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https://www.readbyqxmd.com/read/28098430/behavioral-and-electrophysiological-alterations-for-reinforcement-learning-in-manic-and-euthymic-patients-with-bipolar-disorder
#1
Vin Ryu, Ra Yeon Ha, Su Jin Lee, Kyooseob Ha, Hyun-Sang Cho
AIMS: Bipolar disorder is characterized by behavioral changes such as risk-taking and increasing goal-directed activities, which may result from altered reward processing. Patients with bipolar disorder show impaired reward learning in situations that require the integration of reinforced feedback over time. In this study, we examined the behavioral and electrophysiological characteristics of reward learning in manic and euthymic patients with bipolar disorder using a probabilistic reward task...
January 18, 2017: CNS Neuroscience & Therapeutics
https://www.readbyqxmd.com/read/28097374/effects-of-5-ht1a-5-ht2a-and-5-ht2c-receptor-agonists-and-antagonists-on-responding-for-a-conditioned-reinforcer-and-its-enhancement-by-methylphenidate
#2
Paul J Fletcher, Fiona D Zeeb, Caleb J Browne, Guy A Higgins, Ashlie D Soko
OBJECTIVES: These experiments examined the effects of selective 5-HT1A, 5-HT2A and 5-HT2C receptor ligands on responding for a conditioned reinforcer (CRf). Effects of these ligands were measured under basal conditions and following elevated dopamine (DA) activity produced by the DA reuptake inhibitor methylphenidate. METHODS: Water-restricted rats learned to associate a conditioned stimulus (CS) with water in operant chambers. Subsequently, two response levers were made available; responding on one lever delivered the CS (now a CRf), while responding on the second lever had no consequences...
January 18, 2017: Psychopharmacology
https://www.readbyqxmd.com/read/28095006/can-the-structure-of-motor-variability-predict-learning-rate
#3
David Barbado Murillo, Carla Caballero Sánchez, Janice Moreside, Francisco J Vera-García, Francisco J Moreno
Recent studies show that motor variability is actively regulated as an exploration tool to promote learning in reward-based tasks. However, its role in learning processes during error-based tasks, when a reduction of the motor variability is required to achieve good performance, is still unclear. In this study, we hypothesized that error-based learning not only depends on exploration but also on the individuals' ability to measure and predict the motor error. Previous studies identified a less auto-correlated motor variability as a higher ability to perform motion adjustments...
January 16, 2017: Journal of Experimental Psychology. Human Perception and Performance
https://www.readbyqxmd.com/read/28095003/cocaine-addiction-as-a-homeostatic-reinforcement-learning-disorder
#4
Mehdi Keramati, Audrey Durand, Paul Girardeau, Boris Gutkin, Serge H Ahmed
Drug addiction implicates both reward learning and homeostatic regulation mechanisms of the brain. This has stimulated 2 partially successful theoretical perspectives on addiction. Many important aspects of addiction, however, remain to be explained within a single, unified framework that integrates the 2 mechanisms. Building upon a recently developed homeostatic reinforcement learning theory, the authors focus on a key transition stage of addiction that is well modeled in animals, escalation of drug use, and propose a computational theory of cocaine addiction where cocaine reinforces behavior due to its rapid homeostatic corrective effect, whereas its chronic use induces slow and long-lasting changes in homeostatic setpoint...
January 16, 2017: Psychological Review
https://www.readbyqxmd.com/read/28093474/behavioral-status-influences-the-dependence-of-odorant-induced-change-in-firing-on-pre-stimulus-firing-rate
#5
Anan Li, Ethan M Guthman, Wilder T Doucette, Diego Restrepo
: The firing rate of the mitral/tufted cells in the olfactory bulb is known to undergo significant trial-to-trial variability and is affected by anesthesia. Here we ask whether odorant-elicited changes in firing rate depend on the rate before application of the stimulus in the awake and anesthetized mouse. We find that pre-stimulus firing rate varies widely on a trial-to-trial basis and that the stimulus-induced change in firing rate decreases with increasing pre-stimulus firing rate...
January 16, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28092323/brain-substrates-of-reward-processing-and-the-%C3%AE-opioid-receptor-a-pathway-into-pain
#6
Frauke Nees, Susanne Becker, Sabina Millenet, Tobias Banaschewski, Luise Poustka, Arun Bokde, Uli Bromberg, Christian Büchel, Patricia J Conrod, Sylvane Desrivières, Vincent Frouin, Jürgen Gallinat, Hugh Garavan, Andreas Heinz, Bernd Ittermann, Jean-Luc Martinot, Dimitri Papadopoulos Orfanos, Tomáš Paus, Michael N Smolka, Henrik Walter, Rob Whelan, Gunter Schumann, Herta Flor
The processing of reward and reinforcement learning seems to be important determinants of pain chronicity. However, reward processing is already altered early in life and if this is related to the development of pain symptoms later on is not known. The aim of this study was first to examine whether behavioural and brain-related indicators of reward processing at the age of 14 to 15 years are significant predictors of pain complaints 2 years later, at 16 to 17 years. Second, we investigated the contribution of genetic variations in the opioidergic system, which is linked to the processing of both, reward and pain, to this prediction...
February 2017: Pain
https://www.readbyqxmd.com/read/28090512/surgical-applications-of-three-dimensional-printing-a-review-of-the-current-literature-how-to-get-started
#7
REVIEW
Don Hoang, David Perrault, Milan Stevanovic, Alidad Ghiassi
Three dimensional (3D) printing involves a number of additive manufacturing techniques that are used to build structures from the ground up. This technology has been adapted to a wide range of surgical applications at an impressive rate. It has been used to print patient-specific anatomic models, implants, prosthetics, external fixators, splints, surgical instrumentation, and surgical cutting guides. The profound utility of this technology in surgery explains the exponential growth. It is important to learn how 3D printing has been used in surgery and how to potentially apply this technology...
December 2016: Annals of Translational Medicine
https://www.readbyqxmd.com/read/28089852/dopamine-d1-receptor-agonist-treatment-attenuates-extinction-of-morphine-conditioned-place-preference-while-increasing-dendritic-complexity-in-the-nucleus-accumbens-core
#8
Kendra L Kobrin, Danielle T Arena, Stephen C Heinrichs, Olivia H Nguyen, Gary B Kaplan
The dopamine D1 receptor (D1R) has a role in opioid reward and conditioned place preference (CPP), but its role in CPP extinction is undetermined. We examined the effect of D1R agonist SKF81297 on the extinction of opioid CPP and associated dendritic morphology in the nucleus accumbens (NAc), a region involved with reward integration and its extinction. During the acquisition of morphine CPP, mice received morphine and saline on alternate days; injections were given immediately before each of eight daily conditioning sessions...
January 12, 2017: Behavioural Brain Research
https://www.readbyqxmd.com/read/28088215/non-associative-versus-associative-learning-by-foraging-predatory-mites
#9
Peter Schausberger, Stefan Peneder
BACKGROUND: Learning processes can be broadly categorized into associative and non-associative. Associative learning occurs through the pairing of two previously unrelated stimuli, whereas non-associative learning occurs in response to a single stimulus. How these two principal processes compare in the same learning task and how they contribute to the overall behavioural changes brought about by experience is poorly understood. We tackled this issue by scrutinizing associative and non-associative learning of prey, Western flower thrips Frankliniella occidentalis, by the predatory mite, Neoseiulus californicus...
January 14, 2017: BMC Ecology
https://www.readbyqxmd.com/read/28077716/the-attraction-effect-modulates-reward-prediction-errors-and-intertemporal-choices
#10
Sebastian Gluth, Jared M Hotaling, Jörg Rieskamp
: Classical economic theory contends that the utility of a choice option should be independent of other options. This view is challenged by the attraction effect, in which the relative preference between two options is altered by the addition of a third, asymmetrically dominated option. Here, we leveraged the attraction effect in the context of intertemporal choices to test whether both decisions and reward prediction errors (RPE) in the absence of choice violate the independence of irrelevant alternatives principle...
January 11, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28072417/dopaminergic-dynamics-underlying-sex-specific-cocaine-reward
#11
Erin S Calipari, Barbara Juarez, Carole Morel, Deena M Walker, Michael E Cahill, Efrain Ribeiro, Ciorana Roman-Ortiz, Charu Ramakrishnan, Karl Deisseroth, Ming-Hu Han, Eric J Nestler
Although both males and females become addicted to cocaine, females transition to addiction faster and experience greater difficulties remaining abstinent. We demonstrate an oestrous cycle-dependent mechanism controlling increased cocaine reward in females. During oestrus, ventral tegmental area (VTA) dopamine neuron activity is enhanced and drives post translational modifications at the dopamine transporter (DAT) to increase the ability of cocaine to inhibit its function, an effect mediated by estradiol. Female mice conditioned to associate cocaine with contextual cues during oestrus have enhanced mesolimbic responses to these cues in the absence of drug...
January 10, 2017: Nature Communications
https://www.readbyqxmd.com/read/28071747/deficits-in-reinforcement-learning-but-no-link-to-apathy-in-patients-with-schizophrenia
#12
Matthias N Hartmann-Riemer, Steffen Aschenbrenner, Magdalena Bossert, Celina Westermann, Erich Seifritz, Philippe N Tobler, Matthias Weisbrod, Stefan Kaiser
Negative symptoms in schizophrenia have been linked to selective reinforcement learning deficits in the context of gains combined with intact loss-avoidance learning. Fundamental mechanisms of reinforcement learning and choice are prediction error signaling and the precise representation of reward value for future decisions. It is unclear which of these mechanisms contribute to the impairments in learning from positive outcomes observed in schizophrenia. A recent study suggested that patients with severe apathy symptoms show deficits in the representation of expected value...
January 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28065844/effects-of-the-chronic-restraint-stress-induced-depression-on-reward-related-learning-in-rats
#13
Pan Xu, Kezhu Wang, Cong Lu, Liming Dong, Yixi Chen, Qiong Wang, Zhe Shi, Yanyan Yang, Shanguang Chen, Xinmin Liu
Chronic mild or unpredictability stress produces a persistent depressive-like state. The main symptoms of depression include weight loss, despair, anhedonia, diminished motivation and mild cognition impairment, which could influence the ability of reward-related learning. In the present study, we aimed to evaluate the effects of chronic restraint stress on the performance of reward-related learning of rats. We used the exposure of repeated restraint stress (6h/day, for 28days) to induce depression-like behavior in rats...
January 5, 2017: Behavioural Brain Research
https://www.readbyqxmd.com/read/28065182/increased-fronto-striatal-reward-prediction-errors-moderate-decision-making-in-obsessive-compulsive-disorder
#14
T U Hauser, R Iannaccone, R J Dolan, J Ball, J Hättenschwiler, R Drechsler, M Rufer, D Brandeis, S Walitza, S Brem
BACKGROUND: Obsessive-compulsive disorder (OCD) has been linked to functional abnormalities in fronto-striatal networks as well as impairments in decision making and learning. Little is known about the neurocognitive mechanisms causing these decision-making and learning deficits in OCD, and how they relate to dysfunction in fronto-striatal networks. METHOD: We investigated neural mechanisms of decision making in OCD patients, including early and late onset of disorder, in terms of reward prediction errors (RPEs) using functional magnetic resonance imaging...
January 9, 2017: Psychological Medicine
https://www.readbyqxmd.com/read/28063134/how-can-pricing-and-reimbursement-policies-improve-affordable-access-to-medicines-lessons-learned-from-european-countries
#15
REVIEW
Sabine Vogler, Valérie Paris, Alessandra Ferrario, Veronika J Wirtz, Kees de Joncheere, Peter Schneider, Hanne Bak Pedersen, Guillaume Dedet, Zaheer-Ud-Din Babar
This article discusses pharmaceutical pricing and reimbursement policies in European countries with regard to their ability to ensure affordable access to medicines. A frequently applied pricing policy is external price referencing. While it provides some benchmark for policy-makers and has been shown to be able to generate savings, it may also contribute to delay in product launch in countries where medicine prices are low. Value-based pricing has been proposed as a policy that promotes access while rewarding useful innovation; however, implementing it has proven quite challenging...
January 6, 2017: Applied Health Economics and Health Policy
https://www.readbyqxmd.com/read/28060525/diurnal-rhythms-in-psychological-reward-functioning-in-healthy-young-men-wanting-liking-and-learning
#16
Jamie E M Byrne, Greg Murray
A range of evidence suggests that human reward functioning is partly driven by the endogenous circadian system, generating 24-hour rhythms in behavioural measures of reward activation. Reward functioning is multifaceted but literature to date is largely limited to measures of self-reported positive mood states. The aim of this study was to advance the field by testing for hypothesised diurnal variation in previously unexplored components of psychological reward: 'wanting', liking, and learning using subjective and behavioural measures...
January 6, 2017: Chronobiology International
https://www.readbyqxmd.com/read/28053043/habenula-induced-inhibition-of-midbrain-dopamine-neurons-is-diminished-by-lesions-of-the-rostromedial-tegmental-nucleus
#17
P Leon Brown, Heather Palacorolla, Dana Brady, Katelyn Riegger, Greg I Elmer, Paul D Shepard
: Neurons in the lateral habenula (LHb) are transiently activated by aversive events and have been implicated in associative learning. Functional changes associated with tonic and phasic activation of the LHb are often attributed to a corresponding inhibition of midbrain dopamine (DA) neurons. Activation of GABAergic neurons in the rostromedial tegmental nucleus (RMTg), a region that receives dense projections from the LHb and projects strongly to midbrain monoaminergic nuclei, is believed to underlie the transient inhibition of DA neurons attributed to activation of the LHb...
January 4, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28052091/sense-of-accomplishment-is-modulated-by-a-proper-level-of-instruction-and-represented-in-the-brain-reward-system
#18
Tomoya Nakai, Hironori Nakatani, Chihiro Hosoda, Yulri Nonaka, Kazuo Okanoya
Problem-solving can be facilitated with instructions or hints, which provide information about given problems. The proper amount of instruction that should be provided for learners is controversial. Research shows that tasks with intermediate difficulty induce the largest sense of accomplishment (SA), leading to an intrinsic motivation for learning. To investigate the effect of instructions, we prepared three instruction levels (No hint, Indirect hint, and Direct hint) for the same insight-problem types. We hypothesized that indirect instructions impose intermediate difficulty for each individual, thereby inducing the greatest SA per person...
2017: PloS One
https://www.readbyqxmd.com/read/28048367/th-a-207b-00-shear-wave-imaging-and-a-qiba-us-biomarker-update
#19
Paul Carson
: Imaging of tissue elastic properties is a relatively new and powerful approach to one of the oldest and most important diagnostic tools. Imaging of shear wave speed with ultrasound is has been added to most high-end ultrasound systems. Understanding this exciting imaging mode aiding its most effective use in medicine can be a rewarding effort for medical physicists and other medical imaging and treatment professionals. Assuring consistent, quantitative measurements across the many ultrasound systems in a typical imaging department will constitute a major step toward realizing the great potential of this technique and other quantitative imaging...
June 2016: Medical Physics
https://www.readbyqxmd.com/read/28048257/th-c-brb-01-open-source-hardware-general-overview
#20
F Therriault-Proulx
: By definition, Open Source Hardware (OSH) is "hardware whose design is made publicly available so that anyone can study, modify, distribute, make, and sell the design or hardware based on that design". The advantages of OSH are multiple and the movement has been growing exponentially over the last couple years, leading to the spread and evolution of 3D printing technologies, the creation of affordable and easy to use micro-controller boards (Arduino, Raspberry Pi, etc.), as well as a plurality of other "hands-on"/DIY projects...
June 2016: Medical Physics
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