febrile patients presenting upon returning from the tropics were developed to assist primary care physicians in decision making. Because of the low level of evidence available in this field, there was a need to validate them and assess their feasibility in the context they have been designed for. OBJECTIVES: The objectives of the study were to (1) evaluate physicians' adherence to recommendations; (2) investigate reasons for non-adherence; and (3) ensure good clinical outcome of patients, the ultimate goal being to improve the quality of the guidelines, in particular to tailor them for the needs of the target audience and population. METHODS: Physicians consulting the guidelines on the Internet (www.fevertravel.ch) were invited to participate in the study. Navigation through the decision chart was automatically recorded, including diagnostic tests performed, initial and final diagnoses, and clinical outcomes. The reasons for non-adherence were investigated and qualitative feedback was collected. RESULTS: A total of 539 physician/patient pairs were included in this study. Full adherence to guidelines was observed in 29% of the cases. Figure-specific adherence rate was 54.8%. The main reasons for non-adherence were as follows: no repetition of malaria tests (111/352) and no presumptive antibiotic treatment for febrile diarrhea (64/153) or abdominal pain without leukocytosis (46/101). Overall, 20% of diversions from guidelines were considered reasonable because there was an alternative presumptive diagnosis or the symptoms were mild, which means that the corrected adherence rate per case was 40.6% and corrected adherence per figure was 61.7%. No death was recorded and all complications could be attributed to the underlying illness rather than to adherence to guidelines. CONCLUSIONS: These guidelines proved to be feasible, useful, and leading to good clinical outcomes. Almost one third of physicians strictly adhered to the guidelines. Other physicians used the guidelines not to forget specific diagnoses but finally diverged from the proposed attitudes. These diversions should be scrutinized for further refinement of the guidelines to better fit to physician and patient needs