Model-free and model-based reward prediction errors in EEG.

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Sambrook, Thomas D; Hardwick, Ben; Wills, Andy J; Goslin, Jeremy

2018-05-24

Learning theorists posit two reinforcement learning systems: model-free and model-based. Model-based learning incorporates knowledge about structure and contingencies in the world to assign candidate actions with an expected value. Model-free learning is ignorant of the world's structure; instead, actions hold a value based on prior reinforcement, with this value updated by expectancy violation in the form of a reward prediction error. Because they use such different learning mechanisms, it has been previously assumed that model-based and model-free learning are computationally dissociated in the brain. However, recent fMRI evidence suggests that the brain may compute reward prediction errors to both model-free and model-based estimates of value, signalling the possibility that these systems interact. Because of its poor temporal resolution, fMRI risks confounding reward prediction errors with other feedback-related neural activity. In the present study, EEG was used to show the presence of both model-based and model-free reward prediction errors and their place in a temporal sequence of events including state prediction errors and action value updates. This demonstration of model-based prediction errors questions a long-held assumption that model-free and model-based learning are dissociated in the brain. Copyright © 2018 Elsevier Inc. All rights reserved.

Trial-by-Trial Modulation of Associative Memory Formation by Reward Prediction Error and Reward Anticipation as Revealed by a Biologically Plausible Computational Model.

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Aberg, Kristoffer C; Müller, Julia; Schwartz, Sophie

2017-01-01

Anticipation and delivery of rewards improves memory formation, but little effort has been made to disentangle their respective contributions to memory enhancement. Moreover, it has been suggested that the effects of reward on memory are mediated by dopaminergic influences on hippocampal plasticity. Yet, evidence linking memory improvements to actual reward computations reflected in the activity of the dopaminergic system, i.e., prediction errors and expected values, is scarce and inconclusive. For example, different previous studies reported that the magnitude of prediction errors during a reinforcement learning task was a positive, negative, or non-significant predictor of successfully encoding simultaneously presented images. Individual sensitivities to reward and punishment have been found to influence the activation of the dopaminergic reward system and could therefore help explain these seemingly discrepant results. Here, we used a novel associative memory task combined with computational modeling and showed independent effects of reward-delivery and reward-anticipation on memory. Strikingly, the computational approach revealed positive influences from both reward delivery, as mediated by prediction error magnitude, and reward anticipation, as mediated by magnitude of expected value, even in the absence of behavioral effects when analyzed using standard methods, i.e., by collapsing memory performance across trials within conditions. We additionally measured trait estimates of reward and punishment sensitivity and found that individuals with increased reward (vs. punishment) sensitivity had better memory for associations encoded during positive (vs. negative) prediction errors when tested after 20 min, but a negative trend when tested after 24 h. In conclusion, modeling trial-by-trial fluctuations in the magnitude of reward, as we did here for prediction errors and expected value computations, provides a comprehensive and biologically plausible description of

Pavlovian reward prediction and receipt in schizophrenia: relationship to anhedonia.

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Erin C Dowd

Full Text Available Reward processing abnormalities have been implicated in the pathophysiology of negative symptoms such as anhedonia and avolition in schizophrenia. However, studies examining neural responses to reward anticipation and receipt have largely relied on instrumental tasks, which may confound reward processing abnormalities with deficits in response selection and execution. 25 chronic, medicated outpatients with schizophrenia and 20 healthy controls underwent functional magnetic resonance imaging using a pavlovian reward prediction paradigm with no response requirements. Subjects passively viewed cues that predicted subsequent receipt of monetary reward or non-reward, and blood-oxygen-level-dependent signal was measured at the time of cue presentation and receipt. At the group level, neural responses to both reward anticipation and receipt were largely similar between groups. At the time of cue presentation, striatal anticipatory responses did not differ between patients and controls. Right anterior insula demonstrated greater activation for nonreward than reward cues in controls, and for reward than nonreward cues in patients. At the time of receipt, robust responses to receipt of reward vs. nonreward were seen in striatum, midbrain, and frontal cortex in both groups. Furthermore, both groups demonstrated responses to unexpected versus expected outcomes in cortical areas including bilateral dorsolateral prefrontal cortex. Individual difference analyses in patients revealed an association between physical anhedonia and activity in ventral striatum and ventromedial prefrontal cortex during anticipation of reward, in which greater anhedonia severity was associated with reduced activation to money versus no-money cues. In ventromedial prefrontal cortex, this relationship held among both controls and patients, suggesting a relationship between anticipatory activity and anhedonia irrespective of diagnosis. These findings suggest that in the absence of

Dopamine, reward learning, and active inference

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Thomas eFitzgerald

2015-11-01

Full Text Available Temporal difference learning models propose phasic dopamine signalling encodes reward prediction errors that drive learning. This is supported by studies where optogenetic stimulation of dopamine neurons can stand in lieu of actual reward. Nevertheless, a large body of data also shows that dopamine is not necessary for learning, and that dopamine depletion primarily affects task performance. We offer a resolution to this paradox based on an hypothesis that dopamine encodes the precision of beliefs about alternative actions, and thus controls the outcome-sensitivity of behaviour. We extend an active inference scheme for solving Markov decision processes to include learning, and show that simulated dopamine dynamics strongly resemble those actually observed during instrumental conditioning. Furthermore, simulated dopamine depletion impairs performance but spares learning, while simulated excitation of dopamine neurons drives reward learning, through aberrant inference about outcome states. Our formal approach provides a novel and parsimonious reconciliation of apparently divergent experimental findings.

Association of Elevated Reward Prediction Error Response With Weight Gain in Adolescent Anorexia Nervosa.

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DeGuzman, Marisa; Shott, Megan E; Yang, Tony T; Riederer, Justin; Frank, Guido K W

2017-06-01

Anorexia nervosa is a psychiatric disorder of unknown etiology. Understanding associations between behavior and neurobiology is important in treatment development. Using a novel monetary reward task during functional magnetic resonance brain imaging, the authors tested how brain reward learning in adolescent anorexia nervosa changes with weight restoration. Female adolescents with anorexia nervosa (N=21; mean age, 16.4 years [SD=1.9]) underwent functional MRI (fMRI) before and after treatment; similarly, healthy female control adolescents (N=21; mean age, 15.2 years [SD=2.4]) underwent fMRI on two occasions. Brain function was tested using the reward prediction error construct, a computational model for reward receipt and omission related to motivation and neural dopamine responsiveness. Compared with the control group, the anorexia nervosa group exhibited greater brain response 1) for prediction error regression within the caudate, ventral caudate/nucleus accumbens, and anterior and posterior insula, 2) to unexpected reward receipt in the anterior and posterior insula, and 3) to unexpected reward omission in the caudate body. Prediction error and unexpected reward omission response tended to normalize with treatment, while unexpected reward receipt response remained significantly elevated. Greater caudate prediction error response when underweight was associated with lower weight gain during treatment. Punishment sensitivity correlated positively with ventral caudate prediction error response. Reward system responsiveness is elevated in adolescent anorexia nervosa when underweight and after weight restoration. Heightened prediction error activity in brain reward regions may represent a phenotype of adolescent anorexia nervosa that does not respond well to treatment. Prediction error response could be a neurobiological marker of illness severity that can indicate individual treatment needs.

Different populations of subthalamic neurons encode cocaine vs. sucrose reward and predict future error.

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Lardeux, Sylvie; Paleressompoulle, Dany; Pernaud, Remy; Cador, Martine; Baunez, Christelle

2013-10-01

The search for treatment of cocaine addiction raises the challenge to find a way to diminish motivation for the drug without decreasing it for natural rewards. Subthalamic nucleus (STN) inactivation decreases motivation for cocaine while increasing motivation for food, suggesting that STN can dissociate different rewards. Here, we investigated how rat STN neurons respond to cues predicting cocaine or sucrose and to reward delivery while rats are performing a discriminative stimuli task. We show that different neuronal populations of STN neurons encode cocaine and sucrose. In addition, we show that STN activity at the cue onset predicts future error. When changing the reward predicted unexpectedly, STN neurons show capacities of adaptation, suggesting a role in reward-prediction error. Furthermore, some STN neurons show a response to executive error (i.e., "oops neurons") that is specific to the missed reward. These results position the STN as a nexus where natural rewards and drugs of abuse are coded differentially and can influence the performance. Therefore, STN can be viewed as a structure where action could be taken for the treatment of cocaine addiction.

Signed reward prediction errors drive declarative learning

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De Loof, E.; Ergo, K.; Naert, L.; Janssens, C.; Talsma, D.; van Opstal, F.; Verguts, T.

2018-01-01

Reward prediction errors (RPEs) are thought to drive learning. This has been established in procedural learning (e.g., classical and operant conditioning). However, empirical evidence on whether RPEs drive declarative learning–a quintessentially human form of learning–remains surprisingly absent. We

A simple solution for model comparison in bold imaging: the special case of reward prediction error and reward outcomes.

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Erdeniz, Burak; Rohe, Tim; Done, John; Seidler, Rachael D

2013-01-01

Conventional neuroimaging techniques provide information about condition-related changes of the BOLD (blood-oxygen-level dependent) signal, indicating only where and when the underlying cognitive processes occur. Recently, with the help of a new approach called "model-based" functional neuroimaging (fMRI), researchers are able to visualize changes in the internal variables of a time varying learning process, such as the reward prediction error or the predicted reward value of a conditional stimulus. However, despite being extremely beneficial to the imaging community in understanding the neural correlates of decision variables, a model-based approach to brain imaging data is also methodologically challenging due to the multicollinearity problem in statistical analysis. There are multiple sources of multicollinearity in functional neuroimaging including investigations of closely related variables and/or experimental designs that do not account for this. The source of multicollinearity discussed in this paper occurs due to correlation between different subjective variables that are calculated very close in time. Here, we review methodological approaches to analyzing such data by discussing the special case of separating the reward prediction error signal from reward outcomes.

Neural correlates of reward processing in healthy siblings of patients with schizophrenia

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Hanssen, Esther; van der Velde, J; Gromann, P.; Shergill, S.; de Haan, L.; Bruggeman, R.; Krabbendam, A.C.; Aleman, A.; van Atteveldt, N.M.

2015-01-01

Deficits in motivational behavior and psychotic symptoms often observed in schizophrenia (SZ) may be driven by dysfunctional reward processing (RP). RP can be divided in two different stages; reward anticipation and reward consumption. Aberrant processing during reward anticipation seems to be

When theory and biology differ: The relationship between reward prediction errors and expectancy.

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Williams, Chad C; Hassall, Cameron D; Trska, Robert; Holroyd, Clay B; Krigolson, Olave E

2017-10-01

Comparisons between expectations and outcomes are critical for learning. Termed prediction errors, the violations of expectancy that occur when outcomes differ from expectations are used to modify value and shape behaviour. In the present study, we examined how a wide range of expectancy violations impacted neural signals associated with feedback processing. Participants performed a time estimation task in which they had to guess the duration of one second while their electroencephalogram was recorded. In a key manipulation, we varied task difficulty across the experiment to create a range of different feedback expectancies - reward feedback was either very expected, expected, 50/50, unexpected, or very unexpected. As predicted, the amplitude of the reward positivity, a component of the human event-related brain potential associated with feedback processing, scaled inversely with expectancy (e.g., unexpected feedback yielded a larger reward positivity than expected feedback). Interestingly, the scaling of the reward positivity to outcome expectancy was not linear as would be predicted by some theoretical models. Specifically, we found that the amplitude of the reward positivity was about equivalent for very expected and expected feedback, and for very unexpected and unexpected feedback. As such, our results demonstrate a sigmoidal relationship between reward expectancy and the amplitude of the reward positivity, with interesting implications for theories of reinforcement learning. Copyright © 2017 Elsevier B.V. All rights reserved.

Competition between learned reward and error outcome predictions in anterior cingulate cortex.

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Alexander, William H; Brown, Joshua W

2010-02-15

The anterior cingulate cortex (ACC) is implicated in performance monitoring and cognitive control. Non-human primate studies of ACC show prominent reward signals, but these are elusive in human studies, which instead show mainly conflict and error effects. Here we demonstrate distinct appetitive and aversive activity in human ACC. The error likelihood hypothesis suggests that ACC activity increases in proportion to the likelihood of an error, and ACC is also sensitive to the consequence magnitude of the predicted error. Previous work further showed that error likelihood effects reach a ceiling as the potential consequences of an error increase, possibly due to reductions in the average reward. We explored this issue by independently manipulating reward magnitude of task responses and error likelihood while controlling for potential error consequences in an Incentive Change Signal Task. The fMRI results ruled out a modulatory effect of expected reward on error likelihood effects in favor of a competition effect between expected reward and error likelihood. Dynamic causal modeling showed that error likelihood and expected reward signals are intrinsic to the ACC rather than received from elsewhere. These findings agree with interpretations of ACC activity as signaling both perceptions of risk and predicted reward. Copyright 2009 Elsevier Inc. All rights reserved.

Prediction-error in the context of real social relationships modulates reward system activity.

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Poore, Joshua C; Pfeifer, Jennifer H; Berkman, Elliot T; Inagaki, Tristen K; Welborn, Benjamin L; Lieberman, Matthew D

2012-01-01

The human reward system is sensitive to both social (e.g., validation) and non-social rewards (e.g., money) and is likely integral for relationship development and reputation building. However, data is sparse on the question of whether implicit social reward processing meaningfully contributes to explicit social representations such as trust and attachment security in pre-existing relationships. This event-related fMRI experiment examined reward system prediction-error activity in response to a potent social reward-social validation-and this activity's relation to both attachment security and trust in the context of real romantic relationships. During the experiment, participants' expectations for their romantic partners' positive regard of them were confirmed (validated) or violated, in either positive or negative directions. Primary analyses were conducted using predefined regions of interest, the locations of which were taken from previously published research. Results indicate that activity for mid-brain and striatal reward system regions of interest was modulated by social reward expectation violation in ways consistent with prior research on reward prediction-error. Additionally, activity in the striatum during viewing of disconfirmatory information was associated with both increases in post-scan reports of attachment anxiety and decreases in post-scan trust, a finding that follows directly from representational models of attachment and trust.

Ethanol Exposure History and Alcoholic Reward Differentially Alter Dopamine Release in the Nucleus Accumbens to a Reward-Predictive Cue.

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Fiorenza, Amanda M; Shnitko, Tatiana A; Sullivan, Kaitlin M; Vemuru, Sudheer R; Gomez-A, Alexander; Esaki, Julie Y; Boettiger, Charlotte A; Da Cunha, Claudio; Robinson, Donita L

2018-06-01

Conditioned stimuli (CS) that predict reward delivery acquire the ability to induce phasic dopamine release in the nucleus accumbens (NAc). This dopamine release may facilitate conditioned approach behavior, which often manifests as approach to the site of reward delivery (called "goal-tracking") or to the CS itself (called "sign-tracking"). Previous research has linked sign-tracking in particular to impulsivity and drug self-administration, and addictive drugs may promote the expression of sign-tracking. Ethanol (EtOH) acutely promotes phasic release of dopamine in the accumbens, but it is unknown whether an alcoholic reward alters dopamine release to a CS. We hypothesized that Pavlovian conditioning with an alcoholic reward would increase dopamine release triggered by the CS and subsequent sign-tracking behavior. Moreover, we predicted that chronic intermittent EtOH (CIE) exposure would promote sign-tracking while acute administration of naltrexone (NTX) would reduce it. Rats received 14 doses of EtOH (3 to 5 g/kg, intragastric) or water followed by 6 days of Pavlovian conditioning training. Rewards were a chocolate solution with or without 10% (w/v) alcohol. We used fast-scan cyclic voltammetry to measure phasic dopamine release in the NAc core in response to the CS and the rewards. We also determined the effect of NTX (1 mg/kg, subcutaneous) on conditioned approach. Both CIE and alcoholic reward, individually but not together, associated with greater dopamine to the CS than control conditions. However, this increase in dopamine release was not linked to greater sign-tracking, as both CIE and alcoholic reward shifted conditioned approach from sign-tracking behavior to goal-tracking behavior. However, they both also increased sensitivity to NTX, which reduced goal-tracking behavior. While a history of EtOH exposure or alcoholic reward enhanced dopamine release to a CS, they did not promote sign-tracking under the current conditions. These findings are

Episodic Memory Encoding Interferes with Reward Learning and Decreases Striatal Prediction Errors

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Braun, Erin Kendall; Daw, Nathaniel D.

2014-01-01

Learning is essential for adaptive decision making. The striatum and its dopaminergic inputs are known to support incremental reward-based learning, while the hippocampus is known to support encoding of single events (episodic memory). Although traditionally studied separately, in even simple experiences, these two types of learning are likely to co-occur and may interact. Here we sought to understand the nature of this interaction by examining how incremental reward learning is related to concurrent episodic memory encoding. During the experiment, human participants made choices between two options (colored squares), each associated with a drifting probability of reward, with the goal of earning as much money as possible. Incidental, trial-unique object pictures, unrelated to the choice, were overlaid on each option. The next day, participants were given a surprise memory test for these pictures. We found that better episodic memory was related to a decreased influence of recent reward experience on choice, both within and across participants. fMRI analyses further revealed that during learning the canonical striatal reward prediction error signal was significantly weaker when episodic memory was stronger. This decrease in reward prediction error signals in the striatum was associated with enhanced functional connectivity between the hippocampus and striatum at the time of choice. Our results suggest a mechanism by which memory encoding may compete for striatal processing and provide insight into how interactions between different forms of learning guide reward-based decision making. PMID:25378157

Prediction-error in the context of real social relationships modulates reward system activity

Directory of Open Access Journals (Sweden)

Joshua ePoore

2012-08-01

Full Text Available The human reward system is sensitive to both social (e.g., validation and non-social rewards (e.g., money and is likely integral for relationship development and reputation building. However, data is sparse on the question of whether implicit social reward processing meaningfully contributes to explicit social representations such as trust and attachment security in pre-existing relationships. This event-related fMRI experiment examined reward system prediction-error activity in response to a potent social reward—social validation—and this activity’s relation to both attachment security and trust in the context of real romantic relationships. During the experiment, participants’ expectations for their romantic partners’ positive regard of them were confirmed (validated or violated, in either positive or negative directions. Primary analyses were conducted using predefined regions of interest, the locations of which were taken from previously published research. Results indicate that activity for mid-brain and striatal reward system regions of interest was modulated by social reward expectation violation in ways consistent with prior research on reward prediction-error. Additionally, activity in the striatum during viewing of disconfirmatory information was associated with both increases in post-scan reports of attachment anxiety and decreases in post-scan trust, a finding that follows directly from representational models of attachment and trust.

Reward Prediction Errors in Drug Addiction and Parkinson's Disease: from Neurophysiology to Neuroimaging.

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García-García, Isabel; Zeighami, Yashar; Dagher, Alain

2017-06-01

Surprises are important sources of learning. Cognitive scientists often refer to surprises as "reward prediction errors," a parameter that captures discrepancies between expectations and actual outcomes. Here, we integrate neurophysiological and functional magnetic resonance imaging (fMRI) results addressing the processing of reward prediction errors and how they might be altered in drug addiction and Parkinson's disease. By increasing phasic dopamine responses, drugs might accentuate prediction error signals, causing increases in fMRI activity in mesolimbic areas in response to drugs. Chronic substance dependence, by contrast, has been linked with compromised dopaminergic function, which might be associated with blunted fMRI responses to pleasant non-drug stimuli in mesocorticolimbic areas. In Parkinson's disease, dopamine replacement therapies seem to induce impairments in learning from negative outcomes. The present review provides a holistic overview of reward prediction errors across different pathologies and might inform future clinical strategies targeting impulsive/compulsive disorders.

BOLD responses in reward regions to hypothetical and imaginary monetary rewards.

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Miyapuram, Krishna P; Tobler, Philippe N; Gregorios-Pippas, Lucy; Schultz, Wolfram

2012-01-16

Monetary rewards are uniquely human. Because money is easy to quantify and present visually, it is the reward of choice for most fMRI studies, even though it cannot be handed over to participants inside the scanner. A typical fMRI study requires hundreds of trials and thus small amounts of monetary rewards per trial (e.g. 5p) if all trials are to be treated equally. However, small payoffs can have detrimental effects on performance due to their limited buying power. Hypothetical monetary rewards can overcome the limitations of smaller monetary rewards but it is less well known whether predictors of hypothetical rewards activate reward regions. In two experiments, visual stimuli were associated with hypothetical monetary rewards. In Experiment 1, we used stimuli predicting either visually presented or imagined hypothetical monetary rewards, together with non-rewarding control pictures. Activations to reward predictive stimuli occurred in reward regions, namely the medial orbitofrontal cortex and midbrain. In Experiment 2, we parametrically varied the amount of visually presented hypothetical monetary reward keeping constant the amount of actually received reward. Graded activation in midbrain was observed to stimuli predicting increasing hypothetical rewards. The results demonstrate the efficacy of using hypothetical monetary rewards in fMRI studies. Copyright © 2011 Elsevier Inc. All rights reserved.

Ventromedial Frontal Cortex Is Critical for Guiding Attention to Reward-Predictive Visual Features in Humans.

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Vaidya, Avinash R; Fellows, Lesley K

2015-09-16

Adaptively interacting with our environment requires extracting information that will allow us to successfully predict reward. This can be a challenge, particularly when there are many candidate cues, and when rewards are probabilistic. Recent work has demonstrated that visual attention is allocated to stimulus features that have been associated with reward on previous trials. The ventromedial frontal lobe (VMF) has been implicated in learning in dynamic environments of this kind, but the mechanism by which this region influences this process is not clear. Here, we hypothesized that the VMF plays a critical role in guiding attention to reward-predictive stimulus features based on feedback. We tested the effects of VMF damage in human subjects on a visual search task in which subjects were primed to attend to task-irrelevant colors associated with different levels of reward, incidental to the search task. Consistent with previous work, we found that distractors had a greater influence on reaction time when they appeared in colors associated with high reward in the previous trial compared with colors associated with low reward in healthy control subjects and patients with prefrontal damage sparing the VMF. However, this reward modulation of attentional priming was absent in patients with VMF damage. Thus, an intact VMF is necessary for directing attention based on experience with cue-reward associations. We suggest that this region plays a role in selecting reward-predictive cues to facilitate future learning. There has been a swell of interest recently in the ventromedial frontal cortex (VMF), a brain region critical to associative learning. However, the underlying mechanism by which this region guides learning is not well understood. Here, we tested the effects of damage to this region in humans on a task in which rewards were linked incidentally to visual features, resulting in trial-by-trial attentional priming. Controls and subjects with prefrontal damage

The Distribution of Chromosomal Aberrations in Human Cells Predicted by a Generalized Time-Dependent Model of Radiation-Induced Formation of Aberrations

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Ponomarev, Artem L.; George, K.; Cucinotta, F. A.

2011-01-01

New experimental data show how chromosomal aberrations for low- and high-LET radiation are dependent on DSB repair deficiencies in wild-type, AT and NBS cells. We simulated the development of chromosomal aberrations in these cells lines in a stochastic track-structure-dependent model, in which different cells have different kinetics of DSB repair. We updated a previously formulated model of chromosomal aberrations, which was based on a stochastic Monte Carlo approach, to consider the time-dependence of DSB rejoining. The previous version of the model had an assumption that all DSBs would rejoin, and therefore we called it a time-independent model. The chromosomal-aberrations model takes into account the DNA and track structure for low- and high-LET radiations, and provides an explanation and prediction of the statistics of rare and more complex aberrations. We compared the program-simulated kinetics of DSB rejoining to the experimentally-derived bimodal exponential curves of the DSB kinetics. We scored the formation of translocations, dicentrics, acentric and centric rings, deletions, and inversions. The fraction of DSBs participating in aberrations was studied in relation to the rejoining time. Comparisons of simulated dose dependence for simple aberrations to the experimental dose-dependence for HF19, AT and NBS cells will be made.

Exploring food reward and calorie intake in self-perceived food addicts.

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Ruddock, Helen K; Field, Matt; Hardman, Charlotte A

2017-08-01

Previous research indicates that many people perceive themselves to be addicted to food. These 'self-perceived food addicts' may demonstrate aberrant eating patterns which put them at greater risk of overeating. However this is yet to be empirically investigated. The current study investigated whether self-perceived food addicts would exhibit higher food reward and calorie intake in a laboratory context relative to self-perceived non-addicts. A secondary aim was to investigate whether self-perceived food addicts would demonstrate increased food liking and/or increased hunger ratings. Finally, we explored whether self-perceived food addicts demonstrate patterns of aberrant eating, beyond that predicted by measures of trait dietary disinhibition and restraint. Female participants (self-perceived food addicts n = 31, non-addicts n = 29) completed measures of hunger, food reward (desire-to-eat, willingness-to-pay ratings, and an operant response task) and liking for high- and low-fat foods. Participants completed all measures when they were hungry, and again when they were satiated after consuming a fixed-lunch meal. Finally, participants were provided with ad-libitum access to high-and low-fat foods. Results indicated that self-perceived food addicts consumed more calories from high-fat food compared to non-addicts, despite the absence of any between-group differences in hunger or overall liking ratings. Self-perceived food addicts also displayed higher desire-to-eat ratings across foods compared to non-addicts, but groups did not differ on other measures of food reward. However, the differences in calorie intake and desire-to-eat between self-perceived food addicts and non-addicts were no longer significant after controlling for dietary disinhibition and restraint. These findings suggest that self-perceived food addicts experience food as more rewarding and have a tendency to overeat. However, this may be attributable to increased dietary disinhibition and

Aberrant membranous expression of β-catenin predicts poor prognosis in patients with craniopharyngioma.

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Li, Zongping; Xu, Jianguo; Huang, Siqing; You, Chao

2015-12-01

The objective of this study is to investigate β-catenin expression in craniopharyngioma patients and determine its significance in predicting the prognosis of this disease. Fifty craniopharyngioma patients were enrolled in this study. Expression of β-catenin in tumor specimens collected from these patients was examined through immunostaining. In addition, mutation of exon 3 in the β-catenin gene, CTNNB1, was analyzed using polymerase chain reaction, denaturing high-pressure liquid chromatography, and DNA sequencing. Based on these results, we explored the association between membranous β-catenin expression, clinical and pathologic characteristics, and prognoses in these patients. Of all craniopharyngioma specimens, 31 (62.0%) had preserved membranous β-catenin expression, whereas the remaining 19 specimens (38.0%) displayed aberrant expression. Statistical analysis showed a significant correlation between aberrant membranous β-catenin expression and CTNNB1 exon 3 mutation, as well as between aberrant membranous β-catenin expression and the histopathologic type of craniopharyngioma and type of resection in our patient population. Furthermore, aberrant membranous β-catenin expression was found to be associated with poor patient survival. Results of Kaplan-Meier survival analysis and Cox regression analysis further confirmed this finding. In conclusion, our study demonstrated that aberrant membranous β-catenin expression was significantly correlated with poor survival in patients with craniopharyngioma. This raises the possibility for use of aberrant membranous β-catenin expression as an independent risk factor in predicting the prognosis of this disease. Copyright © 2015 Elsevier Inc. All rights reserved.

Spatiotemporal neural characterization of prediction error valence and surprise during reward learning in humans.

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Fouragnan, Elsa; Queirazza, Filippo; Retzler, Chris; Mullinger, Karen J; Philiastides, Marios G

2017-07-06

Reward learning depends on accurate reward associations with potential choices. These associations can be attained with reinforcement learning mechanisms using a reward prediction error (RPE) signal (the difference between actual and expected rewards) for updating future reward expectations. Despite an extensive body of literature on the influence of RPE on learning, little has been done to investigate the potentially separate contributions of RPE valence (positive or negative) and surprise (absolute degree of deviation from expectations). Here, we coupled single-trial electroencephalography with simultaneously acquired fMRI, during a probabilistic reversal-learning task, to offer evidence of temporally overlapping but largely distinct spatial representations of RPE valence and surprise. Electrophysiological variability in RPE valence correlated with activity in regions of the human reward network promoting approach or avoidance learning. Electrophysiological variability in RPE surprise correlated primarily with activity in regions of the human attentional network controlling the speed of learning. Crucially, despite the largely separate spatial extend of these representations our EEG-informed fMRI approach uniquely revealed a linear superposition of the two RPE components in a smaller network encompassing visuo-mnemonic and reward areas. Activity in this network was further predictive of stimulus value updating indicating a comparable contribution of both signals to reward learning.

Episodic memory encoding interferes with reward learning and decreases striatal prediction errors.

Science.gov (United States)

Wimmer, G Elliott; Braun, Erin Kendall; Daw, Nathaniel D; Shohamy, Daphna

2014-11-05

Learning is essential for adaptive decision making. The striatum and its dopaminergic inputs are known to support incremental reward-based learning, while the hippocampus is known to support encoding of single events (episodic memory). Although traditionally studied separately, in even simple experiences, these two types of learning are likely to co-occur and may interact. Here we sought to understand the nature of this interaction by examining how incremental reward learning is related to concurrent episodic memory encoding. During the experiment, human participants made choices between two options (colored squares), each associated with a drifting probability of reward, with the goal of earning as much money as possible. Incidental, trial-unique object pictures, unrelated to the choice, were overlaid on each option. The next day, participants were given a surprise memory test for these pictures. We found that better episodic memory was related to a decreased influence of recent reward experience on choice, both within and across participants. fMRI analyses further revealed that during learning the canonical striatal reward prediction error signal was significantly weaker when episodic memory was stronger. This decrease in reward prediction error signals in the striatum was associated with enhanced functional connectivity between the hippocampus and striatum at the time of choice. Our results suggest a mechanism by which memory encoding may compete for striatal processing and provide insight into how interactions between different forms of learning guide reward-based decision making. Copyright © 2014 the authors 0270-6474/14/3414901-12$15.00/0.

Decision-making patterns and sensitivity to reward and punishment in children with attention-deficit hyperactivity disorder.

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Masunami, Taiji; Okazaki, Shinji; Maekawa, Hisao

2009-06-01

Earlier studies have demonstrated that attention-deficit hyperactivity disorder (ADHD) is associated with aberrant sensitivity to rewards and punishments. Although some studies have focused on real-life decision making in children with ADHD using the Iowa gambling task, the number of good deck choices, a frequently used index of decision-making ability in the gambling task, is insufficient for investigating the complex decision-making strategies in subjects. In the present study, we investigated decision-making strategies in ADHD children, analyzing T-patterns with rewards, with punishments, and without rewards and punishments during the gambling task, and examined the relationship between decision-making strategies and skin conductance responses (SCRs) to rewards and punishments. We hypothesized that ADHD children and normal children would employ different decision-making strategies depending on their sensitivity to rewards and punishments in the gambling task. Our results revealed that ADHD children had fewer T-patterns with punishments and exhibited a significant tendency to have many T-patterns with rewards, thus supporting our hypothesis. Moreover, in contrast to normal children, ADHD children failed to demonstrate differences between reward and punishment SCRs, supporting the idea that they had an aberrant sensitivity to rewards and punishments. Therefore, we concluded that ADHD children would be impaired in decision-making strategies depending on their aberrant sensitivity to rewards and punishments. However, we were unable to specify whether large reward SCRs or small punishment SCRs is generated in ADHD children.

From prediction error to incentive salience: mesolimbic computation of reward motivation

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Berridge, Kent C.

2011-01-01

Reward contains separable psychological components of learning, incentive motivation and pleasure. Most computational models have focused only on the learning component of reward, but the motivational component is equally important in reward circuitry, and even more directly controls behavior. Modeling the motivational component requires recognition of additional control factors besides learning. Here I will discuss how mesocorticolimbic mechanisms generate the motivation component of incentive salience. Incentive salience takes Pavlovian learning and memory as one input and as an equally important input takes neurobiological state factors (e.g., drug states, appetite states, satiety states) that can vary independently of learning. Neurobiological state changes can produce unlearned fluctuations or even reversals in the ability of a previously-learned reward cue to trigger motivation. Such fluctuations in cue-triggered motivation can dramatically depart from all previously learned values about the associated reward outcome. Thus a consequence of the difference between incentive salience and learning can be to decouple cue-triggered motivation of the moment from previously learned values of how good the associated reward has been in the past. Another consequence can be to produce irrationally strong motivation urges that are not justified by any memories of previous reward values (and without distorting associative predictions of future reward value). Such irrationally strong motivation may be especially problematic in addiction. To comprehend these phenomena, future models of mesocorticolimbic reward function should address the neurobiological state factors that participate to control generation of incentive salience. PMID:22487042

Prediction for the occurrence of clonal chromosome aberrations in human blood lymphocytes

International Nuclear Information System (INIS)

Nakano, M.; Kadama, Y.; Ohtaki, K.; Itoh, M.; Awa, A.; Cologne, J.; Nakamura, N.

2003-01-01

Full text: Identical chromosome aberrations among multiple blood lymphocytes in a blood sample (clonal aberrations) are encountered occasionally during cytogenetic examination of radiation-exposed people. Clonal aberrations are found primarily among high-dose exposed people but no systematic surveys were ever conducted. Therefore, the underlying mechanism is unknown. Here we conducted a large-scale screening for detecting clonal aberrations using FISH followed by Q-banding. Examinations of 500 cells from each of 513 A-bomb survivors led us to detect 96 clones. The clonal cell fraction (Cf) varied from 0.6% to 20% among the 500 cells. As the number of clonal event was inversely proportional to Cf, we hypothesized that the progenitor cells vary extensively in the number of offspring that they can produce and relative number of progenitor cells decreases as the increase of treatment, while other genes such as DNA repair proteinsnumber of progenitor cells capable to form clones (Cf >=0.6%) to be 2 (1 to 3) in non-exposed individuals. The number increased to up to 7 among the high-dose exposed survivors. Further, our preliminary results for the origins of 10 clones indicated that both hematopoietic stem cells (HSCs) and mature T cells contributed to the clone formation roughly equally. Thus, the estimated number of 2 in non-exposed individuals is shared as one HSC and one mature T cells. The model could neatly explain the frequency of clones in two reports. Our model predicts that clonal aberrations are rarely found but clonal expansion of T lymphocytes occurs commonly. In fact, clonal expansions of non-aberrant cells are reported using TCR gene rearrangement patterns as a marker. We now understand the rough structure of lymphocyte pool in humans and can predict the probability of detecting a clone if the individual frequency of non-clonal translocations and the number of cells scored are given

Functional connectivity in cortico-subcortical brain networks underlying reward processing in attention-deficit/hyperactivity disorder

NARCIS (Netherlands)

Oldehinkel, Marianne; Beckmann, Christian F.; Franke, Barbara; Hartman, Catharina A.; Hoekstra, Pieter J.; Oosterlaan, Jaap; Heslenfeld, Dirk; Buitelaar, Jan K.; Mennes, Maarten

2016-01-01

Background: Many patients with attention-deficit/hyperactivity disorder (ADHD) display aberrant reward-related behavior. Task-based fMRI studies have related atypical reward processing in ADHD to altered BOLD activity in regions underlying reward processing such as ventral striatum and orbitofrontal

Dopamine-signalled reward predictions generated by competitive excitation and inhibition in a spiking neural network model

Directory of Open Access Journals (Sweden)

Paul eChorley

2011-05-01

Full Text Available Dopaminergic neurons in the mammalian substantia nigra displaycharacteristic phasic responses to stimuli which reliably predict thereceipt of primary rewards. These responses have been suggested toencode reward prediction-errors similar to those used in reinforcementlearning. Here, we propose a model of dopaminergic activity in whichprediction error signals are generated by the joint action ofshort-latency excitation and long-latency inhibition, in a networkundergoing dopaminergic neuromodulation of both spike-timing dependentsynaptic plasticity and neuronal excitability. In contrast toprevious models, sensitivity to recent events is maintained by theselective modification of specific striatal synapses, efferent tocortical neurons exhibiting stimulus-specific, temporally extendedactivity patterns. Our model shows, in the presence of significantbackground activity, (i a shift in dopaminergic response from rewardto reward predicting stimuli, (ii preservation of a response tounexpected rewards, and (iii a precisely-timed below-baseline dip inactivity observed when expected rewards are omitted.

From prediction error to incentive salience: mesolimbic computation of reward motivation.

Science.gov (United States)

Berridge, Kent C

2012-04-01

Reward contains separable psychological components of learning, incentive motivation and pleasure. Most computational models have focused only on the learning component of reward, but the motivational component is equally important in reward circuitry, and even more directly controls behavior. Modeling the motivational component requires recognition of additional control factors besides learning. Here I discuss how mesocorticolimbic mechanisms generate the motivation component of incentive salience. Incentive salience takes Pavlovian learning and memory as one input and as an equally important input takes neurobiological state factors (e.g. drug states, appetite states, satiety states) that can vary independently of learning. Neurobiological state changes can produce unlearned fluctuations or even reversals in the ability of a previously learned reward cue to trigger motivation. Such fluctuations in cue-triggered motivation can dramatically depart from all previously learned values about the associated reward outcome. Thus, one consequence of the difference between incentive salience and learning can be to decouple cue-triggered motivation of the moment from previously learned values of how good the associated reward has been in the past. Another consequence can be to produce irrationally strong motivation urges that are not justified by any memories of previous reward values (and without distorting associative predictions of future reward value). Such irrationally strong motivation may be especially problematic in addiction. To understand these phenomena, future models of mesocorticolimbic reward function should address the neurobiological state factors that participate to control generation of incentive salience. © 2012 The Author. European Journal of Neuroscience © 2012 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.

Altered neural reward and loss processing and prediction error signalling in depression

Science.gov (United States)

Ubl, Bettina; Kuehner, Christine; Kirsch, Peter; Ruttorf, Michaela

2015-01-01

Dysfunctional processing of reward and punishment may play an important role in depression. However, functional magnetic resonance imaging (fMRI) studies have shown heterogeneous results for reward processing in fronto-striatal regions. We examined neural responsivity associated with the processing of reward and loss during anticipation and receipt of incentives and related prediction error (PE) signalling in depressed individuals. Thirty medication-free depressed persons and 28 healthy controls performed an fMRI reward paradigm. Regions of interest analyses focused on neural responses during anticipation and receipt of gains and losses and related PE-signals. Additionally, we assessed the relationship between neural responsivity during gain/loss processing and hedonic capacity. When compared with healthy controls, depressed individuals showed reduced fronto-striatal activity during anticipation of gains and losses. The groups did not significantly differ in response to reward and loss outcomes. In depressed individuals, activity increases in the orbitofrontal cortex and nucleus accumbens during reward anticipation were associated with hedonic capacity. Depressed individuals showed an absence of reward-related PEs but encoded loss-related PEs in the ventral striatum. Depression seems to be linked to blunted responsivity in fronto-striatal regions associated with limited motivational responses for rewards and losses. Alterations in PE encoding might mirror blunted reward- and enhanced loss-related associative learning in depression. PMID:25567763

Reward rate optimization in two-alternative decision making: empirical tests of theoretical predictions.

Science.gov (United States)

Simen, Patrick; Contreras, David; Buck, Cara; Hu, Peter; Holmes, Philip; Cohen, Jonathan D

2009-12-01

The drift-diffusion model (DDM) implements an optimal decision procedure for stationary, 2-alternative forced-choice tasks. The height of a decision threshold applied to accumulating information on each trial determines a speed-accuracy tradeoff (SAT) for the DDM, thereby accounting for a ubiquitous feature of human performance in speeded response tasks. However, little is known about how participants settle on particular tradeoffs. One possibility is that they select SATs that maximize a subjective rate of reward earned for performance. For the DDM, there exist unique, reward-rate-maximizing values for its threshold and starting point parameters in free-response tasks that reward correct responses (R. Bogacz, E. Brown, J. Moehlis, P. Holmes, & J. D. Cohen, 2006). These optimal values vary as a function of response-stimulus interval, prior stimulus probability, and relative reward magnitude for correct responses. We tested the resulting quantitative predictions regarding response time, accuracy, and response bias under these task manipulations and found that grouped data conformed well to the predictions of an optimally parameterized DDM.

A balance of activity in brain control and reward systems predicts self-regulatory outcomes

OpenAIRE

Lopez, Richard B.; Chen, Pin-Hao A.; Huckins, Jeremy F.; Hofmann, Wilhelm; Kelley, William M.; Heatherton, Todd F.

2017-01-01

Abstract Previous neuroimaging work has shown that increased reward-related activity following exposure to food cues is predictive of self-control failure. The balance model suggests that self-regulation failures result from an imbalance in reward and executive control mechanisms. However, an open question is whether the relative balance of activity in brain systems associated with executive control (vs reward) supports self-regulatory outcomes when people encounter tempting cues in daily lif...

Cognitive capacity limitations and Need for Cognition differentially predict reward-induced cognitive effort expenditure.

Science.gov (United States)

Sandra, Dasha A; Otto, A Ross

2018-03-01

While psychological, economic, and neuroscientific accounts of behavior broadly maintain that people minimize expenditure of cognitive effort, empirical work reveals how reward incentives can mobilize increased cognitive effort expenditure. Recent theories posit that the decision to expend effort is governed, in part, by a cost-benefit tradeoff whereby the potential benefits of mental effort can offset the perceived costs of effort exertion. Taking an individual differences approach, the present study examined whether one's executive function capacity, as measured by Stroop interference, predicts the extent to which reward incentives reduce switch costs in a task-switching paradigm, which indexes additional expenditure of cognitive effort. In accordance with the predictions of a cost-benefit account of effort, we found that a low executive function capacity-and, relatedly, a low intrinsic motivation to expend effort (measured by Need for Cognition)-predicted larger increase in cognitive effort expenditure in response to monetary reward incentives, while individuals with greater executive function capacity-and greater intrinsic motivation to expend effort-were less responsive to reward incentives. These findings suggest that an individual's cost-benefit tradeoff is constrained by the perceived costs of exerting cognitive effort. Copyright © 2017 Elsevier B.V. All rights reserved.

Reward sensitivity predicts ice cream-related attentional bias assessed by inattentional blindness.

Science.gov (United States)

Li, Xiaoming; Tao, Qian; Fang, Ya; Cheng, Chen; Hao, Yangyang; Qi, Jianjun; Li, Yu; Zhang, Wei; Wang, Ying; Zhang, Xiaochu

2015-06-01

The cognitive mechanism underlying the association between individual differences in reward sensitivity and food craving is unknown. The present study explored the mechanism by examining the role of reward sensitivity in attentional bias toward ice cream cues. Forty-nine college students who displayed high level of ice cream craving (HICs) and 46 who displayed low level of ice cream craving (LICs) performed an inattentional blindness (IB) task which was used to assess attentional bias for ice cream. In addition, reward sensitivity and coping style were assessed by the Behavior Inhibition System/Behavior Activation System Scales and Simplified Coping Style Questionnaire. Results showed significant higher identification rate of the critical stimulus in the HICs than LICs, suggesting greater attentional bias for ice cream in the HICs. It was indicated that attentional bias for food cues persisted even under inattentional condition. Furthermore, a significant correlation was found between the attentional bias and reward sensitivity after controlling for coping style, and reward sensitivity predicted attentional bias for food cues. The mediation analyses showed that attentional bias mediated the relationship between reward sensitivity and food craving. Those findings suggest that the association between individual differences in reward sensitivity and food craving may be attributed to attentional bias for food-related cues. Copyright © 2015 Elsevier Ltd. All rights reserved.

The role of reward and reward uncertainty in episodic memory

OpenAIRE

Mason, Alice; Farrell, Simon; Howard-Jones, Paul; Ludwig, Casimir

2017-01-01

Declarative memory has been found to be sensitive to reward-related changes in the environment. The reward signal can be broken down into information regarding the expected value of the reward, reward uncertainty and the prediction error. Research has established that high as opposed to low reward values enhance declarative memory. Research in neuroscience suggests that high uncertainty activates the reward system, which could lead to enhanced learning and memory. Here we present the results ...

Dopamine reward prediction errors reflect hidden state inference across time

Science.gov (United States)

Starkweather, Clara Kwon; Babayan, Benedicte M.; Uchida, Naoshige; Gershman, Samuel J.

2017-01-01

Midbrain dopamine neurons signal reward prediction error (RPE), or actual minus expected reward. The temporal difference (TD) learning model has been a cornerstone in understanding how dopamine RPEs could drive associative learning. Classically, TD learning imparts value to features that serially track elapsed time relative to observable stimuli. In the real world, however, sensory stimuli provide ambiguous information about the hidden state of the environment, leading to the proposal that TD learning might instead compute a value signal based on an inferred distribution of hidden states (a ‘belief state’). In this work, we asked whether dopaminergic signaling supports a TD learning framework that operates over hidden states. We found that dopamine signaling exhibited a striking difference between two tasks that differed only with respect to whether reward was delivered deterministically. Our results favor an associative learning rule that combines cached values with hidden state inference. PMID:28263301

A balance of activity in brain control and reward systems predicts self-regulatory outcomes.

Science.gov (United States)

Lopez, Richard B; Chen, Pin-Hao A; Huckins, Jeremy F; Hofmann, Wilhelm; Kelley, William M; Heatherton, Todd F

2017-05-01

Previous neuroimaging work has shown that increased reward-related activity following exposure to food cues is predictive of self-control failure. The balance model suggests that self-regulation failures result from an imbalance in reward and executive control mechanisms. However, an open question is whether the relative balance of activity in brain systems associated with executive control (vs reward) supports self-regulatory outcomes when people encounter tempting cues in daily life. Sixty-nine chronic dieters, a population known for frequent lapses in self-control, completed a food cue-reactivity task during an fMRI scanning session, followed by a weeklong sampling of daily eating behaviors via ecological momentary assessment. We related participants' food cue activity in brain systems associated with executive control and reward to real-world eating patterns. Specifically, a balance score representing the amount of activity in brain regions associated with self-regulatory control, relative to automatic reward-related activity, predicted dieters' control over their eating behavior during the following week. This balance measure may reflect individual self-control capacity and be useful for examining self-regulation success in other domains and populations. © The Author (2017). Published by Oxford University Press.

Abnormal Striatal BOLD Responses to Reward Anticipation and Reward Delivery in ADHD

Science.gov (United States)

Furukawa, Emi; Bado, Patricia; Tripp, Gail; Mattos, Paulo; Wickens, Jeff R.; Bramati, Ivanei E.; Alsop, Brent; Ferreira, Fernanda Meireles; Lima, Debora; Tovar-Moll, Fernanda; Sergeant, Joseph A.; Moll, Jorge

2014-01-01

Altered reward processing has been proposed to contribute to the symptoms of attention deficit hyperactivity disorder (ADHD). The neurobiological mechanism underlying this alteration remains unclear. We hypothesize that the transfer of dopamine release from reward to reward-predicting cues, as normally observed in animal studies, may be deficient in ADHD. Functional magnetic resonance imaging (fMRI) was used to investigate striatal responses to reward-predicting cues and reward delivery in a classical conditioning paradigm. Data from 14 high-functioning and stimulant-naïve young adults with elevated lifetime symptoms of ADHD (8 males, 6 females) and 15 well-matched controls (8 males, 7 females) were included in the analyses. During reward anticipation, increased blood-oxygen-level-dependent (BOLD) responses in the right ventral and left dorsal striatum were observed in controls, but not in the ADHD group. The opposite pattern was observed in response to reward delivery; the ADHD group demonstrated significantly greater BOLD responses in the ventral striatum bilaterally and the left dorsal striatum relative to controls. In the ADHD group, the number of current hyperactivity/impulsivity symptoms was inversely related to ventral striatal responses during reward anticipation and positively associated with responses to reward. The BOLD response patterns observed in the striatum are consistent with impaired predictive dopamine signaling in ADHD, which may explain altered reward-contingent behaviors and symptoms of ADHD. PMID:24586543

Ventral striatum activation to prosocial rewards predicts longitudinal declines in adolescent risk taking.

Science.gov (United States)

Telzer, Eva H; Fuligni, Andrew J; Lieberman, Matthew D; Galván, Adriana

2013-01-01

Adolescence is a period of intensified emotions and an increase in motivated behaviors and passions. Evidence from developmental neuroscience suggests that this heightened emotionality occurs, in part, due to a peak in functional reactivity to rewarding stimuli, which renders adolescents more oriented toward reward-seeking behaviors. Most prior work has focused on how reward sensitivity may create vulnerabilities, leading to increases in risk taking. Here, we test whether heightened reward sensitivity may potentially be an asset for adolescents when engaged in prosocial activities. Thirty-two adolescents were followed over a one-year period to examine whether ventral striatum activation to prosocial rewards predicts decreases in risk taking over a year. Results show that heightened ventral striatum activation to prosocial stimuli relates to longitudinal declines in risk taking. Therefore, the very same neural region that has conferred vulnerability for adolescent risk taking may also be protective against risk taking. Copyright © 2012 Elsevier Ltd. All rights reserved.

Possible mechanisms of chromosome aberrations. 2. Formation of aberrations after UV-irradiation

International Nuclear Information System (INIS)

Lebedeva, L.I.

1982-01-01

One of mechanisms of chromosome aberrations after UV-radiation of animal cells initiated by thymine dimerization from different dna threads (by cross joints) and finished in mitosis metaphase is discussed. The model of aberration formation, taking a count of peculiarities of chromosome ansate structure and predicting the important role of chromosome isolation during mitosis in realization of structural aberrations, is suggested. An attempt to present aberration formation under conditions of exact repair is the distinguishing feature of the model

Neural alterations of fronto-striatal circuitry during reward anticipation in euthymic bipolar disorder.

Science.gov (United States)

Schreiter, S; Spengler, S; Willert, A; Mohnke, S; Herold, D; Erk, S; Romanczuk-Seiferth, N; Quinlivan, E; Hindi-Attar, C; Banzhaf, C; Wackerhagen, C; Romund, L; Garbusow, M; Stamm, T; Heinz, A; Walter, H; Bermpohl, F

2016-11-01

Bipolar disorder (BD), with the hallmark symptoms of elevated and depressed mood, is thought to be characterized by underlying alterations in reward-processing networks. However, to date the neural circuitry underlying abnormal responses during reward processing in BD remains largely unexplored. The aim of this study was to investigate whether euthymic BD is characterized by aberrant ventral striatal (VS) activation patterns and altered connectivity with the prefrontal cortex in response to monetary gains and losses. During functional magnetic resonance imaging 20 euthymic BD patients and 20 age-, gender- and intelligence quotient-matched healthy controls completed a monetary incentive delay paradigm, to examine neural processing of reward and loss anticipation. A priori defined regions of interest (ROIs) included the VS and the anterior prefrontal cortex (aPFC). Psychophysiological interactions (PPIs) between these ROIs were estimated and tested for group differences for reward and loss anticipation separately. BD participants, relative to healthy controls, displayed decreased activation selectively in the left and right VS during anticipation of reward, but not during loss anticipation. PPI analyses showed decreased functional connectivity between the left VS and aPFC in BD patients compared with healthy controls during reward anticipation. This is the first study showing decreased VS activity and aberrant connectivity in the reward-processing circuitry in euthymic, medicated BD patients during reward anticipation. Our findings contrast with research supporting a reward hypersensitivity model of BD, and add to the body of literature suggesting that blunted activation of reward processing circuits may be a vulnerability factor for mood disorders.

Segregated encoding of reward-identity and stimulus-reward associations in human orbitofrontal cortex.

Science.gov (United States)

Klein-Flügge, Miriam Cornelia; Barron, Helen Catharine; Brodersen, Kay Henning; Dolan, Raymond J; Behrens, Timothy Edward John

2013-02-13

A dominant focus in studies of learning and decision-making is the neural coding of scalar reward value. This emphasis ignores the fact that choices are strongly shaped by a rich representation of potential rewards. Here, using fMRI adaptation, we demonstrate that responses in the human orbitofrontal cortex (OFC) encode a representation of the specific type of food reward predicted by a visual cue. By controlling for value across rewards and by linking each reward with two distinct stimuli, we could test for representations of reward-identity that were independent of associative information. Our results show reward-identity representations in a medial-caudal region of OFC, independent of the associated predictive stimulus. This contrasts with a more rostro-lateral OFC region encoding reward-identity representations tied to the predicate stimulus. This demonstration of adaptation in OFC to reward specific representations opens an avenue for investigation of more complex decision mechanisms that are not immediately accessible in standard analyses, which focus on correlates of average activity.

Amphetamine sensitization alters reward processing in the human striatum and amygdala.

Directory of Open Access Journals (Sweden)

Owen G O'Daly

Full Text Available Dysregulation of mesolimbic dopamine transmission is implicated in a number of psychiatric illnesses characterised by disruption of reward processing and goal-directed behaviour, including schizophrenia, drug addiction and impulse control disorders associated with chronic use of dopamine agonists. Amphetamine sensitization (AS has been proposed to model the development of this aberrant dopamine signalling and the subsequent dysregulation of incentive motivational processes. However, in humans the effects of AS on the dopamine-sensitive neural circuitry associated with reward processing remains unclear. Here we describe the effects of acute amphetamine administration, following a sensitising dosage regime, on blood oxygen level dependent (BOLD signal in dopaminoceptive brain regions during a rewarded gambling task performed by healthy volunteers. Using a randomised, double-blind, parallel-groups design, we found clear evidence for sensitization to the subjective effects of the drug, while rewarded reaction times were unchanged. Repeated amphetamine exposure was associated with reduced dorsal striatal BOLD signal during decision making, but enhanced ventromedial caudate activity during reward anticipation. The amygdala BOLD response to reward outcomes was blunted following repeated amphetamine exposure. Positive correlations between subjective sensitization and changes in anticipation- and outcome-related BOLD signal were seen for the caudate nucleus and amygdala, respectively. These data show for the first time in humans that AS changes the functional impact of acute stimulant exposure on the processing of reward-related information within dopaminoceptive regions. Our findings accord with pathophysiological models which implicate aberrant dopaminergic modulation of striatal and amygdala activity in psychosis and drug-related compulsive disorders.

Working Memory Load Strengthens Reward Prediction Errors.

Science.gov (United States)

Collins, Anne G E; Ciullo, Brittany; Frank, Michael J; Badre, David

2017-04-19

Reinforcement learning (RL) in simple instrumental tasks is usually modeled as a monolithic process in which reward prediction errors (RPEs) 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 investigated how working memory (WM) and incremental RL processes interact to guide human learning. WM load was manipulated by varying the number of stimuli to be learned across blocks. Behavioral results and computational modeling confirmed that learning was best explained as a mixture of two mechanisms: a fast, capacity-limited, and delay-sensitive WM process together with slower RL. Model-based analysis of fMRI data showed that striatum and lateral prefrontal cortex were sensitive to RPE, as shown previously, but, critically, these signals were reduced when the learning problem was within capacity of WM. The degree of this neural interaction related to individual differences in the use of WM to guide behavioral learning. These results indicate that the two systems do not process information independently, but rather interact during learning. SIGNIFICANCE STATEMENT Reinforcement learning (RL) theory has been remarkably productive at improving our understanding of instrumental learning as well as dopaminergic and striatal network function across many mammalian species. However, this neural network is only one contributor to human learning and other mechanisms such as prefrontal cortex working memory also play a key role. Our results also show that these other players interact with the dopaminergic RL system, interfering with its key computation of reward prediction errors. Copyright © 2017 the authors 0270-6474/17/374332-11$15.00/0.

Application of the aberration ring test (ARTEMIS) to determine lens quality and predict its lithographic performance

Science.gov (United States)

Moers, Marco H. P.; van der Laan, Hans; Zellenrath, Mark; de Boeij, Wim; Beaudry, Neil A.; Cummings, Kevin D.; van Zwol, Adriaan; Brecht, Arthur; Willekers, Rob

2001-09-01

ARTEMISTM (Aberration Ring Test Exposed at Multiple Illumination Settings) is a technique to determine in-situ, full-field, low and high order lens aberrations. In this paper we are analyzing the ARTEMISTM data of PAS5500/750TM DUV Step & Scan systems and its use as a lithographic prediction tool. ARTEMISTM is capable of determining Zernike coefficients up to Z25 with a 3(sigma) reproducibility range from 1.5 to 4.5 nm depending on the aberration type. 3D electric field simulations, that take the extended geometry of the phase shift feature into account, have been used for an improved treatment of the extraction of the spherical Zernike coefficients. Knowledge of the extracted Zernike coefficients allows an accurate prediction of the lithographic performance of the scanner system. This ability is demonstrated for a two bar pattern and an isolation pattern. The RMS difference between the ARTEMISTM-based lithographic prediction and the lithographic measurement is 2.5 nm for the two bar pattern and 3 nm for the isolation pattern. The 3(sigma) reproducibility of the prediction for the two bar pattern is 2.5 nm and 1 nm for the isolation pattern. This is better than the reproducibility of the lithographic measurements themselves.

Reward inference by primate prefrontal and striatal neurons.

Science.gov (United States)

Pan, Xiaochuan; Fan, Hongwei; Sawa, Kosuke; Tsuda, Ichiro; Tsukada, Minoru; Sakagami, Masamichi

2014-01-22

The brain contains multiple yet distinct systems involved in reward prediction. To understand the nature of these processes, we recorded single-unit activity from the lateral prefrontal cortex (LPFC) and the striatum in monkeys performing a reward inference task using an asymmetric reward schedule. We found that neurons both in the LPFC and in the striatum predicted reward values for stimuli that had been previously well experienced with set reward quantities in the asymmetric reward task. Importantly, these LPFC neurons could predict the reward value of a stimulus using transitive inference even when the monkeys had not yet learned the stimulus-reward association directly; whereas these striatal neurons did not show such an ability. Nevertheless, because there were two set amounts of reward (large and small), the selected striatal neurons were able to exclusively infer the reward value (e.g., large) of one novel stimulus from a pair after directly experiencing the alternative stimulus with the other reward value (e.g., small). Our results suggest that although neurons that predict reward value for old stimuli in the LPFC could also do so for new stimuli via transitive inference, those in the striatum could only predict reward for new stimuli via exclusive inference. Moreover, the striatum showed more complex functions than was surmised previously for model-free learning.

Signed reward prediction errors drive declarative learning.

Directory of Open Access Journals (Sweden)

Esther De Loof

Full Text Available Reward prediction errors (RPEs are thought to drive learning. This has been established in procedural learning (e.g., classical and operant conditioning. However, empirical evidence on whether RPEs drive declarative learning-a quintessentially human form of learning-remains surprisingly absent. We therefore coupled RPEs to the acquisition of Dutch-Swahili word pairs in a declarative learning paradigm. Signed RPEs (SRPEs; "better-than-expected" signals during declarative learning improved recognition in a follow-up test, with increasingly positive RPEs leading to better recognition. In addition, classic declarative memory mechanisms such as time-on-task failed to explain recognition performance. The beneficial effect of SRPEs on recognition was subsequently affirmed in a replication study with visual stimuli.

Signed reward prediction errors drive declarative learning.

Science.gov (United States)

De Loof, Esther; Ergo, Kate; Naert, Lien; Janssens, Clio; Talsma, Durk; Van Opstal, Filip; Verguts, Tom

2018-01-01

Reward prediction errors (RPEs) are thought to drive learning. This has been established in procedural learning (e.g., classical and operant conditioning). However, empirical evidence on whether RPEs drive declarative learning-a quintessentially human form of learning-remains surprisingly absent. We therefore coupled RPEs to the acquisition of Dutch-Swahili word pairs in a declarative learning paradigm. Signed RPEs (SRPEs; "better-than-expected" signals) during declarative learning improved recognition in a follow-up test, with increasingly positive RPEs leading to better recognition. In addition, classic declarative memory mechanisms such as time-on-task failed to explain recognition performance. The beneficial effect of SRPEs on recognition was subsequently affirmed in a replication study with visual stimuli.

Reward guides vision when it's your thing: trait reward-seeking in reward-mediated visual priming.

Directory of Open Access Journals (Sweden)

Clayton Hickey

Full Text Available Reward-related mesolimbic dopamine is thought to play an important role in guiding animal behaviour, biasing approach towards potentially beneficial environmental stimuli and away from objects unlikely to garner positive outcome. This is considered to result in part from an impact on perceptual and attentional processes: dopamine initiates a series of cognitive events that result in the priming of reward-associated perceptual features. We have provided behavioural and electrophysiological evidence that this mechanism guides human vision in search, an effect we refer to as reward priming. We have also demonstrated that there is substantial individual variability in this effect. Here we show that behavioural differences in reward priming are predicted remarkably well by a personality index that captures the degree to which a person's behaviour is driven by reward outcome. Participants with reward-seeking personalities are found to be those who allocate visual resources to objects characterized by reward-associated visual features. These results add to a rapidly developing literature demonstrating the crucial role reward plays in attentional control. They additionally illustrate the striking impact personality traits can have on low-level cognitive processes like perception and selective attention.

Intersection of reward and memory in monkey rhinal cortex.

Science.gov (United States)

Clark, Andrew M; Bouret, Sebastien; Young, Adrienne M; Richmond, Barry J

2012-05-16

In humans and other animals, the vigor with which a reward is pursued depends on its desirability, that is, on the reward's predicted value. Predicted value is generally context-dependent, varying according to the value of rewards obtained in the recent and distant past. Signals related to reward prediction and valuation are believed to be encoded in a circuit centered around midbrain dopamine neurons and their targets in the prefrontal cortex and basal ganglia. Notably absent from this hypothesized reward pathway are dopaminergic targets in the medial temporal lobe. Here we show that a key part of the medial temporal lobe memory system previously reported to be important for sensory mnemonic and perceptual processing, the rhinal cortex (Rh), is required for using memories of previous reward values to predict the value of forthcoming rewards. We tested monkeys with bilateral Rh lesions on a task in which reward size varied across blocks of uncued trials. In this experiment, the only cues for predicting current reward value are the sizes of rewards delivered in previous blocks. Unexpectedly, monkeys with Rh ablations, but not intact controls, were insensitive to differences in predicted reward, responding as if they expected all rewards to be of equal magnitude. Thus, it appears that Rh is critical for using memory of previous rewards to predict the value of forthcoming rewards. These results are in agreement with accumulating evidence that Rh is critical for establishing the relationships between temporally interleaved events, which is a key element of episodic memory.

Negative Symptoms and Reward Disturbances in Schizophrenia Before and After Antipsychotic Monotherapy

DEFF Research Database (Denmark)

Nielsen, Mette Ødegaard; Rostrup, Egill; Broberg, Brian Villumsen

2018-01-01

BACKGROUND: Negative symptoms (NS) are a central part of the symptomatology of schizophrenia, which is highly correlated to the functional outcome. Disturbances of the brain reward system are suggested to be central in the pathogenesis of NS by decreasing motivation and hedonic experiences...... = .001). DISCUSSION: Patients improving in NS score had a less aberrant reward system at baseline, but reward related activity was reduced over time. Patients not improving in NS showed decreased striatal reward-activity at baseline, which improved over time. Whether this is associated with alteration....... In this study, we compared reward-related brain activity in patients improving and not improving in NS after treatment with amisulpride. METHODS: Thirty-nine antipsychotic-naive patients and 49 healthy controls completed functional magnetic resonance imaging with a modified monetary incentive delay task...

Reward Inference by Primate Prefrontal and Striatal Neurons

OpenAIRE

Pan, Xiaochuan; Fan, Hongwei; Sawa, Kosuke; Tsuda, Ichiro; Tsukada, Minoru; Sakagami, Masamichi

2014-01-01

The brain contains multiple yet distinct systems involved in reward prediction. To understand the nature of these processes, we recorded single-unit activity from the lateral prefrontal cortex (LPFC) and the striatum in monkeys performing a reward inference task using an asymmetric reward schedule. We found that neurons both in the LPFC and in the striatum predicted reward values for stimuli that had been previously well experienced with set reward quantities in the asymmetric reward task. Im...

Aberration characteristics of immersion lenses for LVSEM

International Nuclear Information System (INIS)

Khursheed, Anjam

2002-01-01

This paper investigates the on-axis aberration characteristics of various immersion objective lenses for low voltage scanning electron microscopy (LVSEM). A simple aperture lens model is used to generate smooth axial field distributions. The simulation results show that mixed field electric-magnetic immersion lenses are predicted to have between 1.5 and 2 times smaller aberration limited probe diameters than their pure-field counterparts. At a landing energy of 1 keV, mixed field immersion lenses operating at the vacuum electrical field breakdown limit are predicted to have on-axis aberration coefficients between 50 and 60 μm, yielding an ultimate image resolution of below 1 nm. These aberrations lie in the same range as those for LVSEM systems that employ aberration correctors

Dopamine prediction errors in reward learning and addiction: from theory to neural circuitry

Science.gov (United States)

Keiflin, Ronald; Janak, Patricia H.

2015-01-01

Summary Midbrain dopamine (DA) neurons are proposed to signal reward prediction error (RPE), a fundamental parameter in associative learning models. This RPE hypothesis provides a compelling theoretical framework for understanding DA function in reward learning and addiction. New studies support a causal role for DA-mediated RPE activity in promoting learning about natural reward; however, this question has not been explicitly tested in the context of drug addiction. In this review, we integrate theoretical models with experimental findings on the activity of DA systems, and on the causal role of specific neuronal projections and cell types, to provide a circuit-based framework for probing DA-RPE function in addiction. By examining error-encoding DA neurons in the neural network in which they are embedded, hypotheses regarding circuit-level adaptations that possibly contribute to pathological error-signaling and addiction can be formulated and tested. PMID:26494275

Dopamine Prediction Errors in Reward Learning and Addiction: From Theory to Neural Circuitry.

Science.gov (United States)

Keiflin, Ronald; Janak, Patricia H

2015-10-21

Midbrain dopamine (DA) neurons are proposed to signal reward prediction error (RPE), a fundamental parameter in associative learning models. This RPE hypothesis provides a compelling theoretical framework for understanding DA function in reward learning and addiction. New studies support a causal role for DA-mediated RPE activity in promoting learning about natural reward; however, this question has not been explicitly tested in the context of drug addiction. In this review, we integrate theoretical models with experimental findings on the activity of DA systems, and on the causal role of specific neuronal projections and cell types, to provide a circuit-based framework for probing DA-RPE function in addiction. By examining error-encoding DA neurons in the neural network in which they are embedded, hypotheses regarding circuit-level adaptations that possibly contribute to pathological error signaling and addiction can be formulated and tested. Copyright © 2015 Elsevier Inc. All rights reserved.

Nicotine Withdrawal Induces Neural Deficits in Reward Processing.

Science.gov (United States)

Oliver, Jason A; Evans, David E; Addicott, Merideth A; Potts, Geoffrey F; Brandon, Thomas H; Drobes, David J

2017-06-01

Nicotine withdrawal reduces neurobiological responses to nonsmoking rewards. Insight into these reward deficits could inform the development of targeted interventions. This study examined the effect of withdrawal on neural and behavioral responses during a reward prediction task. Smokers (N = 48) attended two laboratory sessions following overnight abstinence. Withdrawal was manipulated by having participants smoke three regular nicotine (0.6 mg yield; satiation) or very low nicotine (0.05 mg yield; withdrawal) cigarettes. Electrophysiological recordings of neural activity were obtained while participants completed a reward prediction task that involved viewing four combinations of predictive and reward-determining stimuli: (1) Unexpected Reward; (2) Predicted Reward; (3) Predicted Punishment; (4) Unexpected Punishment. The task evokes a medial frontal negativity that mimics the phasic pattern of dopaminergic firing in ventral tegmental regions associated with reward prediction errors. Nicotine withdrawal decreased the amplitude of the medial frontal negativity equally across all trial types (p nicotine dependence (p Nicotine withdrawal had equivocal impact across trial types, suggesting reward processing deficits are unlikely to stem from changes in phasic dopaminergic activity during prediction errors. Effects on tonic activity may be more pronounced. Pharmacological interventions directly targeting the dopamine system and behavioral interventions designed to increase reward motivation and responsiveness (eg, behavioral activation) may aid in mitigating withdrawal symptoms and potentially improving smoking cessation outcomes. Findings from this study indicate nicotine withdrawal impacts reward processing signals that are observable in smokers' neural activity. This may play a role in the subjective aversive experience of nicotine withdrawal and potentially contribute to smoking relapse. Interventions that address abnormal responding to both pleasant and

Attentional Bias Predicts Increased Reward Salience and Risk Taking in Bipolar Disorder.

Science.gov (United States)

Mason, Liam; Trujillo-Barreto, Nelson J; Bentall, Richard P; El-Deredy, Wael

2016-02-15

There is amassing evidence that risky decision-making in bipolar disorder is related to reward-based differences in frontostriatal regions. However, the roles of early attentional and later cognitive processes remain unclear, limiting theoretical understanding and development of targeted interventions. Twenty euthymic bipolar disorder and 19 matched control participants played a Roulette task in which they won and lost money. Event-related potentials and source analysis were used to quantify predominantly sensory-attentional (N1), motivational salience (feedback-related negativities [FRN]), and cognitive appraisal (P300) stages of processing. We predicted that the bipolar disorder group would show increased N1, consistent with increased attentional orienting, and reduced FRN, consistent with a bias to perceive outcomes more favorably. As predicted, the bipolar disorder group showed increased N1 and reduced FRN but no differences in P300. N1 amplitude was additionally associated with real-life risk taking, and N1 source activity was reduced in visual cortex but increased activity in precuneus, frontopolar, and premotor cortex, compared to those of controls. These findings demonstrate an early attentional bias to reward that potentially drives risk taking by priming approach behavior and elevating reward salience in the frontostriatal pathway. Although later cognitive appraisals of these inputs may be relatively intact in remission, interventions targeting attention orienting may also be effective in long-term reduction of relapse. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Aberrant reward center response to partner reputation during a social exchange game in generalized social phobia.

Science.gov (United States)

Sripada, Chandra; Angstadt, Michael; Liberzon, Israel; McCabe, Kevin; Phan, K Luan

2013-04-01

Generalized social anxiety disorder (GSAD) is characterized by excessive fear of public scrutiny and reticence in social engagement. Previous studies have probed the neural basis of GSAD often using static, noninteractive stimuli (e.g., face photographs) and have identified dysfunction in fear circuitry. We sought to investigate brain-based dysfunction in GSAD during more real-world, dynamic social interactions, focusing on the role of reward-related regions that are implicated in social decision-making. Thirty-six healthy individuals (healthy control [HC]) and 36 individuals with GSAD underwent functional magnetic resonance imaging (fMRI) scanning while participating in a behavioral economic game ("Trust Game") involving iterative exchanges with fictive partners who acquire differential reputations for reciprocity. We investigated brain responses to reciprocation of trust in one's social partner, and how these brain responses are modulated by partner reputation for repayment. In both HC and GSAD, receipt of reciprocity robustly engaged ventral striatum, a region implicated in reward. In HC, striatal responses to reciprocity were specific to partners who have consistently returned the investment ("cooperative partners"), and were absent for partners who lack a cooperative reputation. In GSAD, modulation of striatal responses by partner reputation was absent. Social anxiety severity predicted diminished responses to cooperative partners. These results suggest abnormalities in GSAD in reward-related striatal mechanisms that may be important for the initiation, valuation, and maintenance of cooperative social relationships. Moreover, this study demonstrates that dynamic, interactive task paradigms derived from economics can help illuminate novel mechanisms of pathology in psychiatric illnesses in which social dysfunction is a cardinal feature. © 2013 Wiley Periodicals, Inc.

A reward-centred model of anorexia nervosa: a focussed narrative review of the neurological and psychophysiological literature.

Science.gov (United States)

O'Hara, Caitlin B; Campbell, Iain C; Schmidt, Ulrike

2015-05-01

This focussed narrative review examines neurobiological and psychophysiological evidence supporting a role for altered reward processes in the development and maintenance of anorexia nervosa (AN). In AN, there does not appear to be a generalised inability to experience reward. Rather, data suggest that a reluctance to gain weight leads to an aversive appraisal of food- and taste-related stimuli. As a result, cues compatible with this aberrant mode of thinking become rewarding for the individual. Evidence also suggests that attribution of motivational salience to such cues promotes anorectic behaviours. These findings are consistent with models in which interactions between cognition and reward are important in eliciting the anorectic "habit". A model is proposed which is consistent with elements of other theoretical frameworks, but differs in that its emphasis is towards neural overlaps between AN and addiction. It is consistent with AN being a reward-based learned behaviour in which aberrant cognitions related to eating and shape alter functioning of central reward systems. It proposes that the primary neural problem responsible for the development, maintenance, and treatment resistance is centred in the striatal reward system. This helps shift the emphasis of aetiological models towards reward processing, particularly in the context of illness-compatible cues. Furthermore, it suggests that continuing to explore the utility and valued nature of AN in the patient's life would be a useful inclusion in treatment and prevention models. Copyright © 2015. Published by Elsevier Ltd.

Cortical Brain Activity Reflecting Attentional Biasing Toward Reward-Predicting Cues Covaries with Economic Decision-Making Performance.

Science.gov (United States)

San Martín, René; Appelbaum, Lawrence G; Huettel, Scott A; Woldorff, Marty G

2016-01-01

Adaptive choice behavior depends critically on identifying and learning from outcome-predicting cues. We hypothesized that attention may be preferentially directed toward certain outcome-predicting cues. We studied this possibility by analyzing event-related potential (ERP) responses in humans during a probabilistic decision-making task. Participants viewed pairs of outcome-predicting visual cues and then chose to wager either a small (i.e., loss-minimizing) or large (i.e., gain-maximizing) amount of money. The cues were bilaterally presented, which allowed us to extract the relative neural responses to each cue by using a contralateral-versus-ipsilateral ERP contrast. We found an early lateralized ERP response, whose features matched the attention-shift-related N2pc component and whose amplitude scaled with the learned reward-predicting value of the cues as predicted by an attention-for-reward model. Consistently, we found a double dissociation involving the N2pc. Across participants, gain-maximization positively correlated with the N2pc amplitude to the most reliable gain-predicting cue, suggesting an attentional bias toward such cues. Conversely, loss-minimization was negatively correlated with the N2pc amplitude to the most reliable loss-predicting cue, suggesting an attentional avoidance toward such stimuli. These results indicate that learned stimulus-reward associations can influence rapid attention allocation, and that differences in this process are associated with individual differences in economic decision-making performance. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Self-stimulating rats combine subjective reward magnitude and subjective reward rate multiplicatively.

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Leon, M I; Gallistel, C R

1998-07-01

For rats that bar pressed for intracranial electrical stimulation in a 2-lever matching paradigm with concurrent variable interval schedules of reward, the authors found that the time allocation ratio is based on a multiplicative combination of the ratio of subjective reward magnitudes and the ratio of the rates of reward. Multiplicative combining was observed in a range covering approximately 2 orders of magnitude in the ratio of the rates of reward from about 1:10 to 10:1) and an order of magnitude change in the size of rewards. After determining the relation between the pulse frequency of stimulation and subjective reward magnitude, the authors were able to predict from knowledge of the subjective magnitudes of the rewards and the obtained relative rates of reward the subject's time allocation ratio over a range in which it varied by more than 3 orders of magnitude.

Blunted striatal response to monetary reward anticipation during smoking abstinence predicts lapse during a contingency-managed quit attempt.

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Sweitzer, Maggie M; Geier, Charles F; Denlinger, Rachel; Forbes, Erika E; Raiff, Bethany R; Dallery, Jesse; McClernon, F J; Donny, Eric C

2016-03-01

Tobacco smoking is associated with dysregulated reward processing within the striatum, characterized by hypersensitivity to smoking rewards and hyposensitivity to non-smoking rewards. This bias toward smoking reward at the expense of alternative rewards is further exacerbated by deprivation from smoking, which may contribute to difficulty maintaining abstinence during a quit attempt. We examined whether abstinence-induced changes in striatal processing of rewards predicted lapse likelihood during a quit attempt supported by contingency management (CM), in which abstinence from smoking was reinforced with money. Thirty-six non-treatment-seeking smokers participated in two functional MRI (fMRI) sessions, one following 24-h abstinence and one following smoking as usual. During each scan, participants completed a rewarded guessing task designed to elicit striatal activation in which they could earn smoking and monetary rewards delivered after the scan. Participants then engaged in a 3-week CM-supported quit attempt. As previously reported, 24-h abstinence was associated with increased striatal activation in anticipation of smoking reward and decreased activation in anticipation of monetary reward. Individuals exhibiting greater decrements in right striatal activation to monetary reward during abstinence (controlling for activation during non-abstinence) were more likely to lapse during CM (p reward. These results are consistent with a growing number of studies indicating the specific importance of disrupted striatal processing of non-drug reward in nicotine dependence and highlight the importance of individual differences in abstinence-induced deficits in striatal function for smoking cessation.

Observing others stay or switch - How social prediction errors are integrated into reward reversal learning.

Science.gov (United States)

Ihssen, Niklas; Mussweiler, Thomas; Linden, David E J

2016-08-01

Reward properties of stimuli can undergo sudden changes, and the detection of these 'reversals' is often made difficult by the probabilistic nature of rewards/punishments. Here we tested whether and how humans use social information (someone else's choices) to overcome uncertainty during reversal learning. We show a substantial social influence during reversal learning, which was modulated by the type of observed behavior. Participants frequently followed observed conservative choices (no switches after punishment) made by the (fictitious) other player but ignored impulsive choices (switches), even though the experiment was set up so that both types of response behavior would be similarly beneficial/detrimental (Study 1). Computational modeling showed that participants integrated the observed choices as a 'social prediction error' instead of ignoring or blindly following the other player. Modeling also confirmed higher learning rates for 'conservative' versus 'impulsive' social prediction errors. Importantly, this 'conservative bias' was boosted by interpersonal similarity, which in conjunction with the lack of effects observed in a non-social control experiment (Study 2) confirmed its social nature. A third study suggested that relative weighting of observed impulsive responses increased with increased volatility (frequency of reversals). Finally, simulations showed that in the present paradigm integrating social and reward information was not necessarily more adaptive to maximize earnings than learning from reward alone. Moreover, integrating social information increased accuracy only when conservative and impulsive choices were weighted similarly during learning. These findings suggest that to guide decisions in choice contexts that involve reward reversals humans utilize social cues conforming with their preconceptions more strongly than cues conflicting with them, especially when the other is similar. Copyright © 2016 The Authors. Published by Elsevier B

Expected reward value and reward uncertainty have temporally dissociable effects on memory formation

OpenAIRE

Adcock, R; Clement, Nathaniel; Chiew, Kimberly; Dickerson, Kathryn; Stanek, Jessica

2018-01-01

Anticipating rewards has been shown to enhance memory formation. While substantial evidence implicates dopamine in this behavioral effect, the precise mechanisms remain ambiguous. Because dopamine nuclei show two distinct physiological signatures of reward prediction, we hypothesized two dissociable effects on memory formation. These two signatures are a phasic dopamine response immediately following a reward cue that encodes its expected value, and a sustained, ramping dopamine response that...

Reward contingencies and the recalibration of task monitoring and reward systems: a high-density electrical mapping study.

Science.gov (United States)

Morie, K P; De Sanctis, P; Foxe, J J

2014-07-25

Task execution almost always occurs in the context of reward-seeking or punishment-avoiding behavior. As such, ongoing task-monitoring systems are influenced by reward anticipation systems. In turn, when a task has been executed either successfully or unsuccessfully, future iterations of that task will be re-titrated on the basis of the task outcome. Here, we examined the neural underpinnings of the task-monitoring and reward-evaluation systems to better understand how they govern reward-seeking behavior. Twenty-three healthy adult participants performed a task where they accrued points that equated to real world value (gift cards) by responding as rapidly as possible within an allotted timeframe, while success rate was titrated online by changing the duration of the timeframe dependent on participant performance. Informative cues initiated each trial, indicating the probability of potential reward or loss (four levels from very low to very high). We manipulated feedback by first informing participants of task success/failure, after which a second feedback signal indicated actual magnitude of reward/loss. High-density electroencephalography (EEG) recordings allowed for examination of event-related potentials (ERPs) to the informative cues and in turn, to both feedback signals. Distinct ERP components associated with reward cues, task-preparatory and task-monitoring processes, and reward feedback processes were identified. Unsurprisingly, participants displayed increased ERP amplitudes associated with task-preparatory processes following cues that predicted higher chances of reward. They also rapidly updated reward and loss prediction information dependent on task performance after the first feedback signal. Finally, upon reward receipt, initial reward probability was no longer taken into account. Rather, ERP measures suggested that only the magnitude of actual reward or loss was now processed. Reward and task-monitoring processes are clearly dissociable, but

Reward and relief dimensions of temptation to drink: construct validity and role in predicting differential benefit from acamprosate and naltrexone.

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Roos, Corey R; Mann, Karl; Witkiewitz, Katie

2017-11-01

Researchers have sought to distinguish between individuals whose alcohol use disorder (AUD) is maintained by drinking to relieve negative affect ('relief drinkers') and those whose AUD is maintained by the rewarding effects of alcohol ('reward drinkers'). As an opioid receptor antagonist, naltrexone may be particularly effective for reward drinkers. Acamprosate, which has been shown to down-regulate the glutamatergic system, may be particularly effective for relief drinkers. This study sought to replicate and extend prior work (PREDICT study; Glöckner-Rist et al. ) by examining dimensions of reward and relief temptation to drink and subtypes of individuals with distinct patterns of reward/relief temptation. We utilized data from two randomized clinical trials for AUD (Project MATCH, n = 1726 and COMBINE study, n = 1383). We also tested whether classes of reward/relief temptation would predict differential response to naltrexone and acamprosate in COMBINE. Results replicated prior work by identifying reward and relief temptation factors, which had excellent reliability and construct validity. Using factor mixture modeling, we identified five distinct classes of reward/relief temptation that replicated across studies. In COMBINE, we found a significant class-by-acamprosate interaction effect. Among those most likely classified in the high relief/moderate reward temptation class, individuals had better drinking outcomes if assigned to acamprosate versus placebo. We did not find a significant class-by-naltrexone interaction effect. Our study questions the orthogonal classification of drinkers into only two types (reward or relief drinkers) and adds to the body of research on moderators of acamprosate, which may inform clinical decision making in the treatment of AUD. © 2016 Society for the Study of Addiction.

Moderation of the Relationship Between Reward Expectancy and Prediction Error-Related Ventral Striatal Reactivity by Anhedonia in Unmedicated Major Depressive Disorder: Findings From the EMBARC Study.

Science.gov (United States)

Greenberg, Tsafrir; Chase, Henry W; Almeida, Jorge R; Stiffler, Richelle; Zevallos, Carlos R; Aslam, Haris A; Deckersbach, Thilo; Weyandt, Sarah; Cooper, Crystal; Toups, Marisa; Carmody, Thomas; Kurian, Benji; Peltier, Scott; Adams, Phillip; McInnis, Melvin G; Oquendo, Maria A; McGrath, Patrick J; Fava, Maurizio; Weissman, Myrna; Parsey, Ramin; Trivedi, Madhukar H; Phillips, Mary L

2015-09-01

Anhedonia, disrupted reward processing, is a core symptom of major depressive disorder. Recent findings demonstrate altered reward-related ventral striatal reactivity in depressed individuals, but the extent to which this is specific to anhedonia remains poorly understood. The authors examined the effect of anhedonia on reward expectancy (expected outcome value) and prediction error- (discrepancy between expected and actual outcome) related ventral striatal reactivity, as well as the relationship between these measures. A total of 148 unmedicated individuals with major depressive disorder and 31 healthy comparison individuals recruited for the multisite EMBARC (Establishing Moderators and Biosignatures of Antidepressant Response in Clinical Care) study underwent functional MRI during a well-validated reward task. Region of interest and whole-brain data were examined in the first- (N=78) and second- (N=70) recruited cohorts, as well as the total sample, of depressed individuals, and in healthy individuals. Healthy, but not depressed, individuals showed a significant inverse relationship between reward expectancy and prediction error-related right ventral striatal reactivity. Across all participants, and in depressed individuals only, greater anhedonia severity was associated with a reduced reward expectancy-prediction error inverse relationship, even after controlling for other symptoms. The normal reward expectancy and prediction error-related ventral striatal reactivity inverse relationship concords with conditioning models, predicting a shift in ventral striatal responding from reward outcomes to reward cues. This study shows, for the first time, an absence of this relationship in two cohorts of unmedicated depressed individuals and a moderation of this relationship by anhedonia, suggesting reduced reward-contingency learning with greater anhedonia. These findings help elucidate neural mechanisms of anhedonia, as a step toward identifying potential biosignatures

Pain and suicidality: insights from reward and addiction neuroscience.

Science.gov (United States)

Elman, Igor; Borsook, David; Volkow, Nora D

2013-10-01

Suicidality is exceedingly prevalent in pain patients. Although the pathophysiology of this link remains unclear, it may be potentially related to the partial congruence of physical and emotional pain systems. The latter system's role in suicide is also conspicuous during setbacks and losses sustained in the context of social attachments. Here we propose a model based on the neural pathways mediating reward and anti-reward (i.e., allostatic adjustment to recurrent activation of the reward circuitry); both are relevant etiologic factors in pain, suicide and social attachments. A comprehensive literature search on neurobiology of pain and suicidality was performed. The collected articles were critically reviewed and relevant data were extracted and summarized within four key areas: (1) physical and emotional pain, (2) emotional pain and social attachments, (3) pain- and suicide-related alterations of the reward and anti-reward circuits as compared to addiction, which is the premier probe for dysfunction of these circuits and (4) mechanistically informed treatments of co-occurring pain and suicidality. Pain-, stress- and analgesic drugs-induced opponent and proponent states of the mesolimbic dopaminergic pathways may render reward and anti-reward systems vulnerable to sensitization, cross-sensitization and aberrant learning of contents and contexts associated with suicidal acts and behaviors. These findings suggest that pain patients exhibit alterations in the brain circuits mediating reward (depressed function) and anti-reward (sensitized function) that may affect their proclivity for suicide and support pain and suicidality classification among other "reward deficiency syndromes" and a new proposal for "enhanced anti-reward syndromes". We suggest that interventions aimed at restoring the balance between the reward and anti-reward networks in patients with chronic pain may help decreasing their suicide risk. Published by Elsevier Ltd.

Optogenetic stimulation in a computational model of the basal ganglia biases action selection and reward prediction error.

Science.gov (United States)

Berthet, Pierre; Lansner, Anders

2014-01-01

Optogenetic stimulation of specific types of medium spiny neurons (MSNs) in the striatum has been shown to bias the selection of mice in a two choices task. This shift is dependent on the localisation and on the intensity of the stimulation but also on the recent reward history. We have implemented a way to simulate this increased activity produced by the optical flash in our computational model of the basal ganglia (BG). This abstract model features the direct and indirect pathways commonly described in biology, and a reward prediction pathway (RP). The framework is similar to Actor-Critic methods and to the ventral/dorsal distinction in the striatum. We thus investigated the impact on the selection caused by an added stimulation in each of the three pathways. We were able to reproduce in our model the bias in action selection observed in mice. Our results also showed that biasing the reward prediction is sufficient to create a modification in the action selection. However, we had to increase the percentage of trials with stimulation relative to that in experiments in order to impact the selection. We found that increasing only the reward prediction had a different effect if the stimulation in RP was action dependent (only for a specific action) or not. We further looked at the evolution of the change in the weights depending on the stage of learning within a block. A bias in RP impacts the plasticity differently depending on that stage but also on the outcome. It remains to experimentally test how the dopaminergic neurons are affected by specific stimulations of neurons in the striatum and to relate data to predictions of our model.

The amygdala, reward and emotion.

Science.gov (United States)

Murray, Elisabeth A

2007-11-01

Recent research provides new insights into amygdala contributions to positive emotion and reward. Studies of neuronal activity in the monkey amygdala and of autonomic responses mediated by the monkey amygdala show that, contrary to a widely held view, the amygdala is just as important for processing positive reward and reinforcement as it is for negative. In addition, neuropsychological studies reveal that the amygdala is essential for only a fraction of what might be considered 'stimulus-reward processing', and that the neural substrates for emotion and reward are partially nonoverlapping. Finally, evidence suggests that two systems within the amygdala, operating in parallel, enable reward-predicting cues to influence behavior; one mediates a general, arousing effect of reward and the other links the sensory properties of reward to emotion.

Initial uncertainty in Pavlovian reward prediction persistently elevates incentive salience and extends sign-tracking to normally unattractive cues.

Science.gov (United States)

Robinson, Mike J F; Anselme, Patrick; Fischer, Adam M; Berridge, Kent C

2014-06-01

Uncertainty is a component of many gambling games and may play a role in incentive motivation and cue attraction. Uncertainty can increase the attractiveness for predictors of reward in the Pavlovian procedure of autoshaping, visible as enhanced sign-tracking (or approach and nibbles) by rats of a metal lever whose sudden appearance acts as a conditioned stimulus (CS+) to predict sucrose pellets as an unconditioned stimulus (UCS). Here we examined how reward uncertainty might enhance incentive salience as sign-tracking both in intensity and by broadening the range of attractive CS+s. We also examined whether initially induced uncertainty enhancements of CS+ attraction can endure beyond uncertainty itself, and persist even when Pavlovian prediction becomes 100% certain. Our results show that uncertainty can broaden incentive salience attribution to make CS cues attractive that would otherwise not be (either because they are too distal from reward or too risky to normally attract sign-tracking). In addition, uncertainty enhancement of CS+ incentive salience, once induced by initial exposure, persisted even when Pavlovian CS-UCS correlations later rose toward 100% certainty in prediction. Persistence suggests an enduring incentive motivation enhancement potentially relevant to gambling, which in some ways resembles incentive-sensitization. Higher motivation to uncertain CS+s leads to more potent attraction to these cues when they predict the delivery of uncertain rewards. In humans, those cues might possibly include the sights and sounds associated with gambling, which contribute a major component of the play immersion experienced by problematic gamblers. Copyright © 2014 Elsevier B.V. All rights reserved.

Moderation of the Relationship Between Reward Expectancy and Prediction Error-Related Ventral Striatal Reactivity by Anhedonia in Unmedicated Major Depressive Disorder: Findings From the EMBARC Study

Science.gov (United States)

Greenberg, Tsafrir; Chase, Henry W.; Almeida, Jorge R.; Stiffler, Richelle; Zevallos, Carlos R.; Aslam, Haris A.; Deckersbach, Thilo; Weyandt, Sarah; Cooper, Crystal; Toups, Marisa; Carmody, Thomas; Kurian, Benji; Peltier, Scott; Adams, Phillip; McInnis, Melvin G.; Oquendo, Maria A.; McGrath, Patrick J.; Fava, Maurizio; Weissman, Myrna; Parsey, Ramin; Trivedi, Madhukar H.; Phillips, Mary L.

2016-01-01

Objective Anhedonia, disrupted reward processing, is a core symptom of major depressive disorder. Recent findings demonstrate altered reward-related ventral striatal reactivity in depressed individuals, but the extent to which this is specific to anhedonia remains poorly understood. The authors examined the effect of anhedonia on reward expectancy (expected outcome value) and prediction error-(discrepancy between expected and actual outcome) related ventral striatal reactivity, as well as the relationship between these measures. Method A total of 148 unmedicated individuals with major depressive disorder and 31 healthy comparison individuals recruited for the multisite EMBARC (Establishing Moderators and Biosignatures of Antidepressant Response in Clinical Care) study underwent functional MRI during a well-validated reward task. Region of interest and whole-brain data were examined in the first- (N=78) and second- (N=70) recruited cohorts, as well as the total sample, of depressed individuals, and in healthy individuals. Results Healthy, but not depressed, individuals showed a significant inverse relationship between reward expectancy and prediction error-related right ventral striatal reactivity. Across all participants, and in depressed individuals only, greater anhedonia severity was associated with a reduced reward expectancy-prediction error inverse relationship, even after controlling for other symptoms. Conclusions The normal reward expectancy and prediction error-related ventral striatal reactivity inverse relationship concords with conditioning models, predicting a shift in ventral striatal responding from reward outcomes to reward cues. This study shows, for the first time, an absence of this relationship in two cohorts of unmedicated depressed individuals and a moderation of this relationship by anhedonia, suggesting reduced reward-contingency learning with greater anhedonia. These findings help elucidate neural mechanisms of anhedonia, as a step toward

Lower- and higher-order aberrations predicted by an optomechanical model of arcuate keratotomy for astigmatism.

Science.gov (United States)

Navarro, Rafael; Palos, Fernando; Lanchares, Elena; Calvo, Begoña; Cristóbal, José A

2009-01-01

To develop a realistic model of the optomechanical behavior of the cornea after curved relaxing incisions to simulate the induced astigmatic change and predict the optical aberrations produced by the incisions. ICMA Consejo Superior de Investigaciones Científicas and Universidad de Zaragoza, Zaragoza, Spain. A 3-dimensional finite element model of the anterior hemisphere of the ocular surface was used. The corneal tissue was modeled as a quasi-incompressible, anisotropic hyperelastic constitutive behavior strongly dependent on the physiological collagen fibril distribution. Similar behaviors were assigned to the limbus and sclera. With this model, some corneal incisions were computer simulated after the Lindstrom nomogram. The resulting geometry of the biomechanical simulation was analyzed in the optical zone, and finite ray tracing was performed to compute refractive power and higher-order aberrations (HOAs). The finite-element simulation provided new geometry of the corneal surfaces, from which elevation topographies were obtained. The surgically induced astigmatism (SIA) of the simulated incisions according to the Lindstrom nomogram was computed by finite ray tracing. However, paraxial computations would yield slightly different results (undercorrection of astigmatism). In addition, arcuate incisions would induce significant amounts of HOAs. Finite-element models, together with finite ray-tracing computations, yielded realistic simulations of the biomechanical and optical changes induced by relaxing incisions. The model reproduced the SIA indicated by the Lindstrom nomogram for the simulated incisions and predicted a significant increase in optical aberrations induced by arcuate keratotomy.

Validation and extension of the reward-mountain model.

Science.gov (United States)

Breton, Yannick-André; Mullett, Ada; Conover, Kent; Shizgal, Peter

2013-01-01

The reward-mountain model relates the vigor of reward seeking to the strength and cost of reward. Application of this model provides information about the stage of processing at which manipulations such as drug administration, lesions, deprivation states, and optogenetic interventions act to alter reward seeking. The model has been updated by incorporation of new information about frequency following in the directly stimulated neurons responsible for brain stimulation reward and about the function that maps objective opportunity costs into subjective ones. The behavioral methods for applying the model have been updated and improved as well. To assess the impact of these changes, two related predictions of the model that were supported by earlier work have been retested: (1) altering the duration of rewarding brain stimulation should change the pulse frequency required to produce a reward of half-maximal intensity, and (2) this manipulation should not change the opportunity cost at which half-maximal performance is directed at earning a maximally intense reward. Prediction 1 was supported in all six subjects, but prediction 2 was supported in only three. The latter finding is interpreted to reflect recruitment, at some stimulation sites, of a heterogeneous reward substrate comprising dual, parallel circuits that integrate the stimulation-induced neural signals.

Hormonal and neural mechanisms of food reward, eating behaviour and obesity.

Science.gov (United States)

Murray, Susan; Tulloch, Alastair; Gold, Mark S; Avena, Nicole M

2014-09-01

With rising rates of obesity, research continues to explore the contributions of homeostatic and hedonic mechanisms related to eating behaviour. In this Review, we synthesize the existing information on select biological mechanisms associated with reward-related food intake, dealing primarily with consumption of highly palatable foods. In addition to their established functions in normal feeding, three primary peripheral hormones (leptin, ghrelin and insulin) play important parts in food reward. Studies in laboratory animals and humans also show relationships between hyperphagia or obesity and neural pathways involved in reward. These findings have prompted questions regarding the possibility of addictive-like aspects in food consumption. Further exploration of this topic may help to explain aberrant eating patterns, such as binge eating, and provide insight into the current rates of overweight and obesity.

Premotor and Motor Cortices Encode Reward.

Directory of Open Access Journals (Sweden)

Pavan Ramkumar

Full Text Available Rewards associated with actions are critical for motivation and learning about the consequences of one's actions on the world. The motor cortices are involved in planning and executing movements, but it is unclear whether they encode reward over and above limb kinematics and dynamics. Here, we report a categorical reward signal in dorsal premotor (PMd and primary motor (M1 neurons that corresponds to an increase in firing rates when a trial was not rewarded regardless of whether or not a reward was expected. We show that this signal is unrelated to error magnitude, reward prediction error, or other task confounds such as reward consumption, return reach plan, or kinematic differences across rewarded and unrewarded trials. The availability of reward information in motor cortex is crucial for theories of reward-based learning and motivational influences on actions.

The Attraction Effect Modulates Reward Prediction Errors and Intertemporal Choices.

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Gluth, Sebastian; Hotaling, Jared M; Rieskamp, Jörg

2017-01-11

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. We first demonstrate that intertemporal decision making is prone to the attraction effect in humans. In an independent group of participants, we then investigated how this affects the neural and behavioral valuation of outcomes using a novel intertemporal lottery task and fMRI. Participants' behavioral responses (i.e., satisfaction ratings) were modulated systematically by the attraction effect and this modulation was correlated across participants with the respective change of the RPE signal in the nucleus accumbens. Furthermore, we show that, because exponential and hyperbolic discounting models are unable to account for the attraction effect, recently proposed sequential sampling models might be more appropriate to describe intertemporal choices. Our findings demonstrate for the first time that the attraction effect modulates subjective valuation even in the absence of choice. The findings also challenge the prospect of using neuroscientific methods to measure utility in a context-free manner and have important implications for theories of reinforcement learning and delay discounting. Many theories of value-based decision making assume that people first assess the attractiveness of each option independently of each other and then pick the option with the highest subjective value. The attraction effect, however, shows that adding a new option to a choice set can change the relative value of the existing options, which is a violation of the independence

“Liking” and “Wanting” Linked to Reward Deficiency Syndrome (RDS): Hypothesizing Differential Responsivity in Brain Reward Circuitry

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Blum, Kenneth; Gardner, Eliot; Oscar-Berman, Marlene; Gold, Mark

2012-01-01

In an attempt to resolve controversy regarding the causal contributions of mesolimbic dopamine (DA) systems to reward, we evaluate the three main competing explanatory categories: “liking,” “learning,” and “wanting” [1]. That is, DA may mediate (a) the hedonic impact of reward (liking), (b) learned predictions about rewarding effects (learning), or (c) the pursuit of rewards by attributing incentive salience to reward-related stimuli (wanting). We evaluate these hypotheses, especially as they...

Impaired cross-talk between mesolimbic food reward processing and metabolic signaling predicts body mass index

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Joe J Simon

2014-10-01

Full Text Available The anticipation of the pleasure derived from food intake drives the motivation to eat, and hence facilitate overconsumption of food which ultimately results in obesity. Brain imaging studies provide evidence that mesolimbic brain regions underlie both general as well as food related anticipatory reward processing. In light of this knowledge, the present study examined the neural responsiveness of the ventral striatum in participants with a broad BMI spectrum. The study differentiated between general (i.e. monetary and food related anticipatory reward processing. We recruited a sample of volunteers with greatly varying body weights, ranging from a low BMI (below 20 kg/m² over a normal (20 to 25 kg/m² and overweight (25 to 30 kg/m² BMI, to class I (30 to 35 kg/m² and class II (35 to 40 kg/m² obesity. A total of 24 participants underwent functional magnetic resonance imaging whilst performing both a food and monetary incentive delay task, which allows to measure neural activation during the anticipation of rewards. After the presentation of a cue indicating the amount of food or money to be won, participants had to react correctly in order to earn snack points or money coins which could then be exchanged for real food or money, respectively, at the end of the experiment. During the anticipation of both types of rewards, participants displayed activity in the ventral striatum, a region that plays a pivotal role in the anticipation of rewards. Additionally, we observed that specifically anticipatory food reward processing predicted the individual BMI (current and maximum lifetime. This relation was found to be mediated by impaired hormonal satiety signaling, i.e. increased leptin levels and insulin resistance. These findings suggest that heightened food reward motivation contributes to obesity through impaired metabolic signaling.

Low social rhythm regularity predicts first onset of bipolar spectrum disorders among at-risk individuals with reward hypersensitivity.

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Alloy, Lauren B; Boland, Elaine M; Ng, Tommy H; Whitehouse, Wayne G; Abramson, Lyn Y

2015-11-01

The social zeitgeber model (Ehlers, Frank, & Kupfer, 1988) suggests that irregular daily schedules or social rhythms provide vulnerability to bipolar spectrum disorders. This study tested whether social rhythm regularity prospectively predicted first lifetime onset of bipolar spectrum disorders in adolescents already at risk for bipolar disorder based on exhibiting reward hypersensitivity. Adolescents (ages 14-19 years) previously screened to have high (n = 138) or moderate (n = 95) reward sensitivity, but no lifetime history of bipolar spectrum disorder, completed measures of depressive and manic symptoms, family history of bipolar disorder, and the Social Rhythm Metric. They were followed prospectively with semistructured diagnostic interviews every 6 months for an average of 31.7 (SD = 20.1) months. Hierarchical logistic regression indicated that low social rhythm regularity at baseline predicted greater likelihood of first onset of bipolar spectrum disorder over follow-up among high-reward-sensitivity adolescents but not moderate-reward-sensitivity adolescents, controlling for follow-up time, gender, age, family history of bipolar disorder, and initial manic and depressive symptoms (β = -.150, Wald = 4.365, p = .037, odds ratio = .861, 95% confidence interval [.748, .991]). Consistent with the social zeitgeber theory, low social rhythm regularity provides vulnerability to first onset of bipolar spectrum disorder among at-risk adolescents. It may be possible to identify adolescents at risk for developing a bipolar spectrum disorder based on exhibiting both reward hypersensitivity and social rhythm irregularity before onset occurs. (c) 2015 APA, all rights reserved).

Molecular role of dopamine in anhedonia linked to reward deficiency syndrome (RDS) and anti- reward systems.

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Gold, Mark S; Blum, Kenneth; Febo, Marcelo; Baron, David; Modestino, Edward Justin; Elman, Igor; Badgaiyan, Rajendra D

2018-03-01

Anhedonia is a condition that leads to the loss of feelings pleasure in response to natural reinforcers like food, sex, exercise, and social activities. This disorder occurs in addiction, and an array of related neuropsychiatric syndromes, including schizophrenia, depression, and Post Traumatic Stress Disorder (PTSD). Anhedonia may by due to derangements in mesolimbic dopaminergic pathways and their terminal fields (e.g., striatum, amygdala, and prefrontal cortex) that persist long after the traces of the causative drugs are eliminated (pharmacokinetically). Here we postulate that anhedonia is not a distinct entity but is rather an epiphenomenon of hypodopaminergic states and traits arising from the interaction of genetic traits and epigenetic neurobiological alterations in response to environmental influences. Moreover, dopaminergic activity is rather complex, and so it may give rise to differential pathophysiological processes such as incentive sensitization, aberrant learning and stress-like "anti-reward" phenomena. These processes may have additive, synergistic or antagonistic interactions with the concurrent reward deficiency states leading in some instances to more severe and long-lasting symptoms. Operant understanding of the neurogenetic antecedents to reward deficiency syndrome (RDS) and the elucidation of reward gene polymorphisms may provide a map for accessing an individual's genetic risk for developing Anhedonia. Prevention techniques that can restore homeostatic balance via physiological activation of dopaminergic receptors (D2/D3) may be instrumental for targeting not only anhedonia per se but also drug craving and relapse.

Spared internal but impaired external reward prediction error signals in major depressive disorder during reinforcement learning.

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Bakic, Jasmina; Pourtois, Gilles; Jepma, Marieke; Duprat, Romain; De Raedt, Rudi; Baeken, Chris

2017-01-01

Major depressive disorder (MDD) creates debilitating effects on a wide range of cognitive functions, including reinforcement learning (RL). In this study, we sought to assess whether reward processing as such, or alternatively the complex interplay between motivation and reward might potentially account for the abnormal reward-based learning in MDD. A total of 35 treatment resistant MDD patients and 44 age matched healthy controls (HCs) performed a standard probabilistic learning task. RL was titrated using behavioral, computational modeling and event-related brain potentials (ERPs) data. MDD patients showed comparable learning rate compared to HCs. However, they showed decreased lose-shift responses as well as blunted subjective evaluations of the reinforcers used during the task, relative to HCs. Moreover, MDD patients showed normal internal (at the level of error-related negativity, ERN) but abnormal external (at the level of feedback-related negativity, FRN) reward prediction error (RPE) signals during RL, selectively when additional efforts had to be made to establish learning. Collectively, these results lend support to the assumption that MDD does not impair reward processing per se during RL. Instead, it seems to alter the processing of the emotional value of (external) reinforcers during RL, when additional intrinsic motivational processes have to be engaged. © 2016 Wiley Periodicals, Inc.

Reward, Context, and Human Behaviour

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Clare L. Blaukopf

2007-01-01

Full Text Available Animal models of reward processing have revealed an extensive network of brain areas that process different aspects of reward, from expectation and prediction to calculation of relative value. These results have been confirmed and extended in human neuroimaging to encompass secondary rewards more unique to humans, such as money. The majority of the extant literature covers the brain areas associated with rewards whilst neglecting analysis of the actual behaviours that these rewards generate. This review strives to redress this imbalance by illustrating the importance of looking at the behavioural outcome of rewards and the context in which they are produced. Following a brief review of the literature of reward-related activity in the brain, we examine the effect of reward context on actions. These studies reveal how the presence of reward vs. reward and punishment, or being conscious vs. unconscious of reward-related actions, differentially influence behaviour. The latter finding is of particular importance given the extent to which animal models are used in understanding the reward systems of the human mind. It is clear that further studies are needed to learn about the human reaction to reward in its entirety, including any distinctions between conscious and unconscious behaviours. We propose that studies of reward entail a measure of the animal's (human or nonhuman knowledge of the reward and knowledge of its own behavioural outcome to achieve that reward.

Inhibiting food reward: delay discounting, food reward sensitivity, and palatable food intake in overweight and obese women.

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Appelhans, Bradley M; Woolf, Kathleen; Pagoto, Sherry L; Schneider, Kristin L; Whited, Matthew C; Liebman, Rebecca

2011-11-01

Overeating is believed to result when the appetitive motivation to consume palatable food exceeds an individual's capacity for inhibitory control of eating. This hypothesis was supported in recent studies involving predominantly normal weight women, but has not been tested in obese populations. The current study tested the interaction between food reward sensitivity and inhibitory control in predicting palatable food intake among energy-replete overweight and obese women (N = 62). Sensitivity to palatable food reward was measured with the Power of Food Scale. Inhibitory control was assessed with a computerized choice task that captures the tendency to discount large delayed rewards relative to smaller immediate rewards. Participants completed an eating in the absence of hunger protocol in which homeostatic energy needs were eliminated with a bland preload of plain oatmeal, followed by a bogus laboratory taste test of palatable and bland snacks. The interaction between food reward sensitivity and inhibitory control was a significant predictor of palatable food intake in regression analyses controlling for BMI and the amount of preload consumed. Probing this interaction indicated that higher food reward sensitivity predicted greater palatable food intake at low levels of inhibitory control, but was not associated with intake at high levels of inhibitory control. As expected, no associations were found in a similar regression analysis predicting intake of bland foods. Findings support a neurobehavioral model of eating behavior in which sensitivity to palatable food reward drives overeating only when accompanied by insufficient inhibitory control. Strengthening inhibitory control could enhance weight management programs.

Multiple reward-cue contingencies favor expectancy over uncertainty in shaping the reward-cue attentional salience.

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De Tommaso, Matteo; Mastropasqua, Tommaso; Turatto, Massimo

2018-01-25

Reward-predicting cues attract attention because of their motivational value. A debated question regards the conditions under which the cue's attentional salience is governed more by reward expectancy rather than by reward uncertainty. To help shedding light on this relevant issue, here, we manipulated expectancy and uncertainty using three levels of reward-cue contingency, so that, for example, a high level of reward expectancy (p = .8) was compared with the highest level of reward uncertainty (p = .5). In Experiment 1, the best reward-cue during conditioning was preferentially attended in a subsequent visual search task. This result was replicated in Experiment 2, in which the cues were matched in terms of response history. In Experiment 3, we implemented a hybrid procedure consisting of two phases: an omission contingency procedure during conditioning, followed by a visual search task as in the previous experiments. Crucially, during both phases, the reward-cues were never task relevant. Results confirmed that, when multiple reward-cue contingencies are explored by a human observer, expectancy is the major factor controlling both the attentional and the oculomotor salience of the reward-cue.

Flow cytogenetics: progress toward chromosomal aberration detection

International Nuclear Information System (INIS)

Carrano, A.V.; Gray, J.W.; Van Dilla, M.A.

1977-01-01

Using clonal derivatives of the Chinese hamster M3-1 cell line, we demonstrate the potential of flow systems to karyotype homogeneous aberrations (aberrations which are identical and present in every cell) and to detect heterogeneous aberrations (aberrations which occur randomly in a population and are not identical in every cell). Flow cytometry (FCM) of ethidium bromide stained isolated chromosomes from clone 650A of the M3-1 cells distinguishes nine chromosome types from the fourteen present in the actual karyotype. X-irradiation of this parent 650A clone produced two sub-clones with an altered flow karyotype, that is, their FCM distributions were characterized by the addition of new peaks and alterations in area under existing peaks. From the relative DNA content and area for each peak, as determined by computer analysis, we predicted that each clone had undergone a reciprocal translocation involving chromosomes from two peaks. This prediction was confirmed by Giemsa-banding the metaphase cells. Heterogeneous aberrations are reflected in the flow karyotype as an increase in background, that is, an increase in area underlying the chromosome peaks. This increase is dose dependent but, as yet, the sample variability has been too large for quantitative analysis. Flow sorting of the valleys between chromosome peaks produces enriched fractions of aberrant chromosomes for visual analysis. These approaches are potentially applicable to the analysis of chromsomal aberrations induced by environmental contaminants

Assessing the construct validity of aberrant salience

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Kristin Schmidt

2009-12-01

Full Text Available We sought to validate the psychometric properties of a recently developed paradigm that aims to measure salience attribution processes proposed to contribute to positive psychotic symptoms, the Salience Attribution Test (SAT. The “aberrant salience” measure from the SAT showed good face validity in previous results, with elevated scores both in high-schizotypy individuals, and in patients with schizophrenia suffering from delusions. Exploring the construct validity of salience attribution variables derived from the SAT is important, since other factors, including latent inhibition/learned irrelevance, attention, probabilistic reward learning, sensitivity to probability, general cognitive ability and working memory could influence these measures. Fifty healthy participants completed schizotypy scales, the SAT, a learned irrelevance task, and a number of other cognitive tasks tapping into potentially confounding processes. Behavioural measures of interest from each task were entered into a principal components analysis, which yielded a five-factor structure accounting for ~75% percent of the variance in behaviour. Implicit aberrant salience was found to load onto its own factor, which was associated with elevated “Introvertive Anhedonia” schizotypy, replicating our previous finding. Learned irrelevance loaded onto a separate factor, which also included implicit adaptive salience, but was not associated with schizotypy. Explicit adaptive and aberrant salience, along with a measure of probabilistic learning, loaded onto a further factor, though this also did not correlate with schizotypy. These results suggest that the measures of learned irrelevance and implicit adaptive salience might be based on similar underlying processes, which are dissociable both from implicit aberrant salience and explicit measures of salience.

Phasic dopamine as a prediction error of intrinsic and extrinsic reinforcements driving both action acquisition and reward maximization: a simulated robotic study.

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Mirolli, Marco; Santucci, Vieri G; Baldassarre, Gianluca

2013-03-01

An important issue of recent neuroscientific research is to understand the functional role of the phasic release of dopamine in the striatum, and in particular its relation to reinforcement learning. The literature is split between two alternative hypotheses: one considers phasic dopamine as a reward prediction error similar to the computational TD-error, whose function is to guide an animal to maximize future rewards; the other holds that phasic dopamine is a sensory prediction error signal that lets the animal discover and acquire novel actions. In this paper we propose an original hypothesis that integrates these two contrasting positions: according to our view phasic dopamine represents a TD-like reinforcement prediction error learning signal determined by both unexpected changes in the environment (temporary, intrinsic reinforcements) and biological rewards (permanent, extrinsic reinforcements). Accordingly, dopamine plays the functional role of driving both the discovery and acquisition of novel actions and the maximization of future rewards. To validate our hypothesis we perform a series of experiments with a simulated robotic system that has to learn different skills in order to get rewards. We compare different versions of the system in which we vary the composition of the learning signal. The results show that only the system reinforced by both extrinsic and intrinsic reinforcements is able to reach high performance in sufficiently complex conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Hemispheric Asymmetries in Striatal Reward Responses Relate to Approach-Avoidance Learning and Encoding of Positive-Negative Prediction Errors in Dopaminergic Midbrain Regions.

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Aberg, Kristoffer Carl; Doell, Kimberly C; Schwartz, Sophie

2015-10-28

Some individuals are better at learning about rewarding situations, whereas others are inclined to avoid punishments (i.e., enhanced approach or avoidance learning, respectively). In reinforcement learning, action values are increased when outcomes are better than predicted (positive prediction errors [PEs]) and decreased for worse than predicted outcomes (negative PEs). Because actions with high and low values are approached and avoided, respectively, individual differences in the neural encoding of PEs may influence the balance between approach-avoidance learning. Recent correlational approaches also indicate that biases in approach-avoidance learning involve hemispheric asymmetries in dopamine function. However, the computational and neural mechanisms underpinning such learning biases remain unknown. Here we assessed hemispheric reward asymmetry in striatal activity in 34 human participants who performed a task involving rewards and punishments. We show that the relative difference in reward response between hemispheres relates to individual biases in approach-avoidance learning. Moreover, using a computational modeling approach, we demonstrate that better encoding of positive (vs negative) PEs in dopaminergic midbrain regions is associated with better approach (vs avoidance) learning, specifically in participants with larger reward responses in the left (vs right) ventral striatum. Thus, individual dispositions or traits may be determined by neural processes acting to constrain learning about specific aspects of the world. Copyright © 2015 the authors 0270-6474/15/3514491-10$15.00/0.

Sensitivity to Temporal Reward Structure in Amygdala Neurons

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Bermudez, Maria A.; Göbel, Carl; Schultz, Wolfram

2012-01-01

Summary The time of reward and the temporal structure of reward occurrence fundamentally influence behavioral reinforcement and decision processes [1–11]. However, despite knowledge about timing in sensory and motor systems [12–17], we know little about temporal mechanisms of neuronal reward processing. In this experiment, visual stimuli predicted different instantaneous probabilities of reward occurrence that resulted in specific temporal reward structures. Licking behavior demonstrated that...

Social reward shapes attentional biases.

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Anderson, Brian A

2016-01-01

Paying attention to stimuli that predict a reward outcome is important for an organism to survive and thrive. When visual stimuli are associated with tangible, extrinsic rewards such as money or food, these stimuli acquire high attentional priority and come to automatically capture attention. In humans and other primates, however, many behaviors are not motivated directly by such extrinsic rewards, but rather by the social feedback that results from performing those behaviors. In the present study, I examine whether positive social feedback can similarly influence attentional bias. The results show that stimuli previously associated with a high probability of positive social feedback elicit value-driven attentional capture, much like stimuli associated with extrinsic rewards. Unlike with extrinsic rewards, however, such stimuli also influence task-specific motivation. My findings offer a potential mechanism by which social reward shapes the information that we prioritize when perceiving the world around us.

Consolidation power of extrinsic rewards: reward cues enhance long-term memory for irrelevant past events.

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Murayama, Kou; Kitagami, Shinji

2014-02-01

Recent research suggests that extrinsic rewards promote memory consolidation through dopaminergic modulation processes. However, no conclusive behavioral evidence exists given that the influence of extrinsic reward on attention and motivation during encoding and consolidation processes are inherently confounded. The present study provides behavioral evidence that extrinsic rewards (i.e., monetary incentives) enhance human memory consolidation independently of attention and motivation. Participants saw neutral pictures, followed by a reward or control cue in an unrelated context. Our results (and a direct replication study) demonstrated that the reward cue predicted a retrograde enhancement of memory for the preceding neutral pictures. This retrograde effect was observed only after a delay, not immediately upon testing. An additional experiment showed that emotional arousal or unconscious resource mobilization cannot explain the retrograde enhancement effect. These results provide support for the notion that the dopaminergic memory consolidation effect can result from extrinsic reward.

Beyond reward prediction errors: the role of dopamine in movement kinematics

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Joseph eBarter

2015-05-01

Full Text Available We recorded activity of dopamine (DA neurons in the substantia nigra pars compacta in unrestrained mice while monitoring their movements with video tracking. Our approach allows an unbiased examination of the continuous relationship between single unit activity and behavior. Although DA neurons show characteristic burst firing following cue or reward presentation, as previously reported, their activity can be explained by the representation of actual movement kinematics. Unlike neighboring pars reticulata GABAergic output neurons, which can represent vector components of position, DA neurons represent vector components of velocity or acceleration. We found neurons related to movements in four directions—up, down, left right. For horizontal movements, there is significant lateralization of neurons: the left nigra contains more rightward neurons, whereas the right nigra contains more leftward neurons. The relationship between DA activity and movement kinematics was found on both appetitive trials using sucrose and aversive trials using air puff, showing that these neurons belong to a velocity control circuit that can be used for any number of purposes, whether to seek reward or to avoid harm. In support of this conclusion, mimicry of the phasic activation of DA neurons with selective optogenetic stimulation could also generate movements. Contrary to the popular hypothesis that DA neurons encode reward prediction errors, our results suggest that nigrostriatal DA plays an essential role in controlling the kinematics of voluntary movements. We hypothesize that DA signaling implements gain adjustment for adaptive transition control, and describe a new model of BG in which DA functions to adjust the gain of a transition controller. This model has significant implications for our understanding of movement disorders implicating DA and the BG.

Brain Circuits Encoding Reward from Pain Relief.

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Navratilova, Edita; Atcherley, Christopher W; Porreca, Frank

2015-11-01

Relief from pain in humans is rewarding and pleasurable. Primary rewards, or reward-predictive cues, are encoded in brain reward/motivational circuits. While considerable advances have been made in our understanding of reward circuits underlying positive reinforcement, less is known about the circuits underlying the hedonic and reinforcing actions of pain relief. We review findings from electrophysiological, neuroimaging, and behavioral studies supporting the concept that the rewarding effect of pain relief requires opioid signaling in the anterior cingulate cortex (ACC), activation of midbrain dopamine neurons, and the release of dopamine in the nucleus accumbens (NAc). Understanding of circuits that govern the reward of pain relief may allow the discovery of more effective and satisfying therapies for patients with acute or chronic pain.

A neurocomputational account of reward and novelty processing and effects of psychostimulants in attention deficit hyperactivity disorder.

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Sethi, Arjun; Voon, Valerie; Critchley, Hugo D; Cercignani, Mara; Harrison, Neil A

2018-05-01

Computational models of reinforcement learning have helped dissect discrete components of reward-related function and characterize neurocognitive deficits in psychiatric illnesses. Stimulus novelty biases decision-making, even when unrelated to choice outcome, acting as if possessing intrinsic reward value to guide decisions toward uncertain options. Heightened novelty seeking is characteristic of attention deficit hyperactivity disorder, yet how this influences reward-related decision-making is computationally encoded, or is altered by stimulant medication, is currently uncertain. Here we used an established reinforcement-learning task to model effects of novelty on reward-related behaviour during functional MRI in 30 adults with attention deficit hyperactivity disorder and 30 age-, sex- and IQ-matched control subjects. Each participant was tested on two separate occasions, once ON and once OFF stimulant medication. OFF medication, patients with attention deficit hyperactivity disorder showed significantly impaired task performance (P = 0.027), and greater selection of novel options (P = 0.004). Moreover, persistence in selecting novel options predicted impaired task performance (P = 0.025). These behavioural deficits were accompanied by a significantly lower learning rate (P = 0.011) and heightened novelty signalling within the substantia nigra/ventral tegmental area (family-wise error corrected P attention deficit hyperactivity disorder participants' overall task performance (P = 0.011), increased reward-learning rates (P = 0.046) and enhanced their ability to differentiate optimal from non-optimal novel choices (P = 0.032). It also reduced substantia nigra/ventral tegmental area responses to novelty. Preliminary cross-sectional evidence additionally suggested an association between long-term stimulant treatment and a reduction in the rewarding value of novelty. These data suggest that aberrant substantia nigra/ventral tegmental area novelty processing plays an

Individual differences in regulatory focus predict neural response to reward.

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Scult, Matthew A; Knodt, Annchen R; Hanson, Jamie L; Ryoo, Minyoung; Adcock, R Alison; Hariri, Ahmad R; Strauman, Timothy J

2017-08-01

Although goal pursuit is related to both functioning of the brain's reward circuits and psychological factors, the literatures surrounding these concepts have often been separate. Here, we use the psychological construct of regulatory focus to investigate individual differences in neural response to reward. Regulatory focus theory proposes two motivational orientations for personal goal pursuit: (1) promotion, associated with sensitivity to potential gain, and (2) prevention, associated with sensitivity to potential loss. The monetary incentive delay task was used to manipulate reward circuit function, along with instructional framing corresponding to promotion and prevention in a within-subject design. We observed that the more promotion oriented an individual was, the lower their ventral striatum response to gain cues. Follow-up analyses revealed that greater promotion orientation was associated with decreased ventral striatum response even to no-value cues, suggesting that promotion orientation may be associated with relatively hypoactive reward system function. The findings are also likely to represent an interaction between the cognitive and motivational characteristics of the promotion system with the task demands. Prevention orientation did not correlate with ventral striatum response to gain cues, supporting the discriminant validity of regulatory focus theory. The results highlight a dynamic association between individual differences in self-regulation and reward system function.

Response of neural reward regions to food cues in autism spectrum disorders

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Cascio Carissa J

2012-05-01

Full Text Available Abstract Background One hypothesis for the social deficits that characterize autism spectrum disorders (ASD is diminished neural reward response to social interaction and attachment. Prior research using established monetary reward paradigms as a test of non-social reward to compare with social reward may involve confounds in the ability of individuals with ASD to utilize symbolic representation of money and the abstraction required to interpret monetary gains. Thus, a useful addition to our understanding of neural reward circuitry in ASD includes a characterization of the neural response to primary rewards. Method We asked 17 children with ASD and 18 children without ASD to abstain from eating for at least four hours before an MRI scan in which they viewed images of high-calorie foods. We assessed the neural reward network for increases in the blood oxygenation level dependent (BOLD signal in response to the food images Results We found very similar patterns of increased BOLD signal to these images in the two groups; both groups showed increased BOLD signal in the bilateral amygdala, as well as in the nucleus accumbens, orbitofrontal cortex, and insula. Direct group comparisons revealed that the ASD group showed a stronger response to food cues in bilateral insula along the anterior-posterior gradient and in the anterior cingulate cortex than the control group, whereas there were no neural reward regions that showed higher activation for controls than for ASD. Conclusion These results suggest that neural response to primary rewards is not diminished but in fact shows an aberrant enhancement in children with ASD.

The impact of a total reward system of work engagement

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Crystal Hoole

2016-11-01

Research purpose: The overall purpose of this study was to explore the relationship between total rewards and work engagement in a South African context and to determine which reward categories predict work engagement. The study further endeavoured to determine whether gender and age had a moderating effect on the relationship between total rewards and engagement. Motivation for the study: Statistics report that less than 30% of all working people are optimally engaged in their work. Considering that individuals spend more than a third of their lives at work committing themselves emotionally, physically and psychologically – research indicates that employees are no longer satisfied with traditional reward systems and want to feel valued and appreciated. Research approach, design and method: In this quantitative, cross-sectional research design using a non-probability convenience and purposive sampling strategy, 318 questionnaires were collected and analysed from financial institutions in Gauteng in which opinions were sought on the importance of different types of rewards structures and preferences, and how engaged they are in their workplace. The 17-item UWES and Nienaber total reward preference model were the chosen measuring instruments. Main findings: A small statistically significant correlation (r = 0.25; p < 0.05; small effect was found between total rewards and work engagement, and 12% of the variance of work engagement was explained. Only performance and career management significantly predicted work engagement. Practical/Managerial implications: Although small, the significant correlation between total rewards and work engagement implies that total rewards are important motivators for employees in the workplace. Of the total rewards scales tested, only performance and career management significantly predicted work engagement, suggesting that more research is needed. Organisations seeking to implement total reward strategies should pay specific

Aberrant approach-avoidance conflict resolution following repeated cocaine pre-exposure.

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Nguyen, David; Schumacher, Anett; Erb, Suzanne; Ito, Rutsuko

2015-10-01

Addiction is characterized by persistence to seek drug reinforcement despite negative consequences. Drug-induced aberrations in approach and avoidance processing likely facilitate the sustenance of addiction pathology. Currently, the effects of repeated drug exposure on the resolution of conflicting approach and avoidance motivational signals have yet to be thoroughly investigated. The present study sought to investigate the effects of cocaine pre-exposure on conflict resolution using novel approach-avoidance paradigms. We used a novel mixed-valence conditioning paradigm to condition cocaine-pre-exposed rats to associate visuo-tactile cues with either the delivery of sucrose reward or shock punishment in the arms in which the cues were presented. Following training, exploration of an arm containing a superimposition of the cues was assessed as a measure of conflict resolution behavior. We also used a mixed-valence runway paradigm wherein cocaine-pre-exposed rats traversed an alleyway toward a goal compartment to receive a pairing of sucrose reward and shock punishment. Latency to enter the goal compartment across trials was taken as a measure of motivational conflict. Our results reveal that cocaine pre-exposure attenuated learning for the aversive cue association in our conditioning paradigm and enhanced preference for mixed-valence stimuli in both paradigms. Repeated cocaine pre-exposure allows appetitive approach motivations to gain greater influence over behavioral output in the context of motivational conflict, due to aberrant positive and negative incentive motivational processing.

Neurobiological underpinnings of reward anticipation and outcome evaluation in gambling disorder

DEFF Research Database (Denmark)

Linnet, Jakob

2014-01-01

Gambling disorder is characterized by persistent and recurrent maladaptive gambling behavior, which leads to clinically significant impairment or distress. The disorder is associated with dysfunctions in the dopamine system. The dopamine system codes reward anticipation and outcome evaluation....... Reward anticipation refers to dopaminergic activation prior to reward, while outcome evaluation refers to dopaminergic activation after reward. This article reviews evidence of dopaminergic dysfunctions in reward anticipation and outcome evaluation in gambling disorder from two vantage points: a model...... of reward prediction and reward prediction error by Wolfram Schultz et al. and a model of “wanting” and “liking” by Terry E. Robinson and Kent C. Berridge. Both models offer important insights on the study of dopaminergic dysfunctions in addiction, and implications for the study of dopaminergic dysfunctions...

The Roles of Dopamine and Hypocretin in Reward: A Electroencephalographic Study.

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Mensen, Armand; Poryazova, Rositsa; Huegli, Gordana; Baumann, Christian R; Schwartz, Sophie; Khatami, Ramin

2015-01-01

The proper functioning of the mesolimbic reward system is largely dependent on the neurotransmitter dopamine. Recent evidence suggests that the hypocretin system has significant projections to this reward system. We examined the distinct effects of reduced dopamine or reduced hypocretin levels on reward activity in patients with Parkinson's disease, dopamine deficient, as well as patients with narcolepsy-cataplexy, hypocretin depleted, and healthy controls. Participants performed a simple game-like task while high-density electroencephalography was recorded. Topography and timing of event-related potentials for both reward cue, and reward feedback was examined across the entire dataset. While response to reward cue was similar in all groups, two distinct time points were found to distinguish patients and controls for reward feedback. Around 160 ms both patient groups had reduced ERP amplitude compared to controls. Later at 250 ms, both patient groups also showed a clear event-related potential (ERP), which was absent in controls. The initial differences show that both patient groups show a similar, blunted response to reward delivery. The second potential corresponds to the classic feedback-related negativity (FRN) potential which relies on dopamine activity and reflects reward prediction-error signaling. In particular the mismatch between predicted reward and reward subsequently received was significantly higher in PD compared to NC, independent of reward magnitude and valence. The intermediate FRN response in NC highlights the contribution of hypocretin in reward processing, yet also shows that this is not as detrimental to the reward system as in Parkinson's. Furthermore, the inability to generate accurate predictions in NC may explain why hypocretin deficiency mediates cataplexy triggered by both positive and negative emotions.

The Roles of Dopamine and Hypocretin in Reward: A Electroencephalographic Study.

Directory of Open Access Journals (Sweden)

Armand Mensen

Full Text Available The proper functioning of the mesolimbic reward system is largely dependent on the neurotransmitter dopamine. Recent evidence suggests that the hypocretin system has significant projections to this reward system. We examined the distinct effects of reduced dopamine or reduced hypocretin levels on reward activity in patients with Parkinson's disease, dopamine deficient, as well as patients with narcolepsy-cataplexy, hypocretin depleted, and healthy controls. Participants performed a simple game-like task while high-density electroencephalography was recorded. Topography and timing of event-related potentials for both reward cue, and reward feedback was examined across the entire dataset. While response to reward cue was similar in all groups, two distinct time points were found to distinguish patients and controls for reward feedback. Around 160 ms both patient groups had reduced ERP amplitude compared to controls. Later at 250 ms, both patient groups also showed a clear event-related potential (ERP, which was absent in controls. The initial differences show that both patient groups show a similar, blunted response to reward delivery. The second potential corresponds to the classic feedback-related negativity (FRN potential which relies on dopamine activity and reflects reward prediction-error signaling. In particular the mismatch between predicted reward and reward subsequently received was significantly higher in PD compared to NC, independent of reward magnitude and valence. The intermediate FRN response in NC highlights the contribution of hypocretin in reward processing, yet also shows that this is not as detrimental to the reward system as in Parkinson's. Furthermore, the inability to generate accurate predictions in NC may explain why hypocretin deficiency mediates cataplexy triggered by both positive and negative emotions.

Neural correlates of reward processing in healthy siblings of patients with schizophrenia

Directory of Open Access Journals (Sweden)

Esther eHanssen

2015-09-01

Full Text Available Deficits in motivational behavior and psychotic symptoms often observed in schizophrenia (SZ may be driven by dysfunctional reward processing (RP. RP can be divided in two different stages; reward anticipation and reward consumption. Aberrant processing during reward anticipation seems to be related to SZ. Studies in patients with SZ have found less activation in the ventral striatum (VS during anticipation of reward, but these findings do not provide information on effect of the genetic load on reward processing. Therefore, this study investigated RP in healthy first-degree relatives of SZ patients. The sample consisted of 94 healthy siblings of SZ patients and 57 healthy controls. Participants completed a classic RP task, the Monetary Incentive Delay task, during functional magnetic resonance imaging (fMRI. As expected, there were no behavioral differences between groups. In contrast to our expectations, we found no differences in any of the anticipatory reward related brain areas (region of interest analyses. Whole-brain analyses did reveal group differences during both reward anticipation and reward consumption; during reward anticipation siblings showed less deactivation in the insula, posterior cingulate cortex (PCC and medial frontal gyrus (MFG than controls. During reward consumption siblings showed less deactivation in the PCC and the right MFG compared to controls and activation in contrast to deactivation in controls in the precuneus and the left MFG. Exclusively in siblings, MFG activity correlated positively with subclinical negative symptoms. These regions are typically associated with the default mode network (DMN, which normally shows decreases in activation during task-related cognitive processes. Thus, in contrast to prior literature in patients with SZ, the results do not point to altered brain activity in classical RP brain areas, such as the VS. However, the weaker deactivation found outside the reward-related network in

The Role of Aberrant Salience and Self-Concept Clarity in Psychotic-Like Experiences

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Cicero, David C.; Becker, Theresa M.; Martin, Elizabeth A.; Docherty, Anna R.; Kerns, John G.

2013-01-01

Most theories of psychotic-like experiences posit the involvement of social-cognitive mechanisms. The current research examined the relations between psychotic-like experiences and two social-cognitive mechanisms, high aberrant salience and low self-concept clarity. In particular, we examined whether aberrant salience, or the incorrect assignment of importance to neutral stimuli, and low self-concept clarity interacted to predict psychotic-like experiences. The current research included three large samples (n = 667, 724, 744) of participants and over-sampled for increased schizotypal personality traits. In all three studies, an interaction between aberrant salience and self-concept clarity was found such that participants with high aberrant salience and low self-concept clarity had the highest levels of psychotic-like experiences. In addition, aberrant salience and self-concept clarity interacted to predict a supplemental measure of delusions in Study 2. In Study 3, in contrast to low self-concept clarity, neuroticism did not interact with aberrant salience to predict psychotic-like experiences, suggesting that the relation between low self-concept clarity and psychosis may not be due to neuroticism. Additionally, aberrant salience and self-concept clarity did not interact to predict to other schizotypal personality disorder criteria, social anhedonia or trait paranoia, which suggests the interaction is specific to psychotic-like experiences. Overall, our results are consistent with several social-cognitive models of psychosis suggesting that aberrant salience and self-concept clarity might be important mechanisms in the occurrence of psychotic-like symptoms. PMID:22452775

Chromosomal aberration

International Nuclear Information System (INIS)

Ishii, Yutaka

1988-01-01

Chromosomal aberrations are classified into two types, chromosome-type and chromatid-type. Chromosom-type aberrations include terminal deletion, dicentric, ring and interstitial deletion, and chromatid-type aberrations include achromatic lesion, chromatid deletion, isochromatid deletion and chromatid exchange. Clastogens which induce chromosomal aberration are divided into ''S-dependent'' agents and ''S-independent''. It might mean whether they can induce double strand breaks independent of the S phase or not. Double strand breaks may be the ultimate lesions to induce chromosomal aberrations. Caffeine added even in the G 2 phase appeared to modify the frequency of chromatid aberrations induced by X-rays and mitomycin C. Those might suggest that the G 2 phase involves in the chromatid aberration formation. The double strand breaks might be repaired by ''G 2 repair system'', the error of which might yield breakage types of chromatid aberrations and the by-pass of which might yield chromatid exchanges. Chromosome-type aberrations might be formed in the G 1 phase. (author)

Association of contextual cues with morphine reward increases neural and synaptic plasticity in the ventral hippocampus of rats

NARCIS (Netherlands)

Alvandi, M.S.; Bourmpoula, M.; Homberg, J.R.; Fathollahi, Y.

2017-01-01

Drug addiction is associated with aberrant memory and permanent functional changes in neural circuits. It is known that exposure to drugs like morphine is associated with positive emotional states and reward-related memory. However, the underlying mechanisms in terms of neural plasticity in the

Distinct Reward Properties are Encoded via Corticostriatal Interactions.

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Smith, David V; Rigney, Anastasia E; Delgado, Mauricio R

2016-02-02

The striatum serves as a critical brain region for reward processing. Yet, understanding the link between striatum and reward presents a challenge because rewards are composed of multiple properties. Notably, affective properties modulate emotion while informative properties help obtain future rewards. We approached this problem by emphasizing affective and informative reward properties within two independent guessing games. We found that both reward properties evoked activation within the nucleus accumbens, a subregion of the striatum. Striatal responses to informative, but not affective, reward properties predicted subsequent utilization of information for obtaining monetary reward. We hypothesized that activation of the striatum may be necessary but not sufficient to encode distinct reward properties. To investigate this possibility, we examined whether affective and informative reward properties were differentially encoded in corticostriatal interactions. Strikingly, we found that the striatum exhibited dissociable connectivity patterns with the ventrolateral prefrontal cortex, with increasing connectivity for affective reward properties and decreasing connectivity for informative reward properties. Our results demonstrate that affective and informative reward properties are encoded via corticostriatal interactions. These findings highlight how corticostriatal systems contribute to reward processing, potentially advancing models linking striatal activation to behavior.

"Liking" and "wanting" linked to Reward Deficiency Syndrome (RDS): hypothesizing differential responsivity in brain reward circuitry.

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Blum, Kenneth; Gardner, Eliot; Oscar-Berman, Marlene; Gold, Mark

2012-01-01

In an attempt to resolve controversy regarding the causal contributions of mesolimbic dopamine (DA) systems to reward, we evaluate the three main competing explanatory categories: "liking,"learning," and "wanting" [1]. That is, DA may mediate (a) the hedonic impact of reward (liking), (b) learned predictions about rewarding effects (learning), or (c) the pursuit of rewards by attributing incentive salience to reward-related stimuli (wanting). We evaluate these hypotheses, especially as they relate to the Reward Deficiency Syndrome (RDS), and we find that the incentive salience or "wanting" hypothesis of DA function is supported by a majority of the evidence. Neuroimaging studies have shown that drugs of abuse, palatable foods, and anticipated behaviors such as sex and gaming affect brain regions involving reward circuitry, and may not be unidirectional. Drugs of abuse enhance DA signaling and sensitize mesolimbic mechanisms that evolved to attribute incentive salience to rewards. Addictive drugs have in common that they are voluntarily selfadministered, they enhance (directly or indirectly) dopaminergic synaptic function in the nucleus accumbens (NAC), and they stimulate the functioning of brain reward circuitry (producing the "high" that drug users seek). Although originally believed simply to encode the set point of hedonic tone, these circuits now are believed to be functionally more complex, also encoding attention, reward expectancy, disconfirmation of reward expectancy, and incentive motivation. Elevated stress levels, together with polymorphisms of dopaminergic genes and other neurotransmitter genetic variants, may have a cumulative effect on vulnerability to addiction. The RDS model of etiology holds very well for a variety of chemical and behavioral addictions.

Neural responses to threat and reward interact to predict stress-related problem drinking: A novel protective role of the amygdala

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2012-01-01

Background Research into neural mechanisms of drug abuse risk has focused on the role of dysfunction in neural circuits for reward. In contrast, few studies have examined the role of dysfunction in neural circuits of threat in mediating drug abuse risk. Although typically regarded as a risk factor for mood and anxiety disorders, threat-related amygdala reactivity may serve as a protective factor against substance use disorders, particularly in individuals with exaggerated responsiveness to reward. Findings We used well-established neuroimaging paradigms to probe threat-related amygdala and reward-related ventral striatum reactivity in a sample of 200 young adult students from the ongoing Duke Neurogenetics Study. Recent life stress and problem drinking were assessed using self-report. We found a significant three-way interaction between threat-related amygdala reactivity, reward-related ventral striatum reactivity, and recent stress, wherein individuals with higher reward-related ventral striatum reactivity exhibit higher levels of problem drinking in the context of stress, but only if they also have lower threat-related amygdala reactivity. This three-way interaction predicted both contemporaneous problem drinking and problem drinking reported three-months later in a subset of participants. Conclusions These findings suggest complex interactions between stress and neural responsiveness to both threat and reward mediate problem drinking. Furthermore, they highlight a novel protective role for threat-related amygdala reactivity against drug use in individuals with high neural reactivity to reward. PMID:23151390

Reward System Activation in Response to Alcohol Advertisements Predicts College Drinking.

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Courtney, Andrea L; Rapuano, Kristina M; Sargent, James D; Heatherton, Todd F; Kelley, William M

2018-01-01

In this study, we assess whether activation of the brain's reward system in response to alcohol advertisements is associated with college drinking. Previous research has established a relationship between exposure to alcohol marketing and underage drinking. Within other appetitive domains, the relationship between cue exposure and behavioral enactment is known to rely on activation of the brain's reward system. However, the relationship between neural activation to alcohol advertisements and alcohol consumption has not been studied in a nondisordered population. In this cross-sectional study, 53 college students (32 women) completed a functional magnetic resonance imaging scan while viewing alcohol, food, and control (car and technology) advertisements. Afterward, they completed a survey about their alcohol consumption (including frequency of drinking, typical number of drinks consumed, and frequency of binge drinking) over the previous month. In 43 participants (24 women) meeting inclusion criteria, viewing alcohol advertisements elicited activation in the left orbitofrontal cortex and bilateral ventral striatum-regions of the reward system that typically activate to other appetitive rewards and relate to consumption behaviors. Moreover, the level of self-reported drinking correlated with the magnitude of activation in the left orbitofrontal cortex. Results suggest that alcohol cues are processed within the reward system in a way that may motivate drinking behavior.

Sensitivity for cues predicting reward and punishment in young women with eating disorders

NARCIS (Netherlands)

Matton, Annelies; de Jong, Peter; Goossens, Lien; Jonker, Nienke; Van Malderen, Eva; Vervaet, Myriam; De Schryver, Nele; Braet, Caroline

Increasing evidence shows that sensitivity to reward (SR) and punishment (SP) may be involved in eating disorders (EDs). Most studies used self-reported positive/negative effect in rewarding/punishing situations, whereas the implied proneness to detect signals of reward/punishment is largely

Sensitivity for cues predicting reward and punishment in young women with eating disorders

NARCIS (Netherlands)

Matton, Annelies; de Jong, Peter; Goossens, Lien; Jonker, Nienke; Van Malderen, Eva; Vervaet, Myriam; De Schryver, Nele; Braet, Caroline

2017-01-01

Increasing evidence shows that sensitivity to reward (SR) and punishment (SP) may be involved in eating disorders (EDs). Most studies used self-reported positive/negative effect in rewarding/punishing situations, whereas the implied proneness to detect signals of reward/punishment is largely

Reward and Cognition: Integrating Reinforcement Sensitivity Theory and Social Cognitive Theory to Predict Drinking Behavior.

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Hasking, Penelope; Boyes, Mark; Mullan, Barbara

2015-01-01

Both Reinforcement Sensitivity Theory and Social Cognitive Theory have been applied to understanding drinking behavior. We propose that theoretical relationships between these models support an integrated approach to understanding alcohol use and misuse. We aimed to test an integrated model in which the relationships between reward sensitivity and drinking behavior (alcohol consumption, alcohol-related problems, and symptoms of dependence) were mediated by alcohol expectancies and drinking refusal self-efficacy. Online questionnaires assessing the constructs of interest were completed by 443 Australian adults (M age = 26.40, sd = 1.83) in 2013 and 2014. Path analysis revealed both direct and indirect effects and implicated two pathways to drinking behavior with differential outcomes. Drinking refusal self-efficacy both in social situations and for emotional relief was related to alcohol consumption. Sensitivity to reward was associated with alcohol-related problems, but operated through expectations of increased confidence and personal belief in the ability to limit drinking in social situations. Conversely, sensitivity to punishment operated through negative expectancies and drinking refusal self-efficacy for emotional relief to predict symptoms of dependence. Two pathways relating reward sensitivity, alcohol expectancies, and drinking refusal self-efficacy may underlie social and dependent drinking, which has implications for development of intervention to limit harmful drinking.

It's about time: Earlier rewards increase intrinsic motivation.

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Woolley, Kaitlin; Fishbach, Ayelet

2018-06-01

Can immediate (vs. delayed) rewards increase intrinsic motivation? Prior research compared the presence versus absence of rewards. By contrast, this research compared immediate versus delayed rewards, predicting that more immediate rewards increase intrinsic motivation by creating a perceptual fusion between the activity and its goal (i.e., the reward). In support of the hypothesis, framing a reward from watching a news program as more immediate (vs. delayed) increased intrinsic motivation to watch the program (Study 1), and receiving more immediate bonus (vs. delayed, Study 2; and vs. delayed and no bonus, Study 3) increased intrinsic motivation in an experimental task. The effect of reward timing was mediated by the strength of the association between an activity and a reward, and was specific to intrinsic (vs. extrinsic) motivation-immediacy influenced the positive experience of an activity, but not perceived outcome importance (Study 4). In addition, the effect of the timing of rewards was independent of the effect of the magnitude of the rewards (Study 5). (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Post-learning hippocampal dynamics promote preferential retention of rewarding events

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Gruber, Matthias J.; Ritchey, Maureen; Wang, Shao-Fang; Doss, Manoj K.; Ranganath, Charan

2016-01-01

Reward motivation is known to modulate memory encoding, and this effect depends on interactions between the substantia nigra/ ventral tegmental area complex (SN/VTA) and the hippocampus. It is unknown, however, whether these interactions influence offline neural activity in the human brain that is thought to promote memory consolidation. Here, we used functional magnetic resonance imaging (fMRI) to test the effect of reward motivation on post-learning neural dynamics and subsequent memory for objects that were learned in high- or low-reward motivation contexts. We found that post-learning increases in resting-state functional connectivity between the SN/VTA and hippocampus predicted preferential retention of objects that were learned in high-reward contexts. In addition, multivariate pattern classification revealed that hippocampal representations of high-reward contexts were preferentially reactivated during post-learning rest, and the number of hippocampal reactivations was predictive of preferential retention of items learned in high-reward contexts. These findings indicate that reward motivation alters offline post-learning dynamics between the SN/VTA and hippocampus, providing novel evidence for a potential mechanism by which reward could influence memory consolidation. PMID:26875624

Frontal-striatum dysfunction during reward processing: Relationships to amotivation in schizophrenia.

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Chung, Yu Sun; Barch, Deanna M

2016-04-01

Schizophrenia is characterized by deficits of context processing, thought to be related to dorsolateral prefrontal cortex (DLPFC) impairment. Despite emerging evidence suggesting a crucial role of the DLPFC in integrating reward and goal information, we do not know whether individuals with schizophrenia can represent and integrate reward-related context information to modulate cognitive control. To address this question, 36 individuals with schizophrenia (n = 29) or schizoaffective disorder (n = 7) and 27 healthy controls performed a variant of a response conflict task (Padmala & Pessoa, 2011) during fMRI scanning, in both baseline and reward conditions, with monetary incentives on some reward trials. We used a mixed state-item design that allowed us to examine both sustained and transient reward effects on cognitive control. Different from predictions about impaired DLPFC function in schizophrenia, we found an intact pattern of increased sustained DLPFC activity during reward versus baseline blocks in individuals with schizophrenia at a group level but blunted sustained activations in the putamen. Contrary to our predictions, individuals with schizophrenia showed blunted cue-related activations in several regions of the basal ganglia responding to reward-predicting cues. Importantly, as predicted, individual differences in anhedonia/amotivation symptoms severity were significantly associated with reduced sustained DLPFC activation in the same region that showed overall increased activity as a function of reward. These results suggest that individual differences in motivational impairments in schizophrenia may be related to dysfunction of the DLPFC and striatum in motivationally salient situations. (c) 2016 APA, all rights reserved).

Ventral Striatum Functional Connectivity as a Predictor of Adolescent Depressive Disorder in a Longitudinal Community-Based Sample.

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Pan, Pedro Mario; Sato, João R; Salum, Giovanni A; Rohde, Luis A; Gadelha, Ary; Zugman, Andre; Mari, Jair; Jackowski, Andrea; Picon, Felipe; Miguel, Eurípedes C; Pine, Daniel S; Leibenluft, Ellen; Bressan, Rodrigo A; Stringaris, Argyris

2017-11-01

Previous studies have implicated aberrant reward processing in the pathogenesis of adolescent depression. However, no study has used functional connectivity within a distributed reward network, assessed using resting-state functional MRI (fMRI), to predict the onset of depression in adolescents. This study used reward network-based functional connectivity at baseline to predict depressive disorder at follow-up in a community sample of adolescents. A total of 637 children 6-12 years old underwent resting-state fMRI. Discovery and replication analyses tested intrinsic functional connectivity (iFC) among nodes of a putative reward network. Logistic regression tested whether striatal node strength, a measure of reward-related iFC, predicted onset of a depressive disorder at 3-year follow-up. Further analyses investigated the specificity of this prediction. Increased left ventral striatum node strength predicted increased risk for future depressive disorder (odds ratio=1.54, 95% CI=1.09-2.18), even after excluding participants who had depressive disorders at baseline (odds ratio=1.52, 95% CI=1.05-2.20). Among 11 reward-network nodes, only the left ventral striatum significantly predicted depression. Striatal node strength did not predict other common adolescent psychopathology, such as anxiety, attention deficit hyperactivity disorder, and substance use. Aberrant ventral striatum functional connectivity specifically predicts future risk for depressive disorder. This finding further emphasizes the need to understand how brain reward networks contribute to youth depression.

Learning Reward Uncertainty in the Basal Ganglia.

Directory of Open Access Journals (Sweden)

John G Mikhael

2016-09-01

Full Text Available Learning the reliability of different sources of rewards is critical for making optimal choices. However, despite the existence of detailed theory describing how the expected reward is learned in the basal ganglia, it is not known how reward uncertainty is estimated in these circuits. This paper presents a class of models that encode both the mean reward and the spread of the rewards, the former in the difference between the synaptic weights of D1 and D2 neurons, and the latter in their sum. In the models, the tendency to seek (or avoid options with variable reward can be controlled by increasing (or decreasing the tonic level of dopamine. The models are consistent with the physiology of and synaptic plasticity in the basal ganglia, they explain the effects of dopaminergic manipulations on choices involving risks, and they make multiple experimental predictions.

COMT Val158Met genotype is associated with reward learning: A replication study and meta-analysis

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Corral-Frías, Nadia S.; Pizzagalli, Diego A.; Carré, Justin; Michalski, Lindsay J; Nikolova, Yuliya S.; Perlis, Roy H.; Fagerness, Jesen; Lee, Mary R.; Conley, Emily Drabant; Lancaster, Thomas M.; Haddad, Stephen; Wolf, Aaron; Smoller, Jordan W.; Hariri, Ahmad R.; Bogdan, Ryan

2016-01-01

Identifying mechanisms through which individual differences in reward learning emerge offers an opportunity to understand both a fundamental form of adaptive responding as well as etiological pathways through which aberrant reward learning may contribute to maladaptive behaviors and psychopathology. One candidate mechanism through which individual differences in reward learning may emerge is variability in dopaminergic reinforcement signaling. A common functional polymorphism within the catechol-O-methyl transferase gene (COMT; rs4680, Val158Met) has been linked to reward learning where homozygosity for the Met allele (associated with heightened prefrontal dopamine function and decreased dopamine synthesis in the midbrain) has been associated with relatively increased reward learning. Here, we used a probabilistic reward learning task to asses response bias, a behavioral form of reward learning, across 3 separate samples that were combined for analyses (age: 21.80 ± 3.95; n=392; 268 female; European-American, n=208). We replicate prior reports that COMT rs4680 Met allele homozygosity is associated with increased reward learning in European-American participants (β=0.20, t= 2.75, p< 0.01; ΔR2= 0.04). Moreover, a meta-analysis of 4 studies, including the current one, confirmed the association between COMT rs4680 genotype and reward learning (95% CI −0.11 to −0.03; z=3.2; p<0.01). These results suggest that variability in dopamine signaling associated with COMT rs4680 influences individual differences in reward which may potentially contribute to psychopathology characterized by reward dysfunction. PMID:27138112

Authoritarian parenting predicts reduced electrocortical response to observed adolescent offspring rewards

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Speed, Brittany C.; Nelson, Brady; Bress, Jennifer N.; Hajcak, Greg

2017-01-01

Abstract Parenting styles are robust predictors of offspring outcomes, yet little is known about their neural underpinnings. In this study, 44 parent-adolescent dyads (Mage of adolescent = 12.9) completed a laboratory guessing task while EEG was continuously recorded. In the task, each pair member received feedback about their own monetary wins and losses and also observed the monetary wins and losses of the other member of the pair. We examined the association between self-reported parenting style and parents’ electrophysiological responses to watching their adolescent winning and losing money, dubbed the observational Reward Positivity (RewP) and observational feedback negativity (FN), respectively. Self-reported authoritarian parenting predicted reductions in parents’ observational RewP but not FN. This predictive relationship remained after adjusting for sex of both participants, parents’ responsiveness to their own wins, and parental psychopathology. ‘Exploratory analyses found that permissive parenting was associated with a blunting of the adolescents’ response to their parents’ losses’. These findings suggest that parents’ rapid neural responses to their child’s successes may relate to the harsh parenting behaviors associated with authoritarian parenting. PMID:27613780

Reward-Enhanced Memory in Younger and Older Adults

OpenAIRE

Julia Spaniol; Cécile Schain; Holly J. Bowen

2014-01-01

Objectives. We investigated how the anticipation of remote monetary reward modulates intentional episodic memory formation in younger and older adults. On the basis of prior findings of preserved reward–cognition interactions in aging, we predicted that reward anticipation would be associated with enhanced memory in both younger and older adults. On the basis of previous demonstrations of a time-dependent effect of reward anticipation on memory, we expected the memory enhancement to increase ...

Do Substantia Nigra Dopaminergic Neurons Differentiate Between Reward and Punishment?

Institute of Scientific and Technical Information of China (English)

Michael J. Frank; D. James Surmeier

2009-01-01

The activity of dopaminergic neurons are thought to be increased by stimuli that predict reward and decreased by stimuli that predict aversive outcomes. Recent work by Matsumoto and Hikosaka challenges this model by asserting that stimuli associated with either rewarding or aversive outcomes increase the activity of dopaminergic neurons in the substantia nigra pars compacta.

A test of the reward-value hypothesis.

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Smith, Alexandra E; Dalecki, Stefan J; Crystal, Jonathon D

2017-03-01

Rats retain source memory (memory for the origin of information) over a retention interval of at least 1 week, whereas their spatial working memory (radial maze locations) decays within approximately 1 day. We have argued that different forgetting functions dissociate memory systems. However, the two tasks, in our previous work, used different reward values. The source memory task used multiple pellets of a preferred food flavor (chocolate), whereas the spatial working memory task provided access to a single pellet of standard chow-flavored food at each location. Thus, according to the reward-value hypothesis, enhanced performance in the source memory task stems from enhanced encoding/memory of a preferred reward. We tested the reward-value hypothesis by using a standard 8-arm radial maze task to compare spatial working memory accuracy of rats rewarded with either multiple chocolate or chow pellets at each location using a between-subjects design. The reward-value hypothesis predicts superior accuracy for high-valued rewards. We documented equivalent spatial memory accuracy for high- and low-value rewards. Importantly, a 24-h retention interval produced equivalent spatial working memory accuracy for both flavors. These data are inconsistent with the reward-value hypothesis and suggest that reward value does not explain our earlier findings that source memory survives unusually long retention intervals.

Abnormal reward functioning across substance use disorders and major depressive disorder: Considering reward as a transdiagnostic mechanism.

Science.gov (United States)

Baskin-Sommers, Arielle R; Foti, Dan

2015-11-01

A common criticism of the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 2013) is that its criteria are based more on behavioral descriptions than on underlying biological mechanisms. Increasingly, calls have intensified for a more biologically-based approach to conceptualizing, studying, and treating psychological disorders, as exemplified by the Research Domain Criteria Project (RDoC). Among the most well-studied neurobiological mechanisms is reward processing. Moreover, individual differences in reward sensitivity are related to risk for substance abuse and depression. The current review synthesizes the available preclinical, electrophysiological, and neuroimaging literature on reward processing from a transdiagnostic, multidimensional perspective. Findings are organized with respect to key reward constructs within the Positive Valence Systems domain of the RDoC matrix, including initial responsiveness to reward (physiological 'liking'), approach motivation (physiological 'wanting'), and reward learning/habit formation. In the current review, we (a) describe the neural basis of reward, (b) elucidate differences in reward activity in substance abuse and depression, and (c) suggest a framework for integrating these disparate literatures and discuss the utility of shifting focus from diagnosis to process for understanding liability and co-morbidity. Ultimately, we believe that an integrative focus on abnormal reward functioning across the full continuum of clinically heterogeneous samples, rather than within circumscribed diagnostic categories, might actually help to refine the phenotypes and improve the prediction of onset and recovery of these disorders. Copyright © 2015 Elsevier B.V. All rights reserved.

The globus pallidus sends reward-related signals to the lateral habenula.

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Hong, Simon; Hikosaka, Okihide

2008-11-26

As a major output station of the basal ganglia, the globus pallidus internal segment (GPi) projects to the thalamus and brainstem nuclei thereby controlling motor behavior. A less well known fact is that the GPi also projects to the lateral habenula (LHb) which is often associated with the limbic system. Using the monkey performing a saccade task with positionally biased reward outcomes, we found that antidromically identified LHb-projecting neurons were distributed mainly in the dorsal and ventral borders of the GPi and that their activity was strongly modulated by expected reward outcomes. A majority of them were excited by the no-reward-predicting target and inhibited by the reward-predicting target. These reward-dependent modulations were similar to those in LHb neurons but started earlier than those in LHb neurons. These results suggest that GPi may initiate reward-related signals through its effects on the LHb, which then influences the dopaminergic and serotonergic systems.

No unified reward prediction error in local field potentials from the human nucleus accumbens: evidence from epilepsy patients.

Science.gov (United States)

Stenner, Max-Philipp; Rutledge, Robb B; Zaehle, Tino; Schmitt, Friedhelm C; Kopitzki, Klaus; Kowski, Alexander B; Voges, Jürgen; Heinze, Hans-Jochen; Dolan, Raymond J

2015-08-01

Functional magnetic resonance imaging (fMRI), cyclic voltammetry, and single-unit electrophysiology studies suggest that signals measured in the nucleus accumbens (Nacc) during value-based decision making represent reward prediction errors (RPEs), the difference between actual and predicted rewards. Here, we studied the precise temporal and spectral pattern of reward-related signals in the human Nacc. We recorded local field potentials (LFPs) from the Nacc of six epilepsy patients during an economic decision-making task. On each trial, patients decided whether to accept or reject a gamble with equal probabilities of a monetary gain or loss. The behavior of four patients was consistent with choices being guided by value expectations. Expected value signals before outcome onset were observed in three of those patients, at varying latencies and with nonoverlapping spectral patterns. Signals after outcome onset were correlated with RPE regressors in all subjects. However, further analysis revealed that these signals were better explained as outcome valence rather than RPE signals, with gamble gains and losses differing in the power of beta oscillations and in evoked response amplitudes. Taken together, our results do not support the idea that postsynaptic potentials in the Nacc represent a RPE that unifies outcome magnitude and prior value expectation. We discuss the generalizability of our findings to healthy individuals and the relation of our results to measurements of RPE signals obtained from the Nacc with other methods. Copyright © 2015 the American Physiological Society.

Regulating task-monitoring systems in response to variable reward contingencies and outcomes in cocaine addicts.

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Morie, Kristen P; De Sanctis, Pierfilippo; Garavan, Hugh; Foxe, John J

2016-03-01

We investigated anticipatory and consummatory reward processing in cocaine addiction. In addition, we set out to assess whether task-monitoring systems were appropriately recalibrated in light of variable reward schedules. We also examined neural measures of task-monitoring and reward processing as a function of hedonic tone, since anhedonia is a vulnerability marker for addiction that is obviously germane in the context of reward processing. High-density event-related potentials were recorded while participants performed a speeded response task that systematically varied anticipated probabilities of reward receipt. The paradigm dissociated feedback regarding task success (or failure) from feedback regarding the value of reward (or loss), so that task-monitoring and reward processing could be examined in partial isolation. Twenty-three active cocaine abusers and 23 age-matched healthy controls participated. Cocaine abusers showed amplified anticipatory responses to reward predictive cues, but crucially, these responses were not as strongly modulated by reward probability as in controls. Cocaine users also showed blunted responses to feedback about task success or failure and did not use this information to update predictions about reward. In turn, they showed clearly blunted responses to reward feedback. In controls and users, measures of anhedonia were associated with reward motivation. In cocaine users, anhedonia was also associated with diminished monitoring and reward feedback responses. Findings imply that reward anticipation and monitoring deficiencies in addiction are associated with increased responsiveness to reward cues but impaired ability to predict reward in light of task contingencies, compounded by deficits in responding to actual reward outcomes.

DISRUPTION OF CONDITIONED REWARD ASSOCIATION BY TYPICAL AND ATYPICAL ANTIPSYCHOTICS

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Danna, C.L.; Elmer, G.I.

2013-01-01

Antipsychotic drugs are broadly classified into typical and atypical compounds; they vary in their pharmacological profile however a common component is their antagonist effects at the D2 dopamine receptors (DRD2). Unfortunately, diminished DRD2 activation is generally thought to be associated with the severity of neuroleptic-induced anhedonia. The purpose of this study was to determine the effect of the atypical antipsychotic olanzapine and typical antipsychotic haloperidol in a paradigm that reflects the learned transfer of incentive motivational properties to previously neutral stimuli, namely autoshaping. In order to provide a dosing comparison to a therapeutically relevant endpoint, both drugs were tested against amphetamine-induced disruption of prepulse inhibition as well. In the autoshaping task, rats were exposed to repeated pairings of stimuli that were differentially predictive of reward delivery. Conditioned approach to the reward predictive cue (sign-tracking) and to the reward (goal-tracking) increased during repeated pairings in the vehicle treated rats. Haloperidol and olanzapine completely abolished this behavior at relatively low doses (100 μg/kg). This same dose was the threshold dose for each drug to antagonize the sensorimotor gating deficits produced by amphetamine. At lower doses (3–30 μg/kg) both drugs produced a dose-dependent decrease in conditioned approach to the reward predictive cue. There was no difference between drugs at this dose range which indicates that olanzapine disrupts autoshaping at a significantly lower proposed DRD2 receptor occupancy. Interestingly, neither drug disrupted conditioned approach to the reward at the same dose range that disrupted conditioned approach to the reward predictive cue. Thus, haloperidol and olanzapine, at doses well below what is considered therapeutically relevant, disrupts the attribution of incentive motivational value to previously neutral cues. Drug effects on this dimension of reward

Optical Aberrations and Wavefront

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Nihat Polat

2014-08-01

Full Text Available The deviation of light to create normal retinal image in the optical system is called aberration. Aberrations are divided two subgroup: low-order aberrations (defocus: spherical and cylindrical refractive errors and high-order aberrations (coma, spherical, trefoil, tetrafoil, quadrifoil, pentafoil, secondary astigmatism. Aberrations increase with aging. Spherical aberrations are compensated by positive corneal and negative lenticular spherical aberrations in youth. Total aberrations are elevated by positive corneal and positive lenticular spherical aberrations in elderly. In this study, we aimed to analyze the basic terms regarding optic aberrations which have gained significance recently. (Turk J Ophthalmol 2014; 44: 306-11

Intrachromosomal exchange aberrations predicted on the basis of globular interphase chromosome model

International Nuclear Information System (INIS)

Andreev, S.G.; Eidelman, Yu.A.

2002-01-01

One of the key questions in understanding mechanisms of chromosome aberration production is how does interphase chromosome structure affect aberration formation. To explore this a modelling approach is presented which combines Monte Carlo simulation of both a particle track and interphase chromosome structure. The structural state of interphase chromosome influences a dose-effect relationship for intrachromosomal exchange aberrations (intrachanges). It is shown that intrachanges are induced frequently by both X rays and a particles if the chromosome is in the condensed globular but not in the decondensed coiled state. Truly simple intra-arm intrachanges induced by X rays are dose squared in coiled chromosomes, but exhibit linear dose dependence in globular chromosomes. Experimental data on interarm intrachanges obtained by dual arm chromosome painting are analysed by means of the technique presented. Results of analysis support the conclusion about the arms proximity of chromosome 1 in human lymphocytes. (author)

Amygdala mu-opioid receptors mediate the motivating influence of cue-triggered reward expectations.

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Lichtenberg, Nina T; Wassum, Kate M

2017-02-01

Environmental reward-predictive stimuli can retrieve from memory a specific reward expectation that allows them to motivate action and guide choice. This process requires the basolateral amygdala (BLA), but little is known about the signaling systems necessary within this structure. Here we examined the role of the neuromodulatory opioid receptor system in the BLA in such cue-directed action using the outcome-specific Pavlovian-to-instrumental transfer (PIT) test in rats. Inactivation of BLA mu-, but not delta-opioid receptors was found to dose-dependently attenuate the ability of a reward-predictive cue to selectively invigorate the performance of actions directed at the same unique predicted reward (i.e. to express outcome-specific PIT). BLA mu-opioid receptor inactivation did not affect the ability of a reward itself to similarly motivate action (outcome-specific reinstatement), suggesting a more selective role for the BLA mu-opioid receptor in the motivating influence of currently unobservable rewarding events. These data reveal a new role for BLA mu-opioid receptor activation in the cued recall of precise reward memories and the use of this information to motivate specific action plans. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

An aberrant precision account of autism.

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Rebecca P Lawson

2014-05-01

Full Text Available Autism is a neurodevelopmental disorder characterised by problems with social-communication, restricted interests and repetitive behaviour. A recent and controversial article presented a compelling normative explanation for the perceptual symptoms of autism in terms of a failure of Bayesian inference (Pellicano and Burr, 2012. In response, we suggested that when Bayesian interference is grounded in its neural instantiation – namely, predictive coding – many features of autistic perception can be attributed to aberrant precision (or beliefs about precision within the context of hierarchical message passing in the brain (Friston et al., 2013. Here, we unpack the aberrant precision account of autism. Specifically, we consider how empirical findings – that speak directly or indirectly to neurobiological mechanisms – are consistent with the aberrant encoding of precision in autism; in particular, an imbalance of the precision ascribed to sensory evidence relative to prior beliefs.

Authoritarian parenting predicts reduced electrocortical response to observed adolescent offspring rewards.

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Levinson, Amanda R; Speed, Brittany C; Nelson, Brady; Bress, Jennifer N; Hajcak, Greg

2017-03-01

Parenting styles are robust predictors of offspring outcomes, yet little is known about their neural underpinnings. In this study, 44 parent-adolescent dyads (Mage of adolescent = 12.9) completed a laboratory guessing task while EEG was continuously recorded. In the task, each pair member received feedback about their own monetary wins and losses and also observed the monetary wins and losses of the other member of the pair. We examined the association between self-reported parenting style and parents' electrophysiological responses to watching their adolescent winning and losing money, dubbed the observational Reward Positivity (RewP) and observational feedback negativity (FN), respectively. Self-reported authoritarian parenting predicted reductions in parents' observational RewP but not FN. This predictive relationship remained after adjusting for sex of both participants, parents' responsiveness to their own wins, and parental psychopathology. 'Exploratory analyses found that permissive parenting was associated with a blunting of the adolescents' response to their parents' losses'. These findings suggest that parents' rapid neural responses to their child's successes may relate to the harsh parenting behaviors associated with authoritarian parenting. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Adaptive scaling of reward in episodic memory: a replication study.

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Mason, Alice; Ludwig, Casimir; Farrell, Simon

2017-11-01

Reward is thought to enhance episodic memory formation via dopaminergic consolidation. Bunzeck, Dayan, Dolan, and Duzel [(2010). A common mechanism for adaptive scaling of reward and novelty. Human Brain Mapping, 31, 1380-1394] provided functional magnetic resonance imaging (fMRI) and behavioural evidence that reward and episodic memory systems are sensitive to the contextual value of a reward-whether it is relatively higher or lower-as opposed to absolute value or prediction error. We carried out a direct replication of their behavioural study and did not replicate their finding that memory performance associated with reward follows this pattern of adaptive scaling. An effect of reward outcome was in the opposite direction to that in the original study, with lower reward outcomes leading to better memory than higher outcomes. There was a marginal effect of reward context, suggesting that expected value affected memory performance. We discuss the robustness of the reward memory relationship to variations in reward context, and whether other reward-related factors have a more reliable influence on episodic memory.

AN EXTENDED REINFORCEMENT LEARNING MODEL OF BASAL GANGLIA TO UNDERSTAND THE CONTRIBUTIONS OF SEROTONIN AND DOPAMINE IN RISK-BASED DECISION MAKING, REWARD PREDICTION, AND PUNISHMENT LEARNING

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Pragathi Priyadharsini Balasubramani

2014-04-01

Full Text Available Although empirical and neural studies show that serotonin (5HT plays many functional roles in the brain, prior computational models mostly focus on its role in behavioral inhibition. In this study, we present a model of risk based decision making in a modified Reinforcement Learning (RL-framework. The model depicts the roles of dopamine (DA and serotonin (5HT in Basal Ganglia (BG. In this model, the DA signal is represented by the temporal difference error (δ, while the 5HT signal is represented by a parameter (α that controls risk prediction error. This formulation that accommodates both 5HT and DA reconciles some of the diverse roles of 5HT particularly in connection with the BG system. We apply the model to different experimental paradigms used to study the role of 5HT: 1 Risk-sensitive decision making, where 5HT controls risk assessment, 2 Temporal reward prediction, where 5HT controls time-scale of reward prediction, and 3 Reward/Punishment sensitivity, in which the punishment prediction error depends on 5HT levels. Thus the proposed integrated RL model reconciles several existing theories of 5HT and DA in the BG.

Neural reward and punishment sensitivity in cigarette smokers.

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Potts, Geoffrey F; Bloom, Erika L; Evans, David E; Drobes, David J

2014-11-01

Nicotine addiction remains a major public health problem but the neural substrates of addictive behavior remain unknown. One characteristic of smoking behavior is impulsive choice, selecting the immediate reward of smoking despite the potential long-term negative consequences. This suggests that drug users, including cigarette smokers, may be more sensitive to rewards and less sensitive to punishment. We used event-related potentials (ERPs) to test the hypothesis that smokers are more responsive to reward signals and less responsive to punishment, potentially predisposing them to risky behavior. We conducted two experiments, one using a reward prediction design to elicit a Medial Frontal Negativity (MFN) and one using a reward- and punishment-motivated flanker task to elicit an Error Related Negativity (ERN), ERP components thought to index activity in the cortical projection of the dopaminergic reward system. The smokers had a greater MFN response to unpredicted rewards, and non-smokers, but not smokers, had a larger ERN on punishment motivated trials indicating that smokers are more reward sensitive and less punishment sensitive than nonsmokers, overestimating the appetitive value and underestimating aversive outcomes of stimuli and actions. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Altered social reward and attention in anorexia nervosa

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Karli K Watson

2010-09-01

Full Text Available Dysfunctional social reward and social orienting attend a variety of neuropsychiatric disorders including autism, schizophrenia, social anxiety, and psychopathy. Here we show that similar social reward and attention dysfunction attend anorexia nervosa, a disorder defined by avoidance of food and extreme weight loss. We measured the implicit reward value of social stimuli for female participants with (n=11 and without (n=11 anorexia nervosa using an econometric choice task and also tracked gaze patterns during free viewing of images of female faces and bodies. As predicted, the reward value of viewing bodies varied inversely with observed body weight for women with anorexia but not neurotypical women, in contrast with their explicit ratings of attractiveness. Surprisingly, women with anorexia nervosa, unlike neurotypical women, did not find female faces rewarding and avoided looking at both the face and eyes—independent of observed body weight. These findings demonstrate comorbid dysfunction in the neural circuits mediating gustatory and social reward in anorexia nervosa.

Individual differences in the habitual use of cognitive reappraisal predict the reward-related processing.

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Sai, Liyang; Wang, Sisi; Ward, Anne; Ku, Yixuan; Sang, Biao

2015-01-01

Recent studies have shown that instructed cognitive reappraisal can regulate the neural processing of reward. However, it is still unclear whether the habitual use of cognitive reappraisal in everyday life is related to brain activity involved in reward processing. In the present study, participants' neural responses to reward were measured using electroencephalography (EEG) recorded during a gambling task and their tendency to use cognitive reappraisal was assessed using the Emotion Regulation Questionnaire (ERQ). Event-related potential (ERP) results indicated that losses on the gambling task elicited greater negative reward-related feedback negativity (FN) than gains. The differential FN between losses and gains was significantly correlated with cognitive reappraisal scores across participants such that individuals with a higher tendency to use cognitive reappraisal showed stronger reward processing (i.e., amplified FN difference between losses and gains). This correlation remained significant after controlling for expressive suppression scores. However, expressive suppression per se was not correlated with FN differences. Taken together, these results suggest that the habitual use of cognitive reappraisal is associated with increased neural processing of reward.

Medial prefrontal brain activation to anticipated reward and loss in obsessive-compulsive disorder.

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Kaufmann, C; Beucke, J C; Preuße, F; Endrass, T; Schlagenhauf, F; Heinz, A; Juckel, G; Kathmann, N

2013-01-01

Obsessive-compulsive disorder (OCD) is associated with dysfunctional brain activity in several regions which are also involved in the processing of motivational stimuli. Processing of reward and punishment appears to be of special importance to understand clinical symptoms. There is evidence for higher sensitivity to punishment in patients with OCD which raises the question how avoidance of punishment relates to activity within the brain's reward circuitry. We employed the monetary incentive delay task paradigm optimized for modeling the anticipation phase of immediate reward and punishment, in the context of a cross-sectional event-related FMRI study comparing OCD patients and healthy control participants (n = 19 in each group). While overall behavioral performance was similar in both groups, patients showed increased activation upon anticipated losses in a medial and superior frontal cortex region extending into the cingulate cortex, and decreased activation upon anticipated rewards. No evidence was found for altered activation of dorsal or ventral striatal regions. Patients also showed more delayed responses for anticipated rewards than for anticipated losses whereas the reverse was true in healthy participants. The medial prefrontal cortex has been shown to implement a domain-general process comprising negative affect, pain and cognitive control. This process uses information about punishment to control aversively motivated actions by integrating signals arriving from subcortical regions. Our results support the notion that OCD is associated with altered sensitivity to anticipated rewards and losses in a medial prefrontal region whereas there is no significant aberrant activation in ventral or dorsal striatal brain regions during processing of reinforcement anticipation.

Neural correlates of water reward in thirsty Drosophila

OpenAIRE

Lin, Suewei; Owald, David; Chandra, Vikram; Talbot, Clifford; Huetteroth, Wolf; Waddell, Scott

2014-01-01

Drinking water is innately rewarding to thirsty animals. In addition, the consumed value can be assigned to behavioral actions and predictive sensory cues by associative learning. Here we show that thirst converts water avoidance into water-seeking in naive Drosophila melanogaster. Thirst also permitted flies to learn olfactory cues paired with water reward. Water learning required water taste and

Model Checking Markov Reward Models with Impulse Rewards

NARCIS (Netherlands)

Cloth, Lucia; Katoen, Joost-Pieter; Khattri, Maneesh; Pulungan, Reza; Bondavalli, Andrea; Haverkort, Boudewijn; Tang, Dong

This paper considers model checking of Markov reward models (MRMs), continuous-time Markov chains with state rewards as well as impulse rewards. The reward extension of the logic CSL (Continuous Stochastic Logic) is interpreted over such MRMs, and two numerical algorithms are provided to check the

Memory Consolidation and Neural Substrate of Reward

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Redolar-Ripoll, Diego

2012-08-01

Full Text Available The aim of this report is to analyze the relationships between reward and learning and memory processes. Different studies have described how information about rewards influences behavior and how the brain uses this reward information to control learning and memory processes. Reward nature seems to be processed in different ways by neurons in different brain structures, ranging from the detection and perception of rewards to the use of information about predicted rewards for the control of goal-directed behavior. The neural substrate underling this processing of reward information is a reliable way of improving learning and memory processes. Evidence from several studies indicates that this neural system can facilitate memory consolidation in a wide variety of learning tasks. From a molecular perspective, certain cardinal features of reward have been described as forms of memory. Studies of human addicts and studies in animal models of addiction show that chronic drug exposure produces stable changes in the brain at the cellular and molecular levels that underlie the long-lasting behavioral plasticity associated with addiction. These molecular and cellular adaptations involved in addiction are also implicated in learning and memory processes. Dopamine seems to be a critical common signal to activate different genetic mechanisms that ultimately remodel synapses and circuits. Despite memory is an active and complex process mediated by different brain areas, the neural substrate of reward is able to improve memory consolidation in a several paradigms. We believe that there are many equivalent traits between reward and learning and memory processes.

RM-SORN: a reward-modulated self-organizing recurrent neural network.

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Aswolinskiy, Witali; Pipa, Gordon

2015-01-01

Neural plasticity plays an important role in learning and memory. Reward-modulation of plasticity offers an explanation for the ability of the brain to adapt its neural activity to achieve a rewarded goal. Here, we define a neural network model that learns through the interaction of Intrinsic Plasticity (IP) and reward-modulated Spike-Timing-Dependent Plasticity (STDP). IP enables the network to explore possible output sequences and STDP, modulated by reward, reinforces the creation of the rewarded output sequences. The model is tested on tasks for prediction, recall, non-linear computation, pattern recognition, and sequence generation. It achieves performance comparable to networks trained with supervised learning, while using simple, biologically motivated plasticity rules, and rewarding strategies. The results confirm the importance of investigating the interaction of several plasticity rules in the context of reward-modulated learning and whether reward-modulated self-organization can explain the amazing capabilities of the brain.

Neural coding of basic reward terms of animal learning theory, game theory, microeconomics and behavioural ecology.

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Schultz, Wolfram

2004-04-01

Neurons in a small number of brain structures detect rewards and reward-predicting stimuli and are active during the expectation of predictable food and liquid rewards. These neurons code the reward information according to basic terms of various behavioural theories that seek to explain reward-directed learning, approach behaviour and decision-making. The involved brain structures include groups of dopamine neurons, the striatum including the nucleus accumbens, the orbitofrontal cortex and the amygdala. The reward information is fed to brain structures involved in decision-making and organisation of behaviour, such as the dorsolateral prefrontal cortex and possibly the parietal cortex. The neural coding of basic reward terms derived from formal theories puts the neurophysiological investigation of reward mechanisms on firm conceptual grounds and provides neural correlates for the function of rewards in learning, approach behaviour and decision-making.

Functional requirements for reward-modulated spike-timing-dependent plasticity.

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Frémaux, Nicolas; Sprekeler, Henning; Gerstner, Wulfram

2010-10-06

Recent experiments have shown that spike-timing-dependent plasticity is influenced by neuromodulation. We derive theoretical conditions for successful learning of reward-related behavior for a large class of learning rules where Hebbian synaptic plasticity is conditioned on a global modulatory factor signaling reward. We show that all learning rules in this class can be separated into a term that captures the covariance of neuronal firing and reward and a second term that presents the influence of unsupervised learning. The unsupervised term, which is, in general, detrimental for reward-based learning, can be suppressed if the neuromodulatory signal encodes the difference between the reward and the expected reward-but only if the expected reward is calculated for each task and stimulus separately. If several tasks are to be learned simultaneously, the nervous system needs an internal critic that is able to predict the expected reward for arbitrary stimuli. We show that, with a critic, reward-modulated spike-timing-dependent plasticity is capable of learning motor trajectories with a temporal resolution of tens of milliseconds. The relation to temporal difference learning, the relevance of block-based learning paradigms, and the limitations of learning with a critic are discussed.

A test of the reward-contrast hypothesis.

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Dalecki, Stefan J; Panoz-Brown, Danielle E; Crystal, Jonathon D

2017-12-01

Source memory, a facet of episodic memory, is the memory of the origin of information. Whereas source memory in rats is sustained for at least a week, spatial memory degraded after approximately a day. Different forgetting functions may suggest that two memory systems (source memory and spatial memory) are dissociated. However, in previous work, the two tasks used baiting conditions consisting of chocolate and chow flavors; notably, the source memory task used the relatively better flavor. Thus, according to the reward-contrast hypothesis, when chocolate and chow were presented within the same context (i.e., within a single radial maze trial), the chocolate location was more memorable than the chow location because of contrast. We tested the reward-contrast hypothesis using baiting configurations designed to produce reward-contrast. The reward-contrast hypothesis predicts that under these conditions, spatial memory will survive a 24-h retention interval. We documented elimination of spatial memory performance after a 24-h retention interval using a reward-contrast baiting pattern. These data suggest that reward contrast does not explain our earlier findings that source memory survives unusually long retention intervals. Copyright © 2017 Elsevier B.V. All rights reserved.

Striatal dopamine D2 receptor availability predicts the thalamic and medial prefrontal responses to reward in cocaine abusers three years later

International Nuclear Information System (INIS)

Asensio, S.; Goldstein, R.; Romero, M.J.; Romero, F.J.; Wong, C.T.; Alia-Klein, N.; Tomasi, D.; Wang, G.-J.; Telang, F.; Volkow, N.D.; Goldstein, R.Z.

2010-01-01

Low levels of dopamine (DA) D2 receptor availability at a resting baseline have been previously reported in drug addicted individuals and have been associated with reduced ventral and dorsal prefrontal metabolism. The reduction in DA D2 receptor availability along with the reduced ventral frontal metabolism is thought to underlie compromised sensitivity to nondrug reward, a core characteristic of drug addiction. We therefore hypothesized that variability in DA D2 receptor availability at baseline will covary with dynamic responses to monetary reward in addicted individuals. Striatal DA D2 receptor availability was measured with ( 11 C)raclopride and positron emission tomography and response to monetary reward was measured (an average of three years later) with functional magnetic resonance imaging in seven cocaine-addicted individuals. Results show that low DA D2 receptor availability in the dorsal striatum was associated with decreased thalamic response to monetary reward; while low availability in ventral striatum was associated with increased medial prefrontal (Brodmann Area 6/8/32) response to monetary reward. These preliminary results, that need to be replicated in larger sample sizes and validated with healthy controls, suggest that resting striatal DA D2 receptor availability predicts variability in functional responses to a nondrug reinforcer (money) in prefrontal cortex, implicated in behavioral monitoring, and in thalamus, implicated in conditioned responses and expectation, in cocaine-addicted individuals.

Striatal dopamine D2 receptor availability predicts the thalamic and medial prefrontal responses to reward in cocaine abusers three years later

Energy Technology Data Exchange (ETDEWEB)

Asensio, S.; Goldstein, R.; Asensio, S.; Romero, M.J.; Romero, F.J.; Wong, C.T.; Alia-Klein, N.; Tomasi, D.; Wang, G.-J.; Telang, F..; Volkow, N.D.; Goldstein, R.Z.

2010-05-01

Low levels of dopamine (DA) D2 receptor availability at a resting baseline have been previously reported in drug addicted individuals and have been associated with reduced ventral and dorsal prefrontal metabolism. The reduction in DA D2 receptor availability along with the reduced ventral frontal metabolism is thought to underlie compromised sensitivity to nondrug reward, a core characteristic of drug addiction. We therefore hypothesized that variability in DA D2 receptor availability at baseline will covary with dynamic responses to monetary reward in addicted individuals. Striatal DA D2 receptor availability was measured with [{sup 11}C]raclopride and positron emission tomography and response to monetary reward was measured (an average of three years later) with functional magnetic resonance imaging in seven cocaine-addicted individuals. Results show that low DA D2 receptor availability in the dorsal striatum was associated with decreased thalamic response to monetary reward; while low availability in ventral striatum was associated with increased medial prefrontal (Brodmann Area 6/8/32) response to monetary reward. These preliminary results, that need to be replicated in larger sample sizes and validated with healthy controls, suggest that resting striatal DA D2 receptor availability predicts variability in functional responses to a nondrug reinforcer (money) in prefrontal cortex, implicated in behavioral monitoring, and in thalamus, implicated in conditioned responses and expectation, in cocaine-addicted individuals.

Reward associations magnify memory-based biases on perception.

Science.gov (United States)

Doallo, Sonia; Patai, Eva Zita; Nobre, Anna Christina

2013-02-01

Long-term spatial contextual memories are a rich source of predictions about the likely locations of relevant objects in the environment and should enable tuning of neural processing of unfolding events to optimize perception and action. Of particular importance is whether and how the reward outcome of past events can impact perception. We combined behavioral measures with recordings of brain activity with high temporal resolution to test whether the previous reward outcome associated with a memory could modulate the impact of memory-based biases on perception, and if so, the level(s) at which visual neural processing is biased by reward-associated memory-guided attention. Data showed that past rewards potentiate the effects of spatial memories upon the discrimination of target objects embedded within complex scenes starting from early perceptual stages. We show that a single reward outcome of learning impacts on how we perceive events in our complex environments.

Reward-enhanced memory in younger and older adults.

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Spaniol, Julia; Schain, Cécile; Bowen, Holly J

2014-09-01

We investigated how the anticipation of remote monetary reward modulates intentional episodic memory formation in younger and older adults. On the basis of prior findings of preserved reward-cognition interactions in aging, we predicted that reward anticipation would be associated with enhanced memory in both younger and older adults. On the basis of previous demonstrations of a time-dependent effect of reward anticipation on memory, we expected the memory enhancement to increase with study-test delay. In Experiment 1, younger and older participants encoded a series of picture stimuli associated with high- or low-reward values. At test (24-hr postencoding), recognition hits resulted in either high or low monetary rewards, whereas false alarms were penalized to discourage guessing. Experiment 2 was similar to Experiment 1, but the study-test delay was manipulated within subjects (immediate vs 24hr). In Experiment 1, younger and older adults showed enhanced recognition for high-reward pictures compared with low-reward pictures. Experiment 2 replicated this finding and additionally showed that the effect did not extend to immediate recognition. The current findings provide support for a time-dependent mechanism of reward-based memory enhancement. They also suggest that aging leaves intact the positive influence of reward anticipation on intentional long-term memory formation. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Information search with situation-specific reward functions

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Bjorn Meder

2012-03-01

Full Text Available can strongly conflict with the goal of obtaining information for improving payoffs. Two environments with such a conflict were identified through computer optimization. Three subsequent experiments investigated people's search behavior in these environments. Experiments 1 and 2 used a multiple-cue probabilistic category-learning task to convey environmental probabilities. In a subsequent search task subjects could query only a single feature before making a classification decision. The crucial manipulation concerned the search-task reward structure. The payoffs corresponded either to accuracy, with equal rewards associated with the two categories, or to an asymmetric payoff function, with different rewards associated with each category. In Experiment 1, in which learning-task feedback corresponded to the true category, people later preferentially searched the accuracy-maximizing feature, whether or not this would improve monetary rewards. In Experiment 2, an asymmetric reward structure was used during learning. Subjects searched the reward-maximizing feature when asymmetric payoffs were preserved in the search task. However, if search-task payoffs corresponded to accuracy, subjects preferentially searched a feature that was suboptimal for reward and accuracy alike. Importantly, this feature would have been most useful, under the learning-task payoff structure. Experiment 3 found that, if words and numbers are used to convey environmental probabilities, neither reward nor accuracy consistently predicts search. These findings emphasize the necessity of taking into account people's goals and search-and-decision processes during learning, thereby challenging current models of information search.

Rewarding leadership and fair procedures as determinants of self-esteem

OpenAIRE

De Cremer, D.; Knippenberg, D.; Knippenberg, B.; Mullenders, D.; Stinglhamber, F.

2005-01-01

In the present research, the authors examined the effect of procedural fairness and rewarding leadership style on an important variable for employees: self-esteem. The authors predicted that procedural fairness would positively influence people's reported self-esteem if the leader adopted a style of rewarding behavior for a job well done. Results from a scenario experiment, a laboratory experiment, and an organizational survey indeed show that procedural fairness and rewarding leadership styl...

A behavioral economic reward index predicts drinking resolutions: moderation revisited and compared with other outcomes.

Science.gov (United States)

Tucker, Jalie A; Roth, David L; Vignolo, Mary J; Westfall, Andrew O

2009-04-01

Data were pooled from 3 studies of recently resolved community-dwelling problem drinkers to determine whether a behavioral economic index of the value of rewards available over different time horizons distinguished among moderation (n = 30), abstinent (n = 95), and unresolved (n = 77) outcomes. Moderation over 1- to 2-year prospective follow-up intervals was hypothesized to involve longer term behavior regulation processes than abstinence or relapse and to be predicted by more balanced preresolution monetary allocations between short-term and longer term objectives (i.e., drinking and saving for the future). Standardized odds ratios (ORs) based on changes in standard deviation units from a multinomial logistic regression indicated that increases on this "Alcohol-Savings Discretionary Expenditure" index predicted higher rates of abstinence (OR = 1.93, p = .004) and relapse (OR = 2.89, p moderation outcomes. The index had incremental utility in predicting moderation in complex models that included other established predictors. The study adds to evidence supporting a behavioral economic analysis of drinking resolutions and shows that a systematic analysis of preresolution spending patterns aids in predicting moderation.

Reward deficiency and anti-reward in pain chronification

OpenAIRE

Borsook, D.; Linnman, C.; Faria, Vanda; Strassman, A. M.; Becerra, L.; Elman, I.

2016-01-01

Converging lines of evidence suggest that the pathophysiology of pain is mediated to a substantial degree via allostatic neuroadaptations in reward- and stress-related brain circuits. Thus, reward deficiency (RD) represents a within-system neuroadaptation to pain-induced protracted activation of the reward circuits that leads to depletion-like hypodopaminergia, clinically manifested anhedonia, and diminished motivation for natural reinforcers. Anti-reward (AR) conversely pertains to a between...

Theta-band phase locking of orbitofrontal neurons during reward expectancy

NARCIS (Netherlands)

van Wingerden, M.; Vinck, M.; Lankelma, J.; Pennartz, C.M.A.

2010-01-01

The expectancy of a rewarding outcome following actions and cues is coded by a network of brain structures including the orbitofrontal cortex. Thus far, predicted reward was considered to be coded by time-averaged spike rates of neurons. However, besides firing rate, the precise timing of action

Rewards.

Science.gov (United States)

Gunderman, Richard B; Kamer, Aaron P

2011-05-01

For much of the 20th century, psychologists and economists operated on the assumption that work is devoid of intrinsic rewards, and the only way to get people to work harder is through the use of rewards and punishments. This so-called carrot-and-stick model of workplace motivation, when applied to medical practice, emphasizes the use of financial incentives and disincentives to manipulate behavior. More recently, however, it has become apparent that, particularly when applied to certain kinds of work, such approaches can be ineffective or even frankly counterproductive. Instead of focusing on extrinsic rewards such as compensation, organizations and their leaders need to devote more attention to the intrinsic rewards of work itself. This article reviews this new understanding of rewards and traces out its practical implications for radiology today. Copyright © 2011. Published by Elsevier Inc.

Girls’ challenging social experiences in early adolescence predict neural response to rewards and depressive symptoms

Directory of Open Access Journals (Sweden)

Melynda D. Casement

2014-04-01

Full Text Available Developmental models of psychopathology posit that exposure to social stressors may confer risk for depression in adolescent girls by disrupting neural reward circuitry. The current study tested this hypothesis by examining the relationship between early adolescent social stressors and later neural reward processing and depressive symptoms. Participants were 120 girls from an ongoing longitudinal study of precursors to depression across adolescent development. Low parental warmth, peer victimization, and depressive symptoms were assessed when the girls were 11 and 12 years old, and participants completed a monetary reward guessing fMRI task and assessment of depressive symptoms at age 16. Results indicate that low parental warmth was associated with increased response to potential rewards in the medial prefrontal cortex (mPFC, striatum, and amygdala, whereas peer victimization was associated with decreased response to potential rewards in the mPFC. Furthermore, concurrent depressive symptoms were associated with increased reward anticipation response in mPFC and striatal regions that were also associated with early adolescent psychosocial stressors, with mPFC and striatal response mediating the association between social stressors and depressive symptoms. These findings are consistent with developmental models that emphasize the adverse impact of early psychosocial stressors on neural reward processing and risk for depression in adolescence.

State-based versus reward-based motivation in younger and older adults.

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Worthy, Darrell A; Cooper, Jessica A; Byrne, Kaileigh A; Gorlick, Marissa A; Maddox, W Todd

2014-12-01

Recent decision-making work has focused on a distinction between a habitual, model-free neural system that is motivated toward actions that lead directly to reward and a more computationally demanding goal-directed, model-based system that is motivated toward actions that improve one's future state. In this article, we examine how aging affects motivation toward reward-based versus state-based decision making. Participants performed tasks in which one type of option provided larger immediate rewards but the alternative type of option led to larger rewards on future trials, or improvements in state. We predicted that older adults would show a reduced preference for choices that led to improvements in state and a greater preference for choices that maximized immediate reward. We also predicted that fits from a hybrid reinforcement-learning model would indicate greater model-based strategy use in younger than in older adults. In line with these predictions, older adults selected the options that maximized reward more often than did younger adults in three of the four tasks, and modeling results suggested reduced model-based strategy use. In the task where older adults showed similar behavior to younger adults, our model-fitting results suggested that this was due to the utilization of a win-stay-lose-shift heuristic rather than a more complex model-based strategy. Additionally, within older adults, we found that model-based strategy use was positively correlated with memory measures from our neuropsychological test battery. We suggest that this shift from state-based to reward-based motivation may be due to age related declines in the neural structures needed for more computationally demanding model-based decision making.

The habenula governs the attribution of incentive salience to reward predictive cues

OpenAIRE

Danna, Carey L.; Shepard, Paul D.; Elmer, Greg I.

2013-01-01

The attribution of incentive salience to reward associated cues is critical for motivation and the pursuit of rewards. Disruptions in the integrity of the neural systems controlling these processes can lead to avolition and anhedonia, symptoms that cross the diagnostic boundaries of many neuropsychiatric illnesses. Here, we consider whether the habenula (Hb), a region recently demonstrated to encode negatively valenced events, also modulates the attribution of incentive salience to a neutral...

Adaptive scaling of reward in episodic memory:a replication study

OpenAIRE

Mason, Alice; Ludwig, Casimir; Farrell, Simon

2017-01-01

Reward is thought to enhance episodic memory formation via dopaminergic consolidation. Bunzeck, Dayan, Dolan, and Duzel [(2010). A common mechanism for adaptive scaling of reward and novelty. Human Brain Mapping, 31, 1380–1394] provided functional magnetic resonance imaging (fMRI) and behavioural evidence that reward and episodic memory systems are sensitive to the contextual value of a reward—whether it is relatively higher or lower—as opposed to absolute value or prediction error. We carrie...

Determination of aberration center of Ronchigram for automated aberration correctors in scanning transmission electron microscopy

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Sannomiya, Takumi, E-mail: sannomiya@mtl.titech.ac.jp [Tokyo Institute of Technology, Ookayama, Tokyo (Japan); Sawada, Hidetaka; Nakamichi, Tomohiro; Hosokawa, Fumio [JEOL Limited, Akishima, Tokyo (Japan); Nakamura, Yoshio; Tanishiro, Yasumasa; Takayanagi, Kunio [Tokyo Institute of Technology, Ookayama, Tokyo (Japan)

2013-12-15

A generic method to determine the aberration center is established, which can be utilized for aberration calculation and axis alignment for aberration corrected electron microscopes. In this method, decentering induced secondary aberrations from inherent primary aberrations are minimized to find the appropriate axis center. The fitness function to find the optimal decentering vector for the axis was defined as a sum of decentering induced secondary aberrations with properly distributed weight values according to the aberration order. Since the appropriate decentering vector is determined from the aberration values calculated at an arbitrary center axis, only one aberration measurement is in principle required to find the center, resulting in /very fast center search. This approach was tested for the Ronchigram based aberration calculation method for aberration corrected scanning transmission electron microscopy. Both in simulation and in experiments, the center search was confirmed to work well although the convergence to find the best axis becomes slower with larger primary aberrations. Such aberration center determination is expected to fully automatize the aberration correction procedures, which used to require pre-alignment of experienced users. This approach is also applicable to automated aperture positioning. - Highlights: • A generic method to determine the aberration center is established for (S)TEM. • Decentering induced secondary aberrations are utilized to find the center. • The method is tested on Ronchigrams both in simulation and experiment. • Proper weighting of the aberration gives a good convergence. • Larger primary aberration results in a slower convergence.

Individual Differences in the Habitual Use of Cognitive Reappraisal Predict the Reward-related Feedback Negativity

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Liyang eSai

2015-09-01

Full Text Available Recent studies have shown that instructed cognitive reappraisal can regulate the neural processing of reward. However, it is still unclear whether the habitual use of cognitive reappraisal in everyday life can influence brain activity associated with reward processing. In the present study, participant’s neural responses to reward were measured using electroencephalography (EEG recorded during a gambling task, while their tendency to use cognitive reappraisal was assessed using the Emotion Regulation Questionnaire (ERQ. Event-related potential (ERP results indicated that losses on the gambling task elicited greater negative reward-related feedback negativity (FN than gains. The differential FN between losses and gains was significantly correlated with cognitive reappraisal scores across participants, such that individuals with a higher tendency to use cognitive reappraisal showed stronger reward processing (i.e. amplified FN difference between losses and gains. This correlation remained significant after controlling for expressive suppression scores. However, expressive suppression per se was not correlated with FN differences. Taken together, these results suggest that the habitual use of cognitive reappraisal influences the neural processing of reward.

Listening to music in a risk-reward context: The roles of the temporoparietal junction and the orbitofrontal/insular cortices in reward-anticipation, reward-gain, and reward-loss.

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Li, Chia-Wei; Chen, Jyh-Horng; Tsai, Chen-Gia

2015-12-10

Artificial rewards, such as visual arts and music, produce pleasurable feelings. Popular songs in the verse-chorus form provide a useful model for understanding the neural mechanisms underlying the processing of artificial rewards, because the chorus is usually the most rewarding element of a song. In this functional magnetic resonance imaging (fMRI) study, the stimuli were excerpts of 10 popular songs with a tensioned verse-to-chorus transition. We examined the neural correlates of three phases of reward processing: (1) reward-anticipation during the verse-to-chorus transition, (2) reward-gain during the first phrase of the chorus, and (3) reward-loss during the unexpected noise followed by the verse-to-chorus transition. Participants listened to these excerpts in a risk-reward context because the verse was followed by either the chorus or noise with equal probability. The results showed that reward-gain and reward-loss were associated with left- and right-biased temporoparietal junction activation, respectively. The bilateral temporoparietal junctions were active during reward-anticipation. Moreover, we observed left-biased lateral orbitofrontal activation during reward-anticipation, whereas the medial orbitofrontal cortex was activated during reward-gain. The findings are discussed in relation to the cognitive and emotional aspects of reward processing. Copyright © 2015 Elsevier B.V. All rights reserved.

Reward Pays the Cost of Noise Reduction in Motor and Cognitive Control.

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Manohar, Sanjay G; Chong, Trevor T-J; Apps, Matthew A J; Batla, Amit; Stamelou, Maria; Jarman, Paul R; Bhatia, Kailash P; Husain, Masud

2015-06-29

Speed-accuracy trade-off is an intensively studied law governing almost all behavioral tasks across species. Here we show that motivation by reward breaks this law, by simultaneously invigorating movement and improving response precision. We devised a model to explain this paradoxical effect of reward by considering a new factor: the cost of control. Exerting control to improve response precision might itself come at a cost--a cost to attenuate a proportion of intrinsic neural noise. Applying a noise-reduction cost to optimal motor control predicted that reward can increase both velocity and accuracy. Similarly, application to decision-making predicted that reward reduces reaction times and errors in cognitive control. We used a novel saccadic distraction task to quantify the speed and accuracy of both movements and decisions under varying reward. Both faster speeds and smaller errors were observed with higher incentives, with the results best fitted by a model including a precision cost. Recent theories consider dopamine to be a key neuromodulator in mediating motivational effects of reward. We therefore examined how Parkinson's disease (PD), a condition associated with dopamine depletion, alters the effects of reward. Individuals with PD showed reduced reward sensitivity in their speed and accuracy, consistent in our model with higher noise-control costs. Including a cost of control over noise explains how reward may allow apparent performance limits to be surpassed. On this view, the pattern of reduced reward sensitivity in PD patients can specifically be accounted for by a higher cost for controlling noise. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Disentangling reward anticipation with simultaneous pupillometry / fMRI.

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Schneider, Max; Leuchs, Laura; Czisch, Michael; Sämann, Philipp G; Spoormaker, Victor I

2018-05-05

The reward system may provide an interesting intermediate phenotype for anhedonia in affective disorders. Reward anticipation is characterized by an increase in arousal, and previous studies have linked the anterior cingulate cortex (ACC) to arousal responses such as dilation of the pupil. Here, we examined pupil dynamics during a reward anticipation task in forty-six healthy human subjects and evaluated its neural correlates using functional magnetic resonance imaging (fMRI). Pupil size showed a strong increase during monetary reward anticipation, a moderate increase during verbal reward anticipation and a decrease during control trials. For fMRI analyses, average pupil size and pupil change were computed in 1-s time bins during the anticipation phase. Activity in the ventral striatum was inversely related to the pupil size time course, indicating an early onset of activation and a role in reward prediction processing. Pupil dilations were linked to increased activity in the salience network (dorsal ACC and bilateral insula), which likely triggers an increase in arousal to enhance task performance. Finally, increased pupil size preceding the required motor response was associated with activity in the ventral attention network. In sum, pupillometry provides an effective tool for disentangling different phases of reward anticipation, with relevance for affective symptomatology. Copyright © 2018 Elsevier Inc. All rights reserved.

The role of the dorsal raphé nucleus in reward-seeking behavior

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Kae eNakamura

2013-08-01

Full Text Available Pharmacological experiments have shown that the modulation of brain serotonin levels has a strong impact on value-based decision making. Anatomical and physiological evidence also revealed that the dorsal raphé nucleus (DRN, a major source of serotonin, and the dopamine system receive common inputs from brain regions associated with appetitive and aversive information processing. The serotonin and dopamine systems also have reciprocal functional influences on each other. However, the specific mechanism by which serotonin affects value-based decision making is not clear.To understand the information carried by the DRN for reward-seeking behavior, we measured single neuron activity in the primate DRN during the performance of saccade tasks to obtain different amounts of a reward. We found that DRN neuronal activity was characterized by tonic modulation that was altered by the expected and received reward value. Consistent reward-dependent modulation across different task periods suggested that DRN activity kept track of the reward value throughout a trial. The DRN was also characterized by modulation of its activity in the opposite direction by different neuronal subgroups, one firing strongly for the prediction and receipt of large rewards, with the other firing strongly for small rewards. Conversely, putative dopamine neurons showed positive phasic responses to reward-indicating cues and the receipt of an unexpected reward amount, which supports the reward prediction error signal hypothesis of dopamine.I suggest that the tonic reward monitoring signal of the DRN, possibly together with its interaction with the dopamine system, reports a continuous level of motivation throughout the performance of a task. Such a signal may provide reward context information to the targets of DRN projections, where it may be integrated further with incoming motivationally salient information.

Reward deficiency and anti-reward in pain chronification.

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Borsook, D; Linnman, C; Faria, V; Strassman, A M; Becerra, L; Elman, I

2016-09-01

Converging lines of evidence suggest that the pathophysiology of pain is mediated to a substantial degree via allostatic neuroadaptations in reward- and stress-related brain circuits. Thus, reward deficiency (RD) represents a within-system neuroadaptation to pain-induced protracted activation of the reward circuits that leads to depletion-like hypodopaminergia, clinically manifested anhedonia, and diminished motivation for natural reinforcers. Anti-reward (AR) conversely pertains to a between-systems neuroadaptation involving over-recruitment of key limbic structures (e.g., the central and basolateral amygdala nuclei, the bed nucleus of the stria terminalis, the lateral tegmental noradrenergic nuclei of the brain stem, the hippocampus and the habenula) responsible for massive outpouring of stressogenic neurochemicals (e.g., norepinephrine, corticotropin releasing factor, vasopressin, hypocretin, and substance P) giving rise to such negative affective states as anxiety, fear and depression. We propose here the Combined Reward deficiency and Anti-reward Model (CReAM), in which biopsychosocial variables modulating brain reward, motivation and stress functions can interact in a 'downward spiral' fashion to exacerbate the intensity, chronicity and comorbidities of chronic pain syndromes (i.e., pain chronification). Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

PER1 rs3027172 Genotype Interacts with Early Life Stress to Predict Problematic Alcohol Use, but Not Reward-Related Ventral Striatum Activity

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Baranger, David A. A.; Ifrah, Chloé; Prather, Aric A.; Carey, Caitlin E.; Corral-Frías, Nadia S.; Drabant Conley, Emily; Hariri, Ahmad R.; Bogdan, Ryan

2016-01-01

Increasing evidence suggests that the circadian and stress regulatory systems contribute to alcohol use disorder (AUD) risk, which may partially arise through effects on reward-related neural function. The C allele of the PER1 rs3027172 single nucleotide polymorphism (SNP) reduces PER1 expression in cells incubated with cortisol and has been associated with increased risk for adult AUD and problematic drinking among adolescents exposed to high levels of familial psychosocial adversity. Using data from undergraduate students who completed the ongoing Duke Neurogenetics Study (DNS) (n = 665), we tested whether exposure to early life stress (ELS; Childhood Trauma Questionnaire) moderates the association between rs3027172 genotype and later problematic alcohol use (Alcohol Use Disorders Identification Test) as well as ventral striatum (VS) reactivity to reward (card-guessing task while functional magnetic resonance imaging data were acquired). Initial analyses found that PER1 rs3027172 genotype interacted with ELS to predict both problematic drinking and VS reactivity; minor C allele carriers, who were also exposed to elevated ELS reported greater problematic drinking and exhibited greater ventral striatum reactivity to reward-related stimuli. When gene × covariate and environment × covariate interactions were controlled for, the interaction predicting problematic alcohol use remained significant (p < 0.05, corrected) while the interaction predicting VS reactivity was no longer significant. These results extend our understanding of relationships between PER1 genotype, ELS, and problematic alcohol use, and serve as a cautionary tale on the importance of controlling for potential confounders in studies of moderation including gene × environment interactions. PMID:27065929

PER1 rs3027172 genotype interacts with early life stress to predict problematic alcohol use, but not reward-related ventral striatum activity

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David eBaranger

2016-03-01

Full Text Available Increasing evidence suggests that the circadian and stress regulatory systems contribute to alcohol use disorder (AUD risk, which may partially arise through effects on reward-related neural function. The C allele of the PER1 rs3027172 single nucleotide polymorphism reduces PER1 expression in cells incubated with cortisol and has been associated with increased risk for adult AUD and problematic drinking among adolescents exposed to high levels of familial psychosocial adversity. Using data from undergraduate students who completed the ongoing Duke Neurogenetics Study (n=665, we tested whether exposure to early life stress (ELS; Childhood Trauma Questionnaire moderates the association between rs3027172 genotype and later problematic alcohol use (Alcohol Use Disorders Identification Test as well as ventral striatum (VS reactivity to reward (card-guessing task while functional magnetic resonance imaging data were acquired. Initial analyses found that PER1 rs3027172 genotype interacted with ELS to predict both problematic drinking and VS reactivity; minor C allele carriers, who were also exposed to elevated ELS reported greater problematic drinking and exhibited greater ventral striatum reactivity to reward-related stimuli. When gene x covariate and environment x covariate interactions were controlled for, the interaction predicting problematic alcohol use remained significant (p<0.05, corrected while the interaction predicting VS reactivity was no longer significant. These results extend our understanding of relationships between PER1 genotype, early life stress, and problematic alcohol use, and serve as a cautionary tale on the importance of controlling for potential confounders in studies of moderation including gene x environment interactions.

Enriched encoding: reward motivation organizes cortical networks for hippocampal detection of unexpected events.

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Murty, Vishnu P; Adcock, R Alison

2014-08-01

Learning how to obtain rewards requires learning about their contexts and likely causes. How do long-term memory mechanisms balance the need to represent potential determinants of reward outcomes with the computational burden of an over-inclusive memory? One solution would be to enhance memory for salient events that occur during reward anticipation, because all such events are potential determinants of reward. We tested whether reward motivation enhances encoding of salient events like expectancy violations. During functional magnetic resonance imaging, participants performed a reaction-time task in which goal-irrelevant expectancy violations were encountered during states of high- or low-reward motivation. Motivation amplified hippocampal activation to and declarative memory for expectancy violations. Connectivity of the ventral tegmental area (VTA) with medial prefrontal, ventrolateral prefrontal, and visual cortices preceded and predicted this increase in hippocampal sensitivity. These findings elucidate a novel mechanism whereby reward motivation can enhance hippocampus-dependent memory: anticipatory VTA-cortical-hippocampal interactions. Further, the findings integrate literatures on dopaminergic neuromodulation of prefrontal function and hippocampus-dependent memory. We conclude that during reward motivation, VTA modulation induces distributed neural changes that amplify hippocampal signals and records of expectancy violations to improve predictions-a potentially unique contribution of the hippocampus to reward learning. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Crash risk and aberrant driving behaviors among bus drivers: the role of personality and attitudes towards traffic safety.

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Mallia, Luca; Lazuras, Lambros; Violani, Cristiano; Lucidi, Fabio

2015-06-01

Several studies have shown that personality traits and attitudes toward traffic safety predict aberrant driving behaviors and crash involvement. However, this process has not been adequately investigated in professional drivers, such as bus drivers. The present study used a personality-attitudes model to assess whether personality traits predicted aberrant self-reported driving behaviors (driving violations, lapses, and errors) both directly and indirectly, through the effects of attitudes towards traffic safety in a large sample of bus drivers. Additionally, the relationship between aberrant self-reported driving behaviors and crash risk was also assessed. Three hundred and one bus drivers (mean age=39.1, SD=10.7 years) completed a structured and anonymous questionnaire measuring personality traits, attitudes toward traffic safety, self-reported aberrant driving behaviors (i.e., errors, lapses, and traffic violations), and accident risk in the last 12 months. Structural equation modeling analysis revealed that personality traits were associated to aberrant driving behaviors both directly and indirectly. In particular altruism, excitement seeking, and normlessness directly predicted bus drivers' attitudes toward traffic safety which, in turn, were negatively associated with the three types of self-reported aberrant driving behaviors. Personality traits relevant to emotionality directly predicted bus drivers' aberrant driving behaviors, without any mediation of attitudes. Finally, only self-reported violations were related to bus drivers' accident risk. The present findings suggest that the hypothesized personality-attitudes model accounts for aberrant driving behaviors in bus drivers, and provide the empirical basis for evidence-based road safety interventions in the context of public transport. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sensitivity to reward: implications for overeating and overweight.

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Davis, Caroline; Strachan, Shaelyn; Berkson, Marni

2004-04-01

Sensitivity to reward (STR)-a personality trait firmly rooted in the neurobiology of the mesolimbic dopamine system-has been strongly implicated in the risk for addiction. This construct describes the ability to derive pleasure or reward from natural reinforcers like food, and from pharmacologic rewards like addictive drugs. Recently experts in the field of addiction research have acknowledged that psychomotor stimulant drugs are no longer at the heart of all addictions, and that brain circuits can also be deranged with natural rewards like food. The present study tested a model in which STR was expected to relate positively to overeating, which in turn would be associated with higher body weight in woman aged 25-45 years. As predicted, STR was correlated positively with measures of emotional overeating. Also, overweight woman were significantly more sensitive to reward than those of normal weight. Interestingly, however, the obese woman (Body Mass Index>30) were more anhedonic than the overweight woman (Body Mass Index>25reward circuits. Results also indicate that STR may serve as a risk factor for overeating and overweight, especially in cultures such as ours where palatable, calorically-dense food is plentiful.

Aberrant learning in Parkinson's disease: A neurocomputational study on bradykinesia.

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Ursino, Mauro; Baston, Chiara

2018-05-22

Parkinson's disease (PD) is a neurodegenerative disorder characterized by a progressive decline in motor functions, such as bradykinesia, caused by the pathological denervation of nigrostriatal dopaminergic neurons within the basal ganglia (BG). It is acknowledged that dopamine (DA) directly affects the modulatory role of BG towards the cortex. However, a growing body of literature is suggesting that DA-induced aberrant synaptic plasticity could play a role in the core symptoms of PD, thus recalling for a "reconceptualization" of the pathophysiology. The aim of this work was to investigate DA-driven aberrant learning as a concurrent cause of bradykinesia, using a comprehensive, biologically inspired neurocomputational model of action selection in the BG. The model includes the three main pathways operating in the BG circuitry, that is the direct, indirect and hyperdirect pathways, and use a two-term Hebb rule to train synapses in the striatum, based on previous history of rewards and punishments. Levodopa pharmacodynamics is also incorporated. Through model simulations of the Alternate Finger Tapping motor task, we assessed the role of aberrant learning on bradykinesia. The results show that training under drug medication (levodopa) provides not only immediate but also delayed benefit lasting in time. Conversely, if performed in conditions of vanishing levodopa efficacy, training may result in dysfunctional corticostriatal synaptic plasticity, further worsening motor performances in PD subjects. This suggests that bradykinesia may result from the concurrent effects of low DA levels and dysfunctional plasticity and that training can be exploited in medicated subjects to improve levodopa treatment. © 2018 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Individual differences in the attribution of incentive salience to reward-related cues: Implications for addiction.

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Flagel, Shelly B; Akil, Huda; Robinson, Terry E

2009-01-01

Drugs of abuse acquire different degrees of control over thoughts and actions based not only on the effects of drugs themselves, but also on predispositions of the individual. Those individuals who become addicted are unable to shift their thoughts and actions away from drugs and drug-associated stimuli. Thus in addicts, exposure to places or things (cues) that has been previously associated with drug-taking often instigates renewed drug-taking. We and others have postulated that drug-associated cues acquire the ability to maintain and instigate drug-taking behavior in part because they acquire incentive motivational properties through Pavlovian (stimulus-stimulus) learning. In the case of compulsive behavioral disorders, including addiction, such cues may be attributed with pathological incentive value ("incentive salience"). For this reason, we have recently begun to explore individual differences in the tendency to attribute incentive salience to cues that predict rewards. When discrete cues are associated with the non-contingent delivery of food or drug rewards some animals come to quickly approach and engage the cue even if it is located at a distance from where the reward will be delivered. In these animals the reward-predictive cue itself becomes attractive, eliciting approach towards it, presumably because it is attributed with incentive salience. Animals that develop this type of conditional response are called "sign-trackers". Other animals, "goal-trackers", do not approach the reward-predictive cue, but upon cue presentation they immediately go to the location where food will be delivered (the "goal"). For goal-trackers the reward-predictive cue is not attractive, presumably because it is not attributed with incentive salience. We review here preliminary data suggesting that these individual differences in the tendency to attribute incentive salience to cues predictive of reward may confer vulnerability or resistance to compulsive behavioral disorders

The reward probability index: design and validation of a scale measuring access to environmental reward.

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Carvalho, John P; Gawrysiak, Michael J; Hellmuth, Julianne C; McNulty, James K; Magidson, Jessica F; Lejuez, C W; Hopko, Derek R

2011-06-01

Behavioral models of depression implicate decreased response-contingent positive reinforcement (RCPR) as critical toward the development and maintenance of depression (Lewinsohn, 1974). Given the absence of a psychometrically sound self-report measure of RCPR, the Reward Probability Index (RPI) was developed to measure access to environmental reward and to approximate actual RCPR. In Study 1 (n=269), exploratory factor analysis supported a 20-item two-factor model (Reward Probability, Environmental Suppressors) with strong internal consistency (α=.90). In Study 2 (n=281), confirmatory factor analysis supported this two-factor structure and convergent validity was established through strong correlations between the RPI and measures of activity, avoidance, reinforcement, and depression (r=.65 to .81). Discriminant validity was supported via smaller correlations between the RPI and measures of social support and somatic anxiety (r=-.29 to -.40). Two-week test-retest reliability was strong (r=.69). In Study 3 (n=33), controlling for depression symptoms, hierarchical regression supported the incremental validity of the RPI in predicting daily diary reports of environmental reward. The RPI represents a parsimonious, reliable, and valid measure that may facilitate understanding of the etiology of depression and its relationship to overt behaviors. Copyright © 2011. Published by Elsevier Ltd.

A tribute to Charlie Chaplin: Induced positive affect improves reward-based decision-learning in Parkinson’s Disease

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K. Richard eRidderinkhof

2012-06-01

Full Text Available Reward-based decision-learning refers to the process of learning to select those actions that lead to rewards while avoiding actions that lead to punishments. This process, known to rely on dopaminergic activity in striatal brain regions, is compromised in Parkinson’s disease (PD. We hypothesized that such decision-learning deficits are alleviated by induced positive affect, which is thought to incur transient boosts in midbrain and striatal dopaminergic activity. Computational measures of probabilistic reward-based decision-learning were determined for 51 patients diagnosed with PD. Previous work has shown these measures to rely on the nucleus caudatus (outcome evaluation during the early phases of learning and the putamen (reward prediction during later phases of learning. We observed that induced positive affect facilitated learning, through its effects on reward prediction rather than outcome evaluation. Viewing a few minutes of comedy clips served to remedy dopamine-related problems in putamen-based frontostriatal circuitry and, consequently, in learning to predict which actions will yield reward.

A Behavioral Economic Reward Index Predicts Drinking Resolutions: Moderation Re-visited and Compared with Other Outcomes

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Tucker, Jalie A.; Roth, David L.; Vignolo, Mary J.; Westfall, Andrew O.

2014-01-01

Data were pooled from three studies of recently resolved community-dwelling problem drinkers to determine whether a behavioral economic index of the value of rewards available over different time horizons distinguished among moderation (n = 30), abstinent (n = 95), and unresolved (n = 77) outcomes. Moderation over 1-2 year prospective follow-up intervals was hypothesized to involve longer term behavior regulation processes compared to abstinence or relapse and to be predicted by more balanced pre-resolution monetary allocations between short- and longer-term objectives (i.e., drinking and saving for the future). Standardized odds ratios (OR) based on changes in standard deviation units from a multinomial logistic regression indicated that increases on this “Alcohol-Savings Discretionary Expenditure” index predicted higher rates of both abstinence (OR = 1.93, p = .004) and relapse (OR = 2.89, p moderation outcomes. The index had incremental utility in predicting moderation in complex models that included other established predictors. The study adds to evidence supporting a behavioral economic analysis of drinking resolutions and shows that a systematic analysis of pre-resolution spending patterns aids in predicting moderation. PMID:19309182

Reward uncertainty enhances incentive salience attribution as sign-tracking

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Anselme, Patrick; Robinson, Mike J. F.; Berridge, Kent C.

2014-01-01

Conditioned stimuli (CSs) come to act as motivational magnets following repeated association with unconditioned stimuli (UCSs) such as sucrose rewards. By traditional views, the more reliably predictive a Pavlovian CS-UCS association, the more the CS becomes attractive. However, in some cases, less predictability might equal more motivation. Here we examined the effect of introducing uncertainty in CS-UCS association on CS strength as an attractive motivation magnet. In the present study, Experiment 1 assessed the effects of Pavlovian predictability versus uncertainty about reward probability and/or reward magnitude on the acquisition and expression of sign-tracking (ST) and goal-tracking (GT) responses in an autoshaping procedure. Results suggested that uncertainty produced strongest incentive salience expressed as sign-tracking. Experiment 2 examined whether a within-individual temporal shift from certainty to uncertainty conditions could produce a stronger CS motivational magnet when uncertainty began, and found that sign-tracking still increased after the shift. Overall, our results support earlier reports that ST responses become more pronounced in the presence of uncertainty regarding CS-UCS associations, especially when uncertainty combines both probability and magnitude. These results suggest that Pavlovian uncertainty, although diluting predictability, is still able to enhance the incentive motivational power of particular CSs. PMID:23078951

Distinct medial temporal networks encode surprise during motivation by reward versus punishment

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Murty, Vishnu P.; LaBar, Kevin S.; Adcock, R. Alison

2016-01-01

Adaptive motivated behavior requires predictive internal representations of the environment, and surprising events are indications for encoding new representations of the environment. The medial temporal lobe memory system, including the hippocampus and surrounding cortex, encodes surprising events and is influenced by motivational state. Because behavior reflects the goals of an individual, we investigated whether motivational valence (i.e., pursuing rewards versus avoiding punishments) also impacts neural and mnemonic encoding of surprising events. During functional magnetic resonance imaging (fMRI), participants encountered perceptually unexpected events either during the pursuit of rewards or avoidance of punishments. Despite similar levels of motivation across groups, reward and punishment facilitated the processing of surprising events in different medial temporal lobe regions. Whereas during reward motivation, perceptual surprises enhanced activation in the hippocampus, during punishment motivation surprises instead enhanced activation in parahippocampal cortex. Further, we found that reward motivation facilitated hippocampal coupling with ventromedial PFC, whereas punishment motivation facilitated parahippocampal cortical coupling with orbitofrontal cortex. Behaviorally, post-scan testing revealed that reward, but not punishment, motivation resulted in greater memory selectivity for surprising events encountered during goal pursuit. Together these findings demonstrate that neuromodulatory systems engaged by anticipation of reward and punishment target separate components of the medial temporal lobe, modulating medial temporal lobe sensitivity and connectivity. Thus, reward and punishment motivation yield distinct neural contexts for learning, with distinct consequences for how surprises are incorporated into predictive mnemonic models of the environment. PMID:26854903

Distinct medial temporal networks encode surprise during motivation by reward versus punishment.

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Murty, Vishnu P; LaBar, Kevin S; Adcock, R Alison

2016-10-01

Adaptive motivated behavior requires predictive internal representations of the environment, and surprising events are indications for encoding new representations of the environment. The medial temporal lobe memory system, including the hippocampus and surrounding cortex, encodes surprising events and is influenced by motivational state. Because behavior reflects the goals of an individual, we investigated whether motivational valence (i.e., pursuing rewards versus avoiding punishments) also impacts neural and mnemonic encoding of surprising events. During functional magnetic resonance imaging (fMRI), participants encountered perceptually unexpected events either during the pursuit of rewards or avoidance of punishments. Despite similar levels of motivation across groups, reward and punishment facilitated the processing of surprising events in different medial temporal lobe regions. Whereas during reward motivation, perceptual surprises enhanced activation in the hippocampus, during punishment motivation surprises instead enhanced activation in parahippocampal cortex. Further, we found that reward motivation facilitated hippocampal coupling with ventromedial PFC, whereas punishment motivation facilitated parahippocampal cortical coupling with orbitofrontal cortex. Behaviorally, post-scan testing revealed that reward, but not punishment, motivation resulted in greater memory selectivity for surprising events encountered during goal pursuit. Together these findings demonstrate that neuromodulatory systems engaged by anticipation of reward and punishment target separate components of the medial temporal lobe, modulating medial temporal lobe sensitivity and connectivity. Thus, reward and punishment motivation yield distinct neural contexts for learning, with distinct consequences for how surprises are incorporated into predictive mnemonic models of the environment. Copyright © 2016 Elsevier Inc. All rights reserved.

Sensitivity for Cues Predicting Reward and Punishment in Young Women with Eating Disorders.

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Matton, Annelies; de Jong, Peter; Goossens, Lien; Jonker, Nienke; Van Malderen, Eva; Vervaet, Myriam; De Schryver, Nele; Braet, Caroline

2017-11-01

Increasing evidence shows that sensitivity to reward (SR) and punishment (SP) may be involved in eating disorders (EDs). Most studies used self-reported positive/negative effect in rewarding/punishing situations, whereas the implied proneness to detect signals of reward/punishment is largely ignored. This pilot study used a spatial orientation task to examine transdiagnostic and interdiagnostic differences in SR/SP. Participants (14-29 years) were patients with anorexia nervosa of restricting type (AN-R, n = 20), binge/purge ED group [AN of binge/purge type and bulimia nervosa (n = 16)] and non-symptomatic individuals (n = 23). Results revealed stronger difficulties to redirect attention away from signals of rewards in AN-R compared with binge/purge EDs, and binge/purge EDs showed stronger difficulties to direct attention away from signals of punishment compared with AN-R. Findings demonstrate interdiagnostic differences and show that the spatial orientation task is sensitive for individual differences in SP/SR within the context of EDs, thereby sustaining its usefulness as behavioural measure of reinforcement sensitivity. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

Rewarding leadership and fair procedures as determinants of self-esteem.

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De Cremer, David; van Knippenberg, Barbara; van Knippenberg, Daan; Mullenders, Danny; Stinglhamber, Florence

2005-01-01

In the present research, the authors examined the effect of procedural fairness and rewarding leadership style on an important variable for employees: self-esteem. The authors predicted that procedural fairness would positively influence people's reported self-esteem if the leader adopted a style of rewarding behavior for a job well done. Results from a scenario experiment, a laboratory experiment, and an organizational survey indeed show that procedural fairness and rewarding leadership style interacted to influence followers' self-esteem, such that the positive relationship between procedural fairness and self-esteem was more pronounced when the leadership style was high in rewarding behavior. Implications in terms of integrating the leadership and procedural fairness literature are discussed.

Neurogenetics and Nutrigenomics of Neuro-Nutrient Therapy for Reward Deficiency Syndrome (RDS): Clinical Ramifications as a Function of Molecular Neurobiological Mechanisms

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Blum, Kenneth; Oscar-Berman, Marlene; Stuller, Elizabeth; Miller, David; Giordano, John; Morse, Siobhan; McCormick, Lee; Downs, William B; Waite, Roger L; Barh, Debmalya; Neal, Dennis; Braverman, Eric R; Lohmann, Raquel; Borsten, Joan; Hauser, Mary; Han, David; Liu, Yijun; Helman, Manya; Simpatico, Thomas

2013-01-01

In accord with the new definition of addiction published by American Society of Addiction Medicine (ASAM) it is well-known that individuals who present to a treatment center involved in chemical dependency or other documented reward dependence behaviors have impaired brain reward circuitry. They have hypodopaminergic function due to genetic and/or environmental negative pressures upon the reward neuro-circuitry. This impairment leads to aberrant craving behavior and other behaviors such as Substance Use Disorder (SUD). Neurogenetic research in both animal and humans revealed that there is a well-defined cascade in the reward site of the brain that leads to normal dopamine release. This cascade has been termed the “Brain Reward Cascade” (BRC). Any impairment due to either genetics or environmental influences on this cascade will result in a reduced amount of dopamine release in the brain reward site. Manipulation of the BRC has been successfully achieved with neuro-nutrient therapy utilizing nutrigenomic principles. After over four decades of development, neuro-nutrient therapy has provided important clinical benefits when appropriately utilized. This is a review, with some illustrative case histories from a number of addiction professionals, of certain molecular neurobiological mechanisms which if ignored may lead to clinical complications. PMID:23926462

Neurogenetics and Nutrigenomics of Neuro-Nutrient Therapy for Reward Deficiency Syndrome (RDS): Clinical Ramifications as a Function of Molecular Neurobiological Mechanisms.

Science.gov (United States)

Blum, Kenneth; Oscar-Berman, Marlene; Stuller, Elizabeth; Miller, David; Giordano, John; Morse, Siobhan; McCormick, Lee; Downs, William B; Waite, Roger L; Barh, Debmalya; Neal, Dennis; Braverman, Eric R; Lohmann, Raquel; Borsten, Joan; Hauser, Mary; Han, David; Liu, Yijun; Helman, Manya; Simpatico, Thomas

2012-11-27

In accord with the new definition of addiction published by American Society of Addiction Medicine (ASAM) it is well-known that individuals who present to a treatment center involved in chemical dependency or other documented reward dependence behaviors have impaired brain reward circuitry. They have hypodopaminergic function due to genetic and/or environmental negative pressures upon the reward neuro-circuitry. This impairment leads to aberrant craving behavior and other behaviors such as Substance Use Disorder (SUD). Neurogenetic research in both animal and humans revealed that there is a well-defined cascade in the reward site of the brain that leads to normal dopamine release. This cascade has been termed the "Brain Reward Cascade" (BRC). Any impairment due to either genetics or environmental influences on this cascade will result in a reduced amount of dopamine release in the brain reward site. Manipulation of the BRC has been successfully achieved with neuro-nutrient therapy utilizing nutrigenomic principles. After over four decades of development, neuro-nutrient therapy has provided important clinical benefits when appropriately utilized. This is a review, with some illustrative case histories from a number of addiction professionals, of certain molecular neurobiological mechanisms which if ignored may lead to clinical complications.

Rewards and Performance Incentives.

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Zigon, Jack

1994-01-01

Discusses rewards and performance incentives for employees, including types of rewards; how rewards help in managing; dysfunctional awards; selecting the right reward; how to find rewards that fit; and delivering rewards effectively. Examples are included. (three references) (LRW)

Reward loss and the basolateral amygdala: A function in reward comparisons.

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Kawasaki, Katsuyoshi; Annicchiarico, Iván; Glueck, Amanda C; Morón, Ignacio; Papini, Mauricio R

2017-07-28

The neural circuitry underlying behavior in reward loss situations is poorly understood. We considered two such situations: reward devaluation (from large to small rewards) and reward omission (from large rewards to no rewards). There is evidence that the central nucleus of the amygdala (CeA) plays a role in the negative emotion accompanying reward loss. However, little is known about the function of the basolateral nucleus (BLA) in reward loss. Two hypotheses of BLA function in reward loss, negative emotion and reward comparisons, were tested in an experiment involving pretraining excitotoxic BLA lesions followed by training in four tasks: consummatory successive negative contrast (cSNC), autoshaping (AS) acquisition and extinction, anticipatory negative contrast (ANC), and open field testing (OF). Cell counts in the BLA (but not in the CeA) were significantly lower in animals with lesions vs. shams. BLA lesions eliminated cSNC and ANC, and accelerated extinction of lever pressing in AS. BLA lesions had no effect on OF testing: higher activity in the periphery than in the central area. This pattern of results provides support for the hypothesis that BLA neurons are important for reward comparison. The three affected tasks (cSNC, ANC, and AS extinction) involve reward comparisons. However, ANC does not seem to involve negative emotions and it was affected, whereas OF activity is known to involve negative emotion, but it was not affected. It is hypothesized that a circuit involving the thalamus, insular cortex, and BLA is critically involved in the mechanism comparing current and expected rewards. Copyright © 2017 Elsevier B.V. All rights reserved.

Low-energy foil aberration corrector

International Nuclear Information System (INIS)

Aken, R.H. van; Hagen, C.W.; Barth, J.E.; Kruit, P.

2002-01-01

A spherical and chromatic aberration corrector for electron microscopes is proposed, consisting of a thin foil sandwiched between two apertures. The electrons are retarded at the foil to almost zero energy, so that they can travel ballistically through the foil. It is shown that such a low-voltage corrector has a negative spherical aberration for not too large distances between aperture and foil, as well as a negative chromatic aberration. For various distances the third- and fifth-order spherical aberration coefficients and the first- and second-order chromatic aberration coefficients are calculated using ray tracing. Provided that the foils have sufficient electron transmission the corrector is able to correct the third-order spherical aberration and the first-order chromatic aberration of a typical low-voltage scanning electron microscope. Preliminary results show that the fifth-order spherical aberration and the second-order chromatic aberration can be kept sufficiently low

Scaling laws for aberrations in magnetic quadrupole lens systems

International Nuclear Information System (INIS)

Moses, R.W.; Heighway, E.A.; Christian, R.S.; Dragt, A.J.

1987-01-01

A comparison has been made of the third-order (spherical) abberrations in magnetic quadrupole lenses for use in conventional charged particle beam transport systems. An analytical description of the abberrations is presented and this is compared with the results of high order numerical integration. The dependence of the aberration strength on the system geometry and f number is given and a comparison of doublet and triplet systems made. The reduction of the aberrations in both doublet and triplet systems using embedded magnetic octupole lenses is also discussed and analytical predictions are given

A Fly's Eye View of Natural and Drug Reward.

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Lowenstein, Eve G; Velazquez-Ulloa, Norma A

2018-01-01

Animals encounter multiple stimuli each day. Some of these stimuli are innately appetitive or aversive, while others are assigned valence based on experience. Drugs like ethanol can elicit aversion in the short term and attraction in the long term. The reward system encodes the predictive value for different stimuli, mediating anticipation for attractive or punishing stimuli and driving animal behavior to approach or avoid conditioned stimuli. The neurochemistry and neurocircuitry of the reward system is partly evolutionarily conserved. In both vertebrates and invertebrates, including Drosophila melanogaster , dopamine is at the center of a network of neurotransmitters and neuromodulators acting in concert to encode rewards. Behavioral assays in D. melanogaster have become increasingly sophisticated, allowing more direct comparison with mammalian research. Moreover, recent evidence has established the functional modularity of the reward neural circuits in Drosophila . This functional modularity resembles the organization of reward circuits in mammals. The powerful genetic and molecular tools for D. melanogaster allow characterization and manipulation at the single-cell level. These tools are being used to construct a detailed map of the neural circuits mediating specific rewarding stimuli and have allowed for the identification of multiple genes and molecular pathways that mediate the effects of reinforcing stimuli, including their rewarding effects. This report provides an overview of the research on natural and drug reward in D. melanogaster , including natural rewards such as sugar and other food nutrients, and drug rewards including ethanol, cocaine, amphetamine, methamphetamine, and nicotine. We focused mainly on the known genetic and neural mechanisms underlying appetitive reward for sugar and reward for ethanol. We also include genes, molecular pathways, and neural circuits that have been identified using assays that test the palatability of the rewarding

Neural activation to monetary reward is associated with amphetamine reward sensitivity.

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Crane, Natania A; Gorka, Stephanie M; Weafer, Jessica; Langenecker, Scott A; de Wit, Harriet; Phan, K Luan

2018-03-14

One known risk factor for drug use and abuse is sensitivity to rewarding effects of drugs. It is not known whether this risk factor extends to sensitivity to non-drug rewards. In this study with healthy young adults, we examined the association between sensitivity to the subjective rewarding effects of amphetamine and a neural indicator of anticipation of monetary reward. We hypothesized that greater euphorigenic response to amphetamine would be associated with greater neural activation to anticipation of monetary reward (Win > Loss). Healthy participants (N = 61) completed four laboratory sessions in which they received d-amphetamine (20 mg) and placebo in alternating order, providing self-report measures of euphoria and stimulation at regular intervals. At a separate visit 1-3 weeks later, participants completed the guessing reward task (GRT) during fMRI in a drug-free state. Participants reporting greater euphoria after amphetamine also exhibited greater neural activation during monetary reward anticipation in mesolimbic reward regions, including the bilateral caudate and putamen. This is the first study to show a relationship between neural correlates of monetary reward and sensitivity to the subjective rewarding effects of amphetamine in humans. These findings support growing evidence that sensitivity to reward in general is a risk factor for drug use and abuse, and suggest that sensitivity of drug-induced euphoria may reflect a general sensitivity to rewards. This may be an index of vulnerability for drug use or abuse.

Elevated Striatal Reactivity Across Monetary and Social Rewards in Bipolar I Disorder

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Dutra, Sunny J.; Cunningham, William A.; Kober, Hedy; Gruber, June

2016-01-01

Bipolar disorder (BD) is associated with increased reactivity to rewards and heightened positive affectivity. It is less clear to what extent this heightened reward sensitivity is evident across contexts and what the associated neural mechanisms might be. The present investigation employed both a monetary and social incentive delay task among adults with remitted BD type I (N=24) and a healthy non-psychiatric control group (HC; N=25) using fMRI. Both whole-brain and region-of-interest analyses revealed elevated ventral and dorsal striatal reactivity across monetary and social reward receipt, but not anticipation, in the BD group. Post-hoc analyses further suggested that greater striatal reactivity to reward receipt across monetary and social reward tasks predicted decreased self-reported positive affect when anticipating subsequent rewards in the HC, but not BD, group. Results point toward elevated striatal reactivity to reward receipt as a potential neural mechanism of reward reactivity. PMID:26390194

Neural correlates of RDoC reward constructs in adolescents with diverse psychiatric symptoms: A Reward Flanker Task pilot study.

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Bradley, Kailyn A L; Case, Julia A C; Freed, Rachel D; Stern, Emily R; Gabbay, Vilma

2017-07-01

There has been growing interest under the Research Domain Criteria initiative to investigate behavioral constructs and their underlying neural circuitry. Abnormalities in reward processes are salient across psychiatric conditions and may precede future psychopathology in youth. However, the neural circuitry underlying such deficits has not been well defined. Therefore, in this pilot, we studied youth with diverse psychiatric symptoms and examined the neural underpinnings of reward anticipation, attainment, and positive prediction error (PPE, unexpected reward gain). Clinically, we focused on anhedonia, known to reflect deficits in reward function. Twenty-two psychotropic medication-free youth, 16 with psychiatric symptoms, exhibiting a full range of anhedonia, were scanned during the Reward Flanker Task. Anhedonia severity was quantified using the Snaith-Hamilton Pleasure Scale. Functional magnetic resonance imaging analyses were false discovery rate corrected for multiple comparisons. Anticipation activated a broad network, including the medial frontal cortex and ventral striatum, while attainment activated memory and emotion-related regions such as the hippocampus and parahippocampal gyrus, but not the ventral striatum. PPE activated a right-dominant fronto-temporo-parietal network. Anhedonia was only correlated with activation of the right angular gyrus during anticipation and the left precuneus during PPE at an uncorrected threshold. Findings are preliminary due to the small sample size. This pilot characterized the neural circuitry underlying different aspects of reward processing in youth with diverse psychiatric symptoms. These results highlight the complexity of the neural circuitry underlying reward anticipation, attainment, and PPE. Furthermore, this study underscores the importance of RDoC research in youth. Copyright © 2016 Elsevier B.V. All rights reserved.

Beyond Rewards

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Hall, Philip S.

2009-01-01

Using rewards to impact students' behavior has long been common practice. However, using reward systems to enhance student learning conveniently masks the larger and admittedly more difficult task of finding and implementing the structure and techniques that children with special needs require to learn. More important, rewarding the child for good…

Amygdala Contributions to Stimulus–Reward Encoding in the Macaque Medial and Orbital Frontal Cortex during Learning

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Averbeck, Bruno B.

2017-01-01

Orbitofrontal cortex (OFC), medial frontal cortex (MFC), and amygdala mediate stimulus–reward learning, but the mechanisms through which they interact are unclear. Here, we investigated how neurons in macaque OFC and MFC signaled rewards and the stimuli that predicted them during learning with and without amygdala input. Macaques performed a task that required them to evaluate two stimuli and then choose one to receive the reward associated with that option. Four main findings emerged. First, amygdala lesions slowed the acquisition and use of stimulus–reward associations. Further analyses indicated that this impairment was due, at least in part, to ineffective use of negative feedback to guide subsequent decisions. Second, the activity of neurons in OFC and MFC rapidly evolved to encode the amount of reward associated with each stimulus. Third, amygdalectomy reduced encoding of stimulus–reward associations during the evaluation of different stimuli. Reward encoding of anticipated and received reward after choices were made was not altered. Fourth, amygdala lesions led to an increase in the proportion of neurons in MFC, but not OFC, that encoded the instrumental response that monkeys made on each trial. These correlated changes in behavior and neural activity after amygdala lesions strongly suggest that the amygdala contributes to the ability to learn stimulus–reward associations rapidly by shaping encoding within OFC and MFC. SIGNIFICANCE STATEMENT Altered functional interactions among orbital frontal cortex (OFC), medial frontal cortex (MFC), and amygdala are thought to underlie several psychiatric conditions, many related to reward learning. Here, we investigated the causal contribution of the amygdala to the development of neuronal activity in macaque OFC and MFC related to rewards and the stimuli that predict them during learning. Without amygdala inputs, neurons in both OFC and MFC showed decreased encoding of stimulus–reward associations. MFC also

A possible role of midbrain dopamine neurons in short- and long-term adaptation of saccades to position-reward mapping.

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Takikawa, Yoriko; Kawagoe, Reiko; Hikosaka, Okihide

2004-10-01

Dopamine (DA) neurons respond to sensory stimuli that predict reward. To understand how DA neurons acquire such ability, we trained monkeys on a one-direction-rewarded version of memory-guided saccade task (1DR) only when we recorded from single DA neurons. In 1DR, position-reward mapping was changed across blocks of trials. In the early stage of training of 1DR, DA neurons responded to reward delivery; in the later stages, they responded predominantly to the visual cue that predicted reward or no reward (reward predictor) differentially. We found that such a shift of activity from reward to reward predictor also occurred within a block of trials after position-reward mapping was altered. A main effect of long-term training was to accelerate the within-block reward-to-predictor shift of DA neuronal responses. The within-block shift appeared first in the intermediate stage, but was slow, and DA neurons often responded to the cue that indicated reward in the preceding block. In the advanced stage, the reward-to-predictor shift occurred quickly such that the DA neurons' responses to visual cues faithfully matched the current position-reward mapping. Changes in the DA neuronal responses co-varied with the reward-predictive differentiation of saccade latency both in short-term (within-block) and long-term adaptation. DA neurons' response to the fixation point also underwent long-term changes until it occurred predominantly in the first trial within a block. This might trigger a switch between the learned sets. These results suggest that midbrain DA neurons play an essential role in adapting oculomotor behavior to frequent switches in position-reward mapping.

Low level dose induced chromosome aberrations in human blood lymphocytes

International Nuclear Information System (INIS)

Pohl-Rueling, J.

1992-01-01

Unstable structural aberrations in chromosomes of human blood lymphocytes cannot be used as biological dosemeters in the low dose range, when extrapolating from high doses using a linear dose response, as required by the original formula of the dual radiation action theory. A survey is given of experimental dose-response curves of chromosome aberrations, obtained in investigations not only by this institute, in cooperation with many other laboratories, but also by various authors in different areas of the world. The results are not compatible with the predicted linear dose relationships at in vivo dose ranges up to 30 mGy.y -1 . The aberration frequencies rise sharply with dose within the normal environmental exposure up to about twice that level. At higher doses, aberration frequencies increase less rapidly and reach a plateau. Some in vitro experiments of various authors with higher doses of low LET radiations, up to about 400 mGy have found dose responses with steps. (author)

On- and off-eye spherical aberration of soft contact lenses and consequent changes of effective lens power.

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Dietze, Holger H; Cox, Michael J

2003-02-01

Soft contact lenses produce a significant level of spherical aberration affecting their power on-eye. A simple model assuming that a thin soft contact lens aligns to the cornea predicts that these effects are similar on-eye and off-eye. The wavefront aberration for 17 eyes and 33 soft contact lenses on-eye was measured with a Shack-Hartmann wavefront sensor. The Zernike coefficients describing the on-eye spherical aberration of the soft contact lens were compared with off-eye ray-tracing results. Paraxial and effective lens power changes were determined. The model predicts the on-eye spherical aberration of soft contact lenses closely. The resulting power change for a +/- 7.00 D spherical soft contact lens is +/- 0.5 D for a 6-mm pupil diameter and +/- 0.1 D for a 3-mm pupil diameter. Power change is negligible for soft contact lenses corrected for off-eye spherical aberration. For thin soft contact lenses, the level of spherical aberration and the consequent power change is similar on-eye and off-eye. Soft contact lenses corrected for spherical aberration in air will be expected to be aberration-free on-eye and produce only negligibly small power changes. For soft contact lenses without aberration correction, for higher levels of ametropia and large pupils, the soft contact lens power should be determined with trial lenses with their power and p value similar to the prescribed lens. The benefit of soft contact lenses corrected for spherical aberration depends on the level of ocular spherical aberration.

Identity-specific coding of future rewards in the human orbitofrontal cortex.

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Howard, James D; Gottfried, Jay A; Tobler, Philippe N; Kahnt, Thorsten

2015-04-21

Nervous systems must encode information about the identity of expected outcomes to make adaptive decisions. However, the neural mechanisms underlying identity-specific value signaling remain poorly understood. By manipulating the value and identity of appetizing food odors in a pattern-based imaging paradigm of human classical conditioning, we were able to identify dissociable predictive representations of identity-specific reward in orbitofrontal cortex (OFC) and identity-general reward in ventromedial prefrontal cortex (vmPFC). Reward-related functional coupling between OFC and olfactory (piriform) cortex and between vmPFC and amygdala revealed parallel pathways that support identity-specific and -general predictive signaling. The demonstration of identity-specific value representations in OFC highlights a role for this region in model-based behavior and reveals mechanisms by which appetitive behavior can go awry.

Depression-related increases and decreases in appetite reveal dissociable patterns of aberrant activity in reward and interoceptive neurocircuitry

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Simmons, W. Kyle; Burrows, Kaiping; Avery, Jason A.; Kerr, Kara L.; Bodurka, Jerzy; Savage, Cary R.; Drevets, Wayne C.

2016-01-01

Objective Appetite and weight changes are common but variable diagnostic markers in major depressive disorder: some depressed individuals manifest increased appetite, while others lose their appetite. Many of the brain regions implicated in appetitive responses to food have also been implicated in depression. It is thus remarkable that there exists no published research comparing the neural responses to food stimuli of depressed patients with increased versus decreased appetites. Method Using functional magnetic resonance imaging we compared brain activity in unmedicated depressed patients with increased or decreased appetite, and healthy control subjects, while viewing photographs of food and non-food objects. We also measured how resting-state functional connectivity related to subjects’ food pleasantness ratings. Results Within putative reward regions, depressed participants with increased appetites exhibited greater hemodynamic activity to food stimuli than both those reporting appetite decreases and healthy control subjects. In contrast, depressed subjects experiencing appetite loss exhibited hypoactivation within a region of the mid-insula implicated in interoception, with no difference observed in this region between healthy subjects and those with depression-related appetite increases. Mid-insula activity was negatively correlated with food pleasantness ratings of depressed participants with increased appetites, and its functional connectivity to reward circuitry was positively correlated with food pleasantness ratings. Conclusions Depression-related increases in appetite are associated with hyperactivation of putative mesocorticolimbic reward circuitry, while depression-related appetite loss is associated with hypoactivation of insular regions that support monitoring the body’s physiological state. Importantly, the interactions among these regions also contribute to individual differences in the depression-related appetite changes. PMID:26806872

Ethanol induces impulsive-like responding in a delay-of-reward operant choice procedure: impulsivity predicts autoshaping.

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Tomie, A; Aguado, A S; Pohorecky, L A; Benjamin, D

1998-10-01

Autoshaping conditioned responses (CRs) are reflexive and targeted motor responses expressed as a result of experience with reward. To evaluate the hypothesis that autoshaping may be a form of impulsive responding, within-subjects correlations between performance on autoshaping and impulsivity tasks were assessed in 15 Long-Evans hooded rats. Autoshaping procedures [insertion of retractable lever conditioned stimulus (CS) followed by the response-independent delivery of food (US)] were followed by testing for impulsive-like responding in a two-choice lever-press operant delay-of-reward procedure (immediate small food reward versus delayed large food reward). Delay-of-reward functions revealed two distinct subject populations. Subjects in the Sensitive group (n=7) were more impulsive-like, increasing immediate reward choices at longer delays for large reward, while those in the Insensitive group (n=8) responded predominantly on only one lever. During the prior autoshaping phase, the Sensitive group had performed more autoshaping CRs, and correlations revealed that impulsive subjects acquired the autoshaping CR in fewer trials. In the Sensitive group, acute injections of ethanol (0, 0.25, 0.50, 1.00, 1.50 g/kg) given immediately before delay-of-reward sessions yielded an inverted U-shaped dose-response curve with increased impulsivity induced by the 0.25, 0.50, and 1.00 g/kg doses of ethanol, while choice strategy of the Insensitive group was not influenced by ethanol dose. Ethanol induced impulsive-like responding only in rats that were flexible in their response strategy (Sensitive group), and this group also performed more autoshaping CRs. Data support the hypothesis that autoshaping and impulsivity are linked.

Expected reward modulates encoding-related theta activity before an event.

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Gruber, Matthias J; Watrous, Andrew J; Ekstrom, Arne D; Ranganath, Charan; Otten, Leun J

2013-01-01

Oscillatory brain activity in the theta frequency range (4-8 Hz) before the onset of an event has been shown to affect the likelihood of successfully encoding the event into memory. Recent work has also indicated that frontal theta activity might be modulated by reward, but it is not clear how reward expectancy, anticipatory theta activity, and memory formation might be related. Here, we used scalp electroencephalography (EEG) to assess the relationship between these factors. EEG was recorded from healthy adults while they memorized a series of words. Each word was preceded by a cue that indicated whether a high or low monetary reward would be earned if the word was successfully remembered in a later recognition test. Frontal theta power between the presentation of the reward cue and the onset of a word was predictive of later memory for the word, but only in the high reward condition. No theta differences were observed before word onset following low reward cues. The magnitude of prestimulus encoding-related theta activity in the high reward condition was correlated with the number of high reward words that were later confidently recognized. These findings provide strong evidence for a link between reward expectancy, theta activity, and memory encoding. Theta activity before event onset seems to be especially important for the encoding of motivationally significant stimuli. One possibility is that dopaminergic activity during reward anticipation mediates frontal theta activity related to memory. Copyright © 2012 Elsevier Inc. All rights reserved.

Reward and behavioral factors contributing to the tonic activity of monkey pedunculopontine tegmental nucleus neurons during saccade tasks

Directory of Open Access Journals (Sweden)

Ken-ichi Okada

2016-11-01

Full Text Available The pedunculopontine tegmental nucleus (PPTg in the brainstem plays a role in controlling reinforcement learning and executing conditioned behavior. We previously examined activity of PPTg neurons in monkeys during a reward-conditioned, visually guided saccade task, and reported that a population of these neurons exhibited tonic responses throughout the task period. These tonic responses might depend on prediction of the upcoming reward, successful execution of the task, or both. Here, we sought to further distinguish these factors and to investigate how each contributes to the tonic neuronal activity of the PPTg. In our normal visually guided saccade task, the monkey initially fixated on the central fixation target, then made saccades to the peripheral saccade target, and received a juice reward after the saccade target disappeared. Most of the tonic activity terminated shortly after the reward delivery, when the monkey broke fixation. To distinguish between reward and behavioral epochs, we then changed the task sequence for a block of trials, such that the saccade target remained visible after the reward delivery. Under these visible conditions, the monkeys tended to continue fixating on the saccade target even after the reward delivery. Therefore, the prediction of the upcoming reward and the end of an individual trial were separated in time. Regardless of the task conditions, half of the tonically active PPTg neurons terminated their activity around the time of the reward delivery, consistent with the view that PPTg neurons might send reward prediction signals until the time of reward delivery, which is essential for computing reward prediction error in reinforcement learning. On the other hand, the other half of the tonically active PPTg neurons changed their activity dependent on the task condition. In the normal condition, the tonic responses terminated around the time of the reward delivery, while in the visible condition, the activity

Reward and Behavioral Factors Contributing to the Tonic Activity of Monkey Pedunculopontine Tegmental Nucleus Neurons during Saccade Tasks.

Science.gov (United States)

Okada, Ken-Ichi; Kobayashi, Yasushi

2016-01-01

The pedunculopontine tegmental nucleus (PPTg) in the brainstem plays a role in controlling reinforcement learning and executing conditioned behavior. We previously examined the activity of PPTg neurons in monkeys during a reward-conditioned, visually guided saccade task, and reported that a population of these neurons exhibited tonic responses throughout the task period. These tonic responses might depend on prediction of the upcoming reward, successful execution of the task, or both. Here, we sought to further distinguish these factors and to investigate how each contributes to the tonic neuronal activity of the PPTg. In our normal visually guided saccade task, the monkey initially fixated on the central fixation target (FT), then made saccades to the peripheral saccade target and received a juice reward after the saccade target disappeared. Most of the tonic activity terminated shortly after the reward delivery, when the monkey broke fixation. To distinguish between reward and behavioral epochs, we then changed the task sequence for a block of trials, such that the saccade target remained visible after the reward delivery. Under these visible conditions, the monkeys tended to continue fixating on the saccade target even after the reward delivery. Therefore, the prediction of the upcoming reward and the end of an individual trial were separated in time. Regardless of the task conditions, half of the tonically active PPTg neurons terminated their activity around the time of the reward delivery, consistent with the view that PPTg neurons might send reward prediction signals until the time of reward delivery, which is essential for computing reward prediction error in reinforcement learning. On the other hand, the other half of the tonically active PPTg neurons changed their activity dependent on the task condition. In the normal condition, the tonic responses terminated around the time of the reward delivery, while in the visible condition, the activity continued

Negative symptoms in schizophrenia are associated with aberrant striato-cortical connectivity in a rewarded perceptual decision-making task.

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Reckless, Greg E; Andreassen, Ole A; Server, Andres; Østefjells, Tiril; Jensen, Jimmy

2015-01-01

Negative symptoms in schizophrenia have been associated with structural and functional changes in the prefrontal cortex. They often persist after treatment with antipsychotic medication which targets, in particular, the ventral striatum (VS). As schizophrenia has been suggested to arise from dysfunctional connectivity between neural networks, it is possible that residual aberrant striato-cortical connectivity in medicated patients plays a role in enduring negative symptomology. The present study examined the relationship between striato-cortical connectivity and negative symptoms in medicated schizophrenia patients. We manipulated motivation in a perceptual decision-making task during functional magnetic resonance imaging. Comparing healthy controls (n = 21) and medicated patients with schizophrenia (n = 18) we investigated how motivation-mediated changes in VS activation affected functional connectivity with the frontal cortex, and how changes in connectivity strength from the neutral to motivated condition related to negative symptom severity. A pattern of aberrant striato-cortical connectivity was observed in the presence of intact VS, but altered left inferior frontal gyrus (IFG) motivation-mediated activation in patients. The more severe the patient's negative symptoms, the less the connectivity strength between the right VS and left IFG changed from the neutral to the motivated condition. Despite aberrant striato-cortical connectivity and altered recruitment of the left IFG among patients, both patients and healthy controls adopted a more liberal response strategy in the motivated compared to the neutral condition. The present findings suggest that there is a link between dysfunctional striato-cortical connectivity and negative symptom severity, and offer a possible explanation as to why negative symptoms persist after treatment with antipsychotics.

Using food as a reward: An examination of parental reward practices.

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Roberts, Lindsey; Marx, Jenna M; Musher-Eizenman, Dara R

2018-01-01

Eating patterns and taste preferences are often established early in life. Many studies have examined how parental feeding practices may affect children's outcomes, including food intake and preference. The current study focused on a common food parenting practice, using food as a reward, and used Latent Profile Analysis (LPA) to examine whether mothers (n = 376) and fathers (n = 117) of children ages 2.8 to 7.5 (M = 4.7; SD = 1.1) grouped into profiles (i.e., subgroups) based on how they use of food as a reward. The 4-class model was the best-fitting LPA model, with resulting classes based on both the frequency and type of reward used. Classes were: infrequent reward (33%), tangible reward (21%), food reward (27%), and frequent reward (19%). The current study also explored whether children's eating styles (emotional overeating, rood fussiness, food responsiveness, and satiety responsiveness) and parenting style (Authoritative, Authoritarian, and Permissive) varied by reward profile. Analyses of Variance (ANOVA) revealed that the four profiles differed significantly for all outcome variables except satiety responsiveness. It appears that the use of tangible and food-based rewards have important implications in food parenting. More research is needed to better understand how the different rewarding practices affect additional child outcomes. Copyright © 2017 Elsevier Ltd. All rights reserved.

The influence of organisational rewards on workplace trust and work engagement

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Janine Victor

2017-05-01

Full Text Available Orientation: In volatile and competitive business environments, organisations are faced with challenges to retain talented workers. Employees are increasingly leaving their jobs for a number of reasons, one of them being a perceived lack of adequate reward practices. Consequently, this has impacted on employee work engagement and confidence and trust in organisations. Research purpose: The study sought to determine whether there is a relationship between rewards, trust and engagement, as well as whether rewards are able to predict trust and engagement in the South African workplace. Motivation for the study: Organisations can no longer solely rely on extrinsic rewards to retain talent. Companies must draw on both extrinsic and intrinsic reward strategies to improve retention levels through endorsing higher levels of workplace trust and work engagement levels. Research design, approach and method: A quantitative, exploratory and cross-sectional research design was utilised. Non-probability sampling using questionnaires consisting of scales from the Job Satisfaction Survey, Intrinsic Motivation Inventory, Psychological Meaningfulness Scale, Basic Needs at Work Scale, Workplace Trust Survey and Utrecht Work Engagement Scale were administered to a sample (N = 251 of South African employees in various industries within the Gauteng region. Main findings: Results indicated that there is a moderate-to-strong positive relationship between the three constructs, and that rewards are able to predict trust and engagement. Practical and managerial implications: The findings provide insight for behavioural practitioners to potentially draw upon when improving talent management strategies. Both extrinsic and intrinsic rewards are important factors in keeping employees engaged and ultimately retaining them. Contribution: The study provided insight into the influence that organisational rewards may have on workplace trust, work engagement and retaining employees

Reward sensitivity is associated with brain activity during erotic stimulus processing.

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Costumero, Victor; Barrós-Loscertales, Alfonso; Bustamante, Juan Carlos; Ventura-Campos, Noelia; Fuentes, Paola; Rosell-Negre, Patricia; Ávila, César

2013-01-01

The behavioral approach system (BAS) from Gray's reinforcement sensitivity theory is a neurobehavioral system involved in the processing of rewarding stimuli that has been related to dopaminergic brain areas. Gray's theory hypothesizes that the functioning of reward brain areas is modulated by BAS-related traits. To test this hypothesis, we performed an fMRI study where participants viewed erotic and neutral pictures, and cues that predicted their appearance. Forty-five heterosexual men completed the Sensitivity to Reward scale (from the Sensitivity to Punishment and Sensitivity to Reward Questionnaire) to measure BAS-related traits. Results showed that Sensitivity to Reward scores correlated positively with brain activity during reactivity to erotic pictures in the left orbitofrontal cortex, left insula, and right ventral striatum. These results demonstrated a relationship between the BAS and reward sensitivity during the processing of erotic stimuli, filling the gap of previous reports that identified the dopaminergic system as a neural substrate for the BAS during the processing of other rewarding stimuli such as money and food.

Reward sensitivity is associated with brain activity during erotic stimulus processing.

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Victor Costumero

Full Text Available The behavioral approach system (BAS from Gray's reinforcement sensitivity theory is a neurobehavioral system involved in the processing of rewarding stimuli that has been related to dopaminergic brain areas. Gray's theory hypothesizes that the functioning of reward brain areas is modulated by BAS-related traits. To test this hypothesis, we performed an fMRI study where participants viewed erotic and neutral pictures, and cues that predicted their appearance. Forty-five heterosexual men completed the Sensitivity to Reward scale (from the Sensitivity to Punishment and Sensitivity to Reward Questionnaire to measure BAS-related traits. Results showed that Sensitivity to Reward scores correlated positively with brain activity during reactivity to erotic pictures in the left orbitofrontal cortex, left insula, and right ventral striatum. These results demonstrated a relationship between the BAS and reward sensitivity during the processing of erotic stimuli, filling the gap of previous reports that identified the dopaminergic system as a neural substrate for the BAS during the processing of other rewarding stimuli such as money and food.

The reward-based eating drive scale: a self-report index of reward-based eating.

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Elissa S Epel

Full Text Available Why are some individuals more vulnerable to persistent weight gain and obesity than are others? Some obese individuals report factors that drive overeating, including lack of control, lack of satiation, and preoccupation with food, which may stem from reward-related neural circuitry. These are normative and common symptoms and not the sole focus of any existing measures. Many eating scales capture these common behaviors, but are confounded with aspects of dysregulated eating such as binge eating or emotional overeating. Across five studies, we developed items that capture this reward-based eating drive (RED. Study 1 developed the items in lean to obese individuals (n = 327 and examined changes in weight over eight years. In Study 2, the scale was further developed and expert raters evaluated the set of items. Study 3 tested psychometric properties of the final 9 items in 400 participants. Study 4 examined psychometric properties and race invariance (n = 80 women. Study 5 examined psychometric properties and age/gender invariance (n = 381. Results showed that RED scores correlated with BMI and predicted earlier onset of obesity, greater weight fluctuations, and greater overall weight gain over eight years. Expert ratings of RED scale items indicated that the items reflected characteristics of reward-based eating. The RED scale evidenced high internal consistency and invariance across demographic factors. The RED scale, designed to tap vulnerability to reward-based eating behavior, appears to be a useful brief tool for identifying those at higher risk of weight gain over time. Given the heterogeneity of obesity, unique brief profiling of the reward-based aspect of obesity using a self-report instrument such as the RED scale may be critical for customizing effective treatments in the general population.

Temporal dynamics of reward anticipation in the human brain.

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Zhang, Yuanyuan; Li, Qi; Wang, Zhao; Liu, Xun; Zheng, Ya

2017-09-01

Reward anticipation is a complex process including cue evaluation, motor preparation, and feedback anticipation. The present study investigated whether these psychological processes were dissociable on neural dynamics in terms of incentive valence and approach motivation. We recorded EEG when participants were performing a monetary incentive delay task, and found a cue-P3 during the cue-evaluation stage, a contingent negative variation (CNV) during the motor-preparation stage, and a stimulus-preceding negativity (SPN) during the feedback-anticipation stage. Critically, both the cue-P3 and SPN exhibited an enhanced sensitivity to gain versus loss anticipation, which was not observed for the CNV. Moreover, both the cue-P3 and SPN, instead of the CNV, for gain anticipation selectively predicted the participants' approach motivation as measured in a following effort expenditure for rewards task, particularly when reward uncertainty was maximal. Together, these results indicate that reward anticipation consists of several sub-stages, each with distinct functional significance, thus providing implications for neuropsychiatric diseases characterized by dysfunction in anticipatory reward processing. Copyright © 2017 Elsevier B.V. All rights reserved.

Reward signals, attempted suicide, and impulsivity in late-life depression.

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Dombrovski, Alexandre Y; Szanto, Katalin; Clark, Luke; Reynolds, Charles F; Siegle, Greg J

2013-10-01

IMPORTANCE—Suicide can be viewed as an escape from unendurable punishment at the cost of any future rewards. Could faulty estimation of these outcomes predispose to suicidal behavior? In behavioral studies, many of those who have attempted suicide misestimate expected rewards on gambling and probabilistic learning tasks.OBJECTIVES—To describe the neural circuit abnormalities that underlie disadvantageous choices in people at risk for suicide and to relate these abnormalities to impulsivity, which is one of the components of vulnerability to suicide.DESIGN—Case-control functional magnetic resonance imaging study of reward learning using are inforcement learning model.SETTING—University hospital and outpatient clinic.PATIENTS—Fifty-three participants 60 years or older, including 15 depressed patients who had attempted suicide, 18 depressed patients who had never attempted suicide (depressed control subjects), and 20 psychiatrically healthy controls.MAIN OUTCOMES AND MEASURES—Components of the cortical blood oxygenation level–dependent response tracking expected and unpredicted rewards.RESULTS—Depressed elderly participants displayed 2 distinct disruptions of control over reward-guided behavior. First, impulsivity and a history of suicide attempts (particularly poorly planned ones) were associated with a weakened expected reward signal in the paralimbic cortex,which in turn predicted the behavioral insensitivity to contingency change. Second, depression was associated with disrupted corticostriatothalamic encoding of unpredicted rewards, which in turn predicted the behavioral over sensitivity to punishment. These results were robust to the effects of possible brain damage from suicide attempts, depressive severity, co-occurring substance use and anxiety disorders, antidepressant and anticholinergic exposure, lifetime exposure to electroconvulsive therapy, vascular illness, and incipient dementia.CONCLUSIONS AND RELEVANCE—Altered paralimbic reward

Do reward-processing deficits in schizophrenia-spectrum disorders promote cannabis use? An investigation of physiological response to natural rewards and drug cues

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Cassidy, Clifford M.; Brodeur, Mathieu B.; Lepage, Martin; Malla, Ashok

2014-01-01

Background Dysfunctional reward processing is present in individuals with schizophrenia-spectrum disorders (SSD) and may confer vulnerability to addiction. Our objective was to identify a deficit in patients with SSD on response to rewarding stimuli and determine whether this deficit predicts cannabis use. Methods We divided a group of patients with SSD and nonpsychotic controls into cannabis users and nonusers. Response to emotional and cannabis-associated visual stimuli was assessed using self-report, event-related potentials (using the late positive potential [LPP]), facial electromyography and skin-conductance response. Results Our sample comprised 35 patients with SSD and 35 nonpsychotic controls. Compared with controls, the patients with SSD showed blunted LPP response to pleasant stimuli (p = 0.003). Across measures, cannabis-using controls showed greater response to pleasant stimuli than to cannabis stimuli whereas cannabis-using patients showed little bias toward pleasant stimuli. Reduced LPP response to pleasant stimuli was predictive of more frequent subsequent cannabis use (β = −0.24, p = 0.034). Limitations It is not clear if the deficit associated with cannabis use is specific to rewarding stimuli or nonspecific to any kind of emotionally salient stimuli. Conclusion The LPP captures a reward-processing deficit in patients with SSD and shows potential as a biomarker for identifying patients at risk of heavy cannabis use. PMID:24913137

Differences between Dorsal and Ventral Striatum in the Sensitivity of Tonically Active Neurons to Rewarding Events

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Kevin Marche

2017-07-01

Full Text Available Within the striatum, cholinergic interneurons, electrophysiologically identified as tonically active neurons (TANs, represent a relatively homogeneous group in terms of their functional properties. They display typical pause in tonic firing in response to rewarding events which are of crucial importance for reinforcement learning. These responses are uniformly distributed throughout the dorsal striatum (i.e., motor and associative striatum, but it is unknown, at least in monkeys, whether differences in the modulation of TAN activity exist in the ventral striatum (i.e., limbic striatum, a region specialized for processing of motivational information. To address this issue, we examined the activity of dorsal and ventral TANs in two monkeys trained on a Pavlovian conditioning task in which a visual stimulus preceded the delivery of liquid reward by a fixed time interval. We found that the proportion of TANs responding to the stimulus predictive of reward did not vary significantly across regions (58%–80%, whereas the fraction of TANs responding to reward was higher in the limbic striatum (100% compared to the motor (65% and associative striatum (52%. By examining TAN modulation at the level of both the population and the individual neurons, we showed that the duration of pause responses to the stimulus and reward was longer in the ventral than in the dorsal striatal regions. Also, the magnitude of the pause was greater in ventral than dorsal striatum for the stimulus predictive of reward but not for the reward itself. We found similar region-specific differences in pause response duration to the stimulus when the timing of reward was less predictable (fixed replaced by variable time interval. Regional variations in the duration and magnitude of the pause response were transferred from the stimulus to reward when reward was delivered in the absence of any predictive stimulus. It therefore appears that ventral TANs exhibit stronger responses to

Individual differences in anticipatory activity to food rewards predict cue-induced appetitive 50-kHz calls in rats.

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Brenes, Juan C; Schwarting, Rainer K W

2015-10-01

Reward-related stimuli come to acquire incentive salience through Pavlovian learning and become capable of controlling reward-oriented behaviors. Here, we examined individual differences in anticipatory activity elicited by reward-related cues as indicative of how animals attribute incentive salience to otherwise neutral stimuli. Since adult rats can signal incentive motivation states through ultrasonic vocalizations (USVs) at around 50-kHz, such calls were recorded in food-deprived rats trained to associate cues with food rewards, which were subsequently devalued by satiation.We found that the extent to which animals developed conditioned anticipatory activity to food cues while food deprived determined the level of cue-induced appetitive USVs while sated. Re-exposure to reward cues after a free-testing period reinstated USVs, invigorated reward seeking and consumption, and again, increases in calling occurred only in animals with high levels of cue-induced anticipatory activity. Reward-experienced rats systemically challenged with the catecholamine agonist amphetamine or with the dopamine receptor antagonist flupenthixol showed attenuated responses to these drugs, especially for USVs and in subjects with high levels of cue-induced anticipatory activity. Our results suggest that individuals prone to attribute incentive salience to reward cues showed heightened reward-induced USVs which were reliably expressed over time and persisted despite physiological needs being fulfilled. Also, prone subjects seemed to undergo particular adaptations in their dopaminergic system related with incentive learning. Our findings may have translational relevance in preclinical research modeling compulsive disorders, which may be due to excessive attribution of incentive salience to reward cues, such as overeating, pathological gambling, and drug addiction.

A Fly’s Eye View of Natural and Drug Reward

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Lowenstein, Eve G.; Velazquez-Ulloa, Norma A.

2018-01-01

Animals encounter multiple stimuli each day. Some of these stimuli are innately appetitive or aversive, while others are assigned valence based on experience. Drugs like ethanol can elicit aversion in the short term and attraction in the long term. The reward system encodes the predictive value for different stimuli, mediating anticipation for attractive or punishing stimuli and driving animal behavior to approach or avoid conditioned stimuli. The neurochemistry and neurocircuitry of the reward system is partly evolutionarily conserved. In both vertebrates and invertebrates, including Drosophila melanogaster, dopamine is at the center of a network of neurotransmitters and neuromodulators acting in concert to encode rewards. Behavioral assays in D. melanogaster have become increasingly sophisticated, allowing more direct comparison with mammalian research. Moreover, recent evidence has established the functional modularity of the reward neural circuits in Drosophila. This functional modularity resembles the organization of reward circuits in mammals. The powerful genetic and molecular tools for D. melanogaster allow characterization and manipulation at the single-cell level. These tools are being used to construct a detailed map of the neural circuits mediating specific rewarding stimuli and have allowed for the identification of multiple genes and molecular pathways that mediate the effects of reinforcing stimuli, including their rewarding effects. This report provides an overview of the research on natural and drug reward in D. melanogaster, including natural rewards such as sugar and other food nutrients, and drug rewards including ethanol, cocaine, amphetamine, methamphetamine, and nicotine. We focused mainly on the known genetic and neural mechanisms underlying appetitive reward for sugar and reward for ethanol. We also include genes, molecular pathways, and neural circuits that have been identified using assays that test the palatability of the rewarding

A Fly’s Eye View of Natural and Drug Reward

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Eve G. Lowenstein

2018-04-01

Full Text Available Animals encounter multiple stimuli each day. Some of these stimuli are innately appetitive or aversive, while others are assigned valence based on experience. Drugs like ethanol can elicit aversion in the short term and attraction in the long term. The reward system encodes the predictive value for different stimuli, mediating anticipation for attractive or punishing stimuli and driving animal behavior to approach or avoid conditioned stimuli. The neurochemistry and neurocircuitry of the reward system is partly evolutionarily conserved. In both vertebrates and invertebrates, including Drosophila melanogaster, dopamine is at the center of a network of neurotransmitters and neuromodulators acting in concert to encode rewards. Behavioral assays in D. melanogaster have become increasingly sophisticated, allowing more direct comparison with mammalian research. Moreover, recent evidence has established the functional modularity of the reward neural circuits in Drosophila. This functional modularity resembles the organization of reward circuits in mammals. The powerful genetic and molecular tools for D. melanogaster allow characterization and manipulation at the single-cell level. These tools are being used to construct a detailed map of the neural circuits mediating specific rewarding stimuli and have allowed for the identification of multiple genes and molecular pathways that mediate the effects of reinforcing stimuli, including their rewarding effects. This report provides an overview of the research on natural and drug reward in D. melanogaster, including natural rewards such as sugar and other food nutrients, and drug rewards including ethanol, cocaine, amphetamine, methamphetamine, and nicotine. We focused mainly on the known genetic and neural mechanisms underlying appetitive reward for sugar and reward for ethanol. We also include genes, molecular pathways, and neural circuits that have been identified using assays that test the palatability of

Amygdala Contributions to Stimulus-Reward Encoding in the Macaque Medial and Orbital Frontal Cortex during Learning.

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Rudebeck, Peter H; Ripple, Joshua A; Mitz, Andrew R; Averbeck, Bruno B; Murray, Elisabeth A

2017-02-22

Orbitofrontal cortex (OFC), medial frontal cortex (MFC), and amygdala mediate stimulus-reward learning, but the mechanisms through which they interact are unclear. Here, we investigated how neurons in macaque OFC and MFC signaled rewards and the stimuli that predicted them during learning with and without amygdala input. Macaques performed a task that required them to evaluate two stimuli and then choose one to receive the reward associated with that option. Four main findings emerged. First, amygdala lesions slowed the acquisition and use of stimulus-reward associations. Further analyses indicated that this impairment was due, at least in part, to ineffective use of negative feedback to guide subsequent decisions. Second, the activity of neurons in OFC and MFC rapidly evolved to encode the amount of reward associated with each stimulus. Third, amygdalectomy reduced encoding of stimulus-reward associations during the evaluation of different stimuli. Reward encoding of anticipated and received reward after choices were made was not altered. Fourth, amygdala lesions led to an increase in the proportion of neurons in MFC, but not OFC, that encoded the instrumental response that monkeys made on each trial. These correlated changes in behavior and neural activity after amygdala lesions strongly suggest that the amygdala contributes to the ability to learn stimulus-reward associations rapidly by shaping encoding within OFC and MFC. SIGNIFICANCE STATEMENT Altered functional interactions among orbital frontal cortex (OFC), medial frontal cortex (MFC), and amygdala are thought to underlie several psychiatric conditions, many related to reward learning. Here, we investigated the causal contribution of the amygdala to the development of neuronal activity in macaque OFC and MFC related to rewards and the stimuli that predict them during learning. Without amygdala inputs, neurons in both OFC and MFC showed decreased encoding of stimulus-reward associations. MFC also showed

A meta-analytic review of experiments examining the effects of extrinsic rewards on intrinsic motivation.

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Deci, E L; Koestner, R; Ryan, R M

1999-11-01

A meta-analysis of 128 studies examined the effects of extrinsic rewards on intrinsic motivation. As predicted, engagement-contingent, completion-contingent, and performance-contingent rewards significantly undermined free-choice intrinsic motivation (d = -0.40, -0.36, and -0.28, respectively), as did all rewards, all tangible rewards, and all expected rewards. Engagement-contingent and completion-contingent rewards also significantly undermined self-reported interest (d = -0.15, and -0.17), as did all tangible rewards and all expected rewards. Positive feedback enhanced both free-choice behavior (d = 0.33) and self-reported interest (d = 0.31). Tangible rewards tended to be more detrimental for children than college students, and verbal rewards tended to be less enhancing for children than college students. The authors review 4 previous meta-analyses of this literature and detail how this study's methods, analyses, and results differed from the previous ones.

Reward-modulated motor information in identified striatum neurons.

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Isomura, Yoshikazu; Takekawa, Takashi; Harukuni, Rie; Handa, Takashi; Aizawa, Hidenori; Takada, Masahiko; Fukai, Tomoki

2013-06-19

It is widely accepted that dorsal striatum neurons participate in either the direct pathway (expressing dopamine D1 receptors) or the indirect pathway (expressing D2 receptors), controlling voluntary movements in an antagonistically balancing manner. The D1- and D2-expressing neurons are activated and inactivated, respectively, by dopamine released from substantia nigra neurons encoding reward expectation. However, little is known about the functional representation of motor information and its reward modulation in individual striatal neurons constituting the two pathways. In this study, we juxtacellularly recorded the spike activity of single neurons in the dorsolateral striatum of rats performing voluntary forelimb movement in a reward-predictable condition. Some of these neurons were identified morphologically by a combination of juxtacellular visualization and in situ hybridization for D1 mRNA. We found that the striatal neurons exhibited distinct functional activations before and during the forelimb movement, regardless of the expression of D1 mRNA. They were often positively, but rarely negatively, modulated by expecting a reward for the correct motor response. The positive reward modulation was independent of behavioral differences in motor performance. In contrast, regular-spiking and fast-spiking neurons in any layers of the motor cortex displayed only minor and unbiased reward modulation of their functional activation in relation to the execution of forelimb movement. Our results suggest that the direct and indirect pathway neurons cooperatively rather than antagonistically contribute to spatiotemporal control of voluntary movements, and that motor information is subcortically integrated with reward information through dopaminergic and other signals in the skeletomotor loop of the basal ganglia.

Reward-based training of recurrent neural networks for cognitive and value-based tasks.

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Song, H Francis; Yang, Guangyu R; Wang, Xiao-Jing

2017-01-13

Trained neural network models, which exhibit features of neural activity recorded from behaving animals, may provide insights into the circuit mechanisms of cognitive functions through systematic analysis of network activity and connectivity. However, in contrast to the graded error signals commonly used to train networks through supervised learning, animals learn from reward feedback on definite actions through reinforcement learning. Reward maximization is particularly relevant when optimal behavior depends on an animal's internal judgment of confidence or subjective preferences. Here, we implement reward-based training of recurrent neural networks in which a value network guides learning by using the activity of the decision network to predict future reward. We show that such models capture behavioral and electrophysiological findings from well-known experimental paradigms. Our work provides a unified framework for investigating diverse cognitive and value-based computations, and predicts a role for value representation that is essential for learning, but not executing, a task.

Comparing the neural basis of monetary reward and cognitive feedback during information-integration category learning.

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Daniel, Reka; Pollmann, Stefan

2010-01-06

The dopaminergic system is known to play a central role in reward-based learning (Schultz, 2006), yet it was also observed to be involved when only cognitive feedback is given (Aron et al., 2004). Within the domain of information-integration category learning, in which information from several stimulus dimensions has to be integrated predecisionally (Ashby and Maddox, 2005), the importance of contingent feedback is well established (Maddox et al., 2003). We examined the common neural correlates of reward anticipation and prediction error in this task. Sixteen subjects performed two parallel information-integration tasks within a single event-related functional magnetic resonance imaging session but received a monetary reward only for one of them. Similar functional areas including basal ganglia structures were activated in both task versions. In contrast, a single structure, the nucleus accumbens, showed higher activation during monetary reward anticipation compared with the anticipation of cognitive feedback in information-integration learning. Additionally, this activation was predicted by measures of intrinsic motivation in the cognitive feedback task and by measures of extrinsic motivation in the rewarded task. Our results indicate that, although all other structures implicated in category learning are not significantly affected by altering the type of reward, the nucleus accumbens responds to the positive incentive properties of an expected reward depending on the specific type of the reward.

Optical traps with geometric aberrations

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Roichman, Yael; Waldron, Alex; Gardel, Emily; Grier, David G.

2006-01-01

We assess the influence of geometric aberrations on the in-plane performance of optical traps by studying the dynamics of trapped colloidal spheres in deliberately distorted holographic optical tweezers. The lateral stiffness of the traps turns out to be insensitive to moderate amounts of coma, astigmatism, and spherical aberration. Moreover holographic aberration correction enables us to compensate inherent shortcomings in the optical train, thereby adaptively improving its performance. We also demonstrate the effects of geometric aberrations on the intensity profiles of optical vortices, whose readily measured deformations suggest a method for rapidly estimating and correcting geometric aberrations in holographic trapping systems

Serotonergic neurons signal reward and punishment on multiple timescales

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Cohen, Jeremiah Y; Amoroso, Mackenzie W; Uchida, Naoshige

2015-01-01

Serotonin's function in the brain is unclear. One challenge in testing the numerous hypotheses about serotonin's function has been observing the activity of identified serotonergic neurons in animals engaged in behavioral tasks. We recorded the activity of dorsal raphe neurons while mice experienced a task in which rewards and punishments varied across blocks of trials. We ‘tagged’ serotonergic neurons with the light-sensitive protein channelrhodopsin-2 and identified them based on their responses to light. We found three main features of serotonergic neuron activity: (1) a large fraction of serotonergic neurons modulated their tonic firing rates over the course of minutes during reward vs punishment blocks; (2) most were phasically excited by punishments; and (3) a subset was phasically excited by reward-predicting cues. By contrast, dopaminergic neurons did not show firing rate changes across blocks of trials. These results suggest that serotonergic neurons signal information about reward and punishment on multiple timescales. DOI: http://dx.doi.org/10.7554/eLife.06346.001 PMID:25714923

Hedging Your Bets by Learning Reward Correlations in the Human Brain

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Wunderlich, Klaus; Symmonds, Mkael; Bossaerts, Peter; Dolan, Raymond J.

2011-01-01

Summary Human subjects are proficient at tracking the mean and variance of rewards and updating these via prediction errors. Here, we addressed whether humans can also learn about higher-order relationships between distinct environmental outcomes, a defining ecological feature of contexts where multiple sources of rewards are available. By manipulating the degree to which distinct outcomes are correlated, we show that subjects implemented an explicit model-based strategy to learn the associated outcome correlations and were adept in using that information to dynamically adjust their choices in a task that required a minimization of outcome variance. Importantly, the experimentally generated outcome correlations were explicitly represented neuronally in right midinsula with a learning prediction error signal expressed in rostral anterior cingulate cortex. Thus, our data show that the human brain represents higher-order correlation structures between rewards, a core adaptive ability whose immediate benefit is optimized sampling. PMID:21943609

A causal link between prediction errors, dopamine neurons and learning.

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Steinberg, Elizabeth E; Keiflin, Ronald; Boivin, Josiah R; Witten, Ilana B; Deisseroth, Karl; Janak, Patricia H

2013-07-01

Situations in which rewards are unexpectedly obtained or withheld represent opportunities for new learning. Often, this learning includes identifying cues that predict reward availability. Unexpected rewards strongly activate midbrain dopamine neurons. This phasic signal is proposed to support learning about antecedent cues by signaling discrepancies between actual and expected outcomes, termed a reward prediction error. However, it is unknown whether dopamine neuron prediction error signaling and cue-reward learning are causally linked. To test this hypothesis, we manipulated dopamine neuron activity in rats in two behavioral procedures, associative blocking and extinction, that illustrate the essential function of prediction errors in learning. We observed that optogenetic activation of dopamine neurons concurrent with reward delivery, mimicking a prediction error, was sufficient to cause long-lasting increases in cue-elicited reward-seeking behavior. Our findings establish a causal role for temporally precise dopamine neuron signaling in cue-reward learning, bridging a critical gap between experimental evidence and influential theoretical frameworks.

Development of a Self-Report Measure of Reward Sensitivity:A Test in Current and Former Smokers.

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Hughes, John R; Callas, Peter W; Priest, Jeff S; Etter, Jean-Francois; Budney, Alan J; Sigmon, Stacey C

2017-06-01

Tobacco use or abstinence may increase or decrease reward sensitivity. Most existing measures of reward sensitivity were developed decades ago, and few have undergone extensive psychometric testing. We developed a 58-item survey of the anticipated enjoyment from, wanting for, and frequency of common rewards (the Rewarding Events Inventory-REI). The current analysis focuses on ratings of anticipated enjoyment. The first validation study recruited current and former smokers from Internet sites. The second study recruited smokers who wished to quit and monetarily reinforced them to stay abstinent in a laboratory study and a comparison group of former smokers. In both studies, participants completed the inventory on two occasions, 3-7 days apart. They also completed four anhedonia scales and a behavioral test of reduced reward sensitivity. Half of the enjoyment ratings loaded on four factors: socializing, active hobbies, passive hobbies, and sex/drug use. Cronbach's alpha coefficients were all ≥0.73 for overall mean and factor scores. Test-retest correlations were all ≥0.83. Correlations of the overall and factor scores with frequency of rewards and anhedonia scales were 0.19-0.53, except for the sex/drugs factor. The scores did not correlate with behavioral tests of reward and did not differ between current and former smokers. Lower overall mean enjoyment score predicted a shorter time to relapse. Internal reliability and test-retest reliability of the enjoyment outcomes of the REI are excellent, and construct and predictive validity are modest but promising. The REI is comprehensive and up-to-date, yet is short enough to use on repeated occasions. Replication tests, especially predictive validity tests, are needed. Both use of and abstinence from nicotine appear to increase or decrease how rewarding nondrug rewards are; however, self-report scales to test this have limitations. Our inventory of enjoyment from 58 rewards appears to be reliable and valid as well as

Aberrant monocyte responses predict and characterize dengue virus infection in individuals with severe disease.

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Yong, Yean K; Tan, Hong Y; Jen, Soe Hui; Shankar, Esaki M; Natkunam, Santha K; Sathar, Jameela; Manikam, Rishya; Sekaran, Shamala D

2017-05-31

Currently, several assays can diagnose acute dengue infection. However, none of these assays can predict the severity of the disease. Biomarkers that predicts the likelihood that a dengue patient will develop a severe form of the disease could permit more efficient patient triage and allows better supportive care for the individual in need, especially during dengue outbreaks. We measured 20 plasma markers i.e. IFN-γ, IL-10, granzyme-B, CX3CL1, IP-10, RANTES, CXCL8, CXCL6, VCAM, ICAM, VEGF, HGF, sCD25, IL-18, LBP, sCD14, sCD163, MIF, MCP-1 and MIP-1β in 141 dengue patients in over 230 specimens and correlate the levels of these plasma markers with the development of dengue without warning signs (DWS-), dengue with warning signs (DWS+) and severe dengue (SD). Our results show that the elevation of plasma levels of IL-18 at both febrile and defervescence phase was significantly associated with DWS+ and SD; whilst increase of sCD14 and LBP at febrile phase were associated with severity of dengue disease. By using receiver operating characteristic (ROC) analysis, the IL-18, LBP and sCD14 were significantly predicted the development of more severe form of dengue disease (DWS+/SD) (AUC = 0.768, P dengue disease. Given that the elevation IL-18, LBP and sCD14 among patients with severe form of dengue disease, our findings suggest a pathogenic role for an aberrant inflammasome and monocyte activation in the development of severe form of dengue disease.

Paying for performance: Performance incentives increase desire for the reward object.

Science.gov (United States)

Hur, Julia D; Nordgren, Loran F

2016-09-01

The current research examines how exposure to performance incentives affects one's desire for the reward object. We hypothesized that the flexible nature of performance incentives creates an attentional fixation on the reward object (e.g., money), which leads people to become more desirous of the rewards. Results from 5 laboratory experiments and 1 large-scale field study provide support for this prediction. When performance was incentivized with monetary rewards, participants reported being more desirous of money (Study 1), put in more effort to earn additional money in an ensuing task (Study 2), and were less willing to donate money to charity (Study 4). We replicated the result with nonmonetary rewards (Study 5). We also found that performance incentives increased attention to the reward object during the task, which in part explains the observed effects (Study 6). A large-scale field study replicated these findings in a real-world setting (Study 7). One laboratory experiment failed to replicate (Study 3). (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Alterations of the Brain Reward System in Antipsychotic Naïve Schizophrenia Patients

DEFF Research Database (Denmark)

Nielsen, Mette Ødegaard; Rostrup, Egill; Wulff, Sanne

2012-01-01

BACKGROUND: Various schizophrenic symptoms are suggested to be linked to a dysfunction of the brain reward system. Several studies have found alterations in the reward processing in patients with schizophrenia; however, most previous findings might be confounded by medication effects. METHODS...... as arousing events) into behavioral salience (events where a predicted reward requires performance) and valence anticipation (the anticipation of a monetarily significant outcome). Furthermore, the evaluation of monetary gain and loss was assessed. RESULTS: During reward anticipation, patients had...... and nonsignificant for value anticipation. Furthermore, patients showed a changed activation pattern during outcome evaluation in right prefrontal cortex. CONCLUSION: Our results suggest that changes during reward anticipation in schizophrenia are present from the beginning of the disease. This supports a possible...

Pressure to cooperate: is positive reward interdependence really needed in cooperative learning?

Science.gov (United States)

Buchs, Céline; Gilles, Ingrid; Dutrévis, Marion; Butera, Fabrizio

2011-03-01

BACKGROUND. Despite extensive research on cooperative learning, the debate regarding whether or not its effectiveness depends on positive reward interdependence has not yet found clear evidence. AIMS. We tested the hypothesis that positive reward interdependence, as compared to reward independence, enhances cooperative learning only if learners work on a 'routine task'; if the learners work on a 'true group task', positive reward interdependence induces the same level of learning as reward independence. SAMPLE. The study involved 62 psychology students during regular workshops. METHOD. Students worked on two psychology texts in cooperative dyads for three sessions. The type of task was manipulated through resource interdependence: students worked on either identical (routine task) or complementary (true group task) information. Students expected to be assessed with a Multiple Choice Test (MCT) on the two texts. The MCT assessment type was introduced according to two reward interdependence conditions, either individual (reward independence) or common (positive reward interdependence). A follow-up individual test took place 4 weeks after the third session of dyadic work to examine individual learning. RESULTS. The predicted interaction between the two types of interdependence was significant, indicating that students learned more with positive reward interdependence than with reward independence when they worked on identical information (routine task), whereas students who worked on complementary information (group task) learned the same with or without reward interdependence. CONCLUSIONS. This experiment sheds light on the conditions under which positive reward interdependence enhances cooperative learning, and suggests that creating a real group task allows to avoid the need for positive reward interdependence. © 2010 The British Psychological Society.

An ecologically based model of alcohol-consumption decision making: evidence for the discriminative and predictive role of contextual reward and punishment information.

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Bogg, Tim; Finn, Peter R

2009-05-01

Using insights from Ecological Systems Theory and Reinforcement Sensitivity Theory, the current study assessed the utility of a series of hypothetical role-based alcohol-consumption scenarios that varied in their presentation of rewarding and punishing information. The scenarios, along with measures of impulsive sensation seeking and a self-report of weekly alcohol consumption, were administered to a sample of alcohol-dependent and non-alcohol-dependent college-age individuals (N = 170). The results showed scenario attendance decisions were largely unaffected by alcohol-dependence status and variations in contextual reward and punishment information. In contrast to the attendance findings, the results for the alcohol-consumption decisions showed alcohol-dependent individuals reported a greater frequency of deciding to drink, as well as indicating greater alcohol consumption in the contexts of complementary rewarding or nonpunishing information. Regression results provided evidence for the criterion-related validity of scenario outcomes in an account of diagnostic alcohol problems. The results are discussed in terms of the conceptual and predictive gains associated with an assessment approach to alcohol-consumption decision making that combines situational information organized and balanced through the frameworks of Ecological Systems Theory and Reinforcement Sensitivity Theory.

Perceived stress predicts altered reward and loss feedback processing in medial prefrontal cortex

Directory of Open Access Journals (Sweden)

Michael T Treadway

2013-05-01

Full Text Available Stress is significant risk factor for the development of psychopathology, particularly symptoms related to reward processing. Importantly, individuals display marked variation in how they perceive and cope with stressful events, and such differences are strongly linked to risk for developing psychiatric symptoms following stress exposure. However, many questions remain regarding the neural architecture that underlies inter-subject variability in perceptions of stressors. Using functional magnetic resonance imaging (fMRI during a monetary incentive delay paradigm, we examined the effects of self-reported perceived stress levels on neural activity during reward anticipation and feedback in a sample of healthy individuals. We found that subjects reporting more uncontrollable and overwhelming stressors displayed blunted neural responses in medial prefrontal cortex (mPFC following feedback related to monetary gains as well monetary losses. This is consistent with preclinical models that implicate the mPFC as a key site of vulnerability to the noxious effects of uncontrollable stressors. Our data help translate these findings to humans, and elucidate some of the neural mechanisms that may underlie stress-linked risk for developing reward-related psychiatric symptoms.

Heterogeneity of reward mechanisms.

Science.gov (United States)

Lajtha, A; Sershen, H

2010-06-01

The finding that many drugs that have abuse potential and other natural stimuli such as food or sexual activity cause similar chemical changes in the brain, an increase in extracellular dopamine (DA) in the shell of the nucleus accumbens (NAccS), indicated some time ago that the reward mechanism is at least very similar for all stimuli and that the mechanism is relatively simple. The presently available information shows that the mechanisms involved are more complex and have multiple elements. Multiple brain regions, multiple receptors, multiple distinct neurons, multiple transmitters, multiple transporters, circuits, peptides, proteins, metabolism of transmitters, and phosphorylation, all participate in reward mechanisms. The system is variable, is changed during development, is sex-dependent, and is influenced by genetic differences. Not all of the elements participate in the reward of all stimuli. Different set of mechanisms are involved in the reward of different drugs of abuse, yet different mechanisms in the reward of natural stimuli such as food or sexual activity; thus there are different systems that distinguish different stimuli. Separate functions of the reward system such as anticipation, evaluation, consummation and identification; all contain function-specific elements. The level of the stimulus also influences the participation of the elements of the reward system, there are possible reactions to even below threshold stimuli, and excessive stimuli can change reward to aversion involving parts of the system. Learning and memory of past reward is an important integral element of reward and addictive behavior. Many of the reward elements are altered by repeated or chronic stimuli, and chronic exposure to one drug is likely to alter the response to another stimulus. To evaluate and identify the reward stimulus thus requires heterogeneity of the reward components in the brain.

Quantifying individual variation in the propensity to attribute incentive salience to reward cues.

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Meyer, Paul J; Lovic, Vedran; Saunders, Benjamin T; Yager, Lindsay M; Flagel, Shelly B; Morrow, Jonathan D; Robinson, Terry E

2012-01-01

If reward-associated cues acquire the properties of incentive stimuli they can come to powerfully control behavior, and potentially promote maladaptive behavior. Pavlovian incentive stimuli are defined as stimuli that have three fundamental properties: they are attractive, they are themselves desired, and they can spur instrumental actions. We have found, however, that there is considerable individual variation in the extent to which animals attribute Pavlovian incentive motivational properties ("incentive salience") to reward cues. The purpose of this paper was to develop criteria for identifying and classifying individuals based on their propensity to attribute incentive salience to reward cues. To do this, we conducted a meta-analysis of a large sample of rats (N = 1,878) subjected to a classic Pavlovian conditioning procedure. We then used the propensity of animals to approach a cue predictive of reward (one index of the extent to which the cue was attributed with incentive salience), to characterize two behavioral phenotypes in this population: animals that approached the cue ("sign-trackers") vs. others that approached the location of reward delivery ("goal-trackers"). This variation in Pavlovian approach behavior predicted other behavioral indices of the propensity to attribute incentive salience to reward cues. Thus, the procedures reported here should be useful for making comparisons across studies and for assessing individual variation in incentive salience attribution in small samples of the population, or even for classifying single animals.

Motor Planning under Unpredictable Reward: Modulations of Movement Vigor and Primate Striatum Activity

Directory of Open Access Journals (Sweden)

Ioan eOpris

2011-05-01

Full Text Available Although reward probability is an important factor that shapes animal behavior, it is not well understood however, how the primate brain translates reward expectation into the vigor of movement (reaction time and speed. To address this question, we trained two monkeys in a reaction time task that required wrist movements in response to vibrotactile and visual stimuli, with a variable reward schedule. Correct performance was rewarded in 75 % of the trials. Monkeys were certain that they would be rewarded only in the trials immediately following withheld rewards. In these trials, the animals responded sooner and moved faster. Single-unit recordings from the dorsal striatum revealed that modulations in striatal neurons reflected such modulations of movement vigor. First, in the trials with certain rewards, striatal neurons modulated their firing rates earlier. Second, magnitudes of changes in neuronal firing rates depended on whether or not monkeys were certain about the reward. Third, these modulations depended on the sensory modality of the cue (visual vs. vibratory and/or movement direction (flexions vs. extensions. We conclude that dorsal striatum may be a part of the mechanism responsible for the modulation of movement vigor in response to changes of reward predictability.

Reward, dopamine and the control of food intake: implications for obesity

Energy Technology Data Exchange (ETDEWEB)

Volkow N. D.; Wang G.; Volkow, N.D.; Wang, G.-J.; Baler, R.D.

2011-10-01

The ability to resist the urge to eat requires the proper functioning of neuronal circuits involved in top-down control to oppose the conditioned responses that predict reward from eating the food and the desire to eat the food. Imaging studies show that obese subjects might have impairments in dopaminergic pathways that regulate neuronal systems associated with reward sensitivity, conditioning and control. It is known that the neuropeptides that regulate energy balance (homeostatic processes) through the hypothalamus also modulate the activity of dopamine cells and their projections into regions involved in the rewarding processes underlying food intake. It is postulated that this could also be a mechanism by which overeating and the resultant resistance to homoeostatic signals impairs the function of circuits involved in reward sensitivity, conditioning and cognitive control.

Reward, dopamine and the control of food intake: implications for obesity

International Nuclear Information System (INIS)

Volkow, N.D.; Wang, G.J.; Baler, R.D.

2011-01-01

The ability to resist the urge to eat requires the proper functioning of neuronal circuits involved in top-down control to oppose the conditioned responses that predict reward from eating the food and the desire to eat the food. Imaging studies show that obese subjects might have impairments in dopaminergic pathways that regulate neuronal systems associated with reward sensitivity, conditioning and control. It is known that the neuropeptides that regulate energy balance (homeostatic processes) through the hypothalamus also modulate the activity of dopamine cells and their projections into regions involved in the rewarding processes underlying food intake. It is postulated that this could also be a mechanism by which overeating and the resultant resistance to homoeostatic signals impairs the function of circuits involved in reward sensitivity, conditioning and cognitive control.

Probability differently modulating the effects of reward and punishment on visuomotor adaptation.

Science.gov (United States)

Song, Yanlong; Smiley-Oyen, Ann L

2017-12-01

Recent human motor learning studies revealed that punishment seemingly accelerated motor learning but reward enhanced consolidation of motor memory. It is not evident how intrinsic properties of reward and punishment modulate the potentially dissociable effects of reward and punishment on motor learning and motor memory. It is also not clear what causes the dissociation of the effects of reward and punishment. By manipulating probability of distribution, a critical property of reward and punishment, the present study demonstrated that probability had distinct modulation on the effects of reward and punishment in adapting to a sudden visual rotation and consolidation of the adaptation memory. Specifically, two probabilities of monetary reward and punishment distribution, 50 and 100%, were applied during young adult participants adapting to a sudden visual rotation. Punishment and reward showed distinct effects on motor adaptation and motor memory. The group that received punishments in 100% of the adaptation trials adapted significantly faster than the other three groups, but the group that received rewards in 100% of the adaptation trials showed marked savings in re-adapting to the same rotation. In addition, the group that received punishments in 50% of the adaptation trials that were randomly selected also had savings in re-adapting to the same rotation. Sensitivity to sensory prediction error or difference in explicit process induced by reward and punishment may likely contribute to the distinct effects of reward and punishment.

Public praise vs. private pay: Effects of rewards on energy conservation in the workplace

NARCIS (Netherlands)

Handgraaf, M.J.J.; Lidth de Jeude, van M.; Appelt, K.C.

2013-01-01

Any solution to rising levels of CO2 depends on human behavior. One common approach to changing human behavior is rewarding desired behavior. Because financial incentives often have side effects that diminish efficacy, we predict that social rewards are more effective, because they invoke adherence

Public Praise vs. Private Pay: Effects of Rewards on Energy Conservation in the Workplace

NARCIS (Netherlands)

Handgraaf, M.J.J.; Lidth de Jeude, van M.; Appelt, K.C.

2011-01-01

Any solution to rising levels of CO2 depends on human behavior. One common approach to changing human behavior is rewarding desired behavior. Because financial incentives often have side effects that diminish efficacy, we predict that more psychologically oriented social rewards are more effective,

Goal or gold: overlapping reward processes in soccer players upon scoring and winning money.

Directory of Open Access Journals (Sweden)

Alexander Niklas Häusler

Full Text Available Social rewards are important incentives for human behavior. This is especially true in team sports such as the most popular one worldwide: soccer. We investigated reward processing upon scoring a soccer goal in a standard two-versus-one situation and in comparison to winning in a monetary incentive task. The results show a strong overlap in brain activity between the two conditions in established reward regions of the mesolimbic dopaminergic system, including the ventral striatum and ventromedial pre-frontal cortex. The three main components of reward-associated learning, i.e., reward probability (RP, reward reception (RR and reward prediction errors (RPE showed highly similar activation in both con-texts, with only the RR and RPE components displaying overlapping reward activity. Passing and shooting behavior did not correlate with individual egoism scores, but we observe a positive correlation be-tween egoism and activity in the left middle frontal gyrus upon scoring after a pass versus a direct shot. Our findings suggest that rewards in the context of soccer and monetary incentives are based on similar neural processes.

Goal or Gold: Overlapping Reward Processes in Soccer Players upon Scoring and Winning Money

Science.gov (United States)

Häusler, Alexander Niklas; Becker, Benjamin; Bartling, Marcel; Weber, Bernd

2015-01-01

Social rewards are important incentives for human behavior. This is especially true in team sports such as the most popular one worldwide: soccer. We investigated reward processing upon scoring a soccer goal in a standard two-versus-one situation and in comparison to winning in a monetary incentive task. The results show a strong overlap in brain activity between the two conditions in established reward regions of the mesolimbic dopaminergic system, including the ventral striatum and ventromedial pre-frontal cortex. The three main components of reward-associated learning i.e. reward probability (RP), reward reception (RR) and reward prediction errors (RPE) showed highly similar activation in both con-texts, with only the RR and RPE components displaying overlapping reward activity. Passing and shooting behavior did not correlate with individual egoism scores, but we observe a positive correlation be-tween egoism and activity in the left middle frontal gyrus upon scoring after a pass versus a direct shot. Our findings suggest that rewards in the context of soccer and monetary incentives are based on similar neural processes. PMID:25875594

Mask-induced aberration in EUV lithography

Science.gov (United States)

Nakajima, Yumi; Sato, Takashi; Inanami, Ryoichi; Nakasugi, Tetsuro; Higashiki, Tatsuhiko

2009-04-01

We estimated aberrations using Zernike sensitivity analysis. We found the difference of the tolerated aberration with line direction for illumination. The tolerated aberration of perpendicular line for illumination is much smaller than that of parallel line. We consider this difference to be attributable to the mask 3D effect. We call it mask-induced aberration. In the case of the perpendicular line for illumination, there was a difference in CD between right line and left line without aberration. In this report, we discuss the possibility of pattern formation in NA 0.25 generation EUV lithography tool. In perpendicular pattern for EUV light, the dominant part of aberration is mask-induced aberration. In EUV lithography, pattern correction based on the mask topography effect will be more important.

Neuroendocrinology and brain imaging of reward in eating disorders: A possible key to the treatment of anorexia nervosa and bulimia nervosa.

Science.gov (United States)

Monteleone, Alessio Maria; Castellini, Giovanni; Volpe, Umberto; Ricca, Valdo; Lelli, Lorenzo; Monteleone, Palmiero; Maj, Mario

2018-01-03

Anorexia nervosa and bulimia nervosa are severe eating disorders whose etiopathogenesis is still unknown. Clinical features suggest that eating disorders may develop as reward-dependent syndromes, since eating less food is perceived as rewarding in anorexia nervosa while consumption of large amounts of food during binge episodes in bulimia nervosa aims at reducing the patient's negative emotional states. Therefore, brain reward mechanisms have been a major focus of research in the attempt to contribute to the comprehension of the pathophysiology of these disorders. Structural brain imaging data provided the evidence that brain reward circuits may be altered in patients with anorexia or bulimia nervosa. Similarly, functional brain imaging studies exploring the activation of brain reward circuits by food stimuli as well as by stimuli recognized to be potentially rewarding for eating disordered patients, such as body image cues or stimuli related to food deprivation and physical hyperactivity, showed several dysfunctions in ED patients. Moreover, very recently, it has been demonstrated that some of the biochemical homeostatic modulators of eating behavior are also implicated in the regulation of food-related and non-food-related reward, representing a possible link between the aberrant behaviors of ED subjects and their hypothesized deranged reward processes. In particular, changes in leptin and ghrelin occur in patients with anorexia or bulimia nervosa and have been suggested to represent not only homeostatic adaptations to an altered energy balance but to contribute also to the acquisition and/or maintenance of persistent starvation, binge eating and physical hyperactivity, which are potentially rewarding for ED patients. On the basis of such findings new pathogenetic models of EDs have been proposed, and these models may provide new theoretical basis for the development of innovative treatment strategies, either psychological and pharmacological, with the aim to

Reward and relief craving tendencies in patients with alcohol use disorders: results from the PREDICT study.

Science.gov (United States)

Glöckner-Rist, Angelika; Lémenager, Tagrid; Mann, Karl

2013-02-01

Previous research suggests that patients' tendencies toward either reward or relief craving are distinct continuous factorial dimensions of craving for alcohol. According to these tendencies patients with alcohol use disorders (AUD) might also be allocated into distinct subgroups. In personalized treatment, patients of such different subgroups might respond differently to various psychotherapeutic and pharmacological interventions aimed at relapse prevention. To establish that the items of the subscale Temptation to Drink of the Alcohol Abstinence Self-Efficacy Scale (AASE) capture two continuous dimensions of reward and relief craving, and that they allow the identification of respective discrete class factors and subgroups of patients with AUD. Nonlinear confirmatory factor analysis (CFA) and latent class factor analysis (LCFA) were performed with data from 426 detoxified patients with AUD. The validity of continuous relief and reward dimensions, discrete class factors, and subtypes with different craving tendencies was established by including past drinking in positive and negative settings, gender, trait anxiety and perceived stress as covariates in the finally accepted CFA and LCFA measurement models. The AASE temptation items formed two continuous relief and reward craving factors. They also associated themselves to two binary class factors, which defined four craving subgroups. Two of them (21% and 29% of patients) were characterized by high levels of either reward or relief craving tendencies. A third subgroup (31%) rated both tendencies in an equal high measure, while a fourth (18%) reported almost no craving tendencies at all. Past drinking in negative and positive settings was significantly associated with relief or reward craving tendencies. Male patients reported reward drinking more frequently than female patients. Trait anxiety was positively related only to the relief craving tendency. Unexpectedly, patients' level of perceived stress was associated

Imbalance in the sensitivity to different types of rewards in pathological gambling.

Science.gov (United States)

Sescousse, Guillaume; Barbalat, Guillaume; Domenech, Philippe; Dreher, Jean-Claude

2013-08-01

Pathological gambling is an addictive disorder characterized by a persistent and compulsive desire to engage in gambling activities. This maladaptive behaviour has been suggested to result from a decreased sensitivity to experienced rewards, regardless of reward type. Alternatively, pathological gambling might reflect an imbalance in the sensitivity to monetary versus non-monetary incentives. To directly test these two hypotheses, we examined how the brain reward circuit of pathological gamblers responds to different types of rewards. Using functional magnetic resonance imaging, we compared the brain responses of 18 pathological gamblers and 20 healthy control subjects while they engaged in a simple incentive task manipulating both monetary and visual erotic rewards. During reward anticipation, the ventral striatum of pathological gamblers showed a differential response to monetary versus erotic cues, essentially driven by a blunted reactivity to cues predicting erotic stimuli. This differential response correlated with the severity of gambling symptoms and was paralleled by a reduced behavioural motivation for erotic rewards. During reward outcome, a posterior orbitofrontal cortex region, responding to erotic rewards in both groups, was further recruited by monetary gains in pathological gamblers but not in control subjects. Moreover, while ventral striatal activity correlated with subjective ratings assigned to monetary and erotic rewards in control subjects, it only correlated with erotic ratings in gamblers. Our results point to a differential sensitivity to monetary versus non-monetary rewards in pathological gambling, both at the motivational and hedonic levels. Such an imbalance might create a bias towards monetary rewards, potentially promoting addictive gambling behaviour.

Commitment to Self-Rewards

OpenAIRE

Koch, Alexander K.; Nafziger, Julia

2009-01-01

Self-administered rewards are ubiquitous. They serve as incentives for personal accomplish¬ments and are widely recommended as tools for overcoming self-control problems. However, it seems puzzling why self-rewards can work: the prospect of a reward has a motivating force only if the threat of self-denial of the reward after low performance is credible. We explain how a rational forward-looking individual may achieve commitment to self-rewards, by applying Köszegi and Rabin's (2006) model of ...

Adaptive neural reward processing during anticipation and receipt of monetary rewards in mindfulness meditators.

Science.gov (United States)

Kirk, Ulrich; Brown, Kirk Warren; Downar, Jonathan

2015-05-01

Reward seeking is ubiquitous and adaptive in humans. But excessive reward seeking behavior, such as chasing monetary rewards, may lead to diminished subjective well-being. This study examined whether individuals trained in mindfulness meditation show neural evidence of lower susceptibility to monetary rewards. Seventy-eight participants (34 meditators, 44 matched controls) completed the monetary incentive delay task while undergoing functional magnetic resonance imaging. The groups performed equally on the task, but meditators showed lower neural activations in the caudate nucleus during reward anticipation, and elevated bilateral posterior insula activation during reward anticipation. Meditators also evidenced reduced activations in the ventromedial prefrontal cortex during reward receipt compared with controls. Connectivity parameters between the right caudate and bilateral anterior insula were attenuated in meditators during incentive anticipation. In summary, brain regions involved in reward processing-both during reward anticipation and receipt of reward-responded differently in mindfulness meditators than in nonmeditators, indicating that the former are less susceptible to monetary incentives. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Transitionality in addiction: A "temporal continuum" hypotheses involving the aberrant motivation, the hedonic dysregulation, and the aberrant learning.

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Patrono, Enrico; Gasbarri, Antonella; Tomaz, Carlos; Nishijo, Hisao

2016-08-01

Addiction is a chronic compulsion and relapsing disorder. It involves several brain areas and circuits, which encode vary functions such as reward, motivation, and memory. Drug addiction is defined as a "pathological pattern of use of a substance", characterized by the loss of control on drug-taking-related behaviors, the pursuance of those behaviors even in the presence of negative consequences, and a strong motivated activity to assume substances. Three different theories guide experimental research on drug addiction. Each of these theories consider singles features, such as an aberrant motivation, a hedonic dysregulation, and an aberrant habit learning as the main actor to explain the entire process of the addictive behaviors. The major goal of this study is to present a new hypotheses of transitionality from a controlled use to abuse of addictive substances trough the overview of the three different theories, considering all the single features of each single theory together on the same "temporal continuum" from use to abuse of addictive substances. Recently, it has been suggested that common neural systems may be activated by natural and pharmacological stimuli, raising the hypotheses that binge-eating disorders could be considered as addictive behaviors. The second goal of this study is to present evidences in order to highlight a possible psycho-bio-physiological superimposition between drug and "food addiction". Finally, interesting questions are brought up starting from last findings about a theoretical/psycho-bio-physiological superimposition between drug and "food addiction" and their possibly same transitionality along the same "temporal continuum" from use to abuse of addictive substances in order to investigate new therapeutic strategies based on new therapeutic strategies based on the individual moments characterizing the transition from the voluntary intake of substances to the maladaptive addictive behavior. Copyright © 2016. Published by Elsevier

Distinct Roles for the Amygdala and Orbitofrontal Cortex in Representing the Relative Amount of Expected Reward.

Science.gov (United States)

Saez, Rebecca A; Saez, Alexandre; Paton, Joseph J; Lau, Brian; Salzman, C Daniel

2017-07-05

The same reward can possess different motivational meaning depending upon its magnitude relative to other rewards. To study the neurophysiological mechanisms mediating assignment of motivational meaning, we recorded the activity of neurons in the amygdala and orbitofrontal cortex (OFC) of monkeys during a Pavlovian task in which the relative amount of liquid reward associated with one conditioned stimulus (CS) was manipulated by changing the reward amount associated with a second CS. Anticipatory licking tracked relative reward magnitude, implying that monkeys integrated information about recent rewards to adjust the motivational meaning of a CS. Upon changes in relative reward magnitude, neural responses to reward-predictive cues updated more rapidly in OFC than amygdala, and activity in OFC but not the amygdala was modulated by recent reward history. These results highlight a distinction between the amygdala and OFC in assessing reward history to support the flexible assignment of motivational meaning to sensory cues. Copyright © 2017 Elsevier Inc. All rights reserved.

Social anxiety, acute social stress, and reward parameters interact to predict risky decision-making among adolescents.

Science.gov (United States)

Richards, Jessica M; Patel, Nilam; Daniele-Zegarelli, Teresa; MacPherson, Laura; Lejuez, C W; Ernst, Monique

2015-01-01

Risk-taking behavior increases during adolescence, leading to potentially disastrous consequences. Social anxiety emerges in adolescence and may compound risk-taking propensity, particularly during stress and when reward potential is high. However, the manner in which social anxiety, stress, and reward parameters interact to impact adolescent risk-taking is unclear. To clarify this question, a community sample of 35 adolescents (15-18yo), characterized as having high or low social anxiety, participated in a study over two separate days, during each of which they were exposed to either a social stress or a control condition, while performing a risky decision-making task. The task manipulated, orthogonally, reward magnitude and probability across trials. Three findings emerged. First, reward magnitude had a greater impact on the rate of risky decisions in high social anxiety (HSA) than low social anxiety (LSA) adolescents. Second, reaction times (RTs) were similar during the social stress and the control conditions for the HSA group, whereas the LSA group's RTs differed between conditions. Third, HSA adolescents showed the longest RTs on the most negative trials. These findings suggest that risk-taking in adolescents is modulated by context and reward parameters differentially as a function of social anxiety. Published by Elsevier Ltd.

Social Anxiety, Acute Social Stress, and Reward Parameters Interact to Predict Risky Decision-Making among Adolescents

Science.gov (United States)

Richards, Jessica M.; Patel, Nilam; Daniele, Teresa; MacPherson, Laura; Lejuez, C.W.; Ernst, Monique

2014-01-01

Risk-taking behavior increases during adolescence, leading to potentially disastrous consequences. Social anxiety emerges in adolescence and may compound risk-taking propensity, particularly during stress and when reward potential is high. However, the manner in which social anxiety, stress, and reward parameters interact to impact adolescent risk-taking is unclear. To clarify this question, a community sample of 35 adolescents (15 to 18 yo), characterized as having high or low social anxiety, participated in a 2-day study, during each of which they were exposed to either a social stress or a control condition, while performing a risky decision-making task. The task manipulated, orthogonally, reward magnitude and probability across trials. Three findings emerged. First, reward magnitude had a greater impact on the rate of risky decisions in high social anxiety (HSA) than low social anxiety (LSA) adolescents. Second, reaction times (RTs) were similar during the social stress and the control conditions for the HSA group, whereas the LSA group’s RTs differed between conditions. Third, HSA adolescents showed the longest RTs on the most negative trials. These findings suggest that risk-taking in adolescents is modulated by context and reward parameters differentially as a function of social anxiety. PMID:25465884

Camera processing with chromatic aberration.

Science.gov (United States)

Korneliussen, Jan Tore; Hirakawa, Keigo

2014-10-01

Since the refractive index of materials commonly used for lens depends on the wavelengths of light, practical camera optics fail to converge light to a single point on an image plane. Known as chromatic aberration, this phenomenon distorts image details by introducing magnification error, defocus blur, and color fringes. Though achromatic and apochromatic lens designs reduce chromatic aberration to a degree, they are complex and expensive and they do not offer a perfect correction. In this paper, we propose a new postcapture processing scheme designed to overcome these problems computationally. Specifically, the proposed solution is comprised of chromatic aberration-tolerant demosaicking algorithm and post-demosaicking chromatic aberration correction. Experiments with simulated and real sensor data verify that the chromatic aberration is effectively corrected.

Random reward priming is task-contingent: The robustness of the 1-trial reward priming effect

Directory of Open Access Journals (Sweden)

Árni Gunnar Ásgeirsson

2014-04-01

Full Text Available Consistent financial reward of particular features influences the allocation of visual attention in many ways. More surprising are 1-trial reward priming effects on attention where reward schedules are random and reward on one trial influences attentional allocation on the next. Those findings are thought to reflect that rewarded features become more salient than unrewarded ones on the subsequent trial. Here we attempt to conceptually replicate this effect, testing its generalizability. In three versions of an analogous paradigm to the additional singleton paradigm involving singleton search for a Gabor patch of odd spatial frequency we found no evidence of reward priming, while we only partially replicate the reward priming in the exact original paradigm tested by Hickey and colleagues. The results cast doubt on the proposal that random reward enhances salience, suggested in the original papers, and highlight the need for a more nuanced account. In many other paradigms reward effects have been found to progress gradually, becoming stronger as they build up, and we argue that for robust reward priming, reward schedules need to be more consistent than in the original 1-trial reward priming paradigm.

[Psychosocial factors at work and cardiovascular diseases: contribution of the Effort-Reward Imbalance model].

Science.gov (United States)

Niedhammer, I; Siegrist, J

1998-11-01

The effect of psychosocial factors at work on health, especially cardiovascular health, has given rise to growing concern in occupational epidemiology over the last few years. Two theoretical models, Karasek's model and the Effort-Reward Imbalance model, have been developed to evaluate psychosocial factors at work within specific conceptual frameworks in an attempt to take into account the serious methodological difficulties inherent in the evaluation of such factors. Karasek's model, the most widely used model, measures three factors: psychological demands, decision latitude and social support at work. Many studies have shown the predictive effects of these factors on cardiovascular diseases independently of well-known cardiovascular risk factors. More recently, the Effort-Reward Imbalance model takes into account the role of individual coping characteristics which was neglected in the Karasek model. The effort-reward imbalance model focuses on the reciprocity of exchange in occupational life where high-cost/low-gain conditions are considered particularly stressful. Three dimensions of rewards are distinguished: money, esteem and gratifications in terms of promotion prospects and job security. Some studies already support that high-effort/low reward-conditions are predictive of cardiovascular diseases.

A correction term for the covariance of renewal-reward processes with multivariate rewards

NARCIS (Netherlands)

Patch, B.; Nazarathy, Y.; Taimre, T.

We consider a renewal-reward process with multivariate rewards. Such a process is constructed from an i.i.d. sequence of time periods, to each of which there is associated a multivariate reward vector. The rewards in each time period may depend on each other and on the period length, but not on the

Nucleus accumbens mediates relative motivation for rewards in the absence of choice

Directory of Open Access Journals (Sweden)

John A Clithero

2011-08-01

Full Text Available To dissociate a choice from its antecedent neural states, motivation associated with the expected outcome must be captured in the absence of choice. Yet, the neural mechanisms that mediate behavioral idiosyncrasies in motivation, particularly with regard to complex economic preferences, are rarely examined in situations without overt decisions. We employed functional magnetic resonance imaging (fMRI in a large sample of participants while they anticipated earning rewards from two different modalities: monetary and candy rewards. An index for relative motivation toward different reward types was constructed using reaction times to the target for earning rewards. Activation in the nucleus accumbens (NAcc and anterior insula (aINS predicted individual variation in relative motivation between our reward modalities. NAcc activation, however, mediated the effects of aINS, indicating the NAcc is the likely source of this relative weighting. These results demonstrate that neural idiosyncrasies in reward efficacy exist even in the absence of explicit choices, and extend the role of NAcc as a critical brain region for such choice-free motivation.

Quantifying individual variation in the propensity to attribute incentive salience to reward cues.

Directory of Open Access Journals (Sweden)

Paul J Meyer

Full Text Available If reward-associated cues acquire the properties of incentive stimuli they can come to powerfully control behavior, and potentially promote maladaptive behavior. Pavlovian incentive stimuli are defined as stimuli that have three fundamental properties: they are attractive, they are themselves desired, and they can spur instrumental actions. We have found, however, that there is considerable individual variation in the extent to which animals attribute Pavlovian incentive motivational properties ("incentive salience" to reward cues. The purpose of this paper was to develop criteria for identifying and classifying individuals based on their propensity to attribute incentive salience to reward cues. To do this, we conducted a meta-analysis of a large sample of rats (N = 1,878 subjected to a classic Pavlovian conditioning procedure. We then used the propensity of animals to approach a cue predictive of reward (one index of the extent to which the cue was attributed with incentive salience, to characterize two behavioral phenotypes in this population: animals that approached the cue ("sign-trackers" vs. others that approached the location of reward delivery ("goal-trackers". This variation in Pavlovian approach behavior predicted other behavioral indices of the propensity to attribute incentive salience to reward cues. Thus, the procedures reported here should be useful for making comparisons across studies and for assessing individual variation in incentive salience attribution in small samples of the population, or even for classifying single animals.

Withholding a Reward-driven Action: Studies of the Rise and Fall of Motor Activation and the Effect of Cognitive Depletion.

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Freeman, Scott M; Aron, Adam R

2016-02-01

Controlling an inappropriate response tendency in the face of a reward-predicting stimulus likely depends on the strength of the reward-driven activation, the strength of a putative top-down control process, and their relative timing. We developed a rewarded go/no-go paradigm to investigate such dynamics. Participants made rapid responses (on go trials) to high versus low reward-predicting stimuli and sometimes had to withhold responding (on no-go trials) in the face of the same stimuli. Behaviorally, for high versus low reward stimuli, responses were faster on go trials, and there were more errors of commission on no-go trials. We used single-pulse TMS to map out the corticospinal excitability dynamics, especially on no-go trials where control is needed. For successful no-go trials, there was an early rise in motor activation that was then sharply reduced beneath baseline. This activation-reduction pattern was more pronounced for high- versus low-reward trials and in individuals with greater motivational drive for reward. A follow-on experiment showed that, when participants were fatigued by an effortful task, they made more errors on no-go trials for high versus low reward stimuli. Together, these studies show that, when a response is inappropriate, reward-predicting stimuli induce early motor activation, followed by a top-down effortful control process (which we interpret as response suppression) that depends on the strength of the preceding activation. Our findings provide novel information about the activation-suppression dynamics during control over reward-driven actions, and they illustrate how fatigue or depletion leads to control failures in the face of reward.

Motivating forces of human actions. Neuroimaging reward and social interaction.

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Walter, Henrik; Abler, Birgit; Ciaramidaro, Angela; Erk, Susanne

2005-11-15

In neuroeconomics, reward and social interaction are central concepts to understand what motivates human behaviour. Both concepts are investigated in humans using neuroimaging methods. In this paper, we provide an overview about these results and discuss their relevance for economic behaviour. For reward it has been shown that a system exists in humans that is involved in predicting rewards and thus guides behaviour, involving a circuit including the striatum, the orbitofrontal cortex and the amygdala. Recent studies on social interaction revealed a mentalizing system representing the mental states of others. A central part of this system is the medial prefrontal cortex, in particular the anterior paracingulate cortex. The reward as well as the mentalizing system is engaged in economic decision-making. We will discuss implications of this study for neuromarketing as well as general implications of these results that may help to provide deeper insights into the motivating forces of human behaviour.

Selectivity in Postencoding Connectivity with High-Level Visual Cortex Is Associated with Reward-Motivated Memory.

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Murty, Vishnu P; Tompary, Alexa; Adcock, R Alison; Davachi, Lila

2017-01-18

Reward motivation has been demonstrated to enhance declarative memory by facilitating systems-level consolidation. Although high-reward information is often intermixed with lower reward information during an experience, memory for high value information is prioritized. How is this selectivity achieved? One possibility is that postencoding consolidation processes bias memory strengthening to those representations associated with higher reward. To test this hypothesis, we investigated the influence of differential reward motivation on the selectivity of postencoding markers of systems-level memory consolidation. Human participants encoded intermixed, trial-unique memoranda that were associated with either high or low-value during fMRI acquisition. Encoding was interleaved with periods of rest, allowing us to investigate experience-dependent changes in connectivity as they related to later memory. Behaviorally, we found that reward motivation enhanced 24 h associative memory. Analysis of patterns of postencoding connectivity showed that, even though learning trials were intermixed, there was significantly greater connectivity with regions of high-level, category-selective visual cortex associated with high-reward trials. Specifically, increased connectivity of category-selective visual cortex with both the VTA and the anterior hippocampus predicted associative memory for high- but not low-reward memories. Critically, these results were independent of encoding-related connectivity and univariate activity measures. Thus, these findings support a model by which the selective stabilization of memories for salient events is supported by postencoding interactions with sensory cortex associated with reward. Reward motivation is thought to promote memory by supporting memory consolidation. Yet, little is known as to how brain selects relevant information for subsequent consolidation based on reward. We show that experience-dependent changes in connectivity of both the

Extending overjustification: the effect of perceived reward-giver intention on response to rewards.

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Forehand, M R

2000-12-01

The perceived intention model incorporates a new moderator, beliefs about reward-giver intention, into the overjustification paradigm. In 2 simulated shopping studies featuring products paired with promotional rewards, consumers who believed the marketer was promotion focused (reward used to encourage purchase) reported lower purchase intentions and brand attitudes for promoted products after promotion, whereas consumers who believed the marketer was reward focused (promotion used to distribute the reward) showed no attitude change. Promotion-focus beliefs lowered attitudes by heightening the contingency between the promotion and purchase and thereby increasing the perceived causal role of the reward. This effect was contingent on initial behavior--postpromotion attitude change occurred for consumers who actively engaged in product decisions but not for consumers who passively observed the choice sets.

Stress and reward processing in bipolar disorder: an fMRI study

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Berghorst, Lisa H; Kumar, Poornima; Greve, Doug N; Deckersbach, Thilo; Ongur, Dost; Dutra, Sunny; Pizzagalli, Diego A

2016-01-01

Objectives A link between negative life stress and the onset of mood episodes in bipolar disorder (BD) has been established, but processes underlying such a link remain unclear. Growing evidence suggests that stress can negatively affect reward processing and related neurobiological substrates, indicating that a dysregulated reward system may provide a partial explanation. The aim of this study was to test the impact of stress on reward-related neural functioning in BD. Methods Thirteen euthymic or mildly depressed individuals with BD and 15 controls performed a Monetary Incentive Delay task while undergoing functional magnetic resonance imaging during no-stress and stress (negative psychosocial stressor involving poor performance feedback and threat of monetary deductions) conditions. Results In hypothesis-driven region-of- interest-based analyses, a significant group by condition interaction emerged in the amygdala during reward anticipation. Relative to controls, while anticipating a potential reward, subjects with BD were characterized by amygdalar hyperactivation in the no-stress condition but hypoactivation during stress. Moreover, relative to controls, subjects with BD had significantly larger amygdala volumes. After controlling for structural differences, the effects of stress on amygdalar function remained, whereas groups no longer differed during the no-stress condition. During reward consumption, a group by condition interaction emerged in the putamen due to increased putamen activation to rewards in participants with BD during stress, but an opposite pattern in controls. Conclusions Overall, findings highlight possible impairments in using reward-predicting cues to adaptively engage in goal-directed actions in BD, combined with stress-induced hypersensitivity to reward consumption. Potential clinical implications are discussed. PMID:27870507

Neural Processing of Calories in Brain Reward Areas Can be Modulated by Reward Sensitivity

NARCIS (Netherlands)

van Rijn, Inge; Griffioen-Roose, Sanne; de Graaf, Cees; Smeets, Paul A M

A food's reward value is dependent on its caloric content. Furthermore, a food's acute reward value also depends on hunger state. The drive to obtain rewards (reward sensitivity), however, differs between individuals. Here, we assessed the association between brain responses to calories in the mouth

Analyzing the microfoundations of human violence in the DRC - intrinsic and extrinsic rewards and the prediction of appetitive aggression.

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Haer, Roos; Banholzer, Lilli; Elbert, Thomas; Weierstall, Roland

2013-05-17

Civil wars are characterized by intense forms of violence, such as torture, maiming and rape. Political scientists suggest that this form of political violence is fostered through the provision of particular intrinsic and extrinsic rewards to combatants. In the field of psychology, the perpetration of this kind of cruelty is observed to be positively linked to appetitive aggression. Over time, combatants start to enjoy the fights and even the perpetration of atrocities. In this study, we examine how receiving rewards (intrinsic versus extrinsic) influence the level of appetitive aggression exhibited by former combatants. We surveyed 95 former combatants in the eastern provinces of the Democratic Republic of the Congo. Linear regression analyses reveal that intrinsic as well as extrinsic rewards are linked to the former combatants' Appetitive Aggression score. However, this relationship is partly determined by the way in which combatants are recruited: While abducted combatants seem to react more strongly to extrinsic rewards, the score of those that joined voluntarily is primarily determined by intrinsic rewards. We conclude that receiving rewards influence the level of appetitive aggression. However, which type of rewards (intrinsic versus extrinsic) is of most importance is determined by the way combatants are recruited.

Aberrant methylation of cell-free circulating DNA in plasma predicts poor outcome in diffuse large B cell lymphoma

DEFF Research Database (Denmark)

Sommer Kristensen, Lasse; Hansen, Jakob Werner; Kristensen, Søren Sommer

2016-01-01

BACKGROUND: The prognostic value of aberrant DNA methylation of cell-free circulating DNA in plasma has not previously been evaluated in diffuse large B cell lymphoma (DLBCL). The aim of this study was to investigate if aberrant promoter DNA methylation can be detected in plasma from DLBCL patients...

Artificial neural network for the determination of Hubble Space Telescope aberration from stellar images

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Barrett, Todd K.; Sandler, David G.

1993-01-01

An artificial-neural-network method, first developed for the measurement and control of atmospheric phase distortion, using stellar images, was used to estimate the optical aberration of the Hubble Space Telescope. A total of 26 estimates of distortion was obtained from 23 stellar images acquired at several secondary-mirror axial positions. The results were expressed as coefficients of eight orthogonal Zernike polynomials: focus through third-order spherical. For all modes other than spherical the measured aberration was small. The average spherical aberration of the estimates was -0.299 micron rms, which is in good agreement with predictions obtained when iterative phase-retrieval algorithms were used.

Reward Draws the Eye, Uncertainty Holds the Eye: Associative Learning Modulates Distractor Interference in Visual Search

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Stephan Koenig

2017-07-01

Full Text Available Stimuli in our sensory environment differ with respect to their physical salience but moreover may acquire motivational salience by association with reward. If we repeatedly observed that reward is available in the context of a particular cue but absent in the context of another cue the former typically attracts more attention than the latter. However, we also may encounter cues uncorrelated with reward. A cue with 50% reward contingency may induce an average reward expectancy but at the same time induces high reward uncertainty. In the current experiment we examined how both values, reward expectancy and uncertainty, affected overt attention. Two different colors were established as predictive cues for low reward and high reward respectively. A third color was followed by high reward on 50% of the trials and thus induced uncertainty. Colors then were introduced as distractors during search for a shape target, and we examined the relative potential of the color distractors to capture and hold the first fixation. We observed that capture frequency corresponded to reward expectancy while capture duration corresponded to uncertainty. The results may suggest that within trial reward expectancy is represented at an earlier time window than uncertainty.

Reward salience and risk aversion underlie differential ACC activity in substance dependence.

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Alexander, William H; Fukunaga, Rena; Finn, Peter; Brown, Joshua W

2015-01-01

The medial prefrontal cortex, especially the dorsal anterior cingulate cortex (ACC), has long been implicated in cognitive control and error processing. Although the association between ACC and behavior has been established, it is less clear how ACC contributes to dysfunctional behavior such as substance dependence. Evidence from neuroimaging studies investigating ACC function in substance users is mixed, with some studies showing disengagement of ACC in substance dependent individuals (SDs), while others show increased ACC activity related to substance use. In this study, we investigate ACC function in SDs and healthy individuals performing a change signal task for monetary rewards. Using a priori predictions derived from a recent computational model of ACC, we find that ACC activity differs between SDs and controls in factors related to reward salience and risk aversion between SDs and healthy individuals. Quantitative fits of a computational model to fMRI data reveal significant differences in best fit parameters for reward salience and risk preferences. Specifically, the ACC in SDs shows greater risk aversion, defined as concavity in the utility function, and greater attention to rewards relative to reward omission. Furthermore, across participants risk aversion and reward salience are positively correlated. The results clarify the role that ACC plays in both the reduced sensitivity to omitted rewards and greater reward valuation in SDs. Clinical implications of applying computational modeling in psychiatry are also discussed.

Motivation and reward systems

NARCIS (Netherlands)

van Eerde, W.; Vodosek, M.; den Hartog, D.N.; McNett, J.M.

2014-01-01

Reward systems are identified as one of the human resource management (HRM) practices that may impact motivation. Reward systems may consist of several components, including financial and nonfinancial rewards, in fixed and variable amounts. Reinforcement, expectancy, and equity principles are

Major depressive disorder is characterized by greater reward network activation to monetary than pleasant image rewards.

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Smoski, Moria J; Rittenberg, Alison; Dichter, Gabriel S

2011-12-30

Anhedonia, the loss of interest or pleasure in normally rewarding activities, is a hallmark feature of unipolar Major Depressive Disorder (MDD). A growing body of literature has identified frontostriatal dysfunction during reward anticipation and outcomes in MDD. However, no study to date has directly compared responses to different types of rewards such as pleasant images and monetary rewards in MDD. To investigate the neural responses to monetary and pleasant image rewards in MDD, a modified Monetary Incentive Delay task was used during functional magnetic resonance imaging to assess neural responses during anticipation and receipt of monetary and pleasant image rewards. Participants included nine adults with MDD and 13 affectively healthy controls. The MDD group showed lower activation than controls when anticipating monetary rewards in right orbitofrontal cortex and subcallosal cortex, and when anticipating pleasant image rewards in paracingulate and supplementary motor cortex. The MDD group had relatively greater activation in right putamen when anticipating monetary versus pleasant image rewards, relative to the control group. Results suggest reduced reward network activation in MDD when anticipating rewards, as well as relatively greater hypoactivation to pleasant image than monetary rewards. 2011 Elsevier Ireland Ltd. All rights reserved.

Correlations between corneal and total wavefront aberrations

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Mrochen, Michael; Jankov, Mirko; Bueeler, Michael; Seiler, Theo

2002-06-01

Purpose: Corneal topography data expressed as corneal aberrations are frequently used to report corneal laser surgery results. However, the optical image quality at the retina depends on all optical elements of the eye such as the human lens. Thus, the aim of this study was to investigate the correlations between the corneal and total wavefront aberrations and to discuss the importance of corneal aberrations for representing corneal laser surgery results. Methods: Thirty three eyes of 22 myopic subjects were measured with a corneal topography system and a Tschernig-type wavefront analyzer after the pupils were dilated to at least 6 mm in diameter. All measurements were centered with respect to the line of sight. Corneal and total wavefront aberrations were calculated up to the 6th Zernike order in the same reference plane. Results: Statistically significant correlations (p the corneal and total wavefront aberrations were found for the astigmatism (C3,C5) and all 3rd Zernike order coefficients such as coma (C7,C8). No statistically significant correlations were found for all 4th to 6th order Zernike coefficients except for the 5th order horizontal coma C18 (p equals 0.003). On average, all Zernike coefficients for the corneal aberrations were found to be larger compared to Zernike coefficients for the total wavefront aberrations. Conclusions: Corneal aberrations are only of limited use for representing the optical quality of the human eye after corneal laser surgery. This is due to the lack of correlation between corneal and total wavefront aberrations in most of the higher order aberrations. Besides this, the data present in this study yield towards an aberration balancing between corneal aberrations and the optical elements within the eye that reduces the aberration from the cornea by a certain degree. Consequently, ideal customized ablations have to take both, corneal and total wavefront aberrations, into consideration.

Analyzing the microfoundations of human violence in the DRC - intrinsic and extrinsic rewards and the prediction of appetitive aggression

Science.gov (United States)

2013-01-01

Background Civil wars are characterized by intense forms of violence, such as torture, maiming and rape. Political scientists suggest that this form of political violence is fostered through the provision of particular intrinsic and extrinsic rewards to combatants. In the field of psychology, the perpetration of this kind of cruelty is observed to be positively linked to appetitive aggression. Over time, combatants start to enjoy the fights and even the perpetration of atrocities. In this study, we examine how receiving rewards (intrinsic versus extrinsic) influence the level of appetitive aggression exhibited by former combatants. Method We surveyed 95 former combatants in the eastern provinces of the Democratic Republic of the Congo. Results Linear regression analyses reveal that intrinsic as well as extrinsic rewards are linked to the former combatants’ Appetitive Aggression score. However, this relationship is partly determined by the way in which combatants are recruited: While abducted combatants seem to react more strongly to extrinsic rewards, the score of those that joined voluntarily is primarily determined by intrinsic rewards. Conclusions We conclude that receiving rewards influence the level of appetitive aggression. However, which type of rewards (intrinsic versus extrinsic) is of most importance is determined by the way combatants are recruited. PMID:23683122

Frontopolar cortical inefficiency may underpin reward and working memory dysfunction in bipolar disorder.

Science.gov (United States)

Jogia, Jigar; Dima, Danai; Kumari, Veena; Frangou, Sophia

2012-12-01

Emotional dysregulation in bipolar disorder is thought to arise from dysfunction within prefrontal cortical regions involved in cognitive control coupled with increased or aberrant activation within regions engaged in emotional processing. The aim of this study was to determine the common and distinct patterns of functional brain abnormalities during reward and working memory processing in patients with bipolar disorder. Participants were 36 euthymic bipolar disorder patients and 37 healthy comparison subjects matched for age, sex and IQ. Functional magnetic resonance imaging (fMRI) was conducted during the Iowa Gambling Task (IGT) and the n-back working memory task. During both tasks, patients with bipolar disorder demonstrated a pattern of inefficient engagement within the ventral frontopolar prefrontal cortex with evidence of segregation along the medial-lateral dimension for reward and working memory processing, respectively. Moreover, patients also showed greater activation in the anterior cingulate cortex during the Iowa Gambling Task and in the insula during the n-back task. Our data implicate ventral frontopolar dysfunction as a core abnormality underpinning bipolar disorder and confirm that overactivation in regions involved in emotional arousal is present even in tasks that do not typically engage emotional systems.

A Simple Network Architecture Accounts for Diverse Reward Time Responses in Primary Visual Cortex.

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Huertas, Marco A; Hussain Shuler, Marshall G; Shouval, Harel Z

2015-09-16

Many actions performed by animals and humans depend on an ability to learn, estimate, and produce temporal intervals of behavioral relevance. Exemplifying such learning of cued expectancies is the observation of reward-timing activity in the primary visual cortex (V1) of rodents, wherein neural responses to visual cues come to predict the time of future reward as behaviorally experienced in the past. These reward-timing responses exhibit significant heterogeneity in at least three qualitatively distinct classes: sustained increase or sustained decrease in firing rate until the time of expected reward, and a class of cells that reach a peak in firing at the expected delay. We elaborate upon our existing model by including inhibitory and excitatory units while imposing simple connectivity rules to demonstrate what role these inhibitory elements and the simple architectures play in sculpting the response dynamics of the network. We find that simply adding inhibition is not sufficient for obtaining the different distinct response classes, and that a broad distribution of inhibitory projections is necessary for obtaining peak-type responses. Furthermore, although changes in connection strength that modulate the effects of inhibition onto excitatory units have a strong impact on the firing rate profile of these peaked responses, the network exhibits robustness in its overall ability to predict the expected time of reward. Finally, we demonstrate how the magnitude of expected reward can be encoded at the expected delay in the network and how peaked responses express this reward expectancy. Heterogeneity in single-neuron responses is a common feature of neuronal systems, although sometimes, in theoretical approaches, it is treated as a nuisance and seldom considered as conveying a different aspect of a signal. In this study, we focus on the heterogeneous responses in the primary visual cortex of rodents trained with a predictable delayed reward time. We describe under what

Neurological Correlates of Reward Responding in Adolescents With and Without Externalizing Behavior Disorders

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Gatzke-Kopp, Lisa M.; Beauchaine, Theodore P.; Shannon, Katherine E.; Chipman, Jane; Fleming, Andrew P.; Crowell, Sheila E.; Liang, Olivia; Aylward, Elizabeth; Johnson, L. Clark

2009-01-01

Opposing theories of striatal hyper- and hypodopaminergic functioning have been suggested in the pathophysiology of externalizing behavior disorders. To test these competing theories, the authors used functional MRI to evaluate neural activity during a simple reward task in 12- to 16-year-old boys with attention-deficit/hyperactivity disorder and/or conduct disorder (n = 19) and in controls with no psychiatric condition (n = 11). The task proceeded in blocks during which participants received either (a) monetary incentives for correct responses or (b) no rewards for correct responses. Controls exhibited striatal activation only during reward, shifting to anterior cingulate activation during nonreward. In contrast, externalizing adolescents exhibited striatal activation during both reward and nonreward. Externalizing psychopathology appears to be characterized by deficits in processing the omission of predicted reward, which may render behaviors that are acquired through environmental contingencies difficult to extinguish when those contingencies change. PMID:19222326

High temporal discounters overvalue immediate rewards rather than undervalue future rewards: an event-related brain potential study.

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Cherniawsky, Avital S; Holroyd, Clay B

2013-03-01

Impulsivity is characterized in part by heightened sensitivity to immediate relative to future rewards. Although previous research has suggested that "high discounters" in intertemporal choice tasks tend to prefer immediate over future rewards because they devalue the latter, it remains possible that they instead overvalue immediate rewards. To investigate this question, we recorded the reward positivity, a component of the event-related brain potential (ERP) associated with reward processing, with participants engaged in a task in which they received both immediate and future rewards and nonrewards. The participants also completed a temporal discounting task without ERP recording. We found that immediate but not future rewards elicited the reward positivity. High discounters also produced larger reward positivities to immediate rewards than did low discounters, indicating that high discounters relatively overvalued immediate rewards. These findings suggest that high discounters may be more motivated than low discounters to work for monetary rewards, irrespective of the time of arrival of the incentives.

Addictive drugs and brain stimulation reward.

Science.gov (United States)

Wise, R A

1996-01-01

Direct electrical or chemical stimulation of specific brain regions can establish response habits similar to those established by natural rewards such as food or sexual contact. Cocaine, mu and delta opiates, nicotine, phencyclidine, and cannabis each have actions that summate with rewarding electrical stimulation of the medial forebrain bundle (MFB). The reward-potentiating effects of amphetamine and opiates are associated with central sites of action where these drugs also have their direct rewarding effects, suggesting common mechanisms for drug reward per se and for drug potentiation of brain stimulation reward. The central sites at which these and perhaps other drugs of abuse potentiate brain stimulation reward and are rewarding in their own right are consistent with the hypothesis that the laboratory reward of brain stimulation and the pharmacological rewards of addictive drugs are habit forming because they act in the brain circuits that subserve more natural and biologically significant rewards.

Differential Contributions of Nucleus Accumbens Subregions to Cue-Guided Risk/Reward Decision Making and Implementation of Conditional Rules.

Science.gov (United States)

Floresco, Stan B; Montes, David R; Tse, Maric M T; van Holstein, Mieke

2018-02-21

associated with neuropsychiatric disorders, such as attention deficit hyperactivity disorder and schizophrenia, which in turn has been linked to aberrant processing in the nucleus accumbens. However, many preclinical studies have often assessed risk/reward decision making in the absence of explicit cues. The current study fills that gap by using a novel task that allows for the assessment of cue-guided risk/reward decision making in rodents. Our findings identified distinct yet complementary roles for the medial versus lateral portions of this nucleus that provide a broader understanding of the differential contributions it makes to decision making and reward seeking guided by discriminative stimuli. Copyright © 2018 the authors 0270-6474/18/381901-14$15.00/0.

Adolescent neural response to reward is related to participant sex and task motivation.

Science.gov (United States)

Alarcón, Gabriela; Cservenka, Anita; Nagel, Bonnie J

2017-02-01

Risky decision making is prominent during adolescence, perhaps contributed to by heightened sensation seeking and ongoing maturation of reward and dopamine systems in the brain, which are, in part, modulated by sex hormones. In this study, we examined sex differences in the neural substrates of reward sensitivity during a risky decision-making task and hypothesized that compared with girls, boys would show heightened brain activation in reward-relevant regions, particularly the nucleus accumbens, during reward receipt. Further, we hypothesized that testosterone and estradiol levels would mediate this sex difference. Moreover, we predicted boys would make more risky choices on the task. While boys showed increased nucleus accumbens blood oxygen level-dependent (BOLD) response relative to girls, sex hormones did not mediate this effect. As predicted, boys made a higher percentage of risky decisions during the task. Interestingly, boys also self-reported more motivation to perform well and earn money on the task, while girls self-reported higher state anxiety prior to the scan session. Motivation to earn money partially mediated the effect of sex on nucleus accumbens activity during reward. Previous research shows that increased motivation and salience of reinforcers is linked with more robust striatal BOLD response, therefore psychosocial factors, in addition to sex, may play an important role in reward sensitivity. Elucidating neurobiological mechanisms that support adolescent sex differences in risky decision making has important implications for understanding individual differences that lead to advantageous and adverse behaviors that affect health outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

Novelty enhances visual salience independently of reward in the parietal lobe.

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Foley, Nicholas C; Jangraw, David C; Peck, Christopher; Gottlieb, Jacqueline

2014-06-04

Novelty modulates sensory and reward processes, but it remains unknown how these effects interact, i.e., how the visual effects of novelty are related to its motivational effects. A widespread hypothesis, based on findings that novelty activates reward-related structures, is that all the effects of novelty are explained in terms of reward. According to this idea, a novel stimulus is by default assigned high reward value and hence high salience, but this salience rapidly decreases if the stimulus signals a negative outcome. Here we show that, contrary to this idea, novelty affects visual salience in the monkey lateral intraparietal area (LIP) in ways that are independent of expected reward. Monkeys viewed peripheral visual cues that were novel or familiar (received few or many exposures) and predicted whether the trial will have a positive or a negative outcome--i.e., end in a reward or a lack of reward. We used a saccade-based assay to detect whether the cues automatically attracted or repelled attention from their visual field location. We show that salience--measured in saccades and LIP responses--was enhanced by both novelty and positive reward associations, but these factors were dissociable and habituated on different timescales. The monkeys rapidly recognized that a novel stimulus signaled a negative outcome (and withheld anticipatory licking within the first few presentations), but the salience of that stimulus remained high for multiple subsequent presentations. Therefore, novelty can provide an intrinsic bonus for attention that extends beyond the first presentation and is independent of physical rewards. Copyright © 2014 the authors 0270-6474/14/347947-11$15.00/0.

Non-random intrachromosomal distribution of radiation-induced chromatid aberrations in Vicia faba. [Aberration clustering

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Schubert, I; Rieger, R [Akademie der Wissenschaften der DDR, Gatersleben. Zentralinst. fuer Genetik und Kulturpflanzenforschung

1976-04-01

A reconstructed karyotype of Vicia faba, with all chromosomes individually distinguishable, was treated with X-rays, fast neutrons, (/sup 3/H) uridine (/sup 3/HU). The distribution within metaphase chromosomes of induced chromatid aberrations was non-random for all agents used. Aberration clustering, in part agent specific, occurred in chromosome segments containing heterochromatin as defined by the presence of G bands. The pattern of aberration clustering found after treatment with /sup 3/HU did not allow the recognition of chromosome regions active in transcription during treatment. Furthermore, it was impossible to obtain unambiguous indications of the presence of AT- and GC-base clusters from the patterns of /sup 3/HT- and /sup 3/HC-induced chromatid aberrations, respectively. Possible reasons underlying these observations are discussed.

Decision-making in schizophrenia: A predictive-coding perspective.

Science.gov (United States)

Sterzer, Philipp; Voss, Martin; Schlagenhauf, Florian; Heinz, Andreas

2018-05-31

Dysfunctional decision-making has been implicated in the positive and negative symptoms of schizophrenia. Decision-making can be conceptualized within the framework of hierarchical predictive coding as the result of a Bayesian inference process that uses prior beliefs to infer states of the world. According to this idea, prior beliefs encoded at higher levels in the brain are fed back as predictive signals to lower levels. Whenever these predictions are violated by the incoming sensory data, a prediction error is generated and fed forward to update beliefs encoded at higher levels. Well-documented impairments in cognitive decision-making support the view that these neural inference mechanisms are altered in schizophrenia. There is also extensive evidence relating the symptoms of schizophrenia to aberrant signaling of prediction errors, especially in the domain of reward and value-based decision-making. Moreover, the idea of altered predictive coding is supported by evidence for impaired low-level sensory mechanisms and motor processes. We review behavioral and neural findings from these research areas and provide an integrated view suggesting that schizophrenia may be related to a pervasive alteration in predictive coding at multiple hierarchical levels, including cognitive and value-based decision-making processes as well as sensory and motor systems. We relate these findings to decision-making processes and propose that varying degrees of impairment in the implicated brain areas contribute to the variety of psychotic experiences. Copyright © 2018 Elsevier Inc. All rights reserved.

Dimensional psychiatry: reward dysfunction and depressive mood across psychiatric disorders.

Science.gov (United States)

Hägele, Claudia; Schlagenhauf, Florian; Rapp, Michael; Sterzer, Philipp; Beck, Anne; Bermpohl, Felix; Stoy, Meline; Ströhle, Andreas; Wittchen, Hans-Ulrich; Dolan, Raymond J; Heinz, Andreas

2015-01-01

A dimensional approach in psychiatry aims to identify core mechanisms of mental disorders across nosological boundaries. We compared anticipation of reward between major psychiatric disorders, and investigated whether reward anticipation is impaired in several mental disorders and whether there is a common psychopathological correlate (negative mood) of such an impairment. We used functional magnetic resonance imaging (fMRI) and a monetary incentive delay (MID) task to study the functional correlates of reward anticipation across major psychiatric disorders in 184 subjects, with the diagnoses of alcohol dependence (n = 26), schizophrenia (n = 44), major depressive disorder (MDD, n = 24), bipolar disorder (acute manic episode, n = 13), attention deficit/hyperactivity disorder (ADHD, n = 23), and healthy controls (n = 54). Subjects' individual Beck Depression Inventory-and State-Trait Anxiety Inventory-scores were correlated with clusters showing significant activation during reward anticipation. During reward anticipation, we observed significant group differences in ventral striatal (VS) activation: patients with schizophrenia, alcohol dependence, and major depression showed significantly less ventral striatal activation compared to healthy controls. Depressive symptoms correlated with dysfunction in reward anticipation regardless of diagnostic entity. There was no significant correlation between anxiety symptoms and VS functional activation. Our findings demonstrate a neurobiological dysfunction related to reward prediction that transcended disorder categories and was related to measures of depressed mood. The findings underline the potential of a dimensional approach in psychiatry and strengthen the hypothesis that neurobiological research in psychiatric disorders can be targeted at core mechanisms that are likely to be implicated in a range of clinical entities.

A Markov reward model checker

NARCIS (Netherlands)

Katoen, Joost P.; Maneesh Khattri, M.; Zapreev, I.S.; Zapreev, I.S.

2005-01-01

This short tool paper introduces MRMC, a model checker for discrete-time and continuous-time Markov reward models. It supports reward extensions of PCTL and CSL, and allows for the automated verification of properties concerning long-run and instantaneous rewards as well as cumulative rewards. In

Automatic honesty forgoing reward acquisition and punishment avoidance: a functional MRI investigation.

Science.gov (United States)

Yoneda, Mei; Ueda, Ryuhei; Ashida, Hiroshi; Abe, Nobuhito

2017-09-27

Recent neuroimaging investigations into human honesty suggest that honest moral decisions in individuals who consistently behave honestly occur automatically, without the need for active self-control. However, it remains unclear whether this observation can be applied to two different types of honesty: honesty forgoing dishonest reward acquisition and honesty forgoing dishonest punishment avoidance. To address this issue, a functional MRI study, using an incentivized prediction task in which participants were confronted with real and repeated opportunities for dishonest gain leading to reward acquisition and punishment avoidance, was conducted. Behavioral data revealed that the frequency of dishonesty was equivalent between the opportunities for dishonest reward acquisition and for punishment avoidance. Reaction time data demonstrated that two types of honest decisions in the opportunity for dishonest reward acquisition and punishment avoidance required no additional cognitive control. Neuroimaging data revealed that honest decisions in the opportunity for dishonest reward acquisition and those for punishment avoidance required no additional control-related activity compared with a control condition in which no opportunity for dishonest behavior was given. These results suggest that honesty flows automatically, irrespective of the concomitant motivation for dishonesty leading to reward acquisition and punishment avoidance.

Effort-Reward Imbalance at Work and Risk of Long-Term Sickness Absence in the Danish Workforce

NARCIS (Netherlands)

Nielsen, Maj Britt D.; Madsen, Ida E. H.; Bultmann, Ute; Aust, Birgit; Burr, Hermann; Rugulies, Reiner

Objective: To examine whether effort-reward imbalance (ERI) at work predicts onset of register-based long-term sickness absence (LTSA) in a representative sample of the Danish workforce. Methods: We measured effort, reward, ERI, and covariates with self-administered questionnaires in a sample of

Impaired reward responsiveness in schizophrenia.

Science.gov (United States)

Taylor, Nicholas; Hollis, Jeffrey P; Corcoran, Sarah; Gross, Robin; Cuthbert, Bruce; Swails, Lisette W; Duncan, Erica

2018-03-08

Anhedonia is a core negative symptom of schizophrenia. Schizophrenia patients report largely intact pleasure in consuming rewards, but have impairments in generating motivated behavior to pursue rewards, and show reduced fMRI activation of the reward pathway during presentation of rewarded stimuli. A computer based task measuring the development of a response bias in favor of rewarded stimuli permits assessment of reward-induced motivation. We hypothesized that subjects with schizophrenia would be impaired on this task. 58 schizophrenia subjects (SCZ) and 52 healthy controls (CON) were studied with a signal detection task to assess reward responsiveness. In multiple trials over three blocks subjects were asked to correctly identify two stimuli that were paired with unequal chance of monetary reward. The critical outcome variable was response bias, the development of a greater percent correct identification of the stimulus that was rewarded more often. An ANOVA on response bias with Block as a repeated-measures factor and Diagnosis as a between-group factor indicated that SCZ subjects achieved a lower bias to rewarded stimuli than CON subjects (F(1,105)=8.82, p=0.004, η 2 =0.078). Post hoc tests indicated that SCZ subjects had significantly impaired bias in Block 1 (p=0.002) and Block 2 (p=0.05), indicating that SCZ were slower to achieve normal levels of bias during the session. SCZ subjects were slower to develop response bias to rewarded stimuli than CON subjects. This finding is consonant with the hypothesis that people with schizophrenia have a blunted capacity to modify behavior in response to reward. Copyright © 2018. Published by Elsevier B.V.

Monetary rewards modulate inhibitory control

Directory of Open Access Journals (Sweden)

Paula Marcela Herrera

2014-05-01

Full Text Available The ability to override a dominant response, often referred to as behavioural inhibiton, is considered a key element of executive cognition. Poor behavioural inhibition is a defining characteristic of several neurological and psychiatric populations. Recently, there has been increasing interest in the motivational dimension of behavioural inhibition, with some experiments incorporating emotional contingencies in classical inhibitory paradigms such as the Go/Nogo and Stop Signal Tasks. Several studies have reported a positive modulatory effect of reward on the performance of such tasks in pathological conditions such as substance abuse, pathological gambling, and ADHD. However, experiments that directly investigate the modulatory effects of reward magnitudes on the performance of inhibitory paradigms are rare and consequently, little is known about the finer grained relationship between motivation and self-control. Here, we probed the effect of reward and reward magnitude on behavioural inhibition using two modified version of the widely used Stop Signal Task. The first task compared no reward with reward, whilst the other compared two different reward magnitudes. The reward magnitude effect was confirmed by the second study, whereas it was less compelling in the first study, possibly due to the effect of having no reward in some conditions. In addition, our results showed a kick start effect over global performance measures. More specifically, there was a long lasting improvement in performance throughout the task, when participants received the highest reward magnitudes at the beginning of the protocol. These results demonstrate that individuals’ behavioural inhibition capacities are dynamic not static because they are modulated by the reward magnitude and initial reward history of the task at hand.

Reward deficiency syndrome: a biogenetic model for the diagnosis and treatment of impulsive, addictive, and compulsive behaviors.

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Blum, K; Braverman, E R; Holder, J M; Lubar, J F; Monastra, V J; Miller, D; Lubar, J O; Chen, T J; Comings, D E

2000-11-01

behavior. In order to explain the breakdown of the reward cascade due to both multiple genes and environmental stimuli (pleiotropism) and resultant aberrant behaviors, Blum united this hypodopaminergic trait under the rubric of a reward deficiency syndrome.

Commitment to self-rewards

DEFF Research Database (Denmark)

Koch, Alexander; Nafziger, Julia

People often overcome self-control problems by promising to reward themselves for accomplishing a task. Such strategies based on self-administered rewards however require the person to believe that she would indeed deny herself the reward if she should fail to achieve the desired outcome. Drawing...... on Koszegi and Rabin's (2006) model of endogenous reference point formation, we show how a rational forward-looking individual can achieve such internal commitment. But our results also demonstrate the limitations of self regulation based on self-rewards....

Neural sensitivity to social reward and punishment anticipation in social anxiety disorder

OpenAIRE

Cremers, Henk R.; Veer, Ilya M.; Spinhoven, Philip; Rombouts, Serge A. R. B.; Roelofs, Karin

2015-01-01

An imbalance in the neural motivational system may underlie Social Anxiety Disorder (SAD). This study examines social reward and punishment anticipation in SAD, predicting a valence-specific effect: increased striatal activity for punishment avoidance compared to obtaining a reward. Individuals with SAD (n = 20) and age, gender, and education case-matched controls (n = 20) participated in a functional magnetic resonance imaging (fMRI) study. During fMRI scanning, participants performed a Soci...

Introduction: Addiction and Brain Reward and Anti-Reward Pathways

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Gardner, Eliot L.

2013-01-01

Addictive drugs have in common that they are voluntarily self-administered by laboratory animals (usually avidly) and that they enhance the functioning of the reward circuitry of the brain (producing the “high” that the drug-user seeks). The core reward circuitry consists of an “in series” circuit linking the ventral tegmental area, nucleus accumbens, and ventral pallidum - via the medial forebrain bundle. Although originally believed to encode simply the set-point of hedonic tone, these circuits are now believed to be functionally far more complex - also encoding attention, expectancy of reward, disconfirmation of reward expectancy, and incentive motivation. “Hedonic dysregulation” within these circuits may lead to addiction. The “second-stage” dopaminergic component in this reward circuitry is the crucial addictive-drug-sensitive component. All addictive drugs have in common that they enhance (directly or indirectly or even transsynaptically) dopaminergic reward synaptic function in the nucleus accumbens. Drug self-administration is regulated by nucleus accumbens dopamine levels, and is done to keep nucleus accumbens dopamine within a specific elevated range (to maintain a desired hedonic level). For some classes of addictive drugs (e.g., opiates), tolerance to the euphoric effects develops with chronic use. Post-use dysphoria then comes to dominate reward circuit hedonic tone, and addicts no longer use drugs to get “high,” but simply to get back to normal (“get straight”). The brain circuits mediating the pleasurable effects of addictive drugs are anatomically, neurophysiologically, and neurochemically different from those mediating physical dependence, and from those mediating craving and relapse. There are important genetic variations in vulnerability to drug addiction, yet environmental factors such as stress and social defeat also alter brain-reward mechanisms in such a manner as to impart vulnerability to addiction. In short, the �

Monetary rewards influence retrieval orientations.

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Halsband, Teresa M; Ferdinand, Nicola K; Bridger, Emma K; Mecklinger, Axel

2012-09-01

Reward anticipation during learning is known to support memory formation, but its role in retrieval processes is so far unclear. Retrieval orientations, as a reflection of controlled retrieval processing, are one aspect of retrieval that might be modulated by reward. These processes can be measured using the event-related potentials (ERPs) elicited by retrieval cues from tasks with different retrieval requirements, such as via changes in the class of targeted memory information. To determine whether retrieval orientations of this kind are modulated by reward during learning, we investigated the effects of high and low reward expectancy on the ERP correlates of retrieval orientation in two separate experiments. The reward manipulation at study in Experiment 1 was associated with later memory performance, whereas in Experiment 2, reward was directly linked to accuracy in the study task. In both studies, the participants encoded mixed lists of pictures and words preceded by high- or low-reward cues. After 24 h, they performed a recognition memory exclusion task, with words as the test items. In addition to a previously reported material-specific effect of retrieval orientation, a frontally distributed, reward-associated retrieval orientation effect was found in both experiments. These findings suggest that reward motivation during learning leads to the adoption of a reward-associated retrieval orientation to support the retrieval of highly motivational information. Thus, ERP retrieval orientation effects not only reflect retrieval processes related to the sought-for materials, but also relate to the reward conditions with which items were combined during encoding.

Reward and punishment.

Science.gov (United States)

Sigmund, K; Hauert, C; Nowak, M A

2001-09-11

Minigames capturing the essence of Public Goods experiments show that even in the absence of rationality assumptions, both punishment and reward will fail to bring about prosocial behavior. This result holds in particular for the well-known Ultimatum Game, which emerges as a special case. But reputation can induce fairness and cooperation in populations adapting through learning or imitation. Indeed, the inclusion of reputation effects in the corresponding dynamical models leads to the evolution of economically productive behavior, with agents contributing to the public good and either punishing those who do not or rewarding those who do. Reward and punishment correspond to two types of bifurcation with intriguing complementarity. The analysis suggests that reputation is essential for fostering social behavior among selfish agents, and that it is considerably more effective with punishment than with reward.

Lipopolysaccharide Alters Motivated Behavior in a Monetary Reward Task: a Randomized Trial

Science.gov (United States)

Lasselin, Julie; Treadway, Michael T; Lacourt, Tamara E; Soop, Anne; Olsson, Mats J; Karshikoff, Bianka; Paues-Göranson, Sofie; Axelsson, John; Dantzer, Robert; Lekander, Mats

2017-01-01

Inflammation-induced sickness is associated with a large set of behavioral alterations; however, its motivational aspects remain poorly explored in humans. The present study assessed the effect of lipopolysaccharide (LPS) administration at a dose of 2 ng/kg of body weight on motivation in 21 healthy human subjects in a double-blinded, placebo (saline)-controlled, cross-over design. Incentive motivation and reward sensitivity were measured using the Effort Expenditure for Rewards Task (EEfRT), in which motivation for high-effort/high-reward trials vs low-effort/low-reward trials are manipulated by variations in reward magnitude and probability to win. Because of the strong interactions between sleepiness and motivation, the role of sleepiness was also determined. As expected, the probability to win predicted the choice to engage in high-effort/high-reward trials; however, this occurred at a greater extent after LPS than after saline administration. This effect was related to the level of sleepiness. Sleepiness increased motivation to choose the high-effort/high-reward mode of response, but only when the probability to win was the highest. LPS had no effect on reward sensitivity either directly or via sleepiness. These results indicate that systemic inflammation induced by LPS administration causes motivational changes in young healthy subjects, which are associated with sleepiness. Thus, despite its association with energy-saving behaviors, sickness allows increased incentive motivation when the effort is deemed worthwhile. PMID:27620550

Reward-associated stimuli capture the eyes in spite of strategic attentional set.

Science.gov (United States)

Hickey, Clayton; van Zoest, Wieske

2013-11-01

Theories of reinforcement learning have proposed that the association of reward to visual stimuli may cause these objects to become fundamentally salient and thus attention-drawing. A number of recent studies have investigated the oculomotor correlates of this reward-priming effect, but there is some ambiguity in this literature regarding the involvement of top-down attentional set. Existing paradigms tend to create a situation where participants are actively looking for a reward-associated stimulus before subsequently showing that this selective bias sustains when it no longer has strategic purpose. This perseveration of attentional set is potentially different in nature than the direct impact of reward proposed by theory. Here we investigate the effect of reward on saccadic selection in a paradigm where strategic attentional set is decoupled from the effect of reward. We find that during search for a uniquely oriented target, the receipt of reward following selection of a target characterized by an irrelevant unique color causes subsequent stimuli characterized by this color to be preferentially selected. Importantly, this occurs regardless of whether the color characterizes the target or distractor. Other analyses demonstrate that only features associated with correct selection of the target prime the target representation, and that the magnitude of this effect can be predicted by variability in saccadic indices of feedback processing. These results add to a growing literature demonstrating that reward guides visual selection, often in spite of our strategic efforts otherwise. Copyright © 2013 Elsevier B.V. All rights reserved.

Heightened sensitivity to punishment and reward in anorexia nervosa

NARCIS (Netherlands)

Glashouwer, Klaske A; Bloot, Lotte; Veenstra, Esther M; Franken, Ingmar H A; de Jong, Peter J

OBJECTIVE: The aim of this study was to investigate reinforcement sensitivity in anorexia nervosa (AN). It was tested whether self-reported punishment (PS) and reward sensitivity (RS) differed between adolescents with AN and healthy controls, and/or between AN-subtypes. In addition, the predictive

Lower neighborhood quality in adolescence predicts higher mesolimbic sensitivity to reward anticipation in adulthood

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Gonzalez, Marlen Z.; Allen, Joseph P.; Coan, James A.

2016-01-01

Life history theory suggests that adult reward sensitivity should be best explained by childhood, but not current, socioeconomic conditions. In this functional magnetic resonance imaging (fMRI) study, 83 participants from a larger longitudinal sample completed the monetary incentive delay (MID) task in adulthood (~25 years old). Parent-reports of neighborhood quality and parental SES were collected when participants were 13 years of age. Current income level was collected concurrently with scanning. Lower adolescent neighborhood quality, but neither lower current income nor parental SES, was associated with heightened sensitivity to the anticipation of monetary gain in putative mesolimbic reward areas. Lower adolescent neighborhood quality was also associated with heightened sensitivity to the anticipation of monetary loss activation in visuo-motor areas. Lower current income was associated with heightened sensitivity to anticipated loss in occipital areas and the operculum. We tested whether externalizing behaviors in childhood or adulthood could better account for neighborhood quality findings, but they did not. Findings suggest that neighborhood ecology in adolescence is associated with greater neural reward sensitivity in adulthood above the influence of parental SES or current income and not mediated through impulsivity and externalizing behaviors. PMID:27838595

Lower neighborhood quality in adolescence predicts higher mesolimbic sensitivity to reward anticipation in adulthood

Directory of Open Access Journals (Sweden)

Marlen Z. Gonzalez

2016-12-01

Full Text Available Life history theory suggests that adult reward sensitivity should be best explained by childhood, but not current, socioeconomic conditions. In this functional magnetic resonance imaging (fMRI study, 83 participants from a larger longitudinal sample completed the monetary incentive delay (MID task in adulthood (∼25 years old. Parent-reports of neighborhood quality and parental SES were collected when participants were 13 years of age. Current income level was collected concurrently with scanning. Lower adolescent neighborhood quality, but neither lower current income nor parental SES, was associated with heightened sensitivity to the anticipation of monetary gain in putative mesolimbic reward areas. Lower adolescent neighborhood quality was also associated with heightened sensitivity to the anticipation of monetary loss activation in visuo-motor areas. Lower current income was associated with heightened sensitivity to anticipated loss in occipital areas and the operculum. We tested whether externalizing behaviors in childhood or adulthood could better account for neighborhood quality findings, but they did not. Findings suggest that neighborhood ecology in adolescence is associated with greater neural reward sensitivity in adulthood above the influence of parental SES or current income and not mediated through impulsivity and externalizing behaviors.

Reward Experience, Socioeconomic Status, and Sex: Exploring Parameters of the Overjustification Effect.

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Schilling, Deanna E.

The overjustification hypothesis predicts decreased intrinsic motivation when persons are paid to perform an interesting task. The factors of reward experience, socioeconomic status (SES), and sex are examined while testing conflicting predictions of the hypothesis and reinforcement theory. Children from grade 1 at two public elementary schools…

Modulation of neural activity by reward in medial intraparietal cortex is sensitive to temporal sequence of reward

Science.gov (United States)

Rajalingham, Rishi; Stacey, Richard Greg; Tsoulfas, Georgios

2014-01-01

To restore movements to paralyzed patients, neural prosthetic systems must accurately decode patients' intentions from neural signals. Despite significant advancements, current systems are unable to restore complex movements. Decoding reward-related signals from the medial intraparietal area (MIP) could enhance prosthetic performance. However, the dynamics of reward sensitivity in MIP is not known. Furthermore, reward-related modulation in premotor areas has been attributed to behavioral confounds. Here we investigated the stability of reward encoding in MIP by assessing the effect of reward history on reward sensitivity. We recorded from neurons in MIP while monkeys performed a delayed-reach task under two reward schedules. In the variable schedule, an equal number of small- and large-rewards trials were randomly interleaved. In the constant schedule, one reward size was delivered for a block of trials. The memory period firing rate of most neurons in response to identical rewards varied according to schedule. Using systems identification tools, we attributed the schedule sensitivity to the dependence of neural activity on the history of reward. We did not find schedule-dependent behavioral changes, suggesting that reward modulates neural activity in MIP. Neural discrimination between rewards was less in the variable than in the constant schedule, degrading our ability to decode reach target and reward simultaneously. The effect of schedule was mitigated by adding Haar wavelet coefficients to the decoding model. This raises the possibility of multiple encoding schemes at different timescales and reinforces the potential utility of reward information for prosthetic performance. PMID:25008408

Modulation of neural activity by reward in medial intraparietal cortex is sensitive to temporal sequence of reward.

Science.gov (United States)

Rajalingham, Rishi; Stacey, Richard Greg; Tsoulfas, Georgios; Musallam, Sam

2014-10-01

To restore movements to paralyzed patients, neural prosthetic systems must accurately decode patients' intentions from neural signals. Despite significant advancements, current systems are unable to restore complex movements. Decoding reward-related signals from the medial intraparietal area (MIP) could enhance prosthetic performance. However, the dynamics of reward sensitivity in MIP is not known. Furthermore, reward-related modulation in premotor areas has been attributed to behavioral confounds. Here we investigated the stability of reward encoding in MIP by assessing the effect of reward history on reward sensitivity. We recorded from neurons in MIP while monkeys performed a delayed-reach task under two reward schedules. In the variable schedule, an equal number of small- and large-rewards trials were randomly interleaved. In the constant schedule, one reward size was delivered for a block of trials. The memory period firing rate of most neurons in response to identical rewards varied according to schedule. Using systems identification tools, we attributed the schedule sensitivity to the dependence of neural activity on the history of reward. We did not find schedule-dependent behavioral changes, suggesting that reward modulates neural activity in MIP. Neural discrimination between rewards was less in the variable than in the constant schedule, degrading our ability to decode reach target and reward simultaneously. The effect of schedule was mitigated by adding Haar wavelet coefficients to the decoding model. This raises the possibility of multiple encoding schemes at different timescales and reinforces the potential utility of reward information for prosthetic performance. Copyright © 2014 the American Physiological Society.

Fearfulness moderates the link between childhood social withdrawal and adolescent reward response.

Science.gov (United States)

Morgan, Judith K; Shaw, Daniel S; Forbes, Erika E

2015-06-01

Withdrawal from peers during childhood may reflect disruptions in reward functioning that heighten vulnerability to affective disorders during adolescence. The association between socially withdrawn behavior and reward functioning may depend on traits that influence this withdrawal, such as fearfulness or unsociability. In a study of 129 boys, we evaluated how boys' fearfulness and sociability at age 5 and social withdrawal at school at ages 6 to 10 and during a summer camp at age 9/10 were associated with their neural response to reward at age 20. Greater social withdrawal during childhood was associated with heightened striatal and mPFC activation when anticipating rewards at age 20. Fearfulness moderated this effect to indicate that social withdrawal was associated with heightened reward-related response in the striatum for boys high on fearfulness. Altered striatal response associated with social withdrawal and fearfulness predicted greater likelihood to have a lifetime history of depression and social phobia at age 20. These findings add greater specificity to previous findings that children high in traits related to fear of novelty show altered reward responses, by identifying fearfulness (but not low levels of sociability) as a potential underlying mechanism that contributes to reward alterations in withdrawn children. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Reward Learning, Neurocognition, Social Cognition, and Symptomatology in Psychosis.

Science.gov (United States)

Lewandowski, Kathryn E; Whitton, Alexis E; Pizzagalli, Diego A; Norris, Lesley A; Ongur, Dost; Hall, Mei-Hua

2016-01-01

symptoms - across diagnoses, and was predictive of worse social cognition. Reward learning was not associated with neurocognitive performance, suggesting that, across patient groups, social cognition but not neurocognition may share common pathways with this aspect of reinforcement learning. Better understanding of how cognitive dysfunction and reward processing deficits relate to one another, to other key symptom dimensions (e.g., psychosis), and to diagnostic categories, may help clarify shared etiological pathways and guide efforts toward targeted treatment approaches.

Toward an autonomous brain machine interface: integrating sensorimotor reward modulation and reinforcement learning.

Science.gov (United States)

Marsh, Brandi T; Tarigoppula, Venkata S Aditya; Chen, Chen; Francis, Joseph T

2015-05-13

For decades, neurophysiologists have worked on elucidating the function of the cortical sensorimotor control system from the standpoint of kinematics or dynamics. Recently, computational neuroscientists have developed models that can emulate changes seen in the primary motor cortex during learning. However, these simulations rely on the existence of a reward-like signal in the primary sensorimotor cortex. Reward modulation of the primary sensorimotor cortex has yet to be characterized at the level of neural units. Here we demonstrate that single units/multiunits and local field potentials in the primary motor (M1) cortex of nonhuman primates (Macaca radiata) are modulated by reward expectation during reaching movements and that this modulation is present even while subjects passively view cursor motions that are predictive of either reward or nonreward. After establishing this reward modulation, we set out to determine whether we could correctly classify rewarding versus nonrewarding trials, on a moment-to-moment basis. This reward information could then be used in collaboration with reinforcement learning principles toward an autonomous brain-machine interface. The autonomous brain-machine interface would use M1 for both decoding movement intention and extraction of reward expectation information as evaluative feedback, which would then update the decoding algorithm as necessary. In the work presented here, we show that this, in theory, is possible. Copyright © 2015 the authors 0270-6474/15/357374-14$15.00/0.

Effort-Reward Imbalance and Overcommitment in UK Academics: Implications for Mental Health, Satisfaction and Retention

Science.gov (United States)

Kinman, Gail

2016-01-01

This study utilises the effort-reward imbalance (ERI) model of job stress to predict several indices of well-being in academics in the UK: mental ill health, job satisfaction and leaving intentions. This model posits that (a) employees who believe that their efforts are not counterbalanced by sufficient rewards will experience impaired well-being…

Adverse health effects of high-effort/low-reward conditions.

Science.gov (United States)

Siegrist, J

1996-01-01

In addition to the person-environment fit model (J. R. French, R. D. Caplan, & R. V. Harrison, 1982) and the demand-control model (R. A. Karasek & T. Theorell, 1990), a third theoretical concept is proposed to assess adverse health effects of stressful experience at work: the effort-reward imbalance model. The focus of this model is on reciprocity of exchange in occupational life where high-cost/low-gain conditions are considered particularly stressful. Variables measuring low reward in terms of low status control (e.g., lack of promotion prospects, job insecurity) in association with high extrinsic (e.g., work pressure) or intrinsic (personal coping pattern, e.g., high need for control) effort independently predict new cardiovascular events in a prospective study on blue-collar men. Furthermore, these variables partly explain prevalence of cardiovascular risk factors (hypertension, atherogenic lipids) in 2 independent studies. Studying adverse health effects of high-effort/low-reward conditions seems well justified, especially in view of recent developments of the labor market.

Dorsomedial striatum lesions affect adjustment to reward uncertainty, but not to reward devaluation or omission.

Science.gov (United States)

Torres, Carmen; Glueck, Amanda C; Conrad, Shannon E; Morón, Ignacio; Papini, Mauricio R

2016-09-22

The dorsomedial striatum (DMS) has been implicated in the acquisition of reward representations, a proposal leading to the hypothesis that it should play a role in situations involving reward loss. We report the results of an experiment in which the effects of DMS excitotoxic lesions were tested in consummatory successive negative contrast (reward devaluation), autoshaping training with partial vs. continuous reinforcement (reward uncertainty), and appetitive extinction (reward omission). Animals with DMS lesions exhibited reduced lever pressing responding, but enhanced goal entries, during partial reinforcement training in autoshaping. However, they showed normal negative contrast, acquisition under continuous reinforcement (CR), appetitive extinction, and response facilitation in early extinction trials. Open-field testing also indicated normal motor behavior. Thus, DMS lesions selectively affected the behavioral adjustment to a situation involving reward uncertainty, producing a behavioral reorganization according to which goal tracking (goal entries) became predominant at the expense of sign tracking (lever pressing). This pattern of results shows that the function of the DMS in situations involving reward loss is not general, but restricted to reward uncertainty. We suggest that a nonassociative, drive-related process induced by reward uncertainty requires normal output from DMS neurons. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Extinction Can Reduce the Impact of Reward Cues on Reward-Seeking Behavior.

Science.gov (United States)

Lovibond, Peter F; Satkunarajah, Michelle; Colagiuri, Ben

2015-07-01

Reward-associated cues are thought to promote relapse after treatment of appetitive disorders such as drug-taking, binge eating, and gambling. This process has been modelled in the laboratory using a Pavlovian-instrumental transfer (PIT) design in which Pavlovian cues facilitate instrumental reward-directed action. Attempts to reduce facilitation by cue exposure (extinction) have produced mixed results. We tested the effect of extinction in a recently developed PIT procedure using a natural reward, chocolate, in human participants. Facilitation of instrumental responding was only observed in participants who were aware of the Pavlovian contingencies. Pavlovian extinction successfully reduced, but did not completely eliminate, expectancy of reward and facilitation of instrumental responding. The results indicate that exposure can reduce the ability of cues to promote reward-directed behavior in the laboratory. However, the residual potency of extinguished cues means that additional active strategies may be needed in clinical practice to train patients to resist the impact of these cues in their environment. Copyright © 2015. Published by Elsevier Ltd.

Utilization of reward-prospect enhances preparatory attention and reduces stimulus conflict.

Science.gov (United States)

van den Berg, Berry; Krebs, Ruth M; Lorist, Monicque M; Woldorff, Marty G

2014-06-01

The prospect of gaining money is an incentive widely at play in the real world. Such monetary motivation might have particularly strong influence when the cognitive system is challenged, such as when needing to process conflicting stimulus inputs. Here, we employed manipulations of reward-prospect and attentional-preparation levels in a cued-Stroop stimulus conflict task, along with the high temporal resolution of electrical brain recordings, to provide insight into the mechanisms by which reward-prospect and attention interact and modulate cognitive task performance. In this task, the cue indicated whether or not the participant needed to prepare for an upcoming Stroop stimulus and, if so, whether there was the potential for monetary reward (dependent on performance on that trial). Both cued attention and cued reward-prospect enhanced preparatory neural activity, as reflected by increases in the hallmark attention-related negative-polarity ERP slow wave (contingent negative variation [CNV]) and reductions in oscillatory Alpha activity, which was followed by enhanced processing of the subsequent Stroop stimulus. In addition, similar modulations of preparatory neural activity (larger CNVs and reduced Alpha) predicted shorter versus longer response times (RTs) to the subsequent target stimulus, consistent with such modulations reflecting trial-to-trial variations in attention. Particularly striking were the individual differences in the utilization of reward-prospect information. In particular, the size of the reward effects on the preparatory neural activity correlated across participants with the degree to which reward-prospect both facilitated overall task performance (shorter RTs) and reduced conflict-related behavioral interference. Thus, the prospect of reward appears to recruit attentional preparation circuits to enhance processing of task-relevant target information.

BOLD responses in reward regions to hypothetical and imaginary monetary rewards.

OpenAIRE

Miyapuram Krishna P; Tobler Philippe N; Gregorios-Pippas Lucy; Schultz Wolfram

2012-01-01

Monetary rewards are uniquely human. Because money is easy to quantify and present visually, it is the reward of choice for most fMRI studies, even though it cannot be handed over to participants inside the scanner. A typical fMRI study requires hundreds of trials and thus small amounts of monetary rewards per trial (e.g. 5p) if all trials are to be treated equally. However, small payoffs can have detrimental effects on performance due to their limited buying power. Hypothetical monetary rewa...

Iteration of ultrasound aberration correction methods

Science.gov (United States)

Maasoey, Svein-Erik; Angelsen, Bjoern; Varslot, Trond

2004-05-01

Aberration in ultrasound medical imaging is usually modeled by time-delay and amplitude variations concentrated on the transmitting/receiving array. This filter process is here denoted a TDA filter. The TDA filter is an approximation to the physical aberration process, which occurs over an extended part of the human body wall. Estimation of the TDA filter, and performing correction on transmit and receive, has proven difficult. It has yet to be shown that this method works adequately for severe aberration. Estimation of the TDA filter can be iterated by retransmitting a corrected signal and re-estimate until a convergence criterion is fulfilled (adaptive imaging). Two methods for estimating time-delay and amplitude variations in receive signals from random scatterers have been developed. One method correlates each element signal with a reference signal. The other method use eigenvalue decomposition of the receive cross-spectrum matrix, based upon a receive energy-maximizing criterion. Simulations of iterating aberration correction with a TDA filter have been investigated to study its convergence properties. A weak and strong human-body wall model generated aberration. Both emulated the human abdominal wall. Results after iteration improve aberration correction substantially, and both estimation methods converge, even for the case of strong aberration.

Weak reward source memory in depression reflects blunted activation of VTA/SN and parahippocampus.

Science.gov (United States)

Dillon, Daniel G; Dobbins, Ian G; Pizzagalli, Diego A

2014-10-01

Reward responses in the medial temporal lobes and dopaminergic midbrain boost episodic memory formation in healthy adults, and weak memory for emotionally positive material in depression suggests this mechanism may be dysfunctional in major depressive disorder (MDD). To test this hypothesis, we performed a study in which unmedicated adults with MDD and healthy controls encoded drawings paired with reward or zero tokens during functional magnetic resonance imaging. In a recognition test, participants judged whether drawings were previously associated with the reward token ('reward source') or the zero token ('zero source'). Unlike controls, depressed participants failed to show better memory for drawings from the reward source vs the zero source. Consistent with predictions, controls also showed a stronger encoding response to reward tokens vs zero tokens in the right parahippocampus and dopaminergic midbrain, whereas the MDD group showed the opposite pattern-stronger responses to zero vs reward tokens-in these regions. Differential activation of the dopaminergic midbrain by reward vs zero tokens was positively correlated with the reward source memory advantage in controls, but not depressed participants. These data suggest that weaker memory for positive material in depression reflects blunted encoding responses in the dopaminergic midbrain and medial temporal lobes. © The Author (2013). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Immediate perception of a reward is distinct from the reward’s long-term salience

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McGinnis, John P; Jiang, Huoqing; Agha, Moutaz Ali; Sanchez, Consuelo Perez; Lange, Jeff; Yu, Zulin; Marion-Poll, Frederic; Si, Kausik

2016-01-01

Reward perception guides all aspects of animal behavior. However, the relationship between the perceived value of a reward, the latent value of a reward, and the behavioral response remains unclear. Here we report that, given a choice between two sweet and chemically similar sugars—L- and D-arabinose—Drosophila melanogaster prefers D- over L- arabinose, but forms long-term memories of L-arabinose more reliably. Behavioral assays indicate that L-arabinose-generated memories require sugar receptor Gr43a, and calcium imaging and electrophysiological recordings indicate that L- and D-arabinose differentially activate Gr43a-expressing neurons. We posit that the immediate valence of a reward is not always predictive of the long-term reinforcement value of that reward, and that a subset of sugar-sensing neurons may generate distinct representations of similar sugars, allowing for rapid assessment of the salient features of various sugar rewards and generation of reward-specific behaviors. However, how sensory neurons communicate information about L-arabinose quality and concentration—features relevant for long-term memory—remains unknown. DOI: http://dx.doi.org/10.7554/eLife.22283.001 PMID:28005005

Reward eliminates retrieval-induced forgetting.

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Imai, Hisato; Kim, Dongho; Sasaki, Yuka; Watanabe, Takeo

2014-12-02

Although it is well known that reward enhances learning and memory, how extensively such enhancement occurs remains unclear. To address this question, we examined how reward influences retrieval-induced forgetting (RIF) in which the retrieval of a nonpracticed item under the same category as a practiced item is worse than the retrieval of a nonpracticed item outside the category. Subjects were asked to try to encode category-exemplar pairs (e.g., FISH-salmon). Then, they were presented with a category name and a two-letter word stem (e.g., FISH-sa) and were asked to complete an encoded word (retrieval practice). For a correct response, apple juice was given as a reward in the reward condition and a beeping sound was presented in the no-reward condition. Finally, subjects were asked to report whether each exemplar had been presented in the first phase. RIF was replicated in the no-reward condition. However, in the reward condition, RIF was eliminated. These results suggest that reward enhances processing of retrieval of unpracticed members by mechanisms such as spreading activation within the same category, irrespective of whether items were practiced or not.

Neural evidence for description dependent reward processing in the framing effect.

Science.gov (United States)

Yu, Rongjun; Zhang, Ping

2014-01-01

Human decision making can be influenced by emotionally valenced contexts, known as the framing effect. We used event-related brain potentials to investigate how framing influences the encoding of reward. We found that the feedback related negativity (FRN), which indexes the "worse than expected" negative prediction error in the anterior cingulate cortex (ACC), was more negative for the negative frame than for the positive frame in the win domain. Consistent with previous findings that the FRN is not sensitive to "better than expected" positive prediction error, the FRN did not differentiate the positive and negative frame in the loss domain. Our results provide neural evidence that the description invariance principle which states that reward representation and decision making are not influenced by how options are presented is violated in the framing effect.

Neural evidence for description dependent reward processing in the framing effect

Directory of Open Access Journals (Sweden)

Rongjun eYu

2014-03-01

Full Text Available Human decision making can be influenced by emotionally valenced contexts, known as the framing effect. We used event-related brain potentials to investigate how framing influences the encoding of reward. We found that the feedback related negativity (FRN, which indexes the worse than expected negative prediction error in the anterior cingulate cortex, was more negative for the negative frame than for the positive frame in the win domain. Consistent with previous findings that the FRN is not sensitive to better than expected positive prediction error, the FRN did not differentiate the positive and negative frame in the loss domain. Our results provide neural evidence that the description invariance principle which states that reward representation and decision making are not influenced by how options are presented is violated in the framing effect.

Social Anxiety, Acute Social Stress, and Reward Parameters Interact to Predict Risky Decision-Making among Adolescents

OpenAIRE

Richards, Jessica M.; Patel, Nilam; Daniele, Teresa; MacPherson, Laura; Lejuez, C.W.; Ernst, Monique

2014-01-01

Risk-taking behavior increases during adolescence, leading to potentially disastrous consequences. Social anxiety emerges in adolescence and may compound risk-taking propensity, particularly during stress and when reward potential is high. However, the manner in which social anxiety, stress, and reward parameters interact to impact adolescent risk-taking is unclear. To clarify this question, a community sample of 35 adolescents (15 to 18 yo), characterized as having high or low social anxiety...

[Monochromatic aberration in accommodation. Dynamic wavefront analysis].

Science.gov (United States)

Fritzsch, M; Dawczynski, J; Jurkutat, S; Vollandt, R; Strobel, J

2011-06-01

Monochromatic aberrations may influence the visual acuity of the eye. They are not stable and can be affected by different factors. The subject of the following paper is the dynamic investigation of the changes in wavefront aberration with accommodation. Dynamic measurement of higher and lower order aberrations was performed with a WASCA Wavefront Analyzer (Carl-Zeiss-Meditec) and a specially constructed target device for aligning objects in far and near distances on 25 subjects aged from 15 to 27 years old. Wavefront aberrations showed some significant changes in accommodation. In addition to the characteristic sphere reaction accompanying miosis and changes in horizontal prism (Z(1) (1)) in the sense of a convergence movement of the eyeball also occurred. Furthermore defocus rose (Z(2) (0)) and astigmatism (Z(2) (-2)) changed. In higher-order aberrations a decrease in coma-like Zernike polynomials (Z(3) (-1), Z(3) (1)) was found. The most obvious change appeared in spherical aberration (Z(4) (0)) which increased and changed from positive to negative. In addition the secondary astigmatism (Z(4) (-2)) and quadrafoil (Z(4) (4)) rise also increased. The total root mean square (RMS), as well as the higher-order aberrations (RMS-HO) significantly increased in accommodation which is associated with a theoretical reduction of visual acuity. An analysis of the influence of pupil size on aberrations showed significant increases in defocus, spherical aberration, quadrafoil, RMS and RMS HO by increasing pupil diameter. By accommodation-associated miosis, the growing aberrations are partially compensated by focusing on near objects. Temporal analysis of the accommodation process with dynamic wavefront analysis revealed significant delays in pupil response and changing of prism in relation to the sphere reaction. In accommodation to near objects a discrete time ahead of third order aberrations in relation to the sphere response was found. Using dynamic wavefront measurement

Monetary reward speeds up voluntary saccades.

Science.gov (United States)

Chen, Lewis L; Chen, Y Mark; Zhou, Wu; Mustain, William D

2014-01-01

Past studies have shown that reward contingency is critical for sensorimotor learning, and reward expectation speeds up saccades in animals. Whether monetary reward speeds up saccades in human remains unknown. Here we addressed this issue by employing a conditional saccade task, in which human subjects performed a series of non-reflexive, visually-guided horizontal saccades. The subjects were (or were not) financially compensated for making a saccade in response to a centrally-displayed visual congruent (or incongruent) stimulus. Reward modulation of saccadic velocities was quantified independently of the amplitude-velocity coupling. We found that reward expectation significantly sped up voluntary saccades up to 30°/s, and the reward modulation was consistent across tests. These findings suggest that monetary reward speeds up saccades in human in a fashion analogous to how juice reward sped up saccades in monkeys. We further noticed that the idiosyncratic nasal-temporal velocity asymmetry was highly consistent regardless of test order, and its magnitude was not correlated with the magnitude of reward modulation. This suggests that reward modulation and the intrinsic velocity asymmetry may be governed by separate mechanisms that regulate saccade generation.

Developmental changes in the reward positivity: An electrophysiological trajectory of reward processing

Directory of Open Access Journals (Sweden)

Carmen N. Lukie

2014-07-01

Full Text Available Children and adolescents learn to regulate their behavior by utilizing feedback from the environment but exactly how this ability develops remains unclear. To investigate this question, we recorded the event-related brain potential (ERP from children (8–13 years, adolescents (14–17 years and young adults (18–23 years while they navigated a “virtual maze” in pursuit of monetary rewards. The amplitude of the reward positivity, an ERP component elicited by feedback stimuli, was evaluated for each age group. A current theory suggests the reward positivity is produced by the impact of reinforcement learning signals carried by the midbrain dopamine system on anterior cingulate cortex, which utilizes the signals to learn and execute extended behaviors. We found that the three groups produced a reward positivity of comparable size despite relatively longer ERP component latencies for the children, suggesting that the reward processing system reaches maturity early in development. We propose that early development of the midbrain dopamine system facilitates the development of extended goal-directed behaviors in anterior cingulate cortex.

Amphetamine-induced sensitization and reward uncertainty similarly enhance incentive salience for conditioned cues

Science.gov (United States)

Robinson, Mike J.F.; Anselme, Patrick; Suchomel, Kristen; Berridge, Kent C.

2015-01-01

Amphetamine and stress can sensitize mesolimbic dopamine-related systems. In Pavlovian autoshaping, repeated exposure to uncertainty of reward prediction can enhance motivated sign-tracking or attraction to a discrete reward-predicting cue (lever CS+), as well as produce cross-sensitization to amphetamine. However, it remains unknown how amphetamine-sensitization or repeated restraint stress interact with uncertainty in controlling CS+ incentive salience attribution reflected in sign-tracking. Here rats were tested in three successive phases. First, different groups underwent either induction of amphetamine sensitization or repeated restraint stress, or else were not sensitized or stressed as control groups (either saline injections only, or no stress or injection at all). All next received Pavlovian autoshaping training under either certainty conditions (100% CS-UCS association) or uncertainty conditions (50% CS-UCS association and uncertain reward magnitude). During training, rats were assessed for sign-tracking to the lever CS+ versus goal-tracking to the sucrose dish. Finally, all groups were tested for psychomotor sensitization of locomotion revealed by an amphetamine challenge. Our results confirm that reward uncertainty enhanced sign-tracking attraction toward the predictive CS+ lever, at the expense of goal-tracking. We also report that amphetamine sensitization promoted sign-tracking even in rats trained under CS-UCS certainty conditions, raising them to sign-tracking levels equivalent to the uncertainty group. Combining amphetamine sensitization and uncertainty conditions together did not add together to elevate sign-tracking further above the relatively high levels induced by either manipulation alone. In contrast, repeated restraint stress enhanced subsequent amphetamine-elicited locomotion, but did not enhance CS+ attraction. PMID:26076340

Random reward priming is task-contingent

DEFF Research Database (Denmark)

Ásgeirsson, Árni Gunnar; Kristjánsson, Árni

2014-01-01

Consistent financial reward of particular features influences the allocation of visual attention in many ways. More surprising are 1-trial reward priming effects on attention where reward schedules are random and reward on one trial influences attentional allocation on the next. Those findings...

Effort–Reward Imbalance at Work and Incident Coronary Heart Disease

Science.gov (United States)

Siegrist, Johannes; Nyberg, Solja T.; Lunau, Thorsten; Fransson, Eleonor I.; Alfredsson, Lars; Bjorner, Jakob B.; Borritz, Marianne; Burr, Hermann; Erbel, Raimund; Fahlén, Göran; Goldberg, Marcel; Hamer, Mark; Heikkilä, Katriina; Jöckel, Karl-Heinz; Knutsson, Anders; Madsen, Ida E. H.; Nielsen, Martin L.; Nordin, Maria; Oksanen, Tuula; Pejtersen, Jan H.; Pentti, Jaana; Rugulies, Reiner; Salo, Paula; Schupp, Jürgen; Singh-Manoux, Archana; Steptoe, Andrew; Theorell, Töres; Vahtera, Jussi; Westerholm, Peter J. M.; Westerlund, Hugo; Virtanen, Marianna; Zins, Marie; Batty, G. David; Kivimäki, Mika

2017-01-01

Background: Epidemiologic evidence for work stress as a risk factor for coronary heart disease is mostly based on a single measure of stressful work known as job strain, a combination of high demands and low job control. We examined whether a complementary stress measure that assesses an imbalance between efforts spent at work and rewards received predicted coronary heart disease. Methods: This multicohort study (the “IPD-Work” consortium) was based on harmonized individual-level data from 11 European prospective cohort studies. Stressful work in 90,164 men and women without coronary heart disease at baseline was assessed by validated effort–reward imbalance and job strain questionnaires. We defined incident coronary heart disease as the first nonfatal myocardial infarction or coronary death. Study-specific estimates were pooled by random effects meta-analysis. Results: At baseline, 31.7% of study members reported effort–reward imbalance at work and 15.9% reported job strain. During a mean follow-up of 9.8 years, 1,078 coronary events were recorded. After adjustment for potential confounders, a hazard ratio of 1.16 (95% confidence interval, 1.00–1.35) was observed for effort–reward imbalance compared with no imbalance. The hazard ratio was 1.16 (1.01–1.34) for having either effort–reward imbalance or job strain and 1.41 (1.12–1.76) for having both these stressors compared to having neither effort–reward imbalance nor job strain. Conclusions: Individuals with effort–reward imbalance at work have an increased risk of coronary heart disease, and this appears to be independent of job strain experienced. These findings support expanding focus beyond just job strain in future research on work stress. PMID:28570388

Incremental effects of reward on creativity.

Science.gov (United States)

Eisenberger, R; Rhoades, L

2001-10-01

The authors examined 2 ways reward might increase creativity. First, reward contingent on creativity might increase extrinsic motivation. Studies 1 and 2 found that repeatedly giving preadolescent students reward for creative performance in 1 task increased their creativity in subsequent tasks. Study 3 reported that reward promised for creativity increased college students' creative task performance. Second, expected reward for high performance might increase creativity by enhancing perceived self-determination and, therefore, intrinsic task interest. Study 4 found that employees' intrinsic job interest mediated a positive relationship between expected reward for high performance and creative suggestions offered at work. Study 5 found that employees' perceived self-determination mediated a positive relationship between expected reward for high performance and the creativity of anonymous suggestions for helping the organization.

Genetic moderation of the association between regulatory focus and reward responsiveness: a proof-of-concept study.

Science.gov (United States)

Goetz, Elena L; Hariri, Ahmad R; Pizzagalli, Diego A; Strauman, Timothy J

2013-02-01

Recent studies implicate individual differences in regulatory focus as contributing to self-regulatory dysfunction, particularly not responding to positive outcomes. How such individual differences emerge, however, is unclear. We conducted a proof-of-concept study to examine the moderating effects of genetically driven variation in dopamine signaling, a key modulator of neural reward circuits, on the association between regulatory focus and reward cue responsiveness. Healthy Caucasians (N=59) completed a measure of chronic regulatory focus and a probabilistic reward task. A common functional genetic polymorphism impacting prefrontal dopamine signaling (COMT rs4680) was evaluated. Response bias, the participants' propensity to modulate behavior as a function of reward, was predicted by an interaction of regulatory focus and COMT genotype. Specifically, self-perceived success at achieving promotion goals predicted total response bias, but only for individuals with the COMT genotype (Val/Val) associated with relatively increased phasic dopamine signaling and cognitive flexibility. The combination of success in promotion goal pursuit and Val/Val genotype appears to facilitate responding to reward opportunities in the environment. This study is among the first to integrate an assessment of self-regulatory style with an examination of genetic variability that underlies responsiveness to positive outcomes in goal pursuit.

Biomarkers of threat and reward sensitivity demonstrate unique associations with risk for psychopathology.

Science.gov (United States)

Nelson, Brady D; McGowan, Sarah Kate; Sarapas, Casey; Robison-Andrew, E Jenna; Altman, Sarah E; Campbell, Miranda L; Gorka, Stephanie M; Katz, Andrea C; Shankman, Stewart A

2013-08-01

Two emotional/motivational constructs that have been posited to underlie anxiety and depressive disorders are heightened sensitivity to threat and reduced sensitivity to reward, respectively. It is unclear, though, whether these constructs are only epiphenomena or also connote risk for these disorders (and relatedly, whether they connote risk for separate disorders). Using family history of psychopathology as an indicator of risk, the present study examined whether biomarkers of sensitivity to threat (startle potentiation) and reward (frontal EEG asymmetry) were associated with similar or different familial liabilities. In addition, the present study examined whether these biomarkers were associated with risk independent of proband DSM-IV diagnosis. One-hundred and seventy-three individuals diagnosed with panic disorder (PD), early onset major depressive disorder (MDD), both (comorbids), or controls completed two laboratory paradigms assessing sensitivity to predictable/unpredictable threat (measured via startle response) and reward (measured via frontal EEG asymmetry during a gambling task). Results indicated that across all participants: (a) startle potentiation to unpredictable threat was associated with family history of PD (but not MDD); and (b) frontal EEG asymmetry while anticipating reward was associated with family history of MDD (but not PD). Additionally, both measures continued to be associated with family history of psychopathology after controlling for proband DSM-IV diagnosis. Results suggest that the proposed biomarkers of sensitivity to unpredictable threat and reward exhibit discriminant validity and may add to the predictive validity of the DSM-IV defined constructs of PD and MDD, respectively. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Aberrant DNA Methylation in Chronic Myeloid Leukemia: Cell Fate Control, Prognosis, and Therapeutic Response.

Science.gov (United States)

Behzad, Masumeh Maleki; Shahrabi, Saeid; Jaseb, Kaveh; Bertacchini, Jessika; Ketabchi, Neda; Saki, Najmaldin

2018-01-31

Chronic myeloid leukemia (CML) is a hematopoietic stem cell malignancy characterized by the expression of the BCR-ABL1 fusion gene with different chimeric transcripts. Despite the crucial impact of constitutively active tyrosine kinase in CML pathogenesis, aberrant DNA methylation of certain genes plays an important role in disease progression and the development of drug resistance. This article reviews recent findings relevant to the effect of DNA methylation pattern of regulatory genes on various cellular activities such as cell proliferation and survival, as well as cell-signaling molecules in CML. These data might contribute to defining the role of aberrant DNA methylation in disease initiation and progression. However, further studies are needed on the validation of specific aberrant methylation markers regarding the prognosis and prediction of response among the CML patients.

Rewarding Leadership and Fair Procedures as Determinants of Self-Esteem

NARCIS (Netherlands)

de Cremer, D.A.; van Knippenberg, B.M.; van Knippenberg, D.; Mullenders, D.; Stinglhamber, F.

2005-01-01

In the present research, the authors examined the effect of procedural fairness and rewarding leadership style on an important variable for employees: self-esteem. The authors predicted that procedural fairness would positively influence people's reported self-esteem if the leader adopted a style of

Effects of material and non-material rewards on remembering to do things for others

Directory of Open Access Journals (Sweden)

Maria A. Brandimonte

2015-12-01

Full Text Available Recent research has shown that pro-social prospective memory, i.e., remembering to do something for others, is negatively affected by the presence of small material rewards. While this competition between pro-social and self-gain motives leads to poor memory for the intention, people do not seem to be aware of the possible collision effects of competing motives (Brandimonte, Ferrante, Bianco, & Villani, 2010. Extending research on this general topic, in two activity-based prospective memory experiments, we explored the effects of different types and amount of rewards on pro-social prospective remembering. In Experiment 1, participants could receive no reward, a low material reward (1 euro, or a high material reward (20 euro for their pro-social prospective memory action. In Experiment 2, their pro-social prospective memory performance could be rewarded or not with an image reward (publicity of their altruistic behavior. Results revealed that introducing a small material reward (Experiment 1 or a non-material reward (Experiment 2 impaired pro-social prospective memory. However, introducing a high material reward eliminated the impairment (Experiment 1. Importantly, in Experiment 1, ongoing task performance in the pro-social condition was faster than in the No PM condition. However, in Experiment 2, ongoing task costs emerged in the presence of a non-material reward, as compared to the pro-social condition. Also, results from two independent ratings showed that people’s predictions on their future pro-social actions were at odds (Experiment 1 or in line (Experiment 2 with actual PM performance. It is suggested that, according to the nature and amount of rewards, memory for a pro-social future action may be modulated by conscious or unconscious motivational mechanisms.

Sensitivity and bias in decision-making under risk: evaluating the perception of reward, its probability and value.

Directory of Open Access Journals (Sweden)

Madeleine E Sharp

Full Text Available BACKGROUND: There are few clinical tools that assess decision-making under risk. Tests that characterize sensitivity and bias in decisions between prospects varying in magnitude and probability of gain may provide insights in conditions with anomalous reward-related behaviour. OBJECTIVE: We designed a simple test of how subjects integrate information about the magnitude and the probability of reward, which can determine discriminative thresholds and choice bias in decisions under risk. DESIGN/METHODS: Twenty subjects were required to choose between two explicitly described prospects, one with higher probability but lower magnitude of reward than the other, with the difference in expected value between the two prospects varying from 3 to 23%. RESULTS: Subjects showed a mean threshold sensitivity of 43% difference in expected value. Regarding choice bias, there was a 'risk premium' of 38%, indicating a tendency to choose higher probability over higher reward. An analysis using prospect theory showed that this risk premium is the predicted outcome of hypothesized non-linearities in the subjective perception of reward value and probability. CONCLUSIONS: This simple test provides a robust measure of discriminative value thresholds and biases in decisions under risk. Prospect theory can also make predictions about decisions when subjective perception of reward or probability is anomalous, as may occur in populations with dopaminergic or striatal dysfunction, such as Parkinson's disease and schizophrenia.

Sensitivity and Bias in Decision-Making under Risk: Evaluating the Perception of Reward, Its Probability and Value

Science.gov (United States)

Sharp, Madeleine E.; Viswanathan, Jayalakshmi; Lanyon, Linda J.; Barton, Jason J. S.

2012-01-01

Background There are few clinical tools that assess decision-making under risk. Tests that characterize sensitivity and bias in decisions between prospects varying in magnitude and probability of gain may provide insights in conditions with anomalous reward-related behaviour. Objective We designed a simple test of how subjects integrate information about the magnitude and the probability of reward, which can determine discriminative thresholds and choice bias in decisions under risk. Design/Methods Twenty subjects were required to choose between two explicitly described prospects, one with higher probability but lower magnitude of reward than the other, with the difference in expected value between the two prospects varying from 3 to 23%. Results Subjects showed a mean threshold sensitivity of 43% difference in expected value. Regarding choice bias, there was a ‘risk premium’ of 38%, indicating a tendency to choose higher probability over higher reward. An analysis using prospect theory showed that this risk premium is the predicted outcome of hypothesized non-linearities in the subjective perception of reward value and probability. Conclusions This simple test provides a robust measure of discriminative value thresholds and biases in decisions under risk. Prospect theory can also make predictions about decisions when subjective perception of reward or probability is anomalous, as may occur in populations with dopaminergic or striatal dysfunction, such as Parkinson's disease and schizophrenia. PMID:22493669

Multi-layer network utilizing rewarded spike time dependent plasticity to learn a foraging task.

Directory of Open Access Journals (Sweden)

Pavel Sanda

2017-09-01

Full Text Available Neural networks with a single plastic layer employing reward modulated spike time dependent plasticity (STDP are capable of learning simple foraging tasks. Here we demonstrate advanced pattern discrimination and continuous learning in a network of spiking neurons with multiple plastic layers. The network utilized both reward modulated and non-reward modulated STDP and implemented multiple mechanisms for homeostatic regulation of synaptic efficacy, including heterosynaptic plasticity, gain control, output balancing, activity normalization of rewarded STDP and hard limits on synaptic strength. We found that addition of a hidden layer of neurons employing non-rewarded STDP created neurons that responded to the specific combinations of inputs and thus performed basic classification of the input patterns. When combined with a following layer of neurons implementing rewarded STDP, the network was able to learn, despite the absence of labeled training data, discrimination between rewarding patterns and the patterns designated as punishing. Synaptic noise allowed for trial-and-error learning that helped to identify the goal-oriented strategies which were effective in task solving. The study predicts a critical set of properties of the spiking neuronal network with STDP that was sufficient to solve a complex foraging task involving pattern classification and decision making.

Neural evidence for description dependent reward processing in the framing effect

Science.gov (United States)

Yu, Rongjun; Zhang, Ping

2014-01-01

Human decision making can be influenced by emotionally valenced contexts, known as the framing effect. We used event-related brain potentials to investigate how framing influences the encoding of reward. We found that the feedback related negativity (FRN), which indexes the “worse than expected” negative prediction error in the anterior cingulate cortex (ACC), was more negative for the negative frame than for the positive frame in the win domain. Consistent with previous findings that the FRN is not sensitive to “better than expected” positive prediction error, the FRN did not differentiate the positive and negative frame in the loss domain. Our results provide neural evidence that the description invariance principle which states that reward representation and decision making are not influenced by how options are presented is violated in the framing effect. PMID:24733998

Imaging characteristics of Zernike and annular polynomial aberrations.

Science.gov (United States)

Mahajan, Virendra N; Díaz, José Antonio

2013-04-01

The general equations for the point-spread function (PSF) and optical transfer function (OTF) are given for any pupil shape, and they are applied to optical imaging systems with circular and annular pupils. The symmetry properties of the PSF, the real and imaginary parts of the OTF, and the modulation transfer function (MTF) of a system with a circular pupil aberrated by a Zernike circle polynomial aberration are derived. The interferograms and PSFs are illustrated for some typical polynomial aberrations with a sigma value of one wave, and 3D PSFs and MTFs are shown for 0.1 wave. The Strehl ratio is also calculated for polynomial aberrations with a sigma value of 0.1 wave, and shown to be well estimated from the sigma value. The numerical results are compared with the corresponding results in the literature. Because of the same angular dependence of the corresponding annular and circle polynomial aberrations, the symmetry properties of systems with annular pupils aberrated by an annular polynomial aberration are the same as those for a circular pupil aberrated by a corresponding circle polynomial aberration. They are also illustrated with numerical examples.

Signals can trump rewards in attracting seed-dispersing ants.

Directory of Open Access Journals (Sweden)

Kyle M Turner

Full Text Available Both rewards and signals are important in mutualisms. In myrmecochory, or seed dispersal by ants, the benefits to plants are relatively well studied, but less is known about why ants pick up and move seeds. We examined seed dispersal by the ant Aphaenogaster rudis of four co-occurring species of plants, and tested whether morphology, chemical signaling, or the nutritional quality of fatty seed appendages called elaiosomes influenced dispersal rates. In removal trials, ants quickly collected diaspores (seeds plus elaiosomes of Asarum canadense, Trillium grandiflorum, and Sanguinaria canadensis, but largely neglected those of T. erectum. This discrepancy was not explained by differences in the bulk cost-benefit ratio, as assessed by the ratio of seed to elaiosome mass. We also provisioned colonies with diaspores from one of these four plant species or no diaspores as a control. Colonies performed best when fed S. canadensis diaspores, worst when fed T. grandiflorum, and intermediately when fed A. canadense, T. erectum, or no diaspores. Thus, the nutritional rewards in elaiosomes affected colony performance, but did not completely predict seed removal. Instead, high levels of oleic acid in T. grandiflorum elaiosomes may explain why ants disperse these diaspores even though they reduce ant colony performance. We show for the first time that different elaiosome-bearing plants provide rewards of different quality to ant colonies, but also that ants appear unable to accurately assess reward quality when encountering seeds. Instead, we suggest that signals can trump rewards as attractants of ants to seeds.

Discrete-time rewards model-checked

NARCIS (Netherlands)

Larsen, K.G.; Andova, S.; Niebert, Peter; Hermanns, H.; Katoen, Joost P.

2003-01-01

This paper presents a model-checking approach for analyzing discrete-time Markov reward models. For this purpose, the temporal logic probabilistic CTL is extended with reward constraints. This allows to formulate complex measures – involving expected as well as accumulated rewards – in a precise and

Geometric characteristics of aberrations of plane-symmetric optical systems

International Nuclear Information System (INIS)

Lu Lijun; Deng Zhiyong

2009-01-01

The geometric characteristics of aberrations of plane-symmetric optical systems are studied in detail with a wave-aberration theory. It is dealt with as an extension of the Seidel aberrations to realize a consistent aberration theory from axially symmetric to plane-symmetric systems. The aberration distribution is analyzed with the spot diagram of a ray and an aberration curve. Moreover, the root-mean-square value and the centroid of aberration distribution are discussed. The numerical results are obtained with the focusing optics of a toroidal mirror at grazing incidence.

Nodal aberration theory applied to freeform surfaces

Science.gov (United States)

Fuerschbach, Kyle; Rolland, Jannick P.; Thompson, Kevin P.

2014-12-01

When new three-dimensional packages are developed for imaging optical systems, the rotational symmetry of the optical system is often broken, changing its imaging behavior and making the optical performance worse. A method to restore the performance is to use freeform optical surfaces that compensate directly the aberrations introduced from tilting and decentering the optical surfaces. In order to effectively optimize the shape of a freeform surface to restore optical functionality, it is helpful to understand the aberration effect the surface may induce. Using nodal aberration theory the aberration fields induced by a freeform surface in an optical system are explored. These theoretical predications are experimentally validated with the design and implementation of an aberration generating telescope.

Reward reduces conflict by enhancing attentional control and biasing visual cortical processing.

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Padmala, Srikanth; Pessoa, Luiz

2011-11-01

How does motivation interact with cognitive control during challenging behavioral conditions? Here, we investigated the interactions between motivation and cognition during a response conflict task and tested a specific model of the effect of reward on cognitive processing. Behaviorally, participants exhibited reduced conflict during the reward versus no-reward condition. Brain imaging results revealed that a group of subcortical and fronto-parietal regions was robustly influenced by reward at cue processing and, importantly, that cue-related responses in fronto-parietal attentional regions were predictive of reduced conflict-related signals in the medial pFC (MPFC)/ACC during the upcoming target phase. Path analysis revealed that the relationship between cue responses in the right intraparietal sulcus (IPS) and interference-related responses in the MPFC during the subsequent target phase was mediated via signals in the left fusiform gyrus, which we linked to distractor-related processing. Finally, reward increased functional connectivity between the right IPS and both bilateral putamen and bilateral nucleus accumbens during the cue phase, a relationship that covaried with across-individual sensitivity to reward in the case of the right nucleus accumbens. Taken together, our findings are consistent with a model in which motivationally salient cues are employed to upregulate top-down control processes that bias the selection of visual information, thereby leading to more efficient stimulus processing during conflict conditions.

Adolescents, adults and rewards: comparing motivational neurocircuitry recruitment using fMRI.

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James M Bjork

Full Text Available BACKGROUND: Adolescent risk-taking, including behaviors resulting in injury or death, has been attributed in part to maturational differences in mesolimbic incentive-motivational neurocircuitry, including ostensible oversensitivity of the nucleus accumbens (NAcc to rewards. METHODOLOGY/PRINCIPAL FINDINGS: To test whether adolescents showed increased NAcc activation by cues for rewards, or by delivery of rewards, we scanned 24 adolescents (age 12-17 and 24 adults age (22-42 with functional magnetic resonance imaging while they performed a monetary incentive delay (MID task. The MID task was configured to temporally disentangle potential reward or potential loss anticipation-related brain signal from reward or loss notification-related signal. Subjects saw cues signaling opportunities to win or avoid losing $0, $.50, or $5 for responding quickly to a subsequent target. Subjects then viewed feedback of their trial success after a variable interval from cue presentation of between 6 to 17 s. Adolescents showed reduced NAcc recruitment by reward-predictive cues compared to adult controls in a linear contrast with non-incentive cues, and in a volume-of-interest analysis of signal change in the NAcc. In contrast, adolescents showed little difference in striatal and frontocortical responsiveness to reward deliveries compared to adults. CONCLUSIONS/SIGNIFICANCE: In light of divergent developmental difference findings between neuroimaging incentive paradigms (as well as at different stages within the same task, these data suggest that maturational differences in incentive-motivational neurocircuitry: 1 may be sensitive to nuances of incentive tasks or stimuli, such as behavioral or learning contingencies, and 2 may be specific to the component of the instrumental behavior (such as anticipation versus notification.

Reward processing in the value-driven attention network: reward signals tracking cue identity and location.

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Anderson, Brian A

2017-03-01

Through associative reward learning, arbitrary cues acquire the ability to automatically capture visual attention. Previous studies have examined the neural correlates of value-driven attentional orienting, revealing elevated activity within a network of brain regions encompassing the visual corticostriatal loop [caudate tail, lateral occipital complex (LOC) and early visual cortex] and intraparietal sulcus (IPS). Such attentional priority signals raise a broader question concerning how visual signals are combined with reward signals during learning to create a representation that is sensitive to the confluence of the two. This study examines reward signals during the cued reward training phase commonly used to generate value-driven attentional biases. High, compared with low, reward feedback preferentially activated the value-driven attention network, in addition to regions typically implicated in reward processing. Further examination of these reward signals within the visual system revealed information about the identity of the preceding cue in the caudate tail and LOC, and information about the location of the preceding cue in IPS, while early visual cortex represented both location and identity. The results reveal teaching signals within the value-driven attention network during associative reward learning, and further suggest functional specialization within different regions of this network during the acquisition of an integrated representation of stimulus value. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Individual differences in sensitivity to reward and punishment and neural activity during reward and avoidance learning.

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Kim, Sang Hee; Yoon, HeungSik; Kim, Hackjin; Hamann, Stephan

2015-09-01

In this functional neuroimaging study, we investigated neural activations during the process of learning to gain monetary rewards and to avoid monetary loss, and how these activations are modulated by individual differences in reward and punishment sensitivity. Healthy young volunteers performed a reinforcement learning task where they chose one of two fractal stimuli associated with monetary gain (reward trials) or avoidance of monetary loss (avoidance trials). Trait sensitivity to reward and punishment was assessed using the behavioral inhibition/activation scales (BIS/BAS). Functional neuroimaging results showed activation of the striatum during the anticipation and reception periods of reward trials. During avoidance trials, activation of the dorsal striatum and prefrontal regions was found. As expected, individual differences in reward sensitivity were positively associated with activation in the left and right ventral striatum during reward reception. Individual differences in sensitivity to punishment were negatively associated with activation in the left dorsal striatum during avoidance anticipation and also with activation in the right lateral orbitofrontal cortex during receiving monetary loss. These results suggest that learning to attain reward and learning to avoid loss are dependent on separable sets of neural regions whose activity is modulated by trait sensitivity to reward or punishment. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Response of the REWARD detection system to the presence of a Radiological Dispersal Device

International Nuclear Information System (INIS)

Luís, R.; Fleta, C.; Balbuena, J.; Baptista, M.; Barros, S.; Disch, C.; Jumilla, C.; Lozano, M.; Marques, J.G.; Vaz, P.

2016-01-01

The objective of the REWARD project consisted in building a mobile system for real time, wide area radiation surveillance, using a CdZnTe detector for gamma radiation and a neutron detector based on novel silicon technologies. The sensing unit includes a GPS system and a wireless communication interface to send the data remotely to a monitoring base station, where it will be analyzed in real time and correlated with historical data from the tag location, in order to generate an alarm when an abnormal situation is detected. The main objective of this work consisted in making predictions regarding the behavior of the REWARD system in the presence of a Radiological Dispersion Device (RDD), one of the reference scenarios foreseen for REWARD, using experimental data and the Monte Carlo simulation program MCNP6. Experimental tests were performed at the Fire Brigades Facilities in Rome and at the Naples Fire Brigades. The response of the REWARD detection system to the presence of an RDD is predicted and discussed. - Highlights: • A prototype mobile system for real-time, wide-area radiation surveillance was built. • Experimental measurements and Monte Carlo simulations were used to test the system. • The system is suitable to detect and identify radiation sources in threat scenarios.

Visual sexual stimuli – cue or reward? A key for interpreting brain imaging studies on human sexual behaviors

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Mateusz Gola

2016-08-01

Full Text Available There is an increasing number of neuroimaging studies using visual sexual stimuli (VSS for human sexuality studies, including emerging field of research on compulsive sexual behaviors. A central question in this field is whether behaviors such as extensive pornography consumption share common brain mechanisms with widely studied substance and behavioral addictions. Depending on how VSS are conceptualized, different predictions can be formulated within the frameworks of Reinforcement Learning or Incentive Salience Theory, where a crucial distinction is made between conditioned (cue and unconditioned (reward stimuli (related to reward anticipation vs reward consumption, respectively. Surveying 40 recent human neuroimaging studies we show existing ambiguity about the conceptualization of VSS. Therefore, we feel that it is important to address the question of whether VSS should be considered as cues (conditioned stimuli or rewards (unconditioned stimuli. Here we present our own perspective, which is that in most laboratory settings VSS play a role of reward (unconditioned stimuli, as evidenced by: 1. experience of pleasure while watching VSS, possibly accompanied by genital reaction 2. reward-related brain activity correlated with these pleasurable feelings in response to VSS, 3. a willingness to exert effort to view VSS similarly as for other rewarding stimuli such as money, and/or 4. conditioning for cues (CS predictive for. We hope that this perspective paper will initiate a scientific discussion on this important and overlooked topic and increase attention for appropriate interpretations of results of human neuroimaging studies using VSS.

Learned reward association improves visual working memory.

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Gong, Mengyuan; Li, Sheng

2014-04-01

Statistical regularities in the natural environment play a central role in adaptive behavior. Among other regularities, reward association is potentially the most prominent factor that influences our daily life. Recent studies have suggested that pre-established reward association yields strong influence on the spatial allocation of attention. Here we show that reward association can also improve visual working memory (VWM) performance when the reward-associated feature is task-irrelevant. We established the reward association during a visual search training session, and investigated the representation of reward-associated features in VWM by the application of a change detection task before and after the training. The results showed that the improvement in VWM was significantly greater for items in the color associated with high reward than for those in low reward-associated or nonrewarded colors. In particular, the results from control experiments demonstrate that the observed reward effect in VWM could not be sufficiently accounted for by attentional capture toward the high reward-associated item. This was further confirmed when the effect of attentional capture was minimized by presenting the items in the sample and test displays of the change detection task with the same color. The results showed significantly larger improvement in VWM performance when the items in a display were in the high reward-associated color than those in the low reward-associated or nonrewarded colors. Our findings suggest that, apart from inducing space-based attentional capture, the learned reward association could also facilitate the perceptual representation of high reward-associated items through feature-based attentional modulation.

From conflict management to reward-based decision making: actors and critics in primate medial frontal cortex.

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Silvetti, Massimo; Alexander, William; Verguts, Tom; Brown, Joshua W

2014-10-01

The role of the medial prefrontal cortex (mPFC) and especially the anterior cingulate cortex has been the subject of intense debate for the last decade. A number of theories have been proposed to account for its function. Broadly speaking, some emphasize cognitive control, whereas others emphasize value processing; specific theories concern reward processing, conflict detection, error monitoring, and volatility detection, among others. Here we survey and evaluate them relative to experimental results from neurophysiological, anatomical, and cognitive studies. We argue for a new conceptualization of mPFC, arising from recent computational modeling work. Based on reinforcement learning theory, these new models propose that mPFC is an Actor-Critic system. This system is aimed to predict future events including rewards, to evaluate errors in those predictions, and finally, to implement optimal skeletal-motor and visceromotor commands to obtain reward. This framework provides a comprehensive account of mPFC function, accounting for and predicting empirical results across different levels of analysis, including monkey neurophysiology, human ERP, human neuroimaging, and human behavior. Copyright © 2013 Elsevier Ltd. All rights reserved.

BOLD responses in reward regions to hypothetical and imaginary monetary rewards

NARCIS (Netherlands)

Miyapuram, K.P.; Tobler, P.N.; Gregorios-Pippas, L.; Schultz, W.

2012-01-01

Monetary rewards are uniquely human. Because money is easy to quantify and present visually, it is the reward of choice for most fMRI studies, even though it cannot be handed over to participants inside the scanner. A typical fMRI study requires hundreds of trials and thus small amounts of monetary

Neural processing of calories in brain reward areas can be modulated by reward sensitivity

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Inge eVan Rijn

2016-01-01

Full Text Available A food’s reward value is dependent on its caloric content. Furthermore, a food’s acute reward value also depends on hunger state. The drive to obtain rewards (reward sensitivity, however, differs between individuals. Here, we assessed the association between brain responses to calories in the mouth and trait reward sensitivity in different hunger states. Firstly, we assessed this in data from a functional neuroimaging study (van Rijn et al., 2015, in which participants (n=30 tasted simple solutions of a non-caloric sweetener with or without a non-sweet carbohydrate (maltodextrin during hunger and satiety. Secondly, we expanded these analyses to regular drinks by assessing the same relationship in data from a study in which soft drinks sweetened with either sucrose or a non-caloric sweetener were administered during hunger (n=18 (Griffioen-Roose et al., 2013. First, taste activation by the non-caloric solution/soft drink was subtracted from that by the caloric solution/soft drink to eliminate sweetness effects and retain activation induced by calories. Subsequently, this difference in taste activation was correlated with reward sensitivity as measured with the BAS drive subscale of the Behavioral Activation System (BAS questionnaire.When participants were hungry and tasted calories from the simple solution, brain activation in the right ventral striatum (caudate, right amygdala and anterior cingulate cortex (bilaterally correlated negatively with BAS drive scores. In contrast, when participants were satiated, taste responses correlated positively with BAS drive scores in the left caudate. These results were not replicated for soft drinks. Thus, neural responses to oral calories from maltodextrin were modulated by reward sensitivity in reward-related brain areas. This was not the case for sucrose. This may be due to the direct detection of maltodextrin, but not sucrose in the oral cavity. Also, in a familiar beverage, detection of calories per

Neural Processing of Calories in Brain Reward Areas Can be Modulated by Reward Sensitivity.

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van Rijn, Inge; Griffioen-Roose, Sanne; de Graaf, Cees; Smeets, Paul A M

2015-01-01

A food's reward value is dependent on its caloric content. Furthermore, a food's acute reward value also depends on hunger state. The drive to obtain rewards (reward sensitivity), however, differs between individuals. Here, we assessed the association between brain responses to calories in the mouth and trait reward sensitivity in different hunger states. Firstly, we assessed this in data from a functional neuroimaging study (van Rijn et al., 2015), in which participants (n = 30) tasted simple solutions of a non-caloric sweetener with or without a non-sweet carbohydrate (maltodextrin) during hunger and satiety. Secondly, we expanded these analyses to regular drinks by assessing the same relationship in data from a study in which soft drinks sweetened with either sucrose or a non-caloric sweetener were administered during hunger (n = 18) (Griffioen-Roose et al., 2013). First, taste activation by the non-caloric solution/soft drink was subtracted from that by the caloric solution/soft drink to eliminate sweetness effects and retain activation induced by calories. Subsequently, this difference in taste activation was correlated with reward sensitivity as measured with the BAS drive subscale of the Behavioral Activation System (BAS) questionnaire. When participants were hungry and tasted calories from the simple solution, brain activation in the right ventral striatum (caudate), right amygdala and anterior cingulate cortex (bilaterally) correlated negatively with BAS drive scores. In contrast, when participants were satiated, taste responses correlated positively with BAS drive scores in the left caudate. These results were not replicated for soft drinks. Thus, neural responses to oral calories from maltodextrin were modulated by reward sensitivity in reward-related brain areas. This was not the case for sucrose. This may be due to the direct detection of maltodextrin, but not sucrose in the oral cavity. Also, in a familiar beverage, detection of calories per se may be

Excessive body fat linked to blunted somatosensory cortex response to general reward in adolescents.

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Navas, J F; Barrós-Loscertales, A; Costumero-Ramos, V; Verdejo-Román, J; Vilar-López, R; Verdejo-García, A

2018-01-01

The brain reward system is key to understanding adolescent obesity in the current obesogenic environment, rich in highly appetising stimuli, to which adolescents are particularly sensitive. We aimed to examine the association between body fat levels and brain reward system responsivity to general (monetary) rewards in male and female adolescents. Sixty-eight adolescents (34 females; mean age (s.d.)= 16.56 (1.35)) were measured for body fat levels with bioelectric impedance, and underwent a functional magnetic resonance imaging (fMRI) scan during the Monetary Incentive Delay (MID) task. The MID task reliably elicits brain activations associated with two fundamental aspects of reward processing: anticipation and feedback. We conducted regression analyses to examine the association between body fat and brain reward system responsivity during reward anticipation and feedback, while controlling for sex, age and socioeconomic status. We also analysed the moderating impact of sex on the relationship between fat levels and brain responsivity measures. Brain imaging analyses were corrected for multiple comparisons, with a cluster-defining threshold of Preward feedback after controlling for key sociodemographic variables. Although we did not find significant associations between body fat and brain activations during reward anticipation, S1/supramarginal gyrus activation during feedback was linked to increased negative prediction error, that is, less reward than expected, in illustrative post hoc analyses. Sex did not significantly moderate the association between body fat and brain activation in the MID task. In adolescents, higher adiposity is linked to hypo-responsivity of somatosensory regions during general (monetary) reward feedback. Findings suggest that adolescents with excess weight have blunted activation in somatosensory regions involved in reward feedback learning.

Remembering with gains and losses: effects of monetary reward and punishment on successful encoding activation of source memories.

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Shigemune, Yayoi; Tsukiura, Takashi; Kambara, Toshimune; Kawashima, Ryuta

2014-05-01

The motivation of getting rewards or avoiding punishments reinforces learning behaviors. Although the neural mechanisms underlying the effect of rewards on episodic memory have been demonstrated, there is little evidence of the effect of punishments on this memory. Our functional magnetic resonance imaging (fMRI) study investigated the effects of monetary rewards and punishments on activation during the encoding of source memories. During encoding, participants memorized words (item) and locations of presented words (source) under 3 conditions (Reward, Punishment, and Control). During retrieval, participants retrieved item and source memories of the words and were rewarded or penalized according to their performance. Source memories encoded with rewards or punishments were remembered better than those without such encoding. fMRI data demonstrated that the ventral tegmental area and substantia nigra and nucleus accumbens activations reflected both the processes of reward and punishment, whereas insular activation increased as a linear function of punishment. Activation in the hippocampus and parahippocampal cortex predicted subsequent retrieval success of source memories. Additionally, correlations between these reward/punishment-related regions and the hippocampus were significant. The successful encoding of source memories could be enhanced by punishments and rewards, and interactions between reward/punishment-related regions and memory-related regions could contribute to memory enhancement by reward and/or punishment.

Remembering with Gains and Losses: Effects of Monetary Reward and Punishment on Successful Encoding Activation of Source Memories

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Shigemune, Yayoi; Tsukiura, Takashi; Kambara, Toshimune; Kawashima, Ryuta

2014-01-01

The motivation of getting rewards or avoiding punishments reinforces learning behaviors. Although the neural mechanisms underlying the effect of rewards on episodic memory have been demonstrated, there is little evidence of the effect of punishments on this memory. Our functional magnetic resonance imaging (fMRI) study investigated the effects of monetary rewards and punishments on activation during the encoding of source memories. During encoding, participants memorized words (item) and locations of presented words (source) under 3 conditions (Reward, Punishment, and Control). During retrieval, participants retrieved item and source memories of the words and were rewarded or penalized according to their performance. Source memories encoded with rewards or punishments were remembered better than those without such encoding. fMRI data demonstrated that the ventral tegmental area and substantia nigra and nucleus accumbens activations reflected both the processes of reward and punishment, whereas insular activation increased as a linear function of punishment. Activation in the hippocampus and parahippocampal cortex predicted subsequent retrieval success of source memories. Additionally, correlations between these reward/punishment-related regions and the hippocampus were significant. The successful encoding of source memories could be enhanced by punishments and rewards, and interactions between reward/punishment-related regions and memory-related regions could contribute to memory enhancement by reward and/or punishment. PMID:23314939

Amphetamine-induced sensitization and reward uncertainty similarly enhance incentive salience for conditioned cues.

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Robinson, Mike J F; Anselme, Patrick; Suchomel, Kristen; Berridge, Kent C

2015-08-01

Amphetamine and stress can sensitize mesolimbic dopamine-related systems. In Pavlovian autoshaping, repeated exposure to uncertainty of reward prediction can enhance motivated sign-tracking or attraction to a discrete reward-predicting cue (lever-conditioned stimulus; CS+), as well as produce cross-sensitization to amphetamine. However, it remains unknown how amphetamine sensitization or repeated restraint stress interact with uncertainty in controlling CS+ incentive salience attribution reflected in sign-tracking. Here rats were tested in 3 successive phases. First, different groups underwent either induction of amphetamine sensitization or repeated restraint stress, or else were not sensitized or stressed as control groups (either saline injections only, or no stress or injection at all). All next received Pavlovian autoshaping training under either certainty conditions (100% CS-UCS association) or uncertainty conditions (50% CS-UCS association and uncertain reward magnitude). During training, rats were assessed for sign-tracking to the CS+ lever versus goal-tracking to the sucrose dish. Finally, all groups were tested for psychomotor sensitization of locomotion revealed by an amphetamine challenge. Our results confirm that reward uncertainty enhanced sign-tracking attraction toward the predictive CS+ lever, at the expense of goal-tracking. We also reported that amphetamine sensitization promoted sign-tracking even in rats trained under CS-UCS certainty conditions, raising them to sign-tracking levels equivalent to the uncertainty group. Combining amphetamine sensitization and uncertainty conditions did not add together to elevate sign-tracking further above the relatively high levels induced by either manipulation alone. In contrast, repeated restraint stress enhanced subsequent amphetamine-elicited locomotion, but did not enhance CS+ attraction. (c) 2015 APA, all rights reserved).

Burnout among psychosocial oncologists: an application and extension of the effort–reward imbalance model

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Rasmussen, Victoria; Turnell, Adrienne; Butow, Phyllis; Juraskova, Ilona; Kirsten, Laura; Wiener, Lori; Patenaude, Andrea; Hoekstra-Weebers, Josette; Grassi, Luigi

2016-01-01

Objectives Burnout is a significant problem among healthcare professionals working within the oncology setting. This study aimed to investigate predictors of emotional exhaustion (EE) and depersonalisation (DP) in psychosocial oncologists, through the application of the effort–reward imbalance (ERI) model with an additional focus on the role of meaningful work in the burnout process. Methods Psychosocial oncology clinicians (n = 417) in direct patient contact who were proficient in English were recruited from 10 international psychosocial oncology societies. Participants completed an online questionnaire, which included measures of demographic and work characteristics, EE and DP subscales of the Maslach Burnout Inventory-Human Services Survey, the Short Version ERI Questionnaire and the Work and Meaning Inventory. Results Higher effort and lower reward were both significantly associated with greater EE, although not DP. The interaction of higher effort and lower reward did not predict greater EE or DP. Overcommitment predicted both EE and DP but did not moderate the impact of effort and reward on burnout. Overall, the ERI model accounted for 33% of the variance in EE. Meaningful work significantly predicted both EE and DP but accounted for only 2% more of the variance in EE above and beyond the ERI model. Conclusions The ERI was only partially supported as a useful framework for investigating burnout in psychosocial oncology professionals. Meaningful work may be a viable extension of the ERI model. Burnout among health professionals may be reduced by interventions aimed at increasing self-efficacy and changes to the supportive work environment. PMID:26239424

Two spatiotemporally distinct value systems shape reward-based learning in the human brain.

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Fouragnan, Elsa; Retzler, Chris; Mullinger, Karen; Philiastides, Marios G

2015-09-08

Avoiding repeated mistakes and learning to reinforce rewarding decisions is critical for human survival and adaptive actions. Yet, the neural underpinnings of the value systems that encode different decision-outcomes remain elusive. Here coupling single-trial electroencephalography with simultaneously acquired functional magnetic resonance imaging, we uncover the spatiotemporal dynamics of two separate but interacting value systems encoding decision-outcomes. Consistent with a role in regulating alertness and switching behaviours, an early system is activated only by negative outcomes and engages arousal-related and motor-preparatory brain structures. Consistent with a role in reward-based learning, a later system differentially suppresses or activates regions of the human reward network in response to negative and positive outcomes, respectively. Following negative outcomes, the early system interacts and downregulates the late system, through a thalamic interaction with the ventral striatum. Critically, the strength of this coupling predicts participants' switching behaviour and avoidance learning, directly implicating the thalamostriatal pathway in reward-based learning.

Reactivation of Reward-Related Patterns from Single Past Episodes Supports Memory-Based Decision Making.

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Wimmer, G Elliott; Büchel, Christian

2016-03-09

Rewarding experiences exert a strong influence on later decision making. While decades of neuroscience research have shown how reinforcement gradually shapes preferences, decisions are often influenced by single past experiences. Surprisingly, relatively little is known about the influence of single learning episodes. Although recent work has proposed a role for episodes in decision making, it is largely unknown whether and how episodic experiences contribute to value-based decision making and how the values of single episodes are represented in the brain. In multiple behavioral experiments and an fMRI experiment, we tested whether and how rewarding episodes could support later decision making. Participants experienced episodes of high reward or low reward in conjunction with incidental, trial-unique neutral pictures. In a surprise test phase, we found that participants could indeed remember the associated level of reward, as evidenced by accurate source memory for value and preferences to re-engage with rewarded objects. Further, in a separate experiment, we found that high-reward objects shown as primes before a gambling task increased financial risk taking. Neurally, re-exposure to objects in the test phase led to significant reactivation of reward-related patterns. Importantly, individual variability in the strength of reactivation predicted value memory performance. Our results provide a novel demonstration that affect-related neural patterns are reactivated during later experience. Reactivation of value information represents a mechanism by which memory can guide decision making. Copyright © 2016 the authors 0270-6474/16/362868-13$15.00/0.

Freeform aberrations in phase space: an example.

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Babington, James

2017-06-01

We consider how optical propagation and aberrations of freeform systems can be formulated in phase space. As an example system, a freeform prism is analyzed and discussed. Symmetry considerations and their group theory descriptions are given some importance. Numerical aberrations are also highlighted and put into the context of the underlying aberration theory.

Spherical aberrations of human astigmatic corneas.

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Zhao, Huawei; Dai, Guang-Ming; Chen, Li; Weeber, Henk A; Piers, Patricia A

2011-11-01

To evaluate whether the average spherical aberration of human astigmatic corneas is statistically equivalent to human nonastigmatic corneas. Spherical aberrations of 445 astigmatic corneas prior to laser vision correction were retrospectively investigated to determine Zernike coefficients for central corneal areas 6 mm in diameter using CTView (Sarver and Associates). Data were divided into groups according to cylinder power (0.01 to 0.25 diopters [D], 0.26 to 0.75 D, 0.76 to 1.06 D, 1.07 to 1.53 D, 1.54 to 2.00 D, and >2.00 D) and according to age by decade. Spherical aberrations were correlated with age and astigmatic power among groups and the entire population. Statistical analyses were conducted, and P.05 for all tested groups). Mean spherical aberration of astigmatic corneas was not correlated significantly with cylinder power or age (P>.05). Spherical aberrations are similar to those of nonastigmatic corneas, permitting the use of these additional data in the design of aspheric toric intra-ocular lenses. Copyright 2011, SLACK Incorporated.

Circulating Tumor Cells with Aberrant ALK Copy Number Predict Progression-Free Survival during Crizotinib Treatment in ALK-Rearranged Non-Small Cell Lung Cancer Patients.

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Pailler, Emma; Oulhen, Marianne; Borget, Isabelle; Remon, Jordi; Ross, Kirsty; Auger, Nathalie; Billiot, Fanny; Ngo Camus, Maud; Commo, Frédéric; Lindsay, Colin R; Planchard, David; Soria, Jean-Charles; Besse, Benjamin; Farace, Françoise

2017-05-01

The duration and magnitude of clinical response are unpredictable in ALK -rearranged non-small cell lung cancer (NSCLC) patients treated with crizotinib, although all patients invariably develop resistance. Here, we evaluated whether circulating tumor cells (CTC) with aberrant ALK -FISH patterns [ ALK -rearrangement, ALK -copy number gain ( ALK -CNG)] monitored on crizotinib could predict progression-free survival (PFS) in a cohort of ALK -rearranged patients. Thirty-nine ALK -rearranged NSCLC patients treated with crizotinib as first ALK inhibitor were recruited prospectively. Blood samples were collected at baseline and at an early time-point (2 months) on crizotinib. Aberrant ALK -FISH patterns were examined in CTCs using immunofluorescence staining combined with filter-adapted FISH after filtration enrichment. CTCs were classified into distinct subsets according to the presence of ALK -rearrangement and/or ALK -CNG signals. No significant association between baseline numbers of ALK -rearranged or ALK -CNG CTCs and PFS was observed. However, we observed a significant association between the decrease in CTC number with ALK -CNG on crizotinib and a longer PFS (likelihood ratio test, P = 0.025). In multivariate analysis, the dynamic change of CTC with ALK -CNG was the strongest factor associated with PFS (HR, 4.485; 95% confidence interval, 1.543-13.030, P = 0.006). Although not dominant, ALK -CNG has been reported to be one of the mechanisms of acquired resistance to crizotinib in tumor biopsies. Our results suggest that the dynamic change in the numbers of CTCs with ALK -CNG may be a predictive biomarker for crizotinib efficacy in ALK -rearranged NSCLC patients. Serial molecular analysis of CTC shows promise for real-time patient monitoring and clinical outcome prediction in this population. Cancer Res; 77(9); 2222-30. ©2017 AACR . ©2017 American Association for Cancer Research.

Whole eye wavefront aberrations in Mexican male subjects.

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Cantú, Roberto; Rosales, Marco A; Tepichín, Eduardo; Curioca, Andrée; Montes, Victor; Bonilla, Julio

2004-01-01

To analyze the characteristics, incidence, and appearance of wavefront aberrations in undilated, normal, unoperated eyes. Eighty-eight eyes of 44 healthy male Mexican subjects (mean age 25.32 years, range 18 to 36 yr) were divided into three groups based on uncorrected visual acuity of greater than or equal to 20/20, 20/30, or 20/40. UCVA measurements were obtained using an Acuity Max computer screen chart. Wavefront aberrations were measured with the Nidek OPD-Scan ARK 10000, Ver. 1.11b. All measurements were carried out at the same center by the same technician during a single session, following manufacturer instructions. Background illumination was 3 Lux. Wavefront aberration measurements for each group were statistically analyzed using StatView; an average eye was characterized and the resulting aberrations were simulated using MATLAB. We obtained wavefront aberration maps for the 20/20 undilated normal unoperated eyes for total, low, and high order aberration coefficients. Wavefront maps for right eyes were practically the same as those for left eyes. Higher aberrations did not contribute substantially to total wavefront analysis. Average aberrations of this "normal eye" will be used as criteria to decide the necessity of wavefront-guided ablation in our facilities. We will focus on the nearly zero average of high order aberrations in this normal whole eye as a reference to be matched.

Visual Sexual Stimuli-Cue or Reward? A Perspective for Interpreting Brain Imaging Findings on Human Sexual Behaviors.

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Gola, Mateusz; Wordecha, Małgorzata; Marchewka, Artur; Sescousse, Guillaume

2016-01-01

There is an increasing number of neuroimaging studies using visual sexual stimuli (VSS), especially within the emerging field of research on compulsive sexual behaviors (CSB). A central question in this field is whether behaviors such as excessive pornography consumption share common brain mechanisms with widely studied substance and behavioral addictions. Depending on how VSS are conceptualized, different predictions can be formulated within the frameworks of Reinforcement Learning or Incentive Salience Theory, where a crucial distinction is made between conditioned and unconditioned stimuli (related to reward anticipation vs. reward consumption, respectively). Surveying 40 recent human neuroimaging studies we show existing ambiguity about the conceptualization of VSS. Therefore, we feel that it is important to address the question of whether VSS should be considered as conditioned stimuli (cue) or unconditioned stimuli (reward). Here we present our own perspective, which is that in most laboratory settings VSS play a role of reward, as evidenced by: (1) experience of pleasure while watching VSS, possibly accompanied by genital reaction; (2) reward-related brain activity correlated with these pleasurable feelings in response to VSS; (3) a willingness to exert effort to view VSS similarly as for other rewarding stimuli such as money; and (4) conditioning for cues predictive of VSS. We hope that this perspective article will initiate a scientific discussion on this important and overlooked topic and increase attention for appropriate interpretations of results of human neuroimaging studies using VSS.

Visual Sexual Stimuli—Cue or Reward? A Perspective for Interpreting Brain Imaging Findings on Human Sexual Behaviors

Science.gov (United States)

Gola, Mateusz; Wordecha, Małgorzata; Marchewka, Artur; Sescousse, Guillaume

2016-01-01

There is an increasing number of neuroimaging studies using visual sexual stimuli (VSS), especially within the emerging field of research on compulsive sexual behaviors (CSB). A central question in this field is whether behaviors such as excessive pornography consumption share common brain mechanisms with widely studied substance and behavioral addictions. Depending on how VSS are conceptualized, different predictions can be formulated within the frameworks of Reinforcement Learning or Incentive Salience Theory, where a crucial distinction is made between conditioned and unconditioned stimuli (related to reward anticipation vs. reward consumption, respectively). Surveying 40 recent human neuroimaging studies we show existing ambiguity about the conceptualization of VSS. Therefore, we feel that it is important to address the question of whether VSS should be considered as conditioned stimuli (cue) or unconditioned stimuli (reward). Here we present our own perspective, which is that in most laboratory settings VSS play a role of reward, as evidenced by: (1) experience of pleasure while watching VSS, possibly accompanied by genital reaction; (2) reward-related brain activity correlated with these pleasurable feelings in response to VSS; (3) a willingness to exert effort to view VSS similarly as for other rewarding stimuli such as money; and (4) conditioning for cues predictive of VSS. We hope that this perspective article will initiate a scientific discussion on this important and overlooked topic and increase attention for appropriate interpretations of results of human neuroimaging studies using VSS. PMID:27574507

Stated Uptake of Physical Activity Rewards Programmes Among Active and Insufficiently Active Full-Time Employees.

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Ozdemir, Semra; Bilger, Marcel; Finkelstein, Eric A

2017-10-01

Employers are increasingly relying on rewards programmes in an effort to promote greater levels of activity among employees; however, if enrolment in these programmes is dominated by active employees, then they are unlikely to be a good use of resources. This study uses a stated-preference survey to better understand who participates in rewards-based physical activity programmes, and to quantify stated uptake by active and insufficiently active employees. The survey was fielded to a national sample of 950 full-time employees in Singapore between 2012 and 2013. Participants were asked to choose between hypothetical rewards programmes that varied along key dimensions and whether or not they would join their preferred programme if given the opportunity. A mixed logit model was used to analyse the data and estimate predicted uptake for specific programmes. We then simulated employer payments based on predictions for the percentage of each type of employee likely to meet the activity goal. Stated uptake ranged from 31 to 67% of employees, depending on programme features. For each programme, approximately two-thirds of those likely to enrol were insufficiently active. Results showed that insufficiently active employees, who represent the majority, are attracted to rewards-based physical activity programmes, and at approximately the same rate as active employees, even when enrolment fees are required. This suggests that a programme with generous rewards and a modest enrolment fee may have strong employee support and be within the range of what employers may be willing to spend.

Measuring and modeling the interaction among reward size, delay to reward, and satiation level on motivation in monkeys.

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Minamimoto, Takafumi; La Camera, Giancarlo; Richmond, Barry J

2009-01-01

Motivation is usually inferred from the likelihood or the intensity with which behavior is carried out. It is sensitive to external factors (e.g., the identity, amount, and timing of a rewarding outcome) and internal factors (e.g., hunger or thirst). We trained macaque monkeys to perform a nonchoice instrumental task (a sequential red-green color discrimination) while manipulating two external factors: reward size and delay-to-reward. We also inferred the state of one internal factor, level of satiation, by monitoring the accumulated reward. A visual cue indicated the forthcoming reward size and delay-to-reward in each trial. The fraction of trials completed correctly by the monkeys increased linearly with reward size and was hyperbolically discounted by delay-to-reward duration, relations that are similar to those found in free operant and choice tasks. The fraction of correct trials also decreased progressively as a function of the satiation level. Similar (albeit noiser) relations were obtained for reaction times. The combined effect of reward size, delay-to-reward, and satiation level on the proportion of correct trials is well described as a multiplication of the effects of the single factors when each factor is examined alone. These results provide a quantitative account of the interaction of external and internal factors on instrumental behavior, and allow us to extend the concept of subjective value of a rewarding outcome, usually confined to external factors, to account also for slow changes in the internal drive of the subject.

Neural signal during immediate reward anticipation in schizophrenia: Relationship to real-world motivation and function

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Karuna Subramaniam

2015-01-01

Full Text Available Amotivation in schizophrenia is a central predictor of poor functioning, and is thought to occur due to deficits in anticipating future rewards, suggesting that impairments in anticipating pleasure can contribute to functional disability in schizophrenia. In healthy comparison (HC participants, reward anticipation is associated with activity in frontal–striatal networks. By contrast, schizophrenia (SZ participants show hypoactivation within these frontal–striatal networks during this motivated anticipatory brain state. Here, we examined neural activation in SZ and HC participants during the anticipatory phase of stimuli that predicted immediate upcoming reward and punishment, and during the feedback/outcome phase, in relation to trait measures of hedonic pleasure and real-world functional capacity. SZ patients showed hypoactivation in ventral striatum during reward anticipation. Additionally, we found distinct differences between HC and SZ groups in their association between reward-related immediate anticipatory neural activity and their reported experience of pleasure. HC participants recruited reward-related regions in striatum that significantly correlated with subjective consummatory pleasure, while SZ patients revealed activation in attention-related regions, such as the IPL, which correlated with consummatory pleasure and functional capacity. These findings may suggest that SZ patients activate compensatory attention processes during anticipation of immediate upcoming rewards, which likely contribute to their functional capacity in daily life.

Neural signal during immediate reward anticipation in schizophrenia: Relationship to real-world motivation and function