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Reinforcement learning

Gem Mohan, Julius X Scott, Rizwana Nasrin, Latha Sneha, Rakesh Manohar, Lalitha Subramanian, Sowmiya Narayani, Aruna Rajendran
BACKGROUND: The first counseling or the exchange between the physician and the parent(s) of children with cancer is of vital importance as it sets the tone for the rest of the treatment. The goal of our study was to find out the preferences among parents of Indian children with cancer regarding communication and breaking of bad news when fully informed about the diagnosis. MATERIALS AND METHODS: A sample of 60 parents who had been counseled within 3 months from diagnosis were interviewed with a prepared questionnaire directed at eliciting their experiences with the physicians who broke the bad news to them and also suggestions to improve the exchange...
November 2016: Journal of Pediatric Hematology/oncology
Jing Wang, Zhaofeng Chen, Xiaozhe Peng, Tiantian Yang, Peng Li, Fengyu Cong, Hong Li
To investigate brain activity during the reinforcement learning process in social contexts is a topic of increasing research interest. Previous studies have mainly focused on using electroencephalograms (EEGs) for feedback evaluation in reinforcement learning tasks by measuring event-related potentials. Few studies have investigated the time-frequency (TF) profiles of a cue that manifested whether a following feedback is available or not after decision-making. Moreover, it remains unclear whether the TF profiles of the cue interact with different agents to whom the feedback related...
2016: Frontiers in Psychology
Alejandro Agostini, Enric Celaya
Function approximation in online, incremental, reinforcement learning needs to deal with two fundamental problems: biased sampling and nonstationarity. In kinds of tasks, biased sampling occurs because samples are obtained from specific trajectories dictated by the dynamics of the environment and are usually concentrated in particular convergence regions, which in the long term tend to dominate the approximation in the less sampled regions. The nonstationarity comes from the recursive nature of the estimations typical of temporal difference methods...
October 20, 2016: Neural Computation
Volker Wenzel, Nikolaus Gravenstein
PURPOSE OF REVIEW: Mentoring is fundamentally valuable and important to students considering a path into our specialty, as well as to colleagues already in it and with ambition to advance. General principles and personal experiences are collected and described to help inform future mentors and to reinforce the value of having a mentor and the satisfaction (and work) that is associated with such a role. RECENT FINDINGS: Detecting a latent talent among medical students or residents may be challenging but is worth the effort to develop personal careers and the specialty itself...
October 18, 2016: Current Opinion in Anaesthesiology
Pesia Katan, Shani Kahta, Ayelet Sasson, Rachel Schiff
Graph complexity as measured by topological entropy has been previously shown to affect performance on artificial grammar learning tasks among typically developing children. The aim of this study was to examine the effect of graph complexity on implicit sequential learning among children with developmental dyslexia. Our goal was to determine whether children's performance depends on the complexity level of the grammar system learned. We conducted two artificial grammar learning experiments that compared performance of children with developmental dyslexia with that of age- and reading level-matched controls...
October 19, 2016: Annals of Dyslexia
Youngbin Kwak, Scott A Huettel
Adolescence is a period of increased sensitivity to social contexts. To evaluate how social context sensitivity changes over development-and influences reward learning-we investigated how children and adolescents perceive and integrate rewards for oneself and others during a dynamic risky decision-making task. Children and adolescents (N = 75, 8-16 years) performed the Social Gambling Task (SGT, Kwak et al., 2014) and completed a set of questionnaires measuring other-regarding behavior. In the SGT, participants choose amongst four card decks that have different payout structures for oneself and for a charity...
2016: Frontiers in Psychology
Yun Lin, Chao Wang, Jiaxing Wang, Zheng Dou
Cognitive radio sensor networks are one of the kinds of application where cognitive techniques can be adopted and have many potential applications, challenges and future research trends. According to the research surveys, dynamic spectrum access is an important and necessary technology for future cognitive sensor networks. Traditional methods of dynamic spectrum access are based on spectrum holes and they have some drawbacks, such as low accessibility and high interruptibility, which negatively affect the transmission performance of the sensor networks...
October 12, 2016: Sensors
Jeffrey Fagen, Phyllis Ohr, Kimberly Boller
In this article, we reflect upon Carolyn Rovee-Collier's pioneering research on learning and memory in infants, especially that using the mobile conjugate reinforcement task, for our understanding of (a) cognitive development in infants born prematurely and those with Down's syndrome and (b) her prediction that infants' performance in the mobile conjugate reinforcement and similar operant tasks would predict later intellectual functioning. We then examine the implications of her research on time windows (the integration of new information into a memory) and memory reactivation (the retrieval of a forgotten memory as a result of the re-exposure to a component of the original learning experience) for early intervention programs and clinicians treating victims of early trauma...
November 2016: Developmental Psychobiology
Richard J E James, Claire O'Malley, Richard J Tunney
This manuscript reviews the extant literature on key issues related to mobile gambling and considers whether the potential risks of harm emerging from this platform are driven by pre-existing comorbidities or by psychological processes unique to mobile gambling. We propose an account based on associative learning that suggests this form of gambling is likely to show distinctive features compared with other gambling technologies. Smartphones are a rapidly growing platform on which individuals can gamble using specifically designed applications, adapted websites or text messaging...
October 18, 2016: British Journal of Psychology
J E LeDoux, J Moscarello, R Sears, V Campese
Research on avoidance conditioning began in the late 1930s as a way to use laboratory experiments to better understand uncontrollable fear and anxiety. Avoidance was initially conceived of as a two-factor learning process in which fear is first acquired through Pavlovian aversive conditioning (so-called fear conditioning), and then behaviors that reduce the fear aroused by the Pavlovian conditioned stimulus are reinforced through instrumental conditioning. Over the years, criticisms of both the avoidance paradigm and the two-factor fear theory arose...
October 18, 2016: Molecular Psychiatry
Cong Lu, Zhe Shi, Xiuping Sun, Ruile Pan, Shanguang Chen, Yinghui Li, Lina Qu, Lihua Sun, Haixia Dang, Lanlan Bu, Lingling Chen, Xinmin Liu
ETHNOPHARMACOLOGICAL RELEVANCE: Kai Xin San (KXS), a traditional formula of Chinese medicine, has been used to treat dementia. AIM OF THE STUDY: The present study aimed to investigate its ameliorating effects on Aβ1-40-induced cognitive impairment in rats using a series of novel reward-directed instrumental learning tasks, and to determine its possible mechanism of action. MATERIALS AND METHODS: Rats were pretreated with KXS aqueous extract (0...
October 14, 2016: Journal of Ethnopharmacology
David Mathar, Leonora Wilkinson, Anna K Holl, Jane Neumann, Lorenz Deserno, Arno Villringer, Marjan Jahanshahi, Annette Horstmann
Incidental learning of appropriate stimulus-response associations is crucial for optimal functioning within our complex environment. Positive and negative prediction errors (PEs) serve as neural teaching signals within distinct ('direct'/'indirect') dopaminergic pathways to update associations and optimize subsequent behavior. Using a computational reinforcement learning model, we assessed learning from positive and negative PEs on a probabilistic task (Weather Prediction Task - WPT) in three populations that allow different inferences on the role of dopamine (DA) signals: (1) Healthy volunteers that repeatedly underwent [(11)C]raclopride Positron Emission Tomography (PET), allowing for assessment of striatal DA release during learning, (2) Parkinson's disease (PD) patients tested both on and off L-DOPA medication, (3) early Huntington's disease (HD) patients, a disease that is associated with hyper-activation of the 'direct' pathway...
September 19, 2016: Cortex; a Journal Devoted to the Study of the Nervous System and Behavior
Jonathan M Highsmith, Karl L Wuensch, Tuan Tran, Alexandra J Stephenson, D Erik Everhart
ERP studies commonly utilize gambling-based reinforcement tasks to elicit feedback negativity (FN) responses. This study used a pattern learning task in order to limit gambling-related fallacious reasoning and possible affective responses to gambling, while investigating relationships between the FN components between high and low reward expectation conditions. Eighteen undergraduates completed measures of reinforcement sensitivity, trait and state affect, and psychophysiological recording. The pattern learning task elicited a FN component for both high and low win expectancy conditions, which was found to be independent of reward expectation and showed little relationship with task and personality variables...
April 18, 2016: Brain Informatics
Andreas Holzinger
Machine learning (ML) is the fastest growing field in computer science, and health informatics is among the greatest challenges. The goal of ML is to develop algorithms which can learn and improve over time and can be used for predictions. Most ML researchers concentrate on automatic machine learning (aML), where great advances have been made, for example, in speech recognition, recommender systems, or autonomous vehicles. Automatic approaches greatly benefit from big data with many training sets. However, in the health domain, sometimes we are confronted with a small number of data sets or rare events, where aML-approaches suffer of insufficient training samples...
June 2016: Brain Informatics
G Iakimova, S Dimitrova, T Burté
OBJECTIVES: Computer-delivered Cognitive Behavioral Therapies (C-CBT) are emerging as therapeutic techniques which contribute to overcome the barriers of health care access in adult populations with depression. The C-CBTs provide CBT techniques in a highly structured format comprising a number of educational lessons, homework, multimedia illustrations and supplementary materials via interactive computer interfaces. Programs are often administrated with a minimal or regular support provided by a clinician or a technician via email, telephone, online forums, or during face-to-face consultations...
October 10, 2016: L'Encéphale
Radia Bezzar-Bendjazia, Samira Kilani-Morakchi, Nadia Aribi
Azadirachtin, a biorational insecticide, is one of the prominent biopesticide commercialized today and represent an alternative to conventional insecticides. The current study examined the lethal and sublethal effects of azadirachtin on Drosophila melanogaster Meigen, 1830 (Diptera: Drosophilidae) as biological model. Various doses ranging from 0.1 to 2μg were applied topically on early third instar larvae and the cumulative mortality of immature stage was determined. In second series of experiments, azadirachtin was applied at its LD25 (0...
October 2016: Pesticide Biochemistry and Physiology
Rongshuai Wang, Luo Zhuo, Yunyun Wang, Liang Ren, Qian Liu, Liang Liu
BACKGROUND: Tetramine (tetramethylene disulphotetramine, TETS) and fluoroacetamide (FAA) are known as illegal rodenticides with high toxicity to animal species and human beings, which could lead to severe clinical features, including reduction of consciousness, convulsions, coma, and even death. METHODS AND RESULTS: We presented 2 cases that involved rodenticides poisoning. Even though the patients showed severe manifestations, they were initially misdiagnosed, resulting in 2 persons finally died from TETS and FAA poisoning in homicide cases...
October 2016: Medicine (Baltimore)
Heidi C Meyer, David J Bucci
Mounting evidence indicates that adolescents exhibit heightened sensitivity to rewards and reward-related cues compared to adults, and that adolescents are often unable to exert behavioral control in the face of such cues. Moreover, differences in reward processing during adolescence have been linked to heightened risk taking and impulsivity. However, little is known about the processes by which adolescents learn about the appetitive properties of environmental stimuli that signal reward. To address this, Pavlovian conditioning procedures were used to test for differences in excitatory conditioning between adult and adolescent rats using various schedules of reinforcement...
October 11, 2016: Physiology & Behavior
Ayaka Kato, Kenji Morita
It has been suggested that dopamine (DA) represents reward-prediction-error (RPE) defined in reinforcement learning and therefore DA responds to unpredicted but not predicted reward. However, recent studies have found DA response sustained towards predictable reward in tasks involving self-paced behavior, and suggested that this response represents a motivational signal. We have previously shown that RPE can sustain if there is decay/forgetting of learned-values, which can be implemented as decay of synaptic strengths storing learned-values...
October 2016: PLoS Computational Biology
Oliver Rawashdeh, Shannon J Clough, Randall L Hudson, Margarita L Dubocovich
The suprachiasmatic nucleus (SCN)-often referred to as the master circadian clock-is essential in generating physiologic rhythms and orchestrating synchrony among circadian clocks. This study tested the hypothesis that periodic motivation induced by rhythmically pairing 2 reinforcing stimuli [methamphetamine (METH) and running wheel (RW)] restores autonomous circadian activity in arrhythmic SCN-lesioned (SCNX) C3H/HeN mice. Sham-operated and SCNX mice were treated with either METH (1.2 mg/kg, i.p.) or vehicle in association, dissociation, or absence of an RW...
October 12, 2016: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
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