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https://www.readbyqxmd.com/read/28334960/neural-mechanisms-of-reinforcement-learning-in-unmedicated-patients-with-major-depressive-disorder
#1
Marcus Rothkirch, Jonas Tonn, Stephan Köhler, Philipp Sterzer
According to current concepts, major depressive disorder is strongly related to dysfunctional neural processing of motivational information, entailing impairments in reinforcement learning. While computational modelling can reveal the precise nature of neural learning signals, it has not been used to study learning-related neural dysfunctions in unmedicated patients with major depressive disorder so far. We thus aimed at comparing the neural coding of reward and punishment prediction errors, representing indicators of neural learning-related processes, between unmedicated patients with major depressive disorder and healthy participants...
February 20, 2017: Brain: a Journal of Neurology
https://www.readbyqxmd.com/read/28326050/what-to-choose-next-a-paradigm-for-testing-human-sequential-decision-making
#2
Elisa M Tartaglia, Aaron M Clarke, Michael H Herzog
Many of the decisions we make in our everyday lives are sequential and entail sparse rewards. While sequential decision-making has been extensively investigated in theory (e.g., by reinforcement learning models) there is no systematic experimental paradigm to test it. Here, we developed such a paradigm and investigated key components of reinforcement learning models: the eligibility trace (i.e., the memory trace of previous decision steps), the external reward, and the ability to exploit the statistics of the environment's structure (model-free vs...
2017: Frontiers in Psychology
https://www.readbyqxmd.com/read/28324169/roles-of-centromedian-parafascicular-nuclei-of-thalamus-and-cholinergic-interneurons-in-the-dorsal-striatum-in-associative-learning-of-environmental-events
#3
REVIEW
Ko Yamanaka, Yukiko Hori, Takafumi Minamimoto, Hiroshi Yamada, Naoyuki Matsumoto, Kazuki Enomoto, Toshihiko Aosaki, Ann M Graybiel, Minoru Kimura
The thalamus provides a massive input to the striatum, but despite accumulating evidence, the functions of this system remain unclear. It is known, however, that the centromedian (CM) and parafascicular (Pf) nuclei of the thalamus can strongly influence particular striatal neuron subtypes, notably including the cholinergic interneurons of the striatum (CINs), key regulators of striatal function. Here, we highlight the thalamostriatal system through the CM-Pf to striatal CINs. We consider how, by virtue of the direct synaptic connections of the CM and PF, their neural activity contributes to the activity of CINs and striatal projection neurons (SPNs)...
March 21, 2017: Journal of Neural Transmission
https://www.readbyqxmd.com/read/28320846/working-memory-load-strengthens-reward-prediction-errors
#4
Anne G E Collins, Brittany Ciullo, Michael J Frank, David Badre
Reinforcement learning in simple instrumental tasks is usually modeled as a monolithic process in which reward prediction errors are used to update expected values of choice options. This modeling ignores the different contributions of different memory and decision-making systems thought to contribute even to simple learning. In an fMRI experiment, we asked how working memory and incremental reinforcement learning processes interact to guide human learning. Working memory load was manipulated by varying the number of stimuli to be learned across blocks...
March 20, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28320678/reinforced-robust-principal-component-pursuit
#5
Pratik Prabhanjan Brahma, Yiyuan She, Shijie Li, Jiade Li, Dapeng Wu
High-dimensional data present in the real world is often corrupted by noise and gross outliers. Principal component analysis (PCA) fails to learn the true low-dimensional subspace in such cases. This is the reason why robust versions of PCA, which put a penalty on arbitrarily large outlying entries, are preferred to perform dimension reduction. In this paper, we argue that it is necessary to study the presence of outliers not only in the observed data matrix but also in the orthogonal complement subspace of the authentic principal subspace...
March 14, 2017: IEEE Transactions on Neural Networks and Learning Systems
https://www.readbyqxmd.com/read/28316564/functional-circuitry-effect-of-ventral-tegmental-area-deep-brain-stimulation-imaging-and-neurochemical-evidence-of-mesocortical-and-mesolimbic-pathway-modulation
#6
Megan L Settell, Paola Testini, Shinho Cho, Jannifer H Lee, Charles D Blaha, Hang J Jo, Kendall H Lee, Hoon-Ki Min
Background: The ventral tegmental area (VTA), containing mesolimbic and mesocortical dopaminergic neurons, is implicated in processes involving reward, addiction, reinforcement, and learning, which are associated with a variety of neuropsychiatric disorders. Electrical stimulation of the VTA or the medial forebrain bundle and its projection target the nucleus accumbens (NAc) is reported to improve depressive symptoms in patients affected by severe, treatment-resistant major depressive disorder (MDD) and depressive-like symptoms in animal models of depression...
2017: Frontiers in Neuroscience
https://www.readbyqxmd.com/read/28315693/central-glp-1-receptor-activation-modulates-cocaine-evoked-phasic-dopamine-signaling-in-the-nucleus-accumbens-core
#7
Samantha M Fortin, Mitchell F Roitman
Drugs of abuse increase the frequency and magnitude of brief (1-3s), high concentration (phasic) dopamine release events in terminal regions. These are thought to be a critical part of drug reinforcement and ultimately the development of addiction. Recently, metabolic regulatory peptides, including the satiety signal glucagon-like peptide-1 (GLP-1), have been shown to modulate cocaine reward-driven behavior and sustained dopamine levels after cocaine administration. Here, we use fast-scan cyclic voltammetry (FSCV) to explore GLP-1 receptor (GLP-1R) modulation of dynamic dopamine release in the nucleus accumbens (NAc) during cocaine administration...
March 15, 2017: Physiology & Behavior
https://www.readbyqxmd.com/read/28314871/-evidence-based-lichtenstein-technique
#8
W Reinpold, D Chen
Lichtenstein hernioplasty is the number one technique worldwide for open, mesh-based inguinal hernia repair. The principle of Lichtenstein hernioplasty is the tension-free reinforcement of the abdominal wall by covering the transversalis fascia and the oblique muscles with an artificial patch of mesh. The Lichtenstein technique has been modified since its inception. The technique has the benefits of low costs and a rapid learning curve and can be performed with the patient under local anesthesia. The recurrence rates after the Lichtenstein operation are significantly lower compared to open suture repair and equal to laparoendoscopic techniques...
March 17, 2017: Der Chirurg; Zeitschrift Für Alle Gebiete der Operativen Medizen
https://www.readbyqxmd.com/read/28301764/reward-processing-neuroeconomics-and-psychopathology
#9
David H Zald, Michael T Treadway
Abnormal reward processing is a prominent transdiagnostic feature of psychopathology. The present review provides a framework for considering the different aspects of reward processing and their assessment, and highlights recent insights from the field of neuroeconomics that may aid in understanding these processes. Although altered reward processing in psychopathology has often been treated as a general hypo- or hyperresponsivity to reward, increasing data indicate that a comprehensive understanding of reward dysfunction requires characterization within more specific reward-processing domains, including subjective valuation, discounting, hedonics, reward anticipation and facilitation, and reinforcement learning...
March 15, 2017: Annual Review of Clinical Psychology
https://www.readbyqxmd.com/read/28298887/automated-operant-conditioning-in-the-mouse-home-cage
#10
Nikolas A Francis, Patrick O Kanold
Recent advances in neuroimaging and genetics have made mice an advantageous animal model for studying the neurophysiology of sensation, cognition, and locomotion. A key benefit of mice is that they provide a large population of test subjects for behavioral screening. Reflex-based assays of hearing in mice, such as the widely used acoustic startle response, are less accurate than operant conditioning in measuring auditory processing. To date, however, there are few cost-effective options for scalable operant conditioning systems...
2017: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/28297663/disrupting-glutamate-co-transmission-does-not-affect-acquisition-of-conditioned-behavior-reinforced-by-dopamine-neuron-activation
#11
Dong V Wang, Thomas Viereckel, Vivien Zell, Åsa Konradsson-Geuken, Carl J Broker, Aleksandr Talishinsky, Ji Hoon Yoo, Melissa H Galinato, Emma Arvidsson, Andrew J Kesner, Thomas S Hnasko, Åsa Wallén-Mackenzie, Satoshi Ikemoto
Dopamine neurons in the ventral tegmental area (VTA) were previously found to express vesicular glutamate transporter 2 (VGLUT2) and to co-transmit glutamate in the ventral striatum (VStr). This capacity may play an important role in reinforcement learning. Although it is known that activation of the VTA-VStr dopamine system readily reinforces behavior, little is known about the role of glutamate co-transmission in such reinforcement. By combining electrode recording and optogenetics, we found that stimulation of VTA dopamine neurons in vivo evoked fast excitatory responses in many VStr neurons of adult mice...
March 14, 2017: Cell Reports
https://www.readbyqxmd.com/read/28294331/context-dependent-extinction-of-an-appetitive-operant-conditioned-response-in-infant-rats
#12
Estefanía Orellana Barrera, Carlos Arias, Felisa González, Paula Abate
The present study evaluated context-dependent learning under an operant conditioning procedure in infant rats. Preweanling rats were trained in context A during postnatal days (PDs) 16 and 17 to learn an appetitive operant conditioning task, employing milk chocolate as appetitive reinforcer. On PD18 the operant response was extinguished in context A, or in an alternative context B. The change from context A to B between acquisition and extinction did not affect the number of responses during extinction, but slightly modified the shape of the extinction curve...
March 13, 2017: Developmental Psychobiology
https://www.readbyqxmd.com/read/28293993/reflective-practice
#13
Elena Alegado
What was the nature of the CPD activity, practice-related feedback and/or event and/or experience in your practice? The CPD article provided a useful introduction to reflection, defined as a method of using experiential knowledge to enable professional and personal development, while reinforcing continuous learning.
March 15, 2017: Nursing Standard
https://www.readbyqxmd.com/read/28293206/five-year-olds-systematic-errors-in-second-order-false-belief-tasks-are-due-to-first-order-theory-of-mind-strategy-selection-a-computational-modeling-study
#14
Burcu Arslan, Niels A Taatgen, Rineke Verbrugge
The focus of studies on second-order false belief reasoning generally was on investigating the roles of executive functions and language with correlational studies. Different from those studies, we focus on the question how 5-year-olds select and revise reasoning strategies in second-order false belief tasks by constructing two computational cognitive models of this process: an instance-based learning model and a reinforcement learning model. Unlike the reinforcement learning model, the instance-based learning model predicted that children who fail second-order false belief tasks would give answers based on first-order theory of mind (ToM) reasoning as opposed to zero-order reasoning...
2017: Frontiers in Psychology
https://www.readbyqxmd.com/read/28290558/-real-world-data-on-novel-oral-anticoagulants-the-added-value-of-registries-and-observational-studies-focus-on-apixaban
#15
Francesco Pelliccia, Gaetano Tanzilli, Michele Schiariti, Nicola Viceconte, Cesare Greco, Carlo Gaudio
Anticoagulant therapy has been used with great effect for decades for the prevention of stroke among patients with atrial fibrillation. In recent years, the therapeutic armamentarium has been strengthened considerably, with the addition of anticoagulants acting through novel pathways. The currently available novel agents are apixaban, rivaroxaban and dabigatran. These novel oral anticoagulants (NOACs) were approved for use on the basis of major clinical trials clearly demonstrating improved risk reductions compared to warfarin for stroke and/or major bleeding events...
December 2016: Giornale Italiano di Cardiologia
https://www.readbyqxmd.com/read/28289293/the-influence-of-an-academic-pharmacy-mentorship-program-on-mentees-commitment-to-pursue-an-academic-career
#16
Caroline M Sierra, Jennifer Adams
The objective of this study was to determine the influence of the American Association of Colleges of Pharmacy (AACP) Walmart Scholars Program on mentees' attitudes towards and decision to pursue a career in academia. Upon completion of the AACP Walmart Scholars Program, wherein mentor-mentee pairs attend the AACP Annual Meeting to learn about academic pharmacy careers, mentees wrote essays evaluating the program. Their views on academic pharmacy careers were analyzed for themes in the evaluations. Of the mentees who addressed the impact of the program on their perspectives on a career in academic pharmacy, over half stated the program positively influenced pursuit of such a career...
February 25, 2017: American Journal of Pharmaceutical Education
https://www.readbyqxmd.com/read/28287789/effects-of-adolescent-exposure-to-methylmercury-and-d-amphetamine-on-reversal-learning-and-an-extradimensional-shift-in-male-mice
#17
Steven R Boomhower, M Christopher Newland
Adolescence is associated with the continued maturation of dopamine neurotransmission and is implicated in the etiology of many psychiatric illnesses. Adolescent exposure to neurotoxicants that distort dopamine neurotransmission, such as methylmercury (MeHg), may modify the effects of chronic d-amphetamine (d-AMP) administration on reversal learning and attentional-set shifting. Male C57Bl/6n mice were randomly assigned to two MeHg-exposure groups (0 ppm and 3 ppm) and two d-AMP-exposure groups (saline and 1 mg/kg/day), producing four treatment groups (n = 10-12/group): control, MeHg, d-AMP, and MeHg + d-AMP...
March 13, 2017: Experimental and Clinical Psychopharmacology
https://www.readbyqxmd.com/read/28287586/introducing-clicker-training-as-a-cognitive-enrichment-for-laboratory-mice
#18
Charlotte Leidinger, Felix Herrmann, Christa Thöne-Reineke, Nadine Baumgart, Jan Baumgart
Establishing new refinement strategies in laboratory animal science is a central goal in fulfilling the requirements of Directive 2010/63/EU. Previous research determined a profound impact of gentle handling protocols on the well-being of laboratory mice. By introducing clicker training to the keeping of mice, not only do we promote the amicable treatment of mice, but we also enable them to experience cognitive enrichment. Clicker training is a form of positive reinforcement training using a conditioned secondary reinforcer, the "click" sound of a clicker, which serves as a time bridge between the strengthened behavior and an upcoming reward...
March 6, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28286265/vicarious-extinction-learning-during-reconsolidation-neutralizes-fear-memory
#19
Armita Golkar, Cathelijn Tjaden, Merel Kindt
BACKGROUND: Previous studies have suggested that fear memories can be updated when recalled, a process referred to as reconsolidation. Given the beneficial effects of model-based safety learning (i.e. vicarious extinction) in preventing the recovery of short-term fear memory, we examined whether consolidated long-term fear memories could be updated with safety learning accomplished through vicarious extinction learning initiated within the reconsolidation time-window. We assessed this in a final sample of 19 participants that underwent a three-day within-subject fear-conditioning design, using fear-potentiated startle as our primary index of fear learning...
February 22, 2017: Behaviour Research and Therapy
https://www.readbyqxmd.com/read/28285994/midbrain-dopamine-neurons-signal-belief-in-choice-accuracy-during-a-perceptual-decision
#20
Armin Lak, Kensaku Nomoto, Mehdi Keramati, Masamichi Sakagami, Adam Kepecs
Central to the organization of behavior is the ability to predict the values of outcomes to guide choices. The accuracy of such predictions is honed by a teaching signal that indicates how incorrect a prediction was ("reward prediction error," RPE). In several reinforcement learning contexts, such as Pavlovian conditioning and decisions guided by reward history, this RPE signal is provided by midbrain dopamine neurons. In many situations, however, the stimuli predictive of outcomes are perceptually ambiguous...
March 20, 2017: Current Biology: CB
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