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Sample records for aberrant reward prediction

  1. Music models aberrant rule decoding and reward valuation in dementia.

    Science.gov (United States)

    Clark, Camilla N; Golden, Hannah L; McCallion, Oliver; Nicholas, Jennifer M; Cohen, Miriam H; Slattery, Catherine F; Paterson, Ross W; Fletcher, Phillip D; Mummery, Catherine J; Rohrer, Jonathan D; Crutch, Sebastian J; Warren, Jason D

    2017-11-24

    Aberrant rule- and reward-based processes underpin abnormalities of socio-emotional behaviour in major dementias. However, these processes remain poorly characterised. Here we used music to probe rule decoding and reward valuation in patients with frontotemporal dementia syndromes and Alzheimer's disease relative to healthy age-matched individuals. We created short melodies that were either harmonically resolved ('finished') or unresolved ('unfinished'); the task was to classify each melody as finished or unfinished (rule processing) and rate its subjective pleasantness (reward valuation). Results were adjusted for elementary pitch and executive processing; neuroanatomical correlates were assessed using voxel-based morphometry. Relative to healthy older controls, patients with behavioural variant frontotemporal dementia showed impairments of both musical rule decoding and reward valuation, while patients with semantic dementia showed impaired reward valuation but intact rule decoding, patients with Alzheimer's disease showed impaired rule decoding but intact reward valuation and patients with progressive nonfluent aphasia performed comparably to healthy controls. Grey matter associations with task performance were identified in anterior temporal, medial and lateral orbitofrontal cortices, previously implicated in computing diverse biological and non-biological rules and rewards. The processing of musical rules and reward distils cognitive and neuroanatomical mechanisms relevant to complex socio-emotional dysfunction in major dementias. © The Author (2017). Published by Oxford University Press.

  2. Reward positivity: Reward prediction error or salience prediction error?

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    Heydari, Sepideh; Holroyd, Clay B

    2016-08-01

    The reward positivity is a component of the human ERP elicited by feedback stimuli in trial-and-error learning and guessing tasks. A prominent theory holds that the reward positivity reflects a reward prediction error signal that is sensitive to outcome valence, being larger for unexpected positive events relative to unexpected negative events (Holroyd & Coles, 2002). Although the theory has found substantial empirical support, most of these studies have utilized either monetary or performance feedback to test the hypothesis. However, in apparent contradiction to the theory, a recent study found that unexpected physical punishments also elicit the reward positivity (Talmi, Atkinson, & El-Deredy, 2013). The authors of this report argued that the reward positivity reflects a salience prediction error rather than a reward prediction error. To investigate this finding further, in the present study participants navigated a virtual T maze and received feedback on each trial under two conditions. In a reward condition, the feedback indicated that they would either receive a monetary reward or not and in a punishment condition the feedback indicated that they would receive a small shock or not. We found that the feedback stimuli elicited a typical reward positivity in the reward condition and an apparently delayed reward positivity in the punishment condition. Importantly, this signal was more positive to the stimuli that predicted the omission of a possible punishment relative to stimuli that predicted a forthcoming punishment, which is inconsistent with the salience hypothesis. © 2016 Society for Psychophysiological Research.

  3. Decoding the formation of reward predictions across learning.

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    Kahnt, Thorsten; Heinzle, Jakob; Park, Soyoung Q; Haynes, John-Dylan

    2011-10-12

    The predicted reward of different behavioral options plays an important role in guiding decisions. Previous research has identified reward predictions in prefrontal and striatal brain regions. Moreover, it has been shown that the neural representation of a predicted reward is similar to the neural representation of the actual reward outcome. However, it has remained unknown how these representations emerge over the course of learning and how they relate to decision making. Here, we sought to investigate learning of predicted reward representations using functional magnetic resonance imaging and multivariate pattern classification. Using a pavlovian conditioning procedure, human subjects learned multiple novel cue-outcome associations in each scanning run. We demonstrate that across learning activity patterns in the orbitofrontal cortex, the dorsolateral prefrontal cortex (DLPFC), and the dorsal striatum, coding the value of predicted rewards become similar to the patterns coding the value of actual reward outcomes. Furthermore, we provide evidence that predicted reward representations in the striatum precede those in prefrontal regions and that representations in the DLPFC are linked to subsequent value-based choices. Our results show that different brain regions represent outcome predictions by eliciting the neural representation of the actual outcome. Furthermore, they suggest that reward predictions in the DLPFC are directly related to value-based choices.

  4. 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.

  5. Working Memory Load Strengthens Reward Prediction Errors.

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    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.

  6. Reduced reward learning predicts outcome in major depressive disorder.

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    Vrieze, Elske; Pizzagalli, Diego A; Demyttenaere, Koen; Hompes, Titia; Sienaert, Pascal; de Boer, Peter; Schmidt, Mark; Claes, Stephan

    2013-04-01

    Reduced reward learning might contribute to the onset and maintenance of major depressive disorder (MDD). In particular, the inability to utilize rewards to guide behavior is hypothesized to be associated with anhedonia, a core feature and potential trait marker of MDD. Few studies have investigated whether reduced reward learning normalizes with treatment and/or reward learning predicts clinical outcome. Our goal was to test whether MDD is characterized by reduced reward learning, especially in the presence of anhedonic symptoms, and to investigate the relationship between reward learning and MDD diagnosis after 8 weeks of treatment. Seventy-nine inpatients and 63 healthy control subjects performed a probabilistic reward task yielding an objective measure of participants' ability to modulate behavior as a function of reward. We compared reward responsiveness between depressed patients and control subjects, as well as high- versus low-anhedonic MDD patients. We also evaluated whether reward-learning deficits predicted persistence of MDD after 8 weeks of treatment. Relative to control subjects, MDD patients showed reduced reward learning. Moreover, patients with high anhedonia showed diminished reward learning compared with patients with low anhedonia. Reduced reward learning at study entry increased the odds of a persisting diagnosis of MDD after 8 weeks of treatment (odds ratio 7.84). Our findings indicate that depressed patients, especially those with anhedonic features, are characterized by an impaired ability to modulate behavior as a function of reward. Moreover, reduced reward learning increased the odds for the diagnosis of MDD to persist after 8 weeks of treatment. Copyright © 2013 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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

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

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    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.

  9. Music-related reward responses predict episodic memory performance.

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    Ferreri, Laura; Rodriguez-Fornells, Antoni

    2017-12-01

    Music represents a special type of reward involving the recruitment of the mesolimbic dopaminergic system. According to recent theories on episodic memory formation, as dopamine strengthens the synaptic potentiation produced by learning, stimuli triggering dopamine release could result in long-term memory improvements. Here, we behaviourally test whether music-related reward responses could modulate episodic memory performance. Thirty participants rated (in terms of arousal, familiarity, emotional valence, and reward) and encoded unfamiliar classical music excerpts. Twenty-four hours later, their episodic memory was tested (old/new recognition and remember/know paradigm). Results revealed an influence of music-related reward responses on memory: excerpts rated as more rewarding were significantly better recognized and remembered. Furthermore, inter-individual differences in the ability to experience musical reward, measured through the Barcelona Music Reward Questionnaire, positively predicted memory performance. Taken together, these findings shed new light on the relationship between music, reward and memory, showing for the first time that music-driven reward responses are directly implicated in higher cognitive functions and can account for individual differences in memory performance.

  10. Trait Anticipatory Pleasure Predicts Effort Expenditure for Reward

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    Geaney, Joachim T.; Treadway, Michael T.; Smillie, Luke D.

    2015-01-01

    Research in motivation and emotion has been increasingly influenced by the perspective that processes underpinning the motivated approach of rewarding goals are distinct from those underpinning enjoyment during reward consummation. This distinction recently inspired the construction of the Temporal Experience of Pleasure Scale (TEPS), a self-report measure that distinguishes trait anticipatory pleasure (pre-reward feelings of desire) from consummatory pleasure (feelings of enjoyment and gratification upon reward attainment). In a university community sample (N = 97), we examined the TEPS subscales as predictors of (1) the willingness to expend effort for monetary rewards, and (2) affective responses to a pleasant mood induction procedure. Results showed that both anticipatory pleasure and a well-known trait measure of reward motivation predicted effort-expenditure for rewards when the probability of being rewarded was relatively low. Against expectations, consummatory pleasure was unrelated to induced pleasant affect. Taken together, our findings provide support for the validity of the TEPS anticipatory pleasure scale, but not the consummatory pleasure scale. PMID:26115223

  11. Trait Anticipatory Pleasure Predicts Effort Expenditure for Reward.

    Directory of Open Access Journals (Sweden)

    Joachim T Geaney

    Full Text Available Research in motivation and emotion has been increasingly influenced by the perspective that processes underpinning the motivated approach of rewarding goals are distinct from those underpinning enjoyment during reward consummation. This distinction recently inspired the construction of the Temporal Experience of Pleasure Scale (TEPS, a self-report measure that distinguishes trait anticipatory pleasure (pre-reward feelings of desire from consummatory pleasure (feelings of enjoyment and gratification upon reward attainment. In a university community sample (N = 97, we examined the TEPS subscales as predictors of (1 the willingness to expend effort for monetary rewards, and (2 affective responses to a pleasant mood induction procedure. Results showed that both anticipatory pleasure and a well-known trait measure of reward motivation predicted effort-expenditure for rewards when the probability of being rewarded was relatively low. Against expectations, consummatory pleasure was unrelated to induced pleasant affect. Taken together, our findings provide support for the validity of the TEPS anticipatory pleasure scale, but not the consummatory pleasure scale.

  12. Trait Anticipatory Pleasure Predicts Effort Expenditure for Reward.

    Science.gov (United States)

    Geaney, Joachim T; Treadway, Michael T; Smillie, Luke D

    2015-01-01

    Research in motivation and emotion has been increasingly influenced by the perspective that processes underpinning the motivated approach of rewarding goals are distinct from those underpinning enjoyment during reward consummation. This distinction recently inspired the construction of the Temporal Experience of Pleasure Scale (TEPS), a self-report measure that distinguishes trait anticipatory pleasure (pre-reward feelings of desire) from consummatory pleasure (feelings of enjoyment and gratification upon reward attainment). In a university community sample (N = 97), we examined the TEPS subscales as predictors of (1) the willingness to expend effort for monetary rewards, and (2) affective responses to a pleasant mood induction procedure. Results showed that both anticipatory pleasure and a well-known trait measure of reward motivation predicted effort-expenditure for rewards when the probability of being rewarded was relatively low. Against expectations, consummatory pleasure was unrelated to induced pleasant affect. Taken together, our findings provide support for the validity of the TEPS anticipatory pleasure scale, but not the consummatory pleasure scale.

  13. Anticipatory pleasure predicts motivation for reward in major depression.

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    Sherdell, Lindsey; Waugh, Christian E; Gotlib, Ian H

    2012-02-01

    Anhedonia, the lack of interest or pleasure in response to hedonic stimuli or experiences, is a cardinal symptom of depression. This deficit in hedonic processing has been posited to influence depressed individuals' motivation to engage in potentially rewarding experiences. Accumulating evidence indicates that hedonic processing is not a unitary construct but rather consists of an anticipatory and a consummatory phase. We examined how these components of hedonic processing influence motivation to obtain reward in participants diagnosed with major depression and in never-disordered controls. Thirty-eight currently depressed and 30 never-disordered control participants rated their liking of humorous and nonhumorous cartoons and then made a series of choices between viewing a cartoon from either group. Each choice was associated with a specified amount of effort participants would have to exert before viewing the chosen cartoon. Although depressed and control participants did not differ in their consummatory liking of the rewards, levels of reward liking predicted motivation to expend effort for the rewards only in the control participants; in the depressed participants, liking and motivation were dissociated. In the depressed group, levels of anticipatory anhedonia predicted motivation to exert effort for the rewards. These findings support the formulation that anhedonia is not a unitary construct and suggest that, for depressed individuals, deficits in motivation for reward are driven primarily by low anticipatory pleasure and not by decreased consummatory liking. PsycINFO Database Record (c) 2012 APA, all rights reserved.

  14. Dopamine reward prediction-error signalling: a two-component response

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    Schultz, Wolfram

    2017-01-01

    Environmental stimuli and objects, including rewards, are often processed sequentially in the brain. Recent work suggests that the phasic dopamine reward prediction-error response follows a similar sequential pattern. An initial brief, unselective and highly sensitive increase in activity unspecifically detects a wide range of environmental stimuli, then quickly evolves into the main response component, which reflects subjective reward value and utility. This temporal evolution allows the dopamine reward prediction-error signal to optimally combine speed and accuracy. PMID:26865020

  15. Greater striatopallidal adaptive coding during cue-reward learning and food reward habituation predict future weight gain.

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    Burger, Kyle S; Stice, Eric

    2014-10-01

    Animal experiments indicate that after repeated pairings of palatable food receipt and cues that predict palatable food receipt, dopamine signaling increases in response to predictive cues, but decreases in response to food receipt. Using functional MRI and mixed effects growth curve models with 35 females (M age=15.5±0.9; M BMI=24.5±5.4) we documented an increase in BOLD response in the caudate (r=.42) during exposure to cues predicting impending milkshake receipt over repeated exposures, demonstrating a direct measure of in vivo cue-reward learning in humans. Further, we observed a simultaneous decrease in putamen (r=-.33) and ventral pallidum (r=-.45) response during milkshake receipt that occurred over repeated exposures, putatively reflecting food reward habitation. We then tested whether cue-reward learning and habituation slopes predicted future weight over 2-year follow-up. Those who exhibited the greatest escalation in ventral pallidum responsivity to cues and the greatest decrease in caudate response to milkshake receipt showed significantly larger increases in BMI (r=.39 and -.69 respectively). Interestingly, cue-reward learning propensity and food reward habituation were not correlated, implying that these factors may constitute qualitatively distinct vulnerability pathways to excess weight gain. These two individual difference factors may provide insight as to why certain people have shown obesity onset in response to the current obesogenic environment in western cultures, whereas others have not. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Association of Neural and Emotional Impacts of Reward Prediction Errors With Major Depression

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    Moutoussis, Michael; Smittenaar, Peter; Zeidman, Peter; Taylor, Tanja; Hrynkiewicz, Louise; Lam, Jordan; Skandali, Nikolina; Siegel, Jenifer Z.; Ousdal, Olga T.; Prabhu, Gita; Dayan, Peter; Fonagy, Peter; Dolan, Raymond J.

    2017-01-01

    Importance Major depressive disorder (MDD) is associated with deficits in representing reward prediction errors (RPEs), which are the difference between experienced and predicted reward. Reward prediction errors underlie learning of values in reinforcement learning models, are represented by phasic dopamine release, and are known to affect momentary mood. Objective To combine functional neuroimaging, computational modeling, and smartphone-based large-scale data collection to test, in the absence of learning-related concerns, the hypothesis that depression attenuates the impact of RPEs. Design, Setting, and Participants Functional magnetic resonance imaging (fMRI) data were collected on 32 individuals with moderate MDD and 20 control participants who performed a probabilistic reward task. A risky decision task with repeated happiness ratings as a measure of momentary mood was also tested in the laboratory in 74 participants and with a smartphone-based platform in 1833 participants. The study was conducted from November 20, 2012, to February 17, 2015. Main Outcomes and Measures Blood oxygen level–dependent activity was measured in ventral striatum, a dopamine target area known to represent RPEs. Momentary mood was measured during risky decision making. Results Of the 52 fMRI participants (mean [SD] age, 34.0 [9.1] years), 30 (58%) were women and 32 had MDD. Of the 74 participants in the laboratory risky decision task (mean age, 34.2 [10.3] years), 44 (59%) were women and 54 had MDD. Of the smartphone group, 543 (30%) had a depression history and 1290 (70%) had no depression history; 918 (50%) were women, and 593 (32%) were younger than 30 years. Contrary to previous results in reinforcement learning tasks, individuals with moderate depression showed intact RPE signals in ventral striatum (z = 3.16; P = .002) that did not differ significantly from controls (z = 0.91; P = .36). Symptom severity correlated with baseline mood parameters in laboratory (

  17. 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

  18. Reward expectation and prediction error in human medial frontal cortex: an EEG study.

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    Silvetti, Massimo; Nuñez Castellar, Elena; Roger, Clémence; Verguts, Tom

    2014-01-01

    The mammalian medial frontal cortex (MFC) is involved in reward-based decision making. In particular, in nonhuman primates this area constructs expectations about upcoming rewards, given an environmental state or a choice planned by the animal. At the same time, in both humans and nonhuman primates, the MFC computes the difference between such predictions and actual environmental outcomes (reward prediction errors). However, there is a paucity of evidence about the time course of MFC-related activity during reward prediction and prediction error in humans. Here we experimentally investigated this by recording the EEG during a reinforcement learning task. Our results support the hypothesis that human MFC codes for reward prediction during the cue period and for prediction error during the outcome period. Further, reward expectation (cue period) was positively correlated with prediction error (outcome period) in error trials but negatively in correct trials, consistent with updating of reward expectation by prediction error. This demonstrates in humans, like in nonhuman primates, a role of the MFC in the rapid updating of reward expectations through prediction errors. © 2013.

  19. EEG to Primary Rewards: Predictive Utility and Malleability by Brain Stimulation.

    Directory of Open Access Journals (Sweden)

    Nicole Prause

    Full Text Available Theta burst stimulation (TBS is thought to affect reward processing mechanisms, which may increase and decrease reward sensitivity. To test the ability of TBS to modulate response to strong primary rewards, participants hypersensitive to primary rewards were recruited. Twenty men and women with at least two opposite-sex, sexual partners in the last year received two forms of TBS. Stimulations were randomized to avoid order effects and separated by 2 hours to reduce carryover. The two TBS forms have been demonstrated to inhibit (continuous or excite (intermittent the left dorsolateral prefrontal cortex using different pulse patterns, which links to brain areas associated with reward conditioning. After each TBS, participants completed tasks assessing their reward responsiveness to monetary and sexual rewards. Electroencephalography (EEG was recorded. They also reported their number of orgasms in the weekend following stimulation. This signal was malleable by TBS, where excitatory TBS resulted in lower EEG alpha relative to inhibitory TBS to primary rewards. EEG responses to sexual rewards in the lab (following both forms of TBS predicted the number of orgasms experienced over the forthcoming weekend. TBS may be useful in modifying hypersensitivity or hyposensitivity to primary rewards that predict sexual behaviors. Since TBS altered the anticipation of a sexual reward, TBS may offer a novel treatment for sexual desire problems.

  20. EEG to Primary Rewards: Predictive Utility and Malleability by Brain Stimulation

    Science.gov (United States)

    Prause, Nicole; Siegle, Greg J.; Deblieck, Choi; Wu, Allan; Iacoboni, Marco

    2016-01-01

    Theta burst stimulation (TBS) is thought to affect reward processing mechanisms, which may increase and decrease reward sensitivity. To test the ability of TBS to modulate response to strong primary rewards, participants hypersensitive to primary rewards were recruited. Twenty men and women with at least two opposite-sex, sexual partners in the last year received two forms of TBS. Stimulations were randomized to avoid order effects and separated by 2 hours to reduce carryover. The two TBS forms have been demonstrated to inhibit (continuous) or excite (intermittent) the left dorsolateral prefrontal cortex using different pulse patterns, which links to brain areas associated with reward conditioning. After each TBS, participants completed tasks assessing their reward responsiveness to monetary and sexual rewards. Electroencephalography (EEG) was recorded. They also reported their number of orgasms in the weekend following stimulation. This signal was malleable by TBS, where excitatory TBS resulted in lower EEG alpha relative to inhibitory TBS to primary rewards. EEG responses to sexual rewards in the lab (following both forms of TBS) predicted the number of orgasms experienced over the forthcoming weekend. TBS may be useful in modifying hypersensitivity or hyposensitivity to primary rewards that predict sexual behaviors. Since TBS altered the anticipation of a sexual reward, TBS may offer a novel treatment for sexual desire problems. PMID:27902711

  1. EEG to Primary Rewards: Predictive Utility and Malleability by Brain Stimulation.

    Science.gov (United States)

    Prause, Nicole; Siegle, Greg J; Deblieck, Choi; Wu, Allan; Iacoboni, Marco

    2016-01-01

    Theta burst stimulation (TBS) is thought to affect reward processing mechanisms, which may increase and decrease reward sensitivity. To test the ability of TBS to modulate response to strong primary rewards, participants hypersensitive to primary rewards were recruited. Twenty men and women with at least two opposite-sex, sexual partners in the last year received two forms of TBS. Stimulations were randomized to avoid order effects and separated by 2 hours to reduce carryover. The two TBS forms have been demonstrated to inhibit (continuous) or excite (intermittent) the left dorsolateral prefrontal cortex using different pulse patterns, which links to brain areas associated with reward conditioning. After each TBS, participants completed tasks assessing their reward responsiveness to monetary and sexual rewards. Electroencephalography (EEG) was recorded. They also reported their number of orgasms in the weekend following stimulation. This signal was malleable by TBS, where excitatory TBS resulted in lower EEG alpha relative to inhibitory TBS to primary rewards. EEG responses to sexual rewards in the lab (following both forms of TBS) predicted the number of orgasms experienced over the forthcoming weekend. TBS may be useful in modifying hypersensitivity or hyposensitivity to primary rewards that predict sexual behaviors. Since TBS altered the anticipation of a sexual reward, TBS may offer a novel treatment for sexual desire problems.

  2. Chromosomal aberration frequency in lymphocytes predicts the risk of cancer

    DEFF Research Database (Denmark)

    Bonassi, Stefano; Norppa, Hannu; Ceppi, Marcello

    2008-01-01

    Mechanistic evidence linking chromosomal aberration (CA) to early stages of cancer has been recently supported by the results of epidemiological studies that associated CA frequency in peripheral lymphocytes of healthy individuals to future cancer incidence. To overcome the limitations of single...

  3. 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.

  4. Reward and Punishment Histories: A Way of Predicting Teaching Style?

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    Cohen, Joan H.; Amidon, Edmund J.

    2004-01-01

    The authors used preservice teachers' (N = 172) reports of their childhood experiences involving reward and punishment within their families to identify ideal perceptions of direct or indirect teaching style. The most consistent relationship of childhood experience with reward and punishment and perceived teaching style was between the reward…

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

    Science.gov (United States)

    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

  6. Asymmetric frontal cortical activity predicts effort expenditure for reward.

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    Hughes, David M; Yates, Mark J; Morton, Emma E; Smillie, Luke D

    2015-07-01

    An extensive literature shows that greater left, relative to right, frontal cortical activity (LFA) is involved in approach-motivated affective states and reflects stable individual differences in approach motivation. However, relatively few studies have linked LFA to behavioral indices of approach motivation. In this study, we examine the relation between LFA and effort expenditure for reward, a behavioral index of approach motivation. LFA was calculated for 51 right-handed participants (55% female) using power spectral analysis of electroencephalogram recorded at rest. Participants also completed the effort expenditure for rewards task (EEfRT), which presents a series of trials requiring a choice between a low-reward low-effort task and a high-reward high-effort task. We found that individuals with greater resting LFA were more willing to expend greater effort in the pursuit of larger rewards, particularly when reward delivery was less likely. Our findings offer a more nuanced understanding of the motivational significance of LFA, in terms of processes that mitigate the effort- and uncertainty-related costs of pursuing rewarding goals. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

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

    Science.gov (United States)

    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.

  8. Neurophysiology of Reward-Guided Behavior: Correlates Related to Predictions, Value, Motivation, Errors, Attention, and Action.

    Science.gov (United States)

    Bissonette, Gregory B; Roesch, Matthew R

    2016-01-01

    Many brain areas are activated by the possibility and receipt of reward. Are all of these brain areas reporting the same information about reward? Or are these signals related to other functions that accompany reward-guided learning and decision-making? Through carefully controlled behavioral studies, it has been shown that reward-related activity can represent reward expectations related to future outcomes, errors in those expectations, motivation, and signals related to goal- and habit-driven behaviors. These dissociations have been accomplished by manipulating the predictability of positively and negatively valued events. Here, we review single neuron recordings in behaving animals that have addressed this issue. We describe data showing that several brain areas, including orbitofrontal cortex, anterior cingulate, and basolateral amygdala signal reward prediction. In addition, anterior cingulate, basolateral amygdala, and dopamine neurons also signal errors in reward prediction, but in different ways. For these areas, we will describe how unexpected manipulations of positive and negative value can dissociate signed from unsigned reward prediction errors. All of these signals feed into striatum to modify signals that motivate behavior in ventral striatum and guide responding via associative encoding in dorsolateral striatum.

  9. Cognitive strategies regulate fictive, but not reward prediction error signals in a sequential investment task.

    Science.gov (United States)

    Gu, Xiaosi; Kirk, Ulrich; Lohrenz, Terry M; Montague, P Read

    2014-08-01

    Computational models of reward processing suggest that foregone or fictive outcomes serve as important information sources for learning and augment those generated by experienced rewards (e.g. reward prediction errors). An outstanding question is how these learning signals interact with top-down cognitive influences, such as cognitive reappraisal strategies. Using a sequential investment task and functional magnetic resonance imaging, we show that the reappraisal strategy selectively attenuates the influence of fictive, but not reward prediction error signals on investment behavior; such behavioral effect is accompanied by changes in neural activity and connectivity in the anterior insular cortex, a brain region thought to integrate subjective feelings with high-order cognition. Furthermore, individuals differ in the extent to which their behaviors are driven by fictive errors versus reward prediction errors, and the reappraisal strategy interacts with such individual differences; a finding also accompanied by distinct underlying neural mechanisms. These findings suggest that the variable interaction of cognitive strategies with two important classes of computational learning signals (fictive, reward prediction error) represent one contributing substrate for the variable capacity of individuals to control their behavior based on foregone rewards. These findings also expose important possibilities for understanding the lack of control in addiction based on possibly foregone rewarding outcomes. Copyright © 2013 The Authors. Human Brain Mapping Published by Wiley Periodicals, Inc.

  10. 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

  11. Eveningness among late adolescent males predicts neural reactivity to reward and alcohol dependence 2 years later.

    Science.gov (United States)

    Hasler, Brant P; Casement, Melynda D; Sitnick, Stephanie L; Shaw, Daniel S; Forbes, Erika E

    2017-06-01

    Eveningness, a preference for later sleep-wake timing, is linked to altered reward function, which may explain a consistent association with substance abuse. Notably, the extant literature rests largely on cross-sectional data, yet both eveningness and reward function show developmental changes. We examined whether circadian preference during late adolescence predicted the neural response to reward 2 years later. A sample of 93 males reported circadian preference and completed a monetary reward fMRI paradigm at ages 20 and 22. Primary analyses examined longitudinal paths from circadian preference to medial prefrontal cortex (mPFC) and ventral striatal (VS) reward responses. We also explored whether reward responses mediated longitudinal associations between circadian preference and alcohol dependence, frequency of alcohol use, and/or frequency of cannabis use. Age 20 eveningness was positively associated with age 22 mPFC and VS responses to win, but not associated with age 22 reactivity to reward anticipation. Age 20 eveningness was indirectly related to age 22 alcohol dependence via age 22 mPFC response to win. Our findings provide novel evidence that altered reward-related brain function could underlie associations between eveningness and alcohol use problems. Eveningness may be an under-recognized but modifiable risk factor for reward-related problems such as mood and substance use disorders. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Interactions between the nucleus accumbens and auditory cortices predict music reward value

    National Research Council Canada - National Science Library

    Salimpoor, Valorie N; van den Bosch, Iris; Kovacevic, Natasa; McIntosh, Anthony Randal; Dagher, Alain; Zatorre, Robert J

    2013-01-01

    ... unheard music in an auction paradigm. Importantly, the auditory cortices, amygdala, and ventromedial prefrontal regions showed increased activity during listening conditions requiring valuation, but did not predict reward value...

  13. General functioning predicts reward and punishment learning in schizophrenia.

    Science.gov (United States)

    Somlai, Zsuzsanna; Moustafa, Ahmed A; Kéri, Szabolcs; Myers, Catherine E; Gluck, Mark A

    2011-04-01

    Previous studies investigating feedback-driven reinforcement learning in patients with schizophrenia have provided mixed results. In this study, we explored the clinical predictors of reward and punishment learning using a probabilistic classification learning task. Patients with schizophrenia (n=40) performed similarly to healthy controls (n=30) on the classification learning task. However, more severe negative and general symptoms were associated with lower reward-learning performance, whereas poorer general psychosocial functioning was correlated with both lower reward- and punishment-learning performances. Multiple linear regression analyses indicated that general psychosocial functioning was the only significant predictor of reinforcement learning performance when education, antipsychotic dose, and positive, negative and general symptoms were included in the analysis. These results suggest a close relationship between reinforcement learning and general psychosocial functioning in schizophrenia. Published by Elsevier B.V.

  14. Enhanced Neural Responses to Imagined Primary Rewards Predict Reduced Monetary Temporal Discounting.

    Science.gov (United States)

    Hakimi, Shabnam; Hare, Todd A

    2015-09-23

    The pervasive tendency to discount the value of future rewards varies considerably across individuals and has important implications for health and well-being. Here, we used fMRI with human participants to examine whether an individual's neural representation of an imagined primary reward predicts the degree to which the value of delayed monetary payments is discounted. Because future rewards can never be experienced at the time of choice, imagining or simulating the benefits of a future reward may play a critical role in decisions between alternatives with either immediate or delayed benefits. We found that enhanced ventromedial prefrontal cortex response during imagined primary reward receipt was correlated with reduced discounting in a separate monetary intertemporal choice task. Furthermore, activity in enhanced ventromedial prefrontal cortex during reward imagination predicted temporal discounting behavior both between- and within-individual decision makers with 62% and 73% mean balanced accuracy, respectively. These results suggest that the quality of reward imagination may impact the degree to which future outcomes are discounted. Significance statement: We report a novel test of the hypothesis that an important factor influencing the discount rate for future rewards is the quality with which they are imagined or estimated in the present. Previous work has shown that temporal discounting is linked to individual characteristics ranging from general intelligence to the propensity for addiction. We demonstrate that individual differences in a neurobiological measure of primary reward imagination are significantly correlated with discounting rates for future monetary payments. Moreover, our neurobiological measure of imagination can be used to accurately predict choice behavior both between and within individuals. These results suggest that improving reward imagination may be a useful therapeutic target for individuals whose high discount rates promote

  15. Effects of affective arousal on choice behavior, reward prediction errors, and feedback-related negativities in human reward-based decision making

    Directory of Open Access Journals (Sweden)

    Hong-Hsiang eLiu

    2015-05-01

    Full Text Available Emotional experience has a pervasive impact on choice behavior, but the underlying mechanism remains unclear. Introducing facial-expression primes into a probabilistic learning task, we investigated how affective arousal regulates reward-related choice based on behavioral, model fitting, and feedback-related negativity (FRN data. Sixty-six paid subjects were randomly assigned to the Neutral-Neutral (NN, Angry-Neutral (AN, and Happy-Neutral (HN groups. A total of 960 trials were conducted. Subjects in each group were randomly exposed to half trials of the pre-determined emotional faces and another half of the neutral faces before choosing between two cards drawn from two decks with different assigned reward probabilities. Trial-by-trial data were fit with a standard reinforcement learning model using the Bayesian estimation approach. The temporal dynamics of brain activity were simultaneously recorded and analyzed using event-related potentials. Our analyses revealed that subjects in the NN group gained more reward values than those in the other two groups; they also exhibited comparatively differential estimated model-parameter values for reward prediction errors. Computing the difference wave of FRNs in reward versus non-reward trials, compared to the NN group, we found that subjects in the AN and HN groups had larger General FRNs (i.e., FRNs in no-reward trials minus FRNs in reward trials and Expected FRNs (i.e., FRNs in expected reward-omission trials minus FRNs in expected reward-delivery trials, indicating an interruption in predicting reward. Further, both AN and HN groups appeared to be more sensitive to negative outcomes than the NN group. Collectively, our study suggests that affective arousal negatively regulates reward-related choice, probably through overweighting with negative feedback.

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

    Science.gov (United States)

    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

  17. 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.

  18. 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.

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

    Science.gov (United States)

    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.

  20. Response to anticipated reward in the nucleus accumbens predicts behavior in an independent test of honesty.

    Science.gov (United States)

    Abe, Nobuhito; Greene, Joshua D

    2014-08-06

    This study examines the cognitive and neural determinants of honesty and dishonesty. Human subjects undergoing fMRI completed a monetary incentive delay task eliciting responses to anticipated reward in the nucleus accumbens. Subjects next performed an incentivized prediction task, giving them real and repeated opportunities for dishonest gain. Subjects attempted to predict the outcomes of random computerized coin-flips and were financially rewarded for accuracy. In some trials, subjects were rewarded based on self-reported accuracy, allowing them to gain money dishonestly by lying. Dishonest behavior was indexed by improbably high levels of self-reported accuracy. Nucleus accumbens response in the first task, involving only honest rewards, accounted for ∼25% of the variance in dishonest behavior in the prediction task. Individuals showing relatively strong nucleus accumbens responses to anticipated reward also exhibited increased dorsolateral prefrontal activity (bilateral) in response to opportunities for dishonest gain. These results address two hypotheses concerning (dis)honesty. According to the "Will" hypothesis, honesty results from the active deployment of self-control. According to the "Grace" hypothesis, honesty flows more automatically. The present results suggest a reconciliation between these two hypotheses while explaining (dis)honesty in terms of more basic neural mechanisms: relatively weak responses to anticipated rewards make people morally "Graceful," but individuals who respond more strongly may resist temptation by force of Will. Copyright © 2014 the authors 0270-6474/14/3410564-09$15.00/0.

  1. Increased Firing to Cues That Predict Low-Value Reward in the Medial Orbitofrontal Cortex

    Science.gov (United States)

    Burton, Amanda C.; Kashtelyan, Vadim; Bryden, Daniel W.; Roesch, Matthew R.

    2014-01-01

    Anatomical, imaging, and lesion work have suggested that medial and lateral aspects of orbitofrontal cortex (OFC) play different roles in reward-guided decision-making, yet few single-neuron recording studies have examined activity in more medial parts of the OFC (mOFC) making it difficult to fully assess its involvement in motivated behavior. Previously, we have shown that neurons in lateral parts of the OFC (lOFC) selectively fire for rewards of different values. In that study, we trained rats to respond to different fluid wells for rewards of different sizes or delivered at different delays. Rats preferred large over small reward, and rewards delivered after short compared with long delays. Here, we recorded from single neurons in rat rostral mOFC as they performed the same task. Similar to the lOFC, activity was attenuated for rewards that were delivered after long delays and was enhanced for delivery of larger rewards. However, unlike lOFC, odor-responsive neurons in the mOFC were more active when cues predicted low-value outcomes. These data suggest that odor-responsive mOFC neurons signal the association between environmental cues and unfavorable outcomes during decision making. PMID:23901075

  2. 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.

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

    Science.gov (United States)

    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.

  4. Mesolimbic recruitment by nondrug rewards in detoxified alcoholics: effort anticipation, reward anticipation, and reward delivery.

    Science.gov (United States)

    Bjork, James M; Smith, Ashley R; Chen, Gang; Hommer, Daniel W

    2012-09-01

    Aberrant sensitivity of incentive neurocircuitry to nondrug rewards has been suggested as either a risk factor for or consequence of drug addiction. Using functional magnetic resonance imaging, we tested whether alcohol-dependent patients (ADP: n = 29) showed altered recruitment of ventral striatal (VS) incentive neurocircuitry compared to controls (n = 23) by: (1) cues to respond for monetary rewards, (2) post-response anticipation of rewards, or (3) delivery of rewards. Using an instrumental task with two-stage presentation of reward-predictive information, subjects saw cues signaling opportunities to win $0, $1, or $10 for responding to a target. Following this response, subjects were notified whether their success would be indicated by a lexical notification (“Hit?”) or by delivery of a monetary reward (“Win?”). After a variable interval, subjects then viewed the trial outcome. We found no significant group differences in voxelwise activation by task contrasts, or in signal change extracted from VS. Both ADP and controls showed significant VS and other limbic recruitment by pre-response reward anticipation. In addition, controls also showed VS recruitment by post-response reward-anticipation, and ADP had appreciable subthreshold VS activation. Both groups also showed similar mesolimbic responses to reward deliveries. Across all subjects, a questionnaire measure of “hot” impulsivity correlated with VS recruitment by post-response anticipation of low rewards and with VS recruitment by delivery of low rewards. These findings indicate that incentive-motivational processing of nondrug rewards is substantially maintained in recovering alcoholics, and that reward-elicited VS recruitment correlates more with individual differences in trait impulsivity irrespective of addiction.

  5. 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.

  6. Adult age differences in frontostriatal representation of prediction error but not reward outcome.

    Science.gov (United States)

    Samanez-Larkin, Gregory R; Worthy, Darrell A; Mata, Rui; McClure, Samuel M; Knutson, Brian

    2014-06-01

    Emerging evidence from decision neuroscience suggests that although younger and older adults show similar frontostriatal representations of reward magnitude, older adults often show deficits in feedback-driven reinforcement learning. In the present study, healthy adults completed reward-based tasks that did or did not depend on probabilistic learning, while undergoing functional neuroimaging. We observed reductions in the frontostriatal representation of prediction errors during probabilistic learning in older adults. In contrast, we found evidence for stability across adulthood in the representation of reward outcome in a task that did not require learning. Together, the results identify changes across adulthood in the dynamic coding of relational representations of feedback, in spite of preserved reward sensitivity in old age. Overall, the results suggest that the neural representation of prediction error, but not reward outcome, is reduced in old age. These findings reveal a potential dissociation between cognition and motivation with age and identify a potential mechanism for explaining changes in learning-dependent decision making in old adulthood.

  7. Attenuation of Frontostriatal Connectivity During Reward Processing Predicts Response to Psychotherapy in Major Depressive Disorder.

    Science.gov (United States)

    Walsh, Erin; Carl, Hannah; Eisenlohr-Moul, Tory; Minkel, Jared; Crowther, Andrew; Moore, Tyler; Gibbs, Devin; Petty, Chris; Bizzell, Josh; Smoski, Moria J; Dichter, Gabriel S

    2017-03-01

    There are few reliable predictors of response to antidepressant treatments. In the present investigation, we examined pretreatment functional brain connectivity during reward processing as a potential predictor of response to Behavioral Activation Treatment for Depression (BATD), a validated psychotherapy that promotes engagement with rewarding stimuli and reduces avoidance behaviors. Thirty-three outpatients with major depressive disorder (MDD) and 20 matched controls completed two runs of the monetary incentive delay task during functional magnetic resonance imaging after which participants with MDD received up to 15 sessions of BATD. Seed-based generalized psychophysiological interaction analyses focused on task-based connectivity across task runs, as well as the attenuation of connectivity from the first to the second run of the task. The average change in Beck Depression Inventory-II scores due to treatment was 10.54 points, a clinically meaningful response. Groups differed in seed-based functional connectivity among multiple frontostriatal regions. Hierarchical linear modeling revealed that improved treatment response to BATD was predicted by greater connectivity between the left putamen and paracingulate gyrus during reward anticipation. In addition, MDD participants with greater attenuation of connectivity between several frontostriatal seeds, and midline subcallosal cortex and left paracingulate gyrus demonstrated improved response to BATD. These findings indicate that pretreatment frontostriatal functional connectivity during reward processing is predictive of response to a psychotherapy modality that promotes improving approach-related behaviors in MDD. Furthermore, connectivity attenuation among reward-processing regions may be a particularly powerful endophenotypic predictor of response to BATD in MDD.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Reward Seeking and Cognitive Control: Using the Dual Systems Model to Predict Adolescent Sexual Behavior.

    Science.gov (United States)

    Wasserman, Alexander M; Crockett, Lisa J; Hoffman, Lesa

    2017-12-01

    Research has provided support for the dual systems model of adolescent risk taking, but the model has rarely been applied to sexual behavior. Using data from the NICHD SECCYD (N = 958; Mage = 15.07, SD = 0.18), this study examined the effects of cognitive control, reward seeking, and their interaction on sexual behavior. Results of structural equation models revealed that performance on behavioral tasks assessing reward seeking and cognitive control uniquely predicted sexual intercourse, but the interaction between them was not significant. For oral sex, only cognitive control was a significant predictor. The findings provide additional support for the dual systems model, and suggest that reward seeking and cognitive control make unique contributions to adolescent sexual behavior. © 2017 The Authors. Journal of Research on Adolescence © 2017 Society for Research on Adolescence.

  10. 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.

  11. 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.

  12. Orbitofrontal Cortex Signals Expected Outcomes with Predictive Codes When Stable Contingencies Promote the Integration of Reward History.

    Science.gov (United States)

    Riceberg, Justin S; Shapiro, Matthew L

    2017-02-22

    Memory can inform goal-directed behavior by linking current opportunities to past outcomes. The orbitofrontal cortex (OFC) may guide value-based responses by integrating the history of stimulus-reward associations into expected outcomes, representations of predicted hedonic value and quality. Alternatively, the OFC may rapidly compute flexible "online" reward predictions by associating stimuli with the latest outcome. OFC neurons develop predictive codes when rats learn to associate arbitrary stimuli with outcomes, but the extent to which predictive coding depends on most recent events and the integrated history of rewards is unclear. To investigate how reward history modulates OFC activity, we recorded OFC ensembles as rats performed spatial discriminations that differed only in the number of rewarded trials between goal reversals. The firing rate of single OFC neurons distinguished identical behaviors guided by different goals. When >20 rewarded trials separated goal switches, OFC ensembles developed stable and anticorrelated population vectors that predicted overall choice accuracy and the goal selected in single trials. When rewarded trials separated goal switches, OFC population vectors decorrelated rapidly after each switch, but did not develop anticorrelated firing patterns or predict choice accuracy. The results show that, whereas OFC signals respond rapidly to contingency changes, they predict choices only when reward history is relatively stable, suggesting that consecutive rewarded episodes are needed for OFC computations that integrate reward history into expected outcomes.SIGNIFICANCE STATEMENT Adapting to changing contingencies and making decisions engages the orbitofrontal cortex (OFC). Previous work shows that OFC function can either improve or impair learning depending on reward stability, suggesting that OFC guides behavior optimally when contingencies apply consistently. The mechanisms that link reward history to OFC computations remain obscure

  13. 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.

  14. Autocorrelation structure at rest predicts value correlates of single neurons during reward-guided choice.

    Science.gov (United States)

    Cavanagh, Sean E; Wallis, Joni D; Kennerley, Steven W; Hunt, Laurence T

    2016-10-05

    Correlates of value are routinely observed in the prefrontal cortex (PFC) during reward-guided decision making. In previous work (Hunt et al., 2015), we argued that PFC correlates of chosen value are a consequence of varying rates of a dynamical evidence accumulation process. Yet within PFC, there is substantial variability in chosen value correlates across individual neurons. Here we show that this variability is explained by neurons having different temporal receptive fields of integration, indexed by examining neuronal spike rate autocorrelation structure whilst at rest. We find that neurons with protracted resting temporal receptive fields exhibit stronger chosen value correlates during choice. Within orbitofrontal cortex, these neurons also sustain coding of chosen value from choice through the delivery of reward, providing a potential neural mechanism for maintaining predictions and updating stored values during learning. These findings reveal that within PFC, variability in temporal specialisation across neurons predicts involvement in specific decision-making computations.

  15. Belief about nicotine selectively modulates value and reward prediction error signals in smokers

    Science.gov (United States)

    Gu, Xiaosi; Lohrenz, Terry; Salas, Ramiro; Baldwin, Philip R.; Soltani, Alireza; Kirk, Ulrich; Cinciripini, Paul M.; Montague, P. Read

    2015-01-01

    Little is known about how prior beliefs impact biophysically described processes in the presence of neuroactive drugs, which presents a profound challenge to the understanding of the mechanisms and treatments of addiction. We engineered smokers’ prior beliefs about the presence of nicotine in a cigarette smoked before a functional magnetic resonance imaging session where subjects carried out a sequential choice task. Using a model-based approach, we show that smokers’ beliefs about nicotine specifically modulated learning signals (value and reward prediction error) defined by a computational model of mesolimbic dopamine systems. Belief of “no nicotine in cigarette” (compared with “nicotine in cigarette”) strongly diminished neural responses in the striatum to value and reward prediction errors and reduced the impact of both on smokers’ choices. These effects of belief could not be explained by global changes in visual attention and were specific to value and reward prediction errors. Thus, by modulating the expression of computationally explicit signals important for valuation and choice, beliefs can override the physical presence of a potent neuroactive compound like nicotine. These selective effects of belief demonstrate that belief can modulate model-based parameters important for learning. The implications of these findings may be far ranging because belief-dependent effects on learning signals could impact a host of other behaviors in addiction as well as in other mental health problems. PMID:25605923

  16. Testosterone and reward prediction-errors in healthy men and men with schizophrenia.

    Science.gov (United States)

    Morris, R W; Purves-Tyson, T D; Weickert, C Shannon; Rothmond, D; Lenroot, R; Weickert, T W

    2015-11-01

    Sex hormones impact reward processing, which is dysfunctional in schizophrenia; however, the degree to which testosterone levels relate to reward-related brain activity in healthy men and the extent to which this relationship may be altered in men with schizophrenia has not been determined. We used functional magnetic resonance imaging (fMRI) to measure neural responses in the striatum during reward prediction-errors and hormone assays to measure testosterone and prolactin in serum. To determine if testosterone can have a direct effect on dopamine neurons, we also localized and measured androgen receptors in human midbrain with immunohistochemistry and quantitative PCR. We found correlations between testosterone and prediction-error related activity in the ventral striatum of healthy men, but not in men with schizophrenia, such that testosterone increased the size of positive and negative prediction-error related activity in a valence-specific manner. We also identified midbrain dopamine neurons that were androgen receptor immunoreactive, and found that androgen receptor (AR) mRNA was positively correlated with tyrosine hydroxylase (TH) mRNA in human male substantia nigra. The results suggest that sex steroid receptors can potentially influence midbrain dopamine biosynthesis, and higher levels of serum testosterone are linked to better discrimination of motivationally-relevant signals in the ventral striatum, putatively by modulation of the dopamine biosynthesis pathway via AR ligand binding. However, the normal relationship between serum testosterone and ventral striatum activity during reward learning appears to be disrupted in schizophrenia. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

  17. Efficacy, safety, predictability, aberrations and corneal biomechnical parameters after SMILE and FLEx: Meta-analysis

    Science.gov (United States)

    Ma, Jing; Cao, Nan-Jue; Xia, Li-Kun

    2016-01-01

    AIM To identify possible differences of efficacy, safety, predictability, higher-order aberrations and corneal biomechnical parameters after small-incision lenticule extraction (SMILE) and femtosecond lenticule extraction (FLEx). METHODS A systematic literature retrieval was conducted in Medline, Embase and the Cochrane Library, up to October, 2015. The included studies were subject to a Meta-analysis. Comparison between SMILE and FLEx was measured as pooled odds ratio (OR) or weighted mean differences (WMD). Of 95% confidence intervals (CI) were used to analyze data. RESULTS A total of seven studies were included. Firstly, there were no differences in uncorrected distance visual acuity (UDVA) 20/20 or better (OR, 1.37; 95% CI, 0.69 to 2.69; P=0.37) and logMAR UDVA (WMD, -0.02; 95% CI, -0.05 to 0.01; P=0.17) after SMILE versus FLEx. We found no differences in corrected distance visual acuity (CDVA) unchanged (OR, 0.98; 95% CI, 0.46 to 2.11; P=0.97) and logMAR CDVA (WMD, -0.00; 95% CI, -0.01 to 0.01; P=0.90) either. Secondly, we found no differences in refraction within ±1.00 D (OR, 0.98; 95% CI, 0.13 to 7.28; P=0.99) and ±0.50 D (OR, 1.62; 95% CI, 0.62 to 4.28; P=0.33) of target postoperatively. Thirdly, for higher-order aberrations, we found no differences in the total higher-order aberrations (WMD, -0.04; 95% CI, -0.09 to 0.01; P=0.14), coma (WMD, -0.04; 95% CI, -0.09 to 0.01; P=0.11), spherical (WMD, 0.01; 95% CI, -0.02 to 0.03; P=0.60) and trefoil (WMD, -0.00; 95% CI, -0.04 to 0.03; P=0.76). Furthermore, for corneal biomechanical parameters, we also found no differences (WMD, 0.08; 95% CI, -0.17 to 0.33; P=0.54) after SMILE versus FLEx. CONCLUSION There are no statistically differences in efficacy, safety, predictability, higher-order aberrations and corneal biomechnical parameters postoperative between SMILE and FLEx. PMID:27275436

  18. Striatal dopaminergic modulation of reinforcement learning predicts reward-oriented behavior in daily life

    NARCIS (Netherlands)

    Kasanova, Zuzana; Ceccarini, Jenny; Frank, Michael J.; van Amelsvoort, Thérèse; Booij, Jan; Heinzel, Alexander; Mottaghy, Felix; Myin-Germeys, Inez

    2017-01-01

    Much human behavior is driven by rewards. Preclinical neurophysiological and clinical positron emission tomography (PET) studies have implicated striatal phasic dopamine (DA) release as a primary modulator of reward processing. However, the relationship between experimental reward-induced striatal

  19. Stem cell differentiation as a renewal-reward process: predictions and validation in the colonic crypt.

    Science.gov (United States)

    Vanaja, Kiran Gireesan; Feinberg, Andrew P; Levchenko, Andre

    2012-01-01

    Stem cells serve as persistent reservoirs for replenishment of rapidly renewing tissues, frequently also ensuring that the correct tissue morphology is maintained. This process is inherently stochastic due to the small number and stochastic division patterns within the stem cell compartments, as well as the essentially stochastic differentiation events that follow the initial stem cell expansion. Here we propose a new formalism to describe this process, by employing the approach known in statistics as the renewal-reward process. Using this approximation allows application of the mathematical apparatus developed for renewal-reward processes to the stochastic stem cell biology. We show in the context of colonic crypts that the resulting predictions match the experimental results, while also providing a convenient tool for analysis of normal and abnormal differentiation processes.

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

    Science.gov (United States)

    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.

  1. Surprise signals in anterior cingulate cortex: Neuronal encoding of unsigned reward prediction errors driving adjustment in behavior

    OpenAIRE

    Hayden, Benjamin Y.; Heilbronner, Sarah R.; Pearson, John M.; Platt, Michael L.

    2011-01-01

    In attentional models of learning, associations between actions and subsequent rewards are stronger when outcomes are surprising, regardless of their valence. Despite the behavioral evidence that surprising outcomes drive learning, neural correlates of unsigned reward prediction errors remain elusive. Here we show that in a probabilistic choice task, trial-to-trial variations in preference track outcome surprisingness. Concordant with this behavioral pattern, responses of neurons in macaque (...

  2. Putting Reward in Art: A Tentative Prediction Error Account of Visual Art

    Directory of Open Access Journals (Sweden)

    Sander Van de Cruys

    2011-12-01

    Full Text Available The predictive coding model is increasingly and fruitfully used to explain a wide range of findings in perception. Here we discuss the potential of this model in explaining the mechanisms underlying aesthetic experiences. Traditionally art appreciation has been associated with concepts such as harmony, perceptual fluency, and the so-called good Gestalt. We observe that more often than not great artworks blatantly violate these characteristics. Using the concept of prediction error from the predictive coding approach, we attempt to resolve this contradiction. We argue that artists often destroy predictions that they have first carefully built up in their viewers, and thus highlight the importance of negative affect in aesthetic experience. However, the viewer often succeeds in recovering the predictable pattern, sometimes on a different level. The ensuing rewarding effect is derived from this transition from a state of uncertainty to a state of increased predictability. We illustrate our account with several example paintings and with a discussion of art movements and individual differences in preference. On a more fundamental level, our theorizing leads us to consider the affective implications of prediction confirmation and violation. We compare our proposal to other influential theories on aesthetics and explore its advantages and limitations.

  3. Tryptophan depletion disinhibits punishment but not reward prediction: implications for resilience.

    Science.gov (United States)

    Robinson, Oliver J; Cools, Roshan; Sahakian, Barbara J

    2012-01-01

    We have previously shown that tryptophan depletion enhances punishment but not reward prediction (Cools et al. in Neuropsychopharmacology 33:2291-2299, 2008b). This provided evidence for a valence-specific role of serotonin (which declines under depleted tryptophan) in aversive processing. Recent theoretical (Dayan and Huys in PLoS Comput Biol 4:e4, 2008) and experimental (Crockett et al. in J Neurosci 29:11993-11999, 2009) approaches have, however, further specified this role by showing that serotonin is critical for punishment-induced inhibition. We sought to examine the role of serotonin in punishment-induced inhibition. We also examined the impact of induced mood on this effect to assess whether effects of tryptophan depletion on affective inhibition are moderated by mood. Healthy females consumed a balanced amino acid mixture with (N = 20) or without (N = 21) the serotonin precursor tryptophan. Each subject completed either negative or neutral mood induction. All subjects completed the reward and punishment reversal learning task adopted in the previous study. We demonstrate a punishment prediction impairment in individuals who consumed tryptophan which was absent in individuals who were depleted of tryptophan. This effect was impervious to mood state. Our results suggest that serotonin promotes the inhibition of responses to punishing outcomes. This may lead to reduced punishment prediction accuracy in the presence of tryptophan and may contribute to resilience to affective disorders. Reduction of serotonin via tryptophan depletion then removes this inhibition. As such, we highlight a mechanism by which reduced serotonin can contribute to disorders of impulsivity and compulsivity as well as disorders of emotion.

  4. Chronic exposure to a gambling-like schedule of reward predictive stimuli can promote sensitization to amphetamine in rats

    Directory of Open Access Journals (Sweden)

    Martin eZack

    2014-02-01

    Full Text Available Addiction is considered to be a brain disease caused by chronic exposure to drugs. Sensitization of brain dopamine (DA systems partly mediates this effect. Pathological gambling (PG is considered to be a behavioral addiction. Therefore, PG may be caused by chronic exposure to gambling. Identifying a gambling-induced sensitization of DA systems would support this possibility. Gambling rewards evoke DA release. One episode of slot machine play shifts the DA response from reward delivery to onset of cues (spinning reels for reward, in line with temporal difference learning principles. Thus, conditioned stimuli (CS play a key role in DA responses to gambling. In primates, DA response to a CS is strongest when reward probability is 50%. Under this schedule the CS elicits an expectancy of reward but provides no information about whether it will occur on a given trial. During gambling, a 50% schedule should elicit maximal DA release. This closely matches reward frequency (46% on a commercial slot machine. DA release can contribute to sensitization, especially for amphetamine. Chronic exposure to a CS that predicts reward 50% of the time could mimic this effect. We tested this hypothesis in 3 studies with rats. Animals received 15 x 45-min exposures to a CS that predicted reward with a probability of 0, 25, 50, 75 or 100%. The CS was a light; the reward was a 10% sucrose solution. After training, rats received a sensitizing regimen of 5 separate doses (1 mg/kg of d-amphetamine. Lastly they received a 0.5 or 1 mg/kg amphetamine challenge prior to a 90-min locomotor activity test. In all 3 studies the 50% group displayed greater activity than the other groups in response to both challenge doses. Effect sizes were modest but consistent, as reflected by a significant group x rank association ( = .986, p = .025. Chronic exposure to a gambling-like schedule of reward predictive stimuli can promote sensitization to amphetamine much like exposure to

  5. Striatal dopaminergic modulation of reinforcement learning predicts reward-oriented behavior in daily life.

    Science.gov (United States)

    Kasanova, Zuzana; Ceccarini, Jenny; Frank, Michael J; Amelsvoort, Thérèse van; Booij, Jan; Heinzel, Alexander; Mottaghy, Felix; Myin-Germeys, Inez

    2017-07-01

    Much human behavior is driven by rewards. Preclinical neurophysiological and clinical positron emission tomography (PET) studies have implicated striatal phasic dopamine (DA) release as a primary modulator of reward processing. However, the relationship between experimental reward-induced striatal DA release and responsiveness to naturalistic rewards, and therefore functional relevance of these findings, has been elusive. We therefore combined, for the first time, a DA D2/3 receptor [18F]fallypride PET during a probabilistic reinforcement learning (RL) task with a six day ecological momentary assessments (EMA) of reward-related behavior in the everyday life of 16 healthy volunteers. We detected significant reward-induced DA release in the bilateral putamen, caudate nucleus and ventral striatum, the extent of which was associated with better behavioral performance on the RL task across all regions. Furthermore, individual variability in the extent of reward-induced DA release in the right caudate nucleus and ventral striatum modulated the tendency to be actively engaged in a behavior if the active engagement was previously deemed enjoyable. This study suggests a link between striatal reward-related DA release and ecologically relevant reward-oriented behavior, suggesting an avenue for the inquiry into the DAergic basis of optimal and impaired motivational drive. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Dopamine, reward learning, and active inference

    Directory of Open Access Journals (Sweden)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-07-01

    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)

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

    Science.gov (United States)

    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.

  9. States versus Rewards: Dissociable Neural Prediction Error Signals Underlying Model-Based and Model-Free Reinforcement Learning

    OpenAIRE

    Gläscher, Jan; Daw, Nathaniel; Dayan, Peter; O'Doherty, John P.

    2010-01-01

    Reinforcement learning (RL) uses sequential experience with situations (“states”) and outcomes to assess actions. Whereas model-free RL uses this experience directly, in the form of a reward prediction error (RPE), model-based RL uses it indirectly, building a model of the state transition and outcome structure of the environment, and evaluating actions by searching this model. A state prediction error (SPE) plays a central role, reporting discrepancies between the current model and the obser...

  10. Life stress in adolescence predicts early adult reward-related brain function and alcohol dependence.

    Science.gov (United States)

    Casement, Melynda D; Shaw, Daniel S; Sitnick, Stephanie L; Musselman, Samuel C; Forbes, Erika E

    2015-03-01

    Stressful life events increase vulnerability to problematic alcohol use, and they may do this by disrupting reward-related neural circuitry. This is particularly relevant for adolescents because alcohol use rises sharply after mid-adolescence and alcohol abuse peaks at age 20. Adolescents also report more stressors compared with children, and neural reward circuitry may be especially vulnerable to stressors during adolescence because of prefrontal cortex remodeling. Using a large sample of male participants in a longitudinal functional magnetic resonance imaging study (N = 157), we evaluated whether cumulative stressful life events between the ages of 15 and 18 were associated with reward-related brain function and problematic alcohol use at age 20 years. Higher cumulative stressful life events during adolescence were associated with decreased response in the medial prefrontal cortex (mPFC) during monetary reward anticipation and following the receipt of monetary rewards. Stress-related decreases in mPFC response during reward anticipation and following rewarding outcomes were associated with the severity of alcohol dependence. Furthermore, mPFC response mediated the association between stressful life events and later symptoms of alcohol dependence. These data are consistent with neurobiological models of addiction that propose that stressors during adolescence increase risk for problematic alcohol use by disrupting reward circuit function. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  11. Predicting the reward value of faces and bodies from social perception.

    Science.gov (United States)

    Morrison, Danielle; Wang, Hongyi; Hahn, Amanda C; Jones, Benedict C; DeBruine, Lisa M

    2017-01-01

    Social judgments of faces are thought to be underpinned by two perceptual components: valence and dominance. Recent work using a standard key-press task to assess reward value found that these valence and dominance components were both positively related to the reward value of faces. Although bodies play an important role in human social interaction, the perceptual dimensions that underpin social judgments of bodies and their relationship to the reward value of bodies are not yet known. The current study investigated these issues. We replicated previous studies showing that valence and dominance underpin social judgments of faces and that both components are positively related to the reward value of faces. By contrast, social judgments of bodies were underpinned by a single component that reflected aspects of both perceived valence and perceived dominance and was positively correlated with the reward value of bodies. These results highlight differences in how observers process faces and bodies.

  12. Low Social Rhythm Regularity Predicts First Onset of Bipolar Spectrum Disorders Among At Risk Individuals with Reward Hypersensitivity

    Science.gov (United States)

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

    2015-01-01

    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) 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 semi-structured diagnostic interviews every six 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, 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, OR = .861, 95% CI = .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. PMID:26595474

  13. Dissociating the predictive and incentive motivational properties of reward-related cues through the study of individual differences.

    Science.gov (United States)

    Robinson, Terry E; Flagel, Shelly B

    2009-05-15

    If presentation of a stimulus (conditional stimulus, CS) reliably predicts delivery of a reward, the CS will come to evoke a conditional response (CR) through Pavlovian learning, and the CS may also acquire incentive motivational properties. Thus, CSs can have both predictive and incentive properties. We ask here whether it is possible to dissociate the predictive versus incentive properties of a CS in rats by considering individual differences in the nature of the CR. We used Pavlovian procedures to study the ability of a localizable CS (an illuminated lever) to acquire two properties of an incentive stimulus-the ability to attract and the ability to act as a conditional reinforcer. For some rats, the CS evoked a "sign-tracking" CR, consisting of approach toward and engagement with the CS itself. For other rats, the CS instead produced a "goal-tracking" CR: approach was directed away from the CS toward the site of food delivery. For sign-trackers (but not goal-trackers) the CS also acted as an effective conditional reinforcer. The predictive and incentive properties of a CS can be dissociated by considering individual differences in the CR. In a given animal, a cue that is predictive of reward, supporting Pavlovian learning, may or may not be attributed with incentive salience. This procedure may provide a powerful means to test hypotheses regarding the role of neural systems in learning versus incentive motivational functions and to study individual variation in the extent to which reward-associated stimuli act as incentive stimuli.

  14. Girls’ Challenging Social Experiences in Early Adolescence Predict Neural Response to Rewards and Depressive Symptoms1

    Science.gov (United States)

    Casement, Melynda D.; Guyer, Amanda E.; Hipwell, Alison; McAloon, Rose L.; Hoffmann, Amy M.; Keenan, Kathryn; Forbes, Erika E.

    2014-01-01

    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. PMID:24397999

  15. Girls' challenging social experiences in early adolescence predict neural response to rewards and depressive symptoms.

    Science.gov (United States)

    Casement, Melynda D; Guyer, Amanda E; Hipwell, Alison E; McAloon, Rose L; Hoffmann, Amy M; Keenan, Kathryn E; Forbes, Erika E

    2014-04-01

    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. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. 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.

  17. Increased fronto-striatal reward prediction errors moderate decision making in obsessive-compulsive disorder.

    Science.gov (United States)

    Hauser, T U; Iannaccone, R; Dolan, R J; Ball, J; Hättenschwiler, J; Drechsler, R; Rufer, M; Brandeis, D; Walitza, S; Brem, S

    2017-05-01

    Obsessive-compulsive disorder (OCD) has been linked to functional abnormalities in fronto-striatal networks as well as impairments in decision making and learning. Little is known about the neurocognitive mechanisms causing these decision-making and learning deficits in OCD, and how they relate to dysfunction in fronto-striatal networks. We investigated neural mechanisms of decision making in OCD patients, including early and late onset of disorder, in terms of reward prediction errors (RPEs) using functional magnetic resonance imaging. RPEs index a mismatch between expected and received outcomes, encoded by the dopaminergic system, and are known to drive learning and decision making in humans and animals. We used reinforcement learning models and RPE signals to infer the learning mechanisms and to compare behavioural parameters and neural RPE responses of the OCD patients with those of healthy matched controls. Patients with OCD showed significantly increased RPE responses in the anterior cingulate cortex (ACC) and the putamen compared with controls. OCD patients also had a significantly lower perseveration parameter than controls. Enhanced RPE signals in the ACC and putamen extend previous findings of fronto-striatal deficits in OCD. These abnormally strong RPEs suggest a hyper-responsive learning network in patients with OCD, which might explain their indecisiveness and intolerance of uncertainty.

  18. Reward type and behavioural patterns predict dogs' success in a delay of gratification paradigm.

    Science.gov (United States)

    Brucks, Désirée; Soliani, Matteo; Range, Friederike; Marshall-Pescini, Sarah

    2017-03-08

    Inhibiting an immediate behaviour in favour of an alternative but more advantageous behaviour has been linked to individual success in life, especially in humans. Dogs, which have been living in the human environment for thousands of years, are exposed to daily situations that require inhibition different in context from other non-domesticated species. One task regularly used to study inhibitory control is the delay of gratification task, which requires individuals to choose between an immediate option of lower value and a delayed option of higher value. We tested sixteen dogs in a non-social delay of gratification task, conducting two different conditions: a quality and a quantity condition. While the majority of dogs failed to wait for more than 10 s, some dogs tolerated delays of up to 140 s, while one dog waited for 15 minutes. Moreover, dogs had more difficulties to wait if the reward increased in terms of quantity than quality. Interestingly, dogs were able to anticipate the delay duration and some dogs developed behavioural patterns that predicted waiting, which seems similar in some respects to 'coping-strategies' found in children, chimpanzees and parrots. Our results indicate that strategies to cope with impulsivity seem to be consistent and present across animal taxa.

  19. Reward type and behavioural patterns predict dogs’ success in a delay of gratification paradigm

    Science.gov (United States)

    Brucks, Désirée; Soliani, Matteo; Range, Friederike; Marshall-Pescini, Sarah

    2017-01-01

    Inhibiting an immediate behaviour in favour of an alternative but more advantageous behaviour has been linked to individual success in life, especially in humans. Dogs, which have been living in the human environment for thousands of years, are exposed to daily situations that require inhibition different in context from other non-domesticated species. One task regularly used to study inhibitory control is the delay of gratification task, which requires individuals to choose between an immediate option of lower value and a delayed option of higher value. We tested sixteen dogs in a non-social delay of gratification task, conducting two different conditions: a quality and a quantity condition. While the majority of dogs failed to wait for more than 10 s, some dogs tolerated delays of up to 140 s, while one dog waited for 15 minutes. Moreover, dogs had more difficulties to wait if the reward increased in terms of quantity than quality. Interestingly, dogs were able to anticipate the delay duration and some dogs developed behavioural patterns that predicted waiting, which seems similar in some respects to ‘coping-strategies’ found in children, chimpanzees and parrots. Our results indicate that strategies to cope with impulsivity seem to be consistent and present across animal taxa. PMID:28272409

  20. Affective personality predictors of disrupted reward learning and pursuit in major depressive disorder.

    Science.gov (United States)

    DelDonno, Sophie R; Weldon, Anne L; Crane, Natania A; Passarotti, Alessandra M; Pruitt, Patrick J; Gabriel, Laura B; Yau, Wendy; Meyers, Kortni K; Hsu, David T; Taylor, Stephen F; Heitzeg, Mary M; Herbener, Ellen; Shankman, Stewart A; Mickey, Brian J; Zubieta, Jon-Kar; Langenecker, Scott A

    2015-11-30

    Anhedonia, the diminished anticipation and pursuit of reward, is a core symptom of major depressive disorder (MDD). Trait behavioral activation (BA), as a proxy for anhedonia, and behavioral inhibition (BI) may moderate the relationship between MDD and reward-seeking. The present studies probed for reward learning deficits, potentially due to aberrant BA and/or BI, in active or remitted MDD individuals compared to healthy controls (HC). Active MDD (Study 1) and remitted MDD (Study 2) participants completed the modified monetary incentive delay task (mMIDT), a behavioral reward-seeking task whose response window parameters were individually titrated to theoretically elicit equivalent accuracy between groups. Participants completed the BI Scale and BA Reward-Responsiveness and Drive Scales. Despite individual titration, active MDD participants won significantly less money than HCs. Higher Reward-Responsiveness scores predicted more won; Drive and BI were not predictive. Remitted MDD participants' performance did not differ from controls', and trait BA and BI measures did not predict r-MDD performance. These results suggest that diminished reward-responsiveness may contribute to decreased motivation and reward pursuit during active MDD, but that reward learning is intact in remission. Understanding individual reward processing deficits in MDD may inform personalized intervention addressing anhedonia and motivation deficits in select MDD patients. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  1. Reward circuitry responsivity to food predicts future increases in body mass: moderating effects of DRD2 and DRD4.

    Science.gov (United States)

    Stice, Eric; Yokum, Sonja; Bohon, Cara; Marti, Nate; Smolen, Andrew

    2010-05-01

    To determine whether responsivity of reward circuitry to food predicts future increases in body mass and whether polymorphisms in DRD2 and DRD4 moderate these relations. The functional magnetic resonance imaging (fMRI) paradigm investigated blood oxygen level dependent activation in response to imagined intake of palatable foods, unpalatable foods, and glasses of water shown in pictures. DNA was extracted from saliva samples using standard salting-out and solvent precipitation methods. Forty-four adolescent female high school students ranging from lean to obese. Future increases in body mass index (BMI). Weaker activation of the frontal operculum, lateral orbitofrontal cortex, and striatum in response to imagined intake of palatable foods, versus imagined intake of unpalatable foods or water, predicted future increases in body mass for those with the DRD2 TaqIA A1 allele or the DRD4-7R allele. Data also suggest that for those lacking these alleles, greater responsivity of these food reward regions predicted future increases in body mass. This novel prospective fMRI study indicates that responsivity of reward circuitry to food increases risk for future weight gain, but that genes that impact dopamine signaling capacity moderate the predictive effects, suggesting two qualitatively distinct pathways to unhealthy weight gain based on genetic risk. 2010 Elsevier Inc. All rights reserved.

  2. Neural Coding of Reward-Prediction Error Signals During Classical Conditioning With Attractive Faces

    National Research Council Canada - National Science Library

    Signe Bray; John O'Doherty

    2007-01-01

    .... Given that these stimuli appear to act as rewards, we set out to explore whether it was possible to establish conditioning in human subjects by pairing presentation of arbitrary affectively neutral...

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

    Directory of Open Access Journals (Sweden)

    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.

  4. Love to win or hate to lose? Asymmetry of dopamine D2 receptor binding predicts sensitivity to reward vs. punishment

    Science.gov (United States)

    Tomer, Rachel; Slagter, Heleen A; Christian, Bradley T; Fox, Andrew S; King, Carlye R; Murali, Dhanabalan; Gluck, Mark A; Davidson, Richard J

    2014-01-01

    Humans show consistent differences in the extent to which their behavior reflects a bias towards appetitive approach-related behavior or avoidance of aversive stimuli (Elliot, 2008). We examined the hypothesis that in healthy subjects this motivational bias (assessed by self-report and by a probabilistic learning task that allows direct comparison of the relative sensitivity to reward and punishment) reflects lateralization of dopamine signaling. Using [F-18]fallypride to measure D2/D3 binding , we found that self-reported motivational bias was predicted by the asymmetry of frontal D2 binding. Similarly, striatal and frontal asymmetries in D2 dopamine receptor binding, rather than absolute binding levels, predicted individual differences in learning from reward vs. punishment. These results suggest that normal variation in asymmetry of dopamine signaling may, in part, underlie human personality and cognition. PMID:24345165

  5. 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

  6. 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.

  7. 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.

    2009-01-01

    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…

  8. Elevated reward response to receipt of palatable food predicts future weight variability in healthy-weight adolescents.

    Science.gov (United States)

    Winter, Samantha R; Yokum, Sonja; Stice, Eric; Osipowicz, Karol; Lowe, Michael R

    2017-04-01

    Background: Both an elevated brain-reward-region response to palatable food and elevated weight variability have been shown to predict future weight gain. Objective: We examined whether the brain-reward response to food is related to future weight variability. Design: A total of 162 healthy-weight adolescents, who were aged 14-18 y at baseline, were enrolled in the study and were assessed annually over a 3-y follow-up period with 127 participants completing the final 3-y follow-up assessment. With the use of functional magnetic resonance imaging, we tested whether the neural responses to a cue that signaled an impending milkshake receipt and the receipt of the milkshake predicted weight variability over the follow-up period. Weight variability was modeled with a root mean squared error method to reflect fluctuations in weight independent of the net weight change. Results: Elevated activation in the medial prefrontal cortex and supplementary motor area, cingulate gyrus, cuneus and occipital gyrus, and insula in response to milkshake receipt predicted greater weight variability. Greater activation in the precuneus and middle temporal gyrus predicted lower weight variability. Conclusions: From our study data, we suggest that the elevated activation of reward and emotional-regulation brain regions (medial prefrontal cortex, cingulate cortex, and insula) and lower activation in self-reference regions (precuneus) in response to milkshake receipt predict weight variability over 3 y of follow-up. The fact that the reward response in the current study emerged in response to high-calorie palatable food receipt suggests that weight variability may be a measure of propensity periods of a positive energy balance and should be examined in addition to measures of the net weight change. With our collective results, we suggest that weight variability and its brain correlates should be added to other variables that are predictive of weight gain to inform the design of obesity

  9. Personality domains and traits that predict self-reported aberrant driving behaviours in a southeastern US university sample.

    Science.gov (United States)

    Beanland, Vanessa; Sellbom, Martin; Johnson, Alexandria K

    2014-11-01

    Personality traits are meaningful predictors of many significant life outcomes, including mortality. Several studies have investigated the relationship between specific personality traits and driving behaviours, e.g., aggression and speeding, in an attempt to identify traits associated with elevated crash risk. These studies, while valuable, are limited in that they examine only a narrow range of personality constructs and thus do not necessarily reveal which traits in constellation best predict aberrant driving behaviours. The primary aim of this study was to use a comprehensive measure of personality to investigate which personality traits are most predictive of four types of aberrant driving behaviour (Aggressive Violations, Ordinary Violations, Errors, Lapses) as indicated by the Manchester Driver Behaviour Questionnaire (DBQ). We recruited 285 young adults (67% female) from a university in the southeastern US. They completed self-report questionnaires including the DBQ and the Personality Inventory for DSM-5, which indexes 5 broad personality domains (Antagonism, Detachment, Disinhibition, Negative Affectivity, Psychoticism) and 25 specific trait facets. Confirmatory factor analysis showed adequate evidence for the DBQ internal structure. Structural regression analyses revealed that the personality domains of Antagonism and Negative Affectivity best predicted both Aggressive Violations and Ordinary Violations, whereas the best predictors of both Errors and Lapses were Negative Affectivity, Disinhibition and to a lesser extent Antagonism. A more nuanced analysis of trait facets revealed that Hostility was the best predictor of Aggressive Violations; Risk-taking and Hostility of Ordinary Violations; Irresponsibility, Separation Insecurity and Attention Seeking of Errors; and Perseveration and Irresponsibility of Lapses. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Reward processing in neurodegenerative disease

    Science.gov (United States)

    Perry, David C.; Kramer, Joel H.

    2015-01-01

    Representation of reward value involves a distributed network including cortical and subcortical structures. Because neurodegenerative illnesses target specific anatomic networks that partially overlap with the reward circuit they would be predicted to have distinct impairments in reward processing. This review presents the existing evidence of reward processing changes in neurodegenerative diseases including mild cognitive impairment, Alzheimer's disease, frontotemporal dementia, amyotrophic lateral sclerosis, Parkinson's disease, and Huntington's disease, as well as in healthy aging. Carefully distinguishing the different aspects of reward processing (primary rewards, secondary rewards, reward-based learning, and reward-based decision-making) and using tasks that differentiate the stages of processing reward will lead to improved understanding of this fundamental process and clarify a contributing cause of behavioral change in these illnesses. PMID:24417286

  11. The interaction of economic rewards and moral convictions in predicting attitudes toward resource use.

    Directory of Open Access Journals (Sweden)

    Brock Bastian

    Full Text Available When people are morally convicted regarding a specific issue, these convictions exert a powerful influence on their attitudes and behavior. In the current research we examined whether there are boundary conditions to the influence of this effect. Specifically, whether in the context of salient economic rewards, moral convictions may become weaker predictors of attitudes regarding resource use. Focusing on the issue of mining we gathered large-scale samples across three different continents (Australia, Chile, and China. We found that moral convictions against mining were related to a reduced acceptance of mining in each country, while perceived economic rewards from mining increased acceptance. These two motivations interacted, however, such that when perceived economic benefit from mining was high, the influence of moral conviction was weaker. The results highlight the importance of understanding the roles of both moral conviction and financial gain in motivating attitudes towards resource use.

  12. The Interaction of Economic Rewards and Moral Convictions in Predicting Attitudes toward Resource Use

    Science.gov (United States)

    Bastian, Brock; Zhang, Airong; Moffat, Kieren

    2015-01-01

    When people are morally convicted regarding a specific issue, these convictions exert a powerful influence on their attitudes and behavior. In the current research we examined whether there are boundary conditions to the influence of this effect. Specifically, whether in the context of salient economic rewards, moral convictions may become weaker predictors of attitudes regarding resource use. Focusing on the issue of mining we gathered large-scale samples across three different continents (Australia, Chile, and China). We found that moral convictions against mining were related to a reduced acceptance of mining in each country, while perceived economic rewards from mining increased acceptance. These two motivations interacted, however, such that when perceived economic benefit from mining was high, the influence of moral conviction was weaker. The results highlight the importance of understanding the roles of both moral conviction and financial gain in motivating attitudes towards resource use. PMID:26267904

  13. Trait self-control is predicted by how reward associations modulate Stroop interference.

    Science.gov (United States)

    Wolff, Max; Krönke, Klaus-Martin; Goschke, Thomas

    2016-11-01

    Although cognitive control is commonly identified as the basis of self-controlled behavior, correlations found between trait self-control and laboratory measures of cognitive control such as Stroop interference are typically low. Based on the notion that self-control requires the ability to refrain from rewarded behaviors, and inspired by the recent finding that Stroop interference is modulated by reward associations, we propose the idea that the modulation of interference by reward associations (MIRA) is a cognitive marker of trait self-control. Two independent samples of participants completed (1) a modified Stroop task designed to assess MIRA and (2) two common measures of trait self-control: the Brief Self-Control Scale (BSCS) and the Barratt Impulsiveness Scale (BIS-11). MIRA was strongly correlated with the BSCS and moderately correlated with two of the three subscales of the BIS-11. MIRA thus appears to reflect a cognitive endophenotype of individual differences in self-control, and perhaps of related mental disorders.

  14. 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.

  15. 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.

  16. Struggling toward reward: Recent experience of anhedonia interacts with motivation to predict reward pursuit in the face of a stressful manipulation.

    Science.gov (United States)

    Bryant, Jessica; Winer, E Samuel; Salem, Taban; Nadorff, Michael R

    2017-01-01

    Anhedonia, or the loss of interest and/or pleasure, is a core symptom of depression. Individuals experiencing anhedonia have difficulty motivating themselves to pursue rewarding stimuli, which can result in dysfunction. Action orientation is a motivational factor that might interact with anhedonia to potentially buffer against this dysfunction, as action-oriented individuals upregulate positive affect to quickly motivate themselves to complete goals in the face of stress. The Effort-Expenditure for Rewards Task (EEfRT) is a promising new method for examining differences in motivation in individuals experiencing anhedonia. In the EEfRT, participants choose either easier tasks associated with smaller monetary rewards or harder tasks associated with larger monetary rewards. We examined the relationship between action orientation and EEfRT performance following a negative mood induction in a sample with varying levels of anhedonia. There were two competing hypotheses: (1) action orientation would act as a buffer against anhedonia such that action-oriented individuals, regardless of anhedonic symptoms, would be motivated to pursue greater rewards despite stress, or (2) anhedonia would act as a debilitating factor such that individuals with elevated anhedonic symptoms, regardless of action orientation, would not pursue greater rewards. We examined these hypotheses via Generalized Estimating Equations and found an interaction between anhedonia and action orientation. At low levels of anhedonia, action orientation was associated with effort for reward, but this relationship was not present at high levels of anhedonia. Thus, at low levels of anhedonia, action orientation acted as a buffer against stress, but at high levels, anhedonia debilitated action orientation so that it was no longer a promotive factor.

  17. Love to win or hate to Lose? Asymmetry of dopamine D2 receptor binding predicts sensitivity to reward versus punishment.

    Science.gov (United States)

    Tomer, Rachel; Slagter, Heleen A; Christian, Bradley T; Fox, Andrew S; King, Carlye R; Murali, Dhanabalan; Gluck, Mark A; Davidson, Richard J

    2014-05-01

    Humans show consistent differences in the extent to which their behavior reflects a bias toward appetitive approach-related behavior or avoidance of aversive stimuli [Elliot, A. J. Approach and avoidance motivation. In A. J. Elliot (Ed.), Handbook of approach and avoidance motivation (pp. 3-14). New York: Psychology Press, 2008]. We examined the hypothesis that in healthy participants this motivational bias (assessed by self-report and by a probabilistic learning task that allows direct comparison of the relative sensitivity to reward and punishment) reflects lateralization of dopamine signaling. Using [F-18]fallypride to measure D2/D3 binding, we found that self-reported motivational bias was predicted by the asymmetry of frontal D2 binding. Similarly, striatal and frontal asymmetries in D2 dopamine receptor binding, rather than absolute binding levels, predicted individual differences in learning from reward versus punishment. These results suggest that normal variation in asymmetry of dopamine signaling may, in part, underlie human personality and cognition.

  18. Involvement of NMDA and AMPA/KA receptors in the nucleus accumbens core in instrumental learning guided by reward-predictive cues.

    Science.gov (United States)

    Giertler, Christian; Bohn, Ines; Hauber, Wolfgang

    2005-03-01

    The use of reward-predictive cues to guide behavior critically involves the nucleus accumbens. However, little is known regarding the role of ionotropic glutamate receptors in the core subregion of the nucleus accumbens (AcbC) in instrumental learning guided by reward-predictive cues. Here we examined the effects of an intra-AcbC blockade of NMDA and AMPA/KA receptors on the acquisition of an instrumental response in a reaction time (RT) task in rats. In this task, discriminative cues signaled in advance the upcoming reward magnitude (5 or 1 food pellet) associated with a lever release. During early acquisition (days 1-6) rats received daily bilateral injections of either the NMDA receptor antagonist AP5 (5.0 microg per side, n = 14), the AMPA/KA receptor antagonist CNQX (2.5 microg per side, n = 14) or vehicle (0.5 microL per side, n = 19). No treatment was given during late acquisition (days 7-12). The main result was that rats which received intra-AcbC injections of AP5 or CNQX during early acquisition exhibited a general RT increase of responses to high and low reward. However, treatment with AP5 and CNQX did not interfere with discriminative guidance of RTs by cue-associated reward magnitudes, i.e. during acquisition RTs of responses to expected high reward became significantly faster than RTs of responses to expected low reward. Our findings suggest that NMDA and AMPA/KA receptors in the AcbC play a critical role in invigorating responding during instrumental learning, but seem less important in guiding responding according to reward-predictive cues.

  19. States versus rewards: dissociable neural prediction error signals underlying model-based and model-free reinforcement learning.

    Science.gov (United States)

    Gläscher, Jan; Daw, Nathaniel; Dayan, Peter; O'Doherty, John P

    2010-05-27

    Reinforcement learning (RL) uses sequential experience with situations ("states") and outcomes to assess actions. Whereas model-free RL uses this experience directly, in the form of a reward prediction error (RPE), model-based RL uses it indirectly, building a model of the state transition and outcome structure of the environment, and evaluating actions by searching this model. A state prediction error (SPE) plays a central role, reporting discrepancies between the current model and the observed state transitions. Using functional magnetic resonance imaging in humans solving a probabilistic Markov decision task, we found the neural signature of an SPE in the intraparietal sulcus and lateral prefrontal cortex, in addition to the previously well-characterized RPE in the ventral striatum. This finding supports the existence of two unique forms of learning signal in humans, which may form the basis of distinct computational strategies for guiding behavior. Copyright 2010 Elsevier Inc. All rights reserved.

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

    Science.gov (United States)

    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.

  1. Cytoplasmic Drosha Is Aberrant in Precancerous Lesions of Gastric Carcinoma and Its Loss Predicts Worse Outcome for Gastric Cancer Patients.

    Science.gov (United States)

    Zhang, Hailong; Hou, Yixuan; Xu, Liyun; Zeng, Zongyue; Wen, Siyang; Du, Yan-E; Sun, Kexin; Yin, Jiali; Lang, Lei; Tang, Xiaoli; Liu, Manran

    2016-04-01

    The nuclear localization of Drosha is critical for its function as a microRNA maturation regulator. Dephosphorylation of Drosha at serine 300 and serine 302 disrupts its nuclear localization, and aberrant distribution of Drosha has been detected in some tumors. The purpose of the present study was to assess cytoplasmic/nuclear Drosha expression in gastric cancer carcinogenesis and progression. Drosha expression and its subcellular location was investigated by immunohistochemical staining of a set of tissue microarrays composed of normal adjacent tissues (374), chronic gastritis (137), precancerous lesions (94), and gastric adenocarcinoma (829) samples, and in gastric cancer cell lines with varying differentiation by immunofluorescence and western blot assay. Gradual loss of cytoplasmic Drosha was accompanied by tumor progression in both gastric cancer tissues and cell lines, and was inversely associated with tumor volume (P = 0.002), tumor grade (P gastric cancer. High levels of cytoplasmic Drosha predicted longer survival (LR = 7.088, P = 0.008) in gastric cancer patients. Our data provide novel insights into gastric cancer that cytoplasmic Drosha potentially plays a role in preventing carcinogenesis and tumor progression, and may be an independent predictor of patient outcome.

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

    Science.gov (United States)

    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

  3. Aberrant GSTP1 promoter methylation predicts poor prognosis of acute-on-chronic hepatitis B pre-liver failure.

    Science.gov (United States)

    Qiao, Chen-Yang; Li, Feng; Teng, Yue; Zhao, Jing; Hu, Na; Fan, Yu-Chen; Wang, Kai

    2017-07-04

    It has been demonstrated that glutathione-S-transferase P1 (GSTP1) could protect cells from DNA damage mediated by oxidizing agents or electrophiles in hepatic inflammatory response. Our study evaluated the methylation status and the predictive value for prognosis of GSTP1 promoter region in patients with acute-on-chronic hepatitis B pre-liver failure (pre-ACHBLF). Methylation status of GSTP1 promoter in peripheral blood mononuclear cells (PBMCs) and plasma was measured in 103 patients with pre-ACHBLF, 80 patients with chronic hepatitis B (CHB) and 30 healthy controls (HCs) by methylation-specific polymerase chain reaction. The mRNA level of GSTP1 was detected by quantitative real-time polymerase chain reaction. The methylation frequency of GSTP1 promoter region in patients with pre-ACHBLF (35/103 in PBMCs and 33/103 in plasma) was significantly higher than CHB (2/80) and HCs (0/30), respectively. The mRNA level of GSTP1 in patients with pre-ACHBLF was significantly lower than CHB and HCs. Additionally, pre-ACHBLF patients with methylated GSTP1 presented strikingly higher incidence of ACHBLF than those without. Of note, GSTP1 methylation presented distinctly better performance than model for end-stage liver disease score [area under the receiver operating characteristic curves (AUCs) 0.825 in PBMCs and 0.798 in plasma VS 0.589; AUC 0.804 in PBMCs and 0.779 in plasma VS 0.622; AUC 0.767 in PBMCs and 0.744 in plasma VS 0.602, respectively] when used to predict the 1-, 2- or 3-month incidence of ACHBLF in patients with pre-ACHBLF. Aberrant methylation of GSTP1 has potential to be a prognostic biomarker for pre-ACHBLF.

  4. Intact discrimination reversal learning but slowed responding to reward-predictive cues after dopamine D1 and D2 receptor blockade in the nucleus accumbens of rats.

    Science.gov (United States)

    Calaminus, Carsten; Hauber, Wolfgang

    2007-04-01

    The prediction error hypothesis of dopamine action states that dopamine signals are necessary for the brain to update the predictive significance of cues. Yet, little is known whether D1 or D2 receptor-mediated signals in the nucleus accumbens core (AcbC) are required to learn a reversal of the predictive significance of cues. Here we examined the effects of a selective D1 or D2 receptor blockade in the AcbC on learning a reversal of previously acquired cue-reward magnitude contingencies. Rats were trained on a reaction time (RT) task demanding conditioned lever release with discriminative visual cues signalling in advance the upcoming reward magnitude (one or five food pellets). After acquisition, RTs were guided by cue-associated reward magnitudes, i.e. RTs of responses were significantly shorter for expected high vs low reward. Thereafter, cue-reward magnitude contingencies were reversed. Reversal learning was tested for 12 daily sessions with intra-AcbC micro-infusions being given on sessions 1-6. Subjects received pre-trial infusions of the selective D1 or D2 receptor antagonists, SCH23390 (0.5, 2 microg per side) or raclopride (1, 4 microg per side), or vehicle (0.5 microl). Intra-AcbC infusion of SCH23390 (0.5, 2 microg) or raclopride (1, 4 microg) did not inhibit discrimination reversal learning, but the higher dose of each drug increased RTs of instrumental responses. In a visual discrimination task as used here, D1 and D2 receptor-mediated signals in the AcbC seem to be unnecessary in updating the reward-predictive significance of cues, rather, they serve to activate instrumental behaviour.

  5. 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.

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

    Science.gov (United States)

    Asensio, Samuel; Romero, Maria J.; Romero, Francisco J.; Wong, Christopher; Alia-Klein, Nelly; Tomasi, Dardo; Wang, Gene-Jack; Telang, Frank; Volkow, Nora D.; Goldstein, Rita Z.

    2009-01-01

    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 non-drug 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 [11C]raclopride and positron emission tomography and response to monetary reward was measured (an average of 3 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 non-drug reinforcer (money) in prefrontal cortex, implicated in behavioral monitoring, and in thalamus, implicated in conditioned responses and expectation, in cocaine addicted individuals. PMID:20034014

  7. In epithelial cancers, aberrantCOL17A1promoter methylation predicts its misexpression and increased invasion.

    Science.gov (United States)

    Thangavelu, Pulari U; Krenács, Tibor; Dray, Eloise; Duijf, Pascal H G

    2016-01-01

    shown. Paradoxically, collagen XVII is underexpressed in breast cancer and overexpressed in cervical and other epithelial cancers. However, the COL17A1 promoter methylation status accurately predicts both the direction of misexpression and the increased invasive nature for five out of five epithelial cancers. This implies that aberrant epigenetic control is a key driver of COL17A1 gene misexpression and tumor cell invasion. These findings have significant clinical implications, suggesting that the COL17A1 promoter methylation status can be used to predict patient outcome. Moreover, epigenetic targeting of COL17A1 could represent a novel strategy to prevent metastasis in patients.

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

    Science.gov (United States)

    Kristensen, Lasse Sommer; Hansen, Jakob Werner; Kristensen, Søren Sommer; Tholstrup, Dorte; Harsløf, Laurine Bente Schram; Pedersen, Ole Birger; De Nully Brown, Peter; Grønbæk, Kirsten

    2016-01-01

    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 and to evaluate this as a prognostic marker. Furthermore, we wanted to follow possible changes in methylation levels during treatment. Seventy-four patients were enrolled in the study, of which 59 received rituximab and CHOP-like chemotherapy. Plasma samples were collected from all patients at the time of diagnosis and from 14 healthy individuals used as controls. In addition, plasma samples were collected during and after treatment for surviving patients. In total, 158 plasma samples were analyzed for DNA methylation in the promoter regions of DAPK (DAPK1), DBC1, MIR34A, and MIR34B/C using pyrosequencing. Aberrant methylation levels at the time of diagnosis were detected in 19, 16, 8, and 10 % of the DLBCL plasma samples for DAPK1, DBC1, MIR34A, and MIR34B/C, respectively. DAPK1 methylation levels were significantly correlated with DBC1 and MIR34B/C methylation levels (P methylation, respectively. DAPK1 methylation status were significantly correlated with stage (P = 0.015), as all patients with aberrant DAPK1 methylation were stages III and IV. Multivariate analysis identified DAPK1 as an independent prognostic factor for OS with a hazard ratio of 8.9 (95 % CI 2.7-29.3, P methylated cell-free circulating DNA at time of diagnosis, who became long-term survivors, lost the aberrant methylation after treatment initiation. Conversely, patients that maintained or regained aberrant DAPK1 methylation died soon thereafter. Aberrant promoter methylation of cell-free circulating DNA can be detected in plasma from DLBCL patients and hold promise as an easily accessible marker for evaluating response to treatment and for prognostication. In particular, aberrant DAPK1 methylation in

  9. Are persistent delusions in schizophrenia associated with aberrant salience?

    Directory of Open Access Journals (Sweden)

    Rafeef Abboud

    2016-06-01

    Conclusion: These findings do not support the hypothesis that persistent delusions are related to aberrant motivational salience processing in TRS patients. However, they do support the view that patients with schizophrenia have impaired reward learning.

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

    NARCIS (Netherlands)

    Hanssen, Esther; van der Velde, Jorien; Gromann, Paula M.; Shergill, Sukhi S.; de Haan, Lieuwe; Bruggeman, Richard; Krabbendam, Lydia; Aleman, Andre; van Atteveldt, Nienke

    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

  11. Orbitofrontal cortex volume in area 11/13 predicts reward devaluation, but not reversal learning performance, in young and aged monkeys.

    Science.gov (United States)

    Burke, Sara N; Thome, Alex; Plange, Kojo; Engle, James R; Trouard, Theodore P; Gothard, Katalin M; Barnes, Carol A

    2014-07-23

    The orbitofrontal cortex (OFC) and amygdala are both necessary for decisions based on expected outcomes. Although behavioral and imaging data suggest that these brain regions are affected by advanced age, the extent to which aging alters appetitive processes coordinated by the OFC and the amygdala is unknown. In the current experiment, young and aged bonnet macaques were trained on OFC- and amygdala-dependent tasks that test the degree to which response selection is guided by reward value and can be adapted when expected outcomes change. To assess whether the structural integrity of these regions varies with levels of performance on reward devaluation and object reversal tasks, volumes of areas 11/13 and 14 of the OFC, central/medial (CM), and basolateral (BL) nuclei of the amygdala were determined from high-resolution anatomical MRIs. With age, there were significant reductions in OFC, but not CM and BL, volume. Moreover, the aged monkeys showed impairments in the ability to associate an object with a higher value reward, and to reverse a previously learned association. Interestingly, greater OFC volume of area 11/13, but not 14, was significantly correlated with an animal's ability to anticipate the reward outcome associated with an object, and smaller BL volume was predictive of an animal's tendency to choose a higher value reward, but volume of neither region correlated with reversal learning. Together, these data indicate that OFC volume has an impact on monkeys' ability to guide choice behavior based on reward value but does not impact ability to reverse a previously learned association. Copyright © 2014 the authors 0270-6474/14/349905-12$15.00/0.

  12. 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.

    Science.gov (United States)

    Balasubramani, Pragathi P; Chakravarthy, V Srinivasa; Ravindran, Balaraman; Moustafa, Ahmed A

    2014-01-01

    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.

  13. 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

    Directory of Open Access Journals (Sweden)

    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.

  14. The impact of a total reward system of work engagement

    National Research Council Canada - National Science Library

    Crystal Hoole; Gabi Hotz

    2016-01-01

    ... their attention to total reward strategies. 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...

  15. 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.

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

    Science.gov (United States)

    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.

  17. Optical Aberrations and Wavefront

    Directory of Open Access Journals (Sweden)

    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

  18. Orienting of Attention to Gaze Direction Cues in Rhesus Macaques: Species-specificity, and Effects of Cue Motion and Reward Predictiveness

    Directory of Open Access Journals (Sweden)

    Dian eYu

    2012-06-01

    Full Text Available Primates live in complex social groups and rely on social cues to direct their attention. For example, primates react faster to an unpredictable stimulus after seeing a conspecific looking in the direction of that stimulus. In the current study we tested the specificity of facial cues (gaze direction for orienting attention and their interaction with other cues that are known to guide attention. In particular, we tested whether macaque monkeys only respond to gaze cues from conspecifics or if the effect generalizes across species. We found an attentional advantage of conspecific faces over that of other human and cartoon faces. Because gaze cues are often conveyed by gesture, we also explored the effect of image motion (a simulated glance on the orienting of attention in monkeys. We found that the simulated glance did not significantly enhance the speed of orienting for monkey face stimuli, but had a significant effect for images of human faces. Finally, because gaze cues presumably guide attention towards relevant or rewarding stimuli, we explored whether orienting of attention was modulated by reward predictiveness. When the cue predicted reward location, face and non-face cues were effective in speeding responses towards the cued location. This effect was strongest for conspecific faces. In sum, our results suggest that while conspecific gaze cues activate an intrinsic process that reflexively directs spatial attention, its effect is relatively small in comparison to other features including motion and reward predictiveness. It is possible that gaze cues are more important for decision-making and voluntary orienting than for reflexive orienting.

  19. 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.

  20. 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

  1. Reward Modulates Adaptations to Conflict

    Science.gov (United States)

    Braem, Senne; Verguts, Tom; Roggeman, Chantal; Notebaert, Wim

    2012-01-01

    Both cognitive conflict (e.g. Verguts & Notebaert, 2009) and reward signals (e.g. Waszak & Pholulamdeth, 2009) have been proposed to enhance task-relevant associations. Bringing these two notions together, we predicted that reward modulates conflict-based sequential adaptations in cognitive control. This was tested combining either a single…

  2. Social reward shapes attentional biases.

    Science.gov (United States)

    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.

  3. High monetary reward rates and caloric rewards decrease temporal persistence.

    Science.gov (United States)

    Fung, Bowen J; Bode, Stefan; Murawski, Carsten

    2017-02-22

    Temporal persistence refers to an individual's capacity to wait for future rewards, while forgoing possible alternatives. This requires a trade-off between the potential value of delayed rewards and opportunity costs, and is relevant to many real-world decisions, such as dieting. Theoretical models have previously suggested that high monetary reward rates, or positive energy balance, may result in decreased temporal persistence. In our study, 50 fasted participants engaged in a temporal persistence task, incentivised with monetary rewards. In alternating blocks of this task, rewards were delivered at delays drawn randomly from distributions with either a lower or higher maximum reward rate. During some blocks participants received either a caloric drink or water. We used survival analysis to estimate participants' probability of quitting conditional on the delay distribution and the consumed liquid. Participants had a higher probability of quitting in blocks with the higher reward rate. Furthermore, participants who consumed the caloric drink had a higher probability of quitting than those who consumed water. Our results support the predictions from the theoretical models, and importantly, suggest that both higher monetary reward rates and physiologically relevant rewards can decrease temporal persistence, which is a crucial determinant for survival in many species. © 2017 The Authors.

  4. [Comparison of Lasik with femtosecond laser versus Lasik with mechanical microkeratome: predictability of flap depth, corneal biomechanical effects and optical aberrations].

    Science.gov (United States)

    Kouassi, F-X; Blaizeau, M; Buestel, C; Schweitzer, C; Gallois, A; Colin, J; Touboul, D

    2012-01-01

    To compare the predictability of flap thickness, high-order optic aberrations (HOAs), and biomechanical properties of cornea between patients treated by Lasik with mechanical microkeratome versus patients treated by FemtoLasik. Department of ophthalmology, Pellegrin University Hospital, Bordeaux, France. We conducted a retrospective study on 53 myopic patients who underwent Lasik with either mechanical microkeratome (MK group) or femtosecond laser (FS group). Refraction, central corneal thickness, high-order optic aberrations (HOAs), corneal hysteresis (CH), and corneal resistance factor (CRF), were analysed pre- and postoperatively in both groups. The central corneal thickness was measured with OCT-Visante(®) (Carl-Zeiss, Meditec), biomechanical parameters with ORA(®) (Reichert), and optical aberrations with the Wave Scan(®) (AMO) aberrometer. We included 44 eyes of 22 patients in the MK group and 62 eyes of 31 patients in the FS group. Preoperatively, the mean best-corrected visual acuity was 0.95 in both groups. In the MK group, the flap was significantly thicker than expected (162/130 μm), but in the FS group, there was no significant difference (117/120 μm). The biomechanical properties of the cornea were lower in both groups independently of the flap cutting technique. The HOAs increased after Lasik and were not influenced by the flap cutting technique. Neither mechanical microkeratome, nor femtosecond laser for flap creation, increases HOAs and the biomechanical changes of the cornea, according to ORA(®), significantly after Lasik. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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.

  6. Identification of predictive markers for systemic treatment in breast and lung cancer patients. Personalizing medicine using molecular aberrations

    NARCIS (Netherlands)

    Vollebergh, M.A.

    2012-01-01

    Introduction: Currently, there are few markers available which are able to predict who is likely to respond to specific therapeutics in breast and lung cancer patients. This thesis describes candidate predictive markers, which would ultimately reduce cancer mortality as patients would receive

  7. The role of self-reported impulsivity and reward sensitivity versus neurocognitive measures of disinhibition and decision-making in the prediction of relapse in pathological gamblers.

    Science.gov (United States)

    Goudriaan, A E; Oosterlaan, J; De Beurs, E; Van Den Brink, W

    2008-01-01

    Disinhibition and decision-making skills play an important role in theories on the cause and outcome of addictive behaviors such as substance use disorders and pathological gambling. In recent studies, both disinhibition and disadvantageous decision-making strategies, as measured by neurocognitive tests, have been found to influence the course of substance use disorders. Research on factors affecting relapse in pathological gambling is scarce. This study investigated the effect of both self-reported impulsivity and reward sensitivity, and neurocognitively assessed disinhibition and decision-making under conflicting contingencies, on relapse in a group of 46 pathological gamblers. Logistic regression analysis indicated that longer duration of the disorder and neurocognitive indicators of disinhibition (Stop Signal Reaction Time) and decision-making (Card Playing Task) were significant predictors of relapse (explaining 53% of the variance in relapse), whereas self-reported impulsivity and reward sensitivity did not significantly predict relapse. Overall classification accuracy was 76%, with a positive classification accuracy of 76% and a negative classification accuracy of 75%. Duration of the disorder and neurocognitive measures of disinhibition and decision-making are powerful predictors of relapse in pathological gambling. The results suggest that endophenotypical neurocognitive characteristics are more promising in the prediction of relapse in pathological gambling than phenotypical personality characteristics. Neurocognitive predictors may be useful to guide treatment planning of follow-up contacts and booster sessions.

  8. The mismatch between high effort and low reward in household and family work predicts impaired health among mothers.

    Science.gov (United States)

    Sperlich, Stefanie; Arnhold-Kerri, Sonja; Siegrist, Johannes; Geyer, Siegfried

    2013-10-01

    So far, Siegrist's model of effort-reward imbalance (ERI) has been tested almost exclusively for paid employment. This article reports results on a newly developed questionnaire measuring ERI in unpaid household and family work. Using data of a population-based sample of 3129 German mothers, logistic regression analyses were performed to test the following three main assumptions: (i) high effort combined with low reward in household and family work increases the risk of poor health; (ii) a high level of overcommitment may enhance the risk of poor health; and (iii) mothers reporting an extrinsic high ERI and a high level of overcommitment have an even higher risk of poor health. ERI was significantly related to self-rated health, somatic complaints and mental health. A high level of overcommitment increased the risk of poor health, whereas ERI and overcommitment combined was associated with the highest risk of poor health. Statistically significant synergy effects of combined exposure of ERI and overcommitment were found for 'anxiety'. With some limitations, all three assumptions underlying the ERI model were confirmed. Thus, we conclude that ERI is applicable to domestic work and may provide an explanatory framework to assess stress experiences in mothers.

  9. WE-D-BRE-05: Prediction of Late Radiation-Induced Proctitis in Prostate Cancer Patients Using Chromosome Aberration and Cell Proliferation Rate

    Energy Technology Data Exchange (ETDEWEB)

    Oh, J; Deasy, J [Memorial Sloan Kettering Cancer Center, New York, NY (United States)

    2014-06-15

    Purpose: Chromosome damage and cell proliferation rate have been investigated as potential biomarkers for the early prediction of late radiationinduced toxicity. Incorporating these endpoints, we explored the predictive power for late radiation proctitis using a machine learning method. Methods: Recently, Beaton et al. showed that chromosome aberration and cell proliferation rate could be used as biomarkers to predict late radiation proctitis (Beaton et al. (2013) Int J Rad Onc Biol Phys, 85:1346–1352). For the identification of radiosensitive biomarkers, blood samples were collected from 10 patients with grade 3 late proctitis along with 20 control patients with grade 0 proctitis. After irradiation at 6 Gy, statistically significant difference was observed between the two groups, using the number of dicentrics and excess fragments, and the number of cells in metaphase 2 (M2). However, Beaton et al. did not show the usefulness of combining these endpoints. We reanalyzed the dataset to investigate whether incorporating these endpoints can increase the predictive power of radiation proctitis, using a support vector machine (SVM). Results: Using the SVM method with the number of fragments and M2 endpoints, perfect classification was achieved. In addition, to avoid biased estimate of the classification method, leave-one-out cross-validation (LOO-CV) was performed. The best performance was achieved when all three endpoints were used with 87% accuracy, 90% sensitivity, 85% specificity, and 0.85 AUC (the area under the receiver operating characteristic (ROC) curve). The most significant endpoint was the number of fragments that obtained 83% accuracy, 70% sensitivity, 90% specificity, and 0.82 AUC. Conclusion: We demonstrated that chromosome damage and cell proliferation rate could be significant biomarkers to predict late radiation proctitis. When these endpoints were used together in conjunction with a machine learning method, the better performance was obtained

  10. Effects of reward bundling on male rats' preference for larger-later food rewards.

    Science.gov (United States)

    Stein, Jeffrey S; Smits, Rochelle R; Johnson, Patrick S; Liston, Kennan J; Madden, Gregory J

    2013-03-01

    In both humans and nonhumans, prior research demonstrates increased preference for larger-later over smaller-sooner rewards when rewards are bundled together in a series (i.e., when an operant choice produces multiple discrete reward deliveries, as opposed to only a single delivery). These findings can be predicted using a traditional hyperbolic delay-discounting model. The present study was designed to examine the parametric effects of the size of the reward bundle on larger-later reward preference in male rats. During a reward-bundling phase, rats were exposed to bundle-sizes of either 1 (i.e., no bundling), 3, or 9 rewards. Rats in the Bundle-size 9 group showed significantly greater larger-later reward preference across a range of delays (0-17.5 s) than rats in any other group, but no other significant differences in choice were observed between groups. In addition, when choice for unbundled rewards was assessed following the reward-bundling phase, rats in the Bundle-size 9 group showed a significant increase in larger-later reward preference (compared to a pre-test). Obtained data from the reward-bundling phase are compared to model-predicted data, and potential mechanisms of the observed increase in self-control for unbundled rewards are discussed. © Society for the Experimental Analysis of Behavior.

  11. Chromosomal aberrations in lymphocytes predict human cancer independently of exposure to carcinogens. European Study Group on Cytogenetic Biomarkers and Health

    DEFF Research Database (Denmark)

    Bonassi, S; Hagmar, L; Strömberg, U

    2000-01-01

    played by exposure to carcinogens is still uncertain because of the requisite information concerning occupation and lifestyle was lacking. We evaluated in the present study whether CAs predicted cancer because they were the result of past exposure to carcinogens or because they were an intermediate end...... in the regression model. The risk for high versus low levels of CAs was similar in subjects heavily exposed to carcinogens and in those who had never, to their knowledge, been exposed to any major carcinogenic agent during their lifetime, supporting the idea that chromosome damage itself is involved in the pathway...

  12. 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

  13. Feedback that confirms reward expectation triggers auditory cortex activity.

    Science.gov (United States)

    Weis, Tina; Brechmann, André; Puschmann, Sebastian; Thiel, Christiane M

    2013-10-01

    Associative learning studies have shown that the anticipation of reward and punishment shapes the representation of sensory stimuli, which is further modulated by dopamine. Less is known about whether and how reward delivery activates sensory cortices and the role of dopamine at that time point of learning. We used an appetitive instrumental learning task in which participants had to learn that a specific class of frequency-modulated tones predicted a monetary reward following fast and correct responses in a succeeding reaction time task. These fMRI data were previously analyzed regarding the effect of reward anticipation, but here we focused on neural activity to the reward outcome relative to the reward expectation and tested whether such activation in the reward reception phase is modulated by L-DOPA. We analyzed neural responses at the time point of reward outcome under three different conditions: 1) when a reward was expected and received, 2) when a reward was expected but not received, and 3) when a reward was not expected and not received. Neural activity in auditory cortex was enhanced during feedback delivery either when an expected reward was received or when the expectation of obtaining no reward was correct. This differential neural activity in auditory cortex was only seen in subjects who learned the reward association and not under dopaminergic modulation. Our data provide evidence that auditory cortices are active at the time point of reward outcome. However, responses are not dependent on the reward itself but on whether the outcome confirmed the subject's expectations.

  14. An aberrant precision account of autism

    National Research Council Canada - National Science Library

    Lawson, Rebecca P; Rees, Geraint; Friston, Karl J

    2014-01-01

    ... (Pellicano and Burr, 2012). In response, we suggested that when Bayesian inference is grounded in its neural instantiation-namely, predictive coding-many features of autistic perception can be attributed to aberrant precision...

  15. Dopamine neurons learn relative chosen value from probabilistic rewards.

    Science.gov (United States)

    Lak, Armin; Stauffer, William R; Schultz, Wolfram

    2016-10-27

    Economic theories posit reward probability as one of the factors defining reward value. Individuals learn the value of cues that predict probabilistic rewards from experienced reward frequencies. Building on the notion that responses of dopamine neurons increase with reward probability and expected value, we asked how dopamine neurons in monkeys acquire this value signal that may represent an economic decision variable. We found in a Pavlovian learning task that reward probability-dependent value signals arose from experienced reward frequencies. We then assessed neuronal response acquisition during choices among probabilistic rewards. Here, dopamine responses became sensitive to the value of both chosen and unchosen options. Both experiments showed also the novelty responses of dopamine neurones that decreased as learning advanced. These results show that dopamine neurons acquire predictive value signals from the frequency of experienced rewards. This flexible and fast signal reflects a specific decision variable and could update neuronal decision mechanisms.

  16. I can't wait! Neural reward signals in impulsive individuals exaggerate the difference between immediate and future rewards.

    Science.gov (United States)

    Schmidt, Barbara; Holroyd, Clay B; Debener, Stefan; Hewig, Johannes

    2017-03-01

    Waiting for rewards is difficult, and highly impulsive individuals with low self-control have an especially hard time with it. Here, we investigated whether neural responses to rewards in a delayed gratification task predict impulsivity and self-control. The EEG was recorded from participants engaged in a guessing game in which on each trial they could win either a large or small reward, paid either now or after 6 months. Ratings confirmed that participants preferred immediate, large rewards over small, delayed rewards. Electrophysiological reward signals reflecting the difference between immediate and future rewards predicted self-report measures of impulsivity and self-control. Further, these signals were highly reliable across two sessions over a 1-week interval, showing high temporal stability like stable personality traits. These results suggest that greater valuation of immediate rewards causes impulsive individuals to redirect control away from delayed rewards, indicating why it is so hard for them to wait. © 2016 Society for Psychophysiological Research.

  17. Linear combination of one-step predictive information with an external reward in an episodic policy gradient setting: a critical analysis

    Directory of Open Access Journals (Sweden)

    Keyan eZahedi

    2013-11-01

    Full Text Available One of the main challenges in the field of embodied artificial intelligence is the open-ended autonomous learning of complex behaviours. Our approach is to use task-independent, information-driven intrinsic motivation(s to support task-dependent learning. The work presented here is a preliminary step in which we investigate the predictive information (the mutual information of the past and future of the sensor stream as an intrinsic drive, ideally supporting any kind of task acquisition. Previous experiments have shown that the predictive information (PI is a good candidate to support autonomous, open-ended learning of complex behaviours, because a maximisation of the PI corresponds to an exploration of morphology- and environment-dependent behavioural regularities. The idea is that these regularities can then be exploited in order to solve any given task. Three different experiments are presented and their results lead to the conclusion that the linear combination of the one-step PI with an external reward function is not generally recommended in an episodic policy gradient setting. Only for hard tasks a great speed-up can be achieved at the cost of an asymptotic performance lost.

  18. 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.

  19. Abnormal striatal BOLD responses to reward anticipation and reward delivery in ADHD.

    Directory of Open Access Journals (Sweden)

    Emi Furukawa

    Full Text Available 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.

  20. Sleep deprivation amplifies striatal activation to monetary reward.

    Science.gov (United States)

    Mullin, B C; Phillips, M L; Siegle, G J; Buysse, D J; Forbes, E E; Franzen, P L

    2013-10-01

    Sleep loss produces abnormal increases in reward seeking but the mechanisms underlying this phenomenon are poorly understood. The present study examined the influence of one night of sleep deprivation on neural responses to a monetary reward task in a sample of late adolescents/young adults. Using a within-subjects crossover design, 27 healthy, right-handed late adolescents/young adults (16 females, 11 males; mean age 23.1 years) underwent functional magnetic resonance imaging (fMRI) following a night of sleep deprivation and following a night of normal sleep. Participants’ recent sleep history was monitored using actigraphy for 1 week prior to each sleep condition. Following sleep deprivation, participants exhibited increased activity in the ventral striatum (VS) and reduced deactivation in the medial prefrontal cortex (mPFC) during the winning of monetary reward, relative to the same task following normal sleep conditions. Shorter total sleep time over the five nights before the sleep-deprived testing condition was associated with reduced deactivation in the mPFC during reward. These findings support the hypothesis that sleep loss produces aberrant functioning in reward neural circuitry, increasing the salience of positively reinforcing stimuli. Aberrant reward functioning related to insufficient sleep may contribute to the development and maintenance of reward dysfunction-related disorders, such as compulsive gambling, eating, substance abuse and mood disorders.

  1. Time Discounting for Primary Rewards

    National Research Council Canada - National Science Library

    McClure, Samuel M; Ericson, Keith M; Laibson, David I; Loewenstein, George; Cohen, Jonathan D

    2007-01-01

    Previous research, involving monetary rewards, found that limbic reward-related areas show greater activity when an intertemporal choice includes an immediate reward than when the options include only delayed rewards...

  2. 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.

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

    Science.gov (United States)

    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.

  4. 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.

  5. Learning Contextual Reward Expectations for Value Adaptation.

    Science.gov (United States)

    Rigoli, Francesco; Chew, Benjamin; Dayan, Peter; Dolan, Raymond J

    2018-01-01

    Substantial evidence indicates that subjective value is adapted to the statistics of reward expected within a given temporal context. However, how these contextual expectations are learned is poorly understood. To examine such learning, we exploited a recent observation that participants performing a gambling task adjust their preferences as a function of context. We show that, in the absence of contextual cues providing reward information, an average reward expectation was learned from recent past experience. Learning dependent on contextual cues emerged when two contexts alternated at a fast rate, whereas both cue-independent and cue-dependent forms of learning were apparent when two contexts alternated at a slower rate. Motivated by these behavioral findings, we reanalyzed a previous fMRI data set to probe the neural substrates of learning contextual reward expectations. We observed a form of reward prediction error related to average reward such that, at option presentation, activity in ventral tegmental area/substantia nigra and ventral striatum correlated positively and negatively, respectively, with the actual and predicted value of options. Moreover, an inverse correlation between activity in ventral tegmental area/substantia nigra (but not striatum) and predicted option value was greater in participants showing enhanced choice adaptation to context. The findings help understanding the mechanisms underlying learning of contextual reward expectation.

  6. Role of Reward Sensitivity and Processing in Major Depressive and Bipolar Spectrum Disorders

    Science.gov (United States)

    Alloy, Lauren B.; Olino, Thomas; Freed, Rachel D.; Nusslock, Robin

    2016-01-01

    Since Costello’s (1972) seminal Behavior Therapy article on loss of reinforcers or reinforcer effectiveness in depression, the role of reward sensitivity and processing in both depression and bipolar disorder has become a central area of investigation. In this article, we review the evidence for a model of reward sensitivity in mood disorders, with unipolar depression characterized by reward hyposensitivity and bipolar disorders by reward hypersensitivity. We address whether aberrant reward sensitivity and processing are correlates of, mood-independent traits of, vulnerabilities for, and/or predictors of the course of depression and bipolar spectrum disorders, covering evidence from self-report, behavioral, neurophysiological, and neural levels of analysis. We conclude that substantial evidence documents that blunted reward sensitivity and processing are involved in unipolar depression and heightened reward sensitivity and processing are characteristic of hypomania/mania. We further conclude that aberrant reward sensitivity has a trait component, but more research is needed to clearly demonstrate that reward hyposensitivity and hypersensitivity are vulnerabilities for depression and bipolar disorder, respectively. Moreover, additional research is needed to determine whether bipolar depression is similar to unipolar depression and characterized by reward hyposensitivity, or whether like bipolar hypomania/mania, it involves reward hypersensitivity. PMID:27816074

  7. The role of reward in dynamic decision making

    Directory of Open Access Journals (Sweden)

    Magda eOsman

    2012-03-01

    Full Text Available The present study investigates two aspects of decision making that have yet to be explored within a dynamic environment, 1 comparing the accuracy of cue-outcome knowledge under conditions in which knowledge acquisition is either through Prediction or Choice, and 2 examining the effects of reward on both Prediction and Choice. In the present study participants either learnt about the cue-outcome relations in the environment by choosing cue values in order to maintain an outcome to criterion (Choice-based decision making, or learnt to predict the outcome from seeing changes to the cue values (Prediction-based decision making. During training participants received outcome feedback and one of four types of reward manipulations: Positive Reward, Negative Reward, Both Positive + Negative Reward, No Reward. After training both groups of learners were tested on prediction and choice based tasks. In the main, the findings revealed that cue-outcome knowledge was more accurate when knowledge acquisition was Choice-based rather than Prediction-based. During learning Negative-Reward adversely affected Choice-based decision making while Positive-Reward adversely affected predictive-based decision making. During the test phase only performance on tests of choice was adversely affected by having received Positive Reward or Negative Reward during training. This article proposes that the adverse effects of reward may reflect the additional demands placed on processing rewards which compete for cognitive resources required to perform the main goal of the task. This in turn implies that, rather than facilitate decision making, the presentation of rewards can interfere with Choice-based and Prediction-based decisions.

  8. Do Effort and Reward at Work Predict Changes in Cognitive Function? First Longitudinal Results from the Representative German Socio-Economic Panel

    Directory of Open Access Journals (Sweden)

    Natalie Riedel

    2017-11-01

    Full Text Available It has been suggested that work characteristics, such as mental demands, job control, and occupational complexity, are prospectively related to cognitive function. However, current evidence on links between psychosocial working conditions and cognitive change over time is inconsistent. In this study, we applied the effort–reward imbalance model that allows to build on previous research on mental demands and to introduce reward-based learning as a principle with beneficial effect on cognitive function. We aimed to investigate whether high effort, high reward, and low over-commitment in 2006 were associated with positive changes in cognitive function in terms of perceptual speed and word fluency (2006–2012, and whether the co-manifestation of high effort and high reward would yield the strongest association. To this end, we used data on 1031 employees who participated in a large and representative study. Multivariate linear regression analyses supported our main hypotheses (separate and combined effects of effort and reward, particularly on changes in perceptual speed, whereas the effects of over-commitment did not reach the level of statistical significance. Our findings extend available knowledge by examining the course of cognitive function over time. If corroborated by further evidence, organization-based measures in the workplace can enrich efforts towards preventing cognitive decline in ageing workforces.

  9. Markov reward processes

    Science.gov (United States)

    Smith, R. M.

    1991-01-01

    Numerous applications in the area of computer system analysis can be effectively studied with Markov reward models. These models describe the behavior of the system with a continuous-time Markov chain, where a reward rate is associated with each state. In a reliability/availability model, upstates may have reward rate 1 and down states may have reward rate zero associated with them. In a queueing model, the number of jobs of certain type in a given state may be the reward rate attached to that state. In a combined model of performance and reliability, the reward rate of a state may be the computational capacity, or a related performance measure. Expected steady-state reward rate and expected instantaneous reward rate are clearly useful measures of the Markov reward model. More generally, the distribution of accumulated reward or time-averaged reward over a finite time interval may be determined from the solution of the Markov reward model. This information is of great practical significance in situations where the workload can be well characterized (deterministically, or by continuous functions e.g., distributions). The design process in the development of a computer system is an expensive and long term endeavor. For aerospace applications the reliability of the computer system is essential, as is the ability to complete critical workloads in a well defined real time interval. Consequently, effective modeling of such systems must take into account both performance and reliability. This fact motivates our use of Markov reward models to aid in the development and evaluation of fault tolerant computer systems.

  10. Reward Adaptation and the Mechanisms of Learning: Contrast Changes Reward Value in Rats and Drives Learning.

    Science.gov (United States)

    Dwyer, Dominic Michael; Figueroa, Jaime; Gasalla, Patricia; López, Matías

    2017-11-01

    Formal theories of learning suggest that associations between events are determined by the internal representations of those events. Thus, learning should depend on perceived reward value-even when perceptions differ from objective values. We examined this prediction in flavor-preference learning in rats. In two experiments, simultaneous contrast either increased perceived reward value, which was paired with a distinctive flavor cue (the positive conditioned stimulus, CS+), or decreased the perceived value of the same reward, which was then paired with a second flavor (the negative conditioned stimulus, CS-). Even though the CS+ and CS- were paired with the same objective reward, there was a preference for the CS+ in subsequent tests. Moreover, the size of contrast-produced changes in reward value during training predicted the preference for the CS+ at test. This contrast-produced learning effect illustrates the mechanisms by which associations, which normally track veridical relationships between events in the world, are formed.

  11. Prior fear conditioning and reward learning interact in fear and reward networks

    Directory of Open Access Journals (Sweden)

    Lisa eBulganin

    2014-03-01

    Full Text Available The ability to flexibly adapt responses to changes in the environment is important for survival. Previous research in humans separately examined the mechanisms underlying acquisition and extinction of aversive and appetitive conditioned responses. It is yet unclear how aversive and appetitive learning interact on a neural level during counterconditioning in humans. This functional magnetic resonance imaging (fMRI study investigated the interaction of fear conditioning and subsequent reward learning. In the first phase (fear acquisition, images predicted aversive electric shocks or no aversive outcome. In the second phase (counterconditioning, half of the CS+ and CS- were associated with monetary reward in the absence of electric stimulation. The third phase initiated reinstatement of fear through presentation of electric shocks, followed by CS presentation in the absence of shock or reward. Results indicate that participants were impaired at learning the reward contingencies for stimuli previously associated with shock. In the counterconditioning phase, prior fear association interacted with reward representation in the amygdala, where activation was decreased for rewarded compared to unrewarded CS- trials, while there was no reward-related difference in CS+ trials. In the reinstatement phase, an interaction of previous fear association and previous reward status was observed in a reward network consisting of substantia nigra / ventral tegmental area (SN/VTA, striatum and orbitofrontal cortex (OFC, where activation was increased by previous reward association only for CS- but not for CS+ trials. These findings suggest that during counterconditioning, prior fear conditioning interferes with reward learning, subsequently leading to lower activation of the reward network.

  12. Epigenetic silencing of the NR4A3 tumor suppressor, by aberrant JAK/STAT signaling, predicts prognosis in gastric cancer

    Science.gov (United States)

    Yeh, Chung-Min; Chang, Liang-Yu; Lin, Shu-Hui; Chou, Jian-Liang; Hsieh, Hsiao-Yen; Zeng, Li-Han; Chuang, Sheng-Yu; Wang, Hsiao-Wen; Dittner, Claudia; Lin, Cheng-Yu; Lin, Jora M. J.; Huang, Yao-Ting; Ng, Enders K. W.; Cheng, Alfred S. L.; Wu, Shu-Fen; Lin, Jiayuh; Yeh, Kun-Tu; Chan, Michael W. Y.

    2016-08-01

    While aberrant JAK/STAT signaling is crucial to the development of gastric cancer (GC), its effects on epigenetic alterations of its transcriptional targets remains unclear. In this study, by expression microarrays coupled with bioinformatic analyses, we identified a putative STAT3 target gene, NR4A3 that was downregulated in MKN28 GC daughter cells overexpressing a constitutively activated STAT3 mutant (S16), as compared to an empty vector control (C9). Bisulphite pyrosequencing and demethylation treatment showed that NR4A3 was epigenetically silenced by promoter DNA methylation in S16 and other GC cell lines including AGS cells, showing constitutive activation of STAT3. Subsequent experiments revealed that NR4A3 promoter binding by STAT3 might repress its transcription. Long-term depletion of STAT3 derepressed NR4A3 expression, by promoter demethylation, in AGS GC cells. NR4A3 re-expression in GC cell lines sensitized the cells to cisplatin, and inhibited tumor growth in vitro and in vivo, in an animal model. Clinically, GC patients with high NR4A3 methylation, or lower NR4A3 protein expression, had significantly shorter overall survival. Intriguingly, STAT3 activation significantly associated only with NR4A3 methylation in low-stage patient samples. Taken together, aberrant JAK/STAT3 signaling epigenetically silences a potential tumor suppressor, NR4A3, in gastric cancer, plausibly representing a reliable biomarker for gastric cancer prognosis.

  13. Characterising reward outcome signals in sensory cortex.

    Science.gov (United States)

    FitzGerald, Thomas H B; Friston, Karl J; Dolan, Raymond J

    2013-12-01

    Reward outcome signalling in the sensory cortex is held as important for linking stimuli to their consequences and for modulating perceptual learning in response to incentives. Evidence for reward outcome signalling has been found in sensory regions including the visual, auditory and somatosensory cortices across a range of different paradigms, but it is unknown whether the population of neurons signalling rewarding outcomes are the same as those processing predictive stimuli. We addressed this question using a multivariate analysis of high-resolution functional magnetic resonance imaging (fMRI), in a task where subjects were engaged in instrumental learning with visual predictive cues and auditory signalled reward feedback. We found evidence that outcome signals in sensory regions localise to the same areas involved in stimulus processing. These outcome signals are non-specific and we show that the neuronal populations involved in stimulus representation are not their exclusive target, in keeping with theoretical models of value learning. Thus, our results reveal one likely mechanism through which rewarding outcomes are linked to predictive sensory stimuli, a link that may be key for both reward and perceptual learning. © 2013.

  14. Motivated To Win: Relationship between Anticipatory and Outcome Reward-Related Neural Activity

    Science.gov (United States)

    Nusslock, Robin

    2015-01-01

    Reward-processing involves two temporal stages characterized by two distinct neural processes: reward-anticipation and reward-outcome. Intriguingly, very little research has examined the relationship between neural processes involved in reward-anticipation and reward-outcome. To investigate this, one needs to consider the heterogeneity of reward-processing within each stage. To identify different stages of reward processing, we adapted a reward time-estimation task. While EEG data were recorded, participants were instructed to button-press 3.5 s after the onset of an Anticipation-Cue and received monetary reward for good time-estimation on the Reward trials, but not on No-Reward trials. We first separated reward-anticipation into event related potentials (ERPs) occurring at three sub-stages: reward/no-reward cue-evaluation, motor-preparation and feedback-anticipation. During reward/no-reward cue-evaluation, the Reward-Anticipation Cue led to a smaller N2 and larger P3. During motor-preparation, we report, for the first time, that the Reward-Anticipation Cue enhanced the Readiness Potential (RP), starting approximately 1 s before movement. At the subsequent feedback-anticipation stage, the Reward-Anticipation Cue elevated the Stimulus-Preceding Negativity (SPN). We also separated reward-outcome ERPs into different components occurring at different time-windows: the Feedback-Related Negativity (FRN), Feedback-P3 (FB-P3) and Late-Positive Potentials (LPP). Lastly, we examined the relationship between reward-anticipation and reward-outcome ERPs. We report that individual-differences in specific reward-anticipation ERPs uniquely predicted specific reward-outcome ERPs. In particular, the reward-anticipation Early-RP (1 to .8 s before movement) predicted early reward-outcome ERPs (FRN and FB-P3), whereas, the reward-anticipation SPN most strongly predicted a later reward-outcome ERP (LPP). Results have important implications for understanding the nature of the

  15. Motivated to win: Relationship between anticipatory and outcome reward-related neural activity.

    Science.gov (United States)

    Pornpattananangkul, Narun; Nusslock, Robin

    2015-11-01

    Reward-processing involves two temporal stages characterized by two distinct neural processes: reward-anticipation and reward-outcome. Intriguingly, very little research has examined the relationship between neural processes involved in reward-anticipation and reward-outcome. To investigate this, one needs to consider the heterogeneity of reward-processing within each stage. To identify different stages of reward processing, we adapted a reward time-estimation task. While EEG data were recorded, participants were instructed to button-press 3.5s after the onset of an Anticipation-Cue and received monetary reward for good time-estimation on the Reward trials, but not on No-Reward trials. We first separated reward-anticipation into event related potentials (ERPs) occurring at three sub-stages: reward/no-reward cue-evaluation, motor-preparation and feedback-anticipation. During reward/no-reward cue-evaluation, the Reward-Anticipation Cue led to a smaller N2 and larger P3. During motor-preparation, we report, for the first time, that the Reward-Anticipation Cue enhanced the Readiness Potential (RP), starting approximately 1s before movement. At the subsequent feedback-anticipation stage, the Reward-Anticipation Cue elevated the Stimulus-Preceding Negativity (SPN). We also separated reward-outcome ERPs into different components occurring at different time-windows: the Feedback-Related Negativity (FRN), Feedback-P3 (FB-P3) and Late-Positive Potentials (LPP). Lastly, we examined the relationship between reward-anticipation and reward-outcome ERPs. We report that individual-differences in specific reward-anticipation ERPs uniquely predicted specific reward-outcome ERPs. In particular, the reward-anticipation Early-RP (1-.8s before movement) predicted early reward-outcome ERPs (FRN and FB-P3), whereas, the reward-anticipation SPN most strongly predicted a later reward-outcome ERP (LPP). Results have important implications for understanding the nature of the relationship

  16. Academic staff reward

    African Journals Online (AJOL)

    User

    structures and management systems. As a result, many universities are rethinking their reward strategies to better align them with the new realities in order to improve teaching staff motivation and retention. This study was conducted to identify academic staff reward related problems and to examine the effectiveness of both ...

  17. Academic staff reward

    African Journals Online (AJOL)

    User

    has a major role to play in achieving the objectives of the institution. ... Exceptionally, well motivated academic staff can, with appropriate ... significance attributed to the work. **To perform at their best, most individuals need to have financial or other extrinsic rewards tied to their performance. Rewards. Intrinsic*. Extrinsic**.

  18. Reward Merit with Praise.

    Science.gov (United States)

    Andrews, Hans A.

    1987-01-01

    Describes the efforts of two educational institutions to reward teaching excellence using positive feedback rather than merit pay incentives. An Arizona district, drawing on Herzberg's motivation theories, offers highly individualized rewards ranging from computers to conference money, while an Illinois community college bestows engraved plaques…

  19. Prediction of a rare chromosomal aberration simultaneously with next generation sequencing-based comprehensive chromosome screening in human preimplantation embryos for recurrent pregnancy loss.

    Science.gov (United States)

    Lee, Yi-Xuan; Chen, Chien-Wen; Lin, Yi-Hui; Tzeng, Chii-Ruey; Chen, Chi-Huang

    2017-09-30

    Preimplantation genetic testing has been used widely in recent years as a part of assisted reproductive technology (ART) owing to the breakthrough development of deoxyribonucleic acid (DNA) sequencing. With the advancement of technology and increased resolution of next generation sequencing (NGS), extensive comprehensive chromosome screening along with small clinically significant deletions and duplications can possibly be performed simultaneously. Here, we present a case of rare chromosomal aberrations: 46,XY,dup(15)(q11.2q13),t(16;18)(q23;p11.2), which resulted in a normally developed adult but abnormal gametes leading to recurrent pregnancy loss (RPL). To our best knowledge, this is the first report of t(16;18) translocation with such a small exchanged segment detected by NGS platform of MiSeq system in simultaneous 24-chromosome aneuploidy screening.

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

    Science.gov (United States)

    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.

  1. Reward skewness coding in the insula independent of probability and loss

    NARCIS (Netherlands)

    Burke, C.; Tobler, P.N.

    2011-01-01

    Rewards in the natural environment are rarely predicted with complete certainty. Uncertainty relating to future rewards has typically been defined as the variance of the potential outcomes. However, the asymmetry of predicted reward distributions, known as skewness, constitutes a distinct but

  2. An aberrant precision account of autism.

    Directory of Open Access Journals (Sweden)

    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.

  3. 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.

  4. The influence of organisational rewards on workplace trust and work engagement

    National Research Council Canada - National Science Library

    Janine Victor; Crystal Hoole

    2017-01-01

    .... 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...

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

    Science.gov (United States)

    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.

  6. Neural activity in the reward-related brain regions predicts implicit self-esteem: A novel validity test of psychological measures using neuroimaging.

    Science.gov (United States)

    Izuma, Keise; Kennedy, Kate; Fitzjohn, Alexander; Sedikides, Constantine; Shibata, Kazuhisa

    2018-03-01

    Self-esteem, arguably the most important attitudes an individual possesses, has been a premier research topic in psychology for more than a century. Following a surge of interest in implicit attitude measures in the 90s, researchers have tried to assess self-esteem implicitly to circumvent the influence of biases inherent in explicit measures. However, the validity of implicit self-esteem measures remains elusive. Critical tests are often inconclusive, as the validity of such measures is examined in the backdrop of imperfect behavioral measures. To overcome this serious limitation, we tested the neural validity of the most widely used implicit self-esteem measure, the implicit association test (IAT). Given the conceptualization of self-esteem as attitude toward the self, and neuroscience findings that the reward-related brain regions represent an individual's attitude or preference for an object when viewing its image, individual differences in implicit self-esteem should be associated with neural signals in the reward-related regions during passive-viewing of self-face (the most obvious representation of the self). Using multi-voxel pattern analysis (MVPA) on functional MRI (fMRI) data, we demonstrate that the neural signals in the reward-related regions were robustly associated with implicit (but not explicit) self-esteem, thus providing unique evidence for the neural validity of the self-esteem IAT. In addition, both implicit and explicit self-esteem were related, although differently, to neural signals in regions involved in self-processing. Our finding highlights the utility of neuroscience methods in addressing fundamental psychological questions and providing unique insights into important psychological constructs. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  7. A universal role of the ventral striatum in reward-based learning: Evidence from human studies

    OpenAIRE

    Daniel, Reka; Pollmann, Stefan

    2014-01-01

    Reinforcement learning enables organisms to adjust their behavior in order to maximize rewards. Electrophysiological recordings of dopaminergic midbrain neurons have shown that they code the difference between actual and predicted rewards, i.e., the reward prediction error, in many species. This error signal is conveyed to both the striatum and cortical areas and is thought to play a central role in learning to optimize behavior. However, in human daily life rewards are dive...

  8. Research Review: altered reward function in adolescent depression: what, when and how?

    Science.gov (United States)

    Forbes, Erika E; Dahl, Ronald E

    2012-01-01

    Conceptual models and recent evidence indicate that neural response to reward is altered in depression. Taking a developmental approach to investigating reward function in adolescent depression can elucidate the etiology, pathophysiology and course of depression, a disorder that typically begins during adolescence and has high rates of recurrence. This conceptual review describes the what, when and how of altered reward function in adolescent depression. With the goal of generating new, testable hypotheses within a developmental affective neuroscience framework, we critically review findings and suggest future directions. Peer-reviewed empirical papers for inclusion in this critical review were obtained by searching PubMed, PsycInfo and ScienceDirect for the years 1990-2010. A pattern of low striatal response and high medial prefrontal response to reward is evident in adolescents and adults with depression. Given the salience of social stimuli for positive affect and depression, reward function might be especially disrupted in response to social rewards. Because of changes in the dopamine system and reward function with aging, altered reward function in depression might be more evident during adolescence than later in life; however, low reward function may also be a stable characteristic of people who experience depression. Mechanisms of altered reward function in depression could include disrupted balance of corticostriatal circuit function, with disruption occurring as aberrant adolescent brain development. Future studies should examine responses to social rewards; employ longitudinal and prospective designs; and investigate patterns of functional connectivity in reward circuits. Understanding altered reward function in depression has potential implications for treatment development. A more rigorous approach to investigating anhedonia, threat-reward interactions and comorbid anxiety will be valuable to future progress in describing the role of reward function in

  9. Running is rewarding and antidepressive

    OpenAIRE

    Brené, Stefan; Bjørnebekk, Astrid; Åberg, Elin; Mathé, Aleksander A; Olson, Lars; Werme, Martin

    2007-01-01

    Natural behaviors such as eating, drinking, reproduction and exercise activate brain reward pathways and consequently the individual engages in these behaviors to receive the reward. However, drugs of abuse are even more potent to activate the reward pathways. Rewarding behaviors and addictive drugs also affect other parts of the brain not directly involved in the mediation of reward. For instance, running increases neurogenesis in hippocampus and is beneficial as an antidepressant in a genet...

  10. Reward processing by the opioid system in the brain

    OpenAIRE

    Le Merrer, Julie; Becker, Jérôme,; Befort, K.; Kieffer, B L

    2009-01-01

    The opioid system consists of three receptors, mu, delta, and kappa, which are activated by endogenous opioid peptides processed from three protein precursors, proopiomelanocortin, proenkephalin, and prodynorphin. Opioid receptors are recruited in response to natural rewarding stimuli and drugs of abuse, and both endogenous opioids and their receptors are modified as addiction develops. Mechanisms whereby aberrant activation and modifications of the opioid system contribute to drug craving an...

  11. Altered social reward and attention in anorexia nervosa

    Directory of Open Access Journals (Sweden)

    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.

  12. Dopamine neurons learn relative chosen value from probabilistic rewards

    Science.gov (United States)

    Lak, Armin; Stauffer, William R; Schultz, Wolfram

    2016-01-01

    Economic theories posit reward probability as one of the factors defining reward value. Individuals learn the value of cues that predict probabilistic rewards from experienced reward frequencies. Building on the notion that responses of dopamine neurons increase with reward probability and expected value, we asked how dopamine neurons in monkeys acquire this value signal that may represent an economic decision variable. We found in a Pavlovian learning task that reward probability-dependent value signals arose from experienced reward frequencies. We then assessed neuronal response acquisition during choices among probabilistic rewards. Here, dopamine responses became sensitive to the value of both chosen and unchosen options. Both experiments showed also the novelty responses of dopamine neurones that decreased as learning advanced. These results show that dopamine neurons acquire predictive value signals from the frequency of experienced rewards. This flexible and fast signal reflects a specific decision variable and could update neuronal decision mechanisms. DOI: http://dx.doi.org/10.7554/eLife.18044.001 PMID:27787196

  13. Value Orientation, Organizational Rewards, and Job Satisfaction.

    Science.gov (United States)

    Cascio, Wayne F.

    The nationwide sales force (N=540) of a large food and beverage firm responded to a mail survey designed to investigate the role of value orientation as a moderator of the relationship between organizational rewards and job satisfaction. Of the two main elements in the investigation, the first was concerned with the predictive efficiency of two…

  14. Neural dynamics of reward probability coding: a Magnetoencephalographic study in humans

    Directory of Open Access Journals (Sweden)

    Julie eThomas

    2013-11-01

    Full Text Available Prediction of future rewards and discrepancy between actual and expected outcomes (prediction error are crucial signals for adaptive behavior. In humans, a number of fMRI studies demonstrated that reward probability modulates these two signals in a large brain network. Yet, the spatio-temporal dynamics underlying the neural coding of reward probability remains unknown. Here, using magnetoencephalography, we investigated the neural dynamics of prediction and reward prediction error computations while subjects learned to associate cues of slot machines with monetary rewards with different probabilities. We showed that event-related magnetic fields (ERFs arising from the visual cortex coded the expected reward value 155 ms after the cue, demonstrating that reward value signals emerge early in the visual stream. Moreover, a prediction error was reflected in ERF peaking 300 ms after the rewarded outcome and showing decreasing amplitude with higher reward probability. This prediction error signal was generated in a network including the anterior and posterior cingulate cortex. These findings pinpoint the spatio-temporal characteristics underlying reward probability coding. Together, our results provide insights into the neural dynamics underlying the ability to learn probabilistic stimuli-reward contingencies.

  15. Stress and reward

    DEFF Research Database (Denmark)

    Chumbley, J R; Hulme, O; Köchli, H

    2014-01-01

    Healthy individuals tend to consume available rewards like food and sex. This tendency is attenuated or amplified in most stress-related psychiatric conditions, so we asked if it depends on endogenous levels of the 'canonical stress hormone' cortisol. We unobtrusively quantified how hard healthy...

  16. The Rewards of Mentoring

    Science.gov (United States)

    Green-Powell, Patricia

    2012-01-01

    A growing body of knowledge exists which describes the rewards and importance of mentors in the professional development of young men and women, particularly with relation to their interactions in professional and organizational settings. Research in both educational settings and the workplace indicates that students and employees alike are more…

  17. 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...

  18. Enhanced neural responsiveness to reward associated with obesity in the absence of food-related stimuli.

    Science.gov (United States)

    Opel, Nils; Redlich, Ronny; Grotegerd, Dominik; Dohm, Katharina; Haupenthal, Cordula; Heindel, Walter; Kugel, Harald; Arolt, Volker; Dannlowski, Udo

    2015-06-01

    Obesity has been characterized by alterations in brain structure and function associated with emotion processing and regulation. Particularly, aberrations in food-related reward processing have been frequently demonstrated in obese subjects. However, it remains unclear whether reward-associated functional aberrations in obesity are specific for food-related stimuli or represent a general deficit in reward processing, extending to other stimulus domains. Given the crucial role of rewarding effects in the development of obesity and the ongoing discussion on overlapping neurobiological traits of obesity and psychiatric disorders such as depression and substance-related disorders, this study aimed to investigate the possibility of altered reward processing in obese subjects to occur in the absence of food-related stimuli during a monetary reward condition. Twenty-nine healthy obese subjects (body mass index >30) and 29 healthy, age-, and sex-matched control subjects of normal weight underwent functional MRI during a frequently used card guessing paradigm. A Group × Condition (win vs. loss) ANOVA was conducted to investigate differences between obese and normal-weight subjects. We found significant Group × Condition interaction effects in brain areas involved in emotion regulation and reward processing including the insula, the striatum, and the orbitofrontal cortex (OFC). This interaction was predominantly driven by a significant increase in blood oxygenation level dependent (BOLD) response in obese individuals while experiencing reward. Enhanced neural activation in obesity during reward processing seems to be apparent even in the absence of food-related stimuli and, thus, might point to generalized dysfunctions in reward-related brain circuits in obese individuals. © 2015 Wiley Periodicals, Inc.

  19. Higher effort-reward imbalance and lower job control predict exit from the labour market at the age of 61 years or younger: evidence from the English Longitudinal Study of Ageing.

    Science.gov (United States)

    Hintsa, T; Kouvonen, A; McCann, M; Jokela, M; Elovainio, M; Demakakos, P

    2015-06-01

    We examined whether higher effort-reward imbalance (ERI) and lower job control are associated with exit from the labour market. There were 1263 participants aged 50-74 years from the English Longitudinal Study on Ageing with data on working status and work-related psychosocial factors at baseline (wave 2; 2004-2005), and working status at follow-up (wave 5; 2010-2011). Psychosocial factors at work were assessed using a short validated version of ERI and job control. An allostatic load index was formed using 13 biological parameters. Depressive symptoms were measured using the Center for Epidemiologic Studies Depression Scale. Exit from the labour market was defined as not working in the labour market when 61 years old or younger in 2010-2011. Higher ERI OR=1.62 (95% CI 1.01 to 2.61, p=0.048) predicted exit from the labour market independent of age, sex, education, occupational class, allostatic load and depression. Job control OR=0.60 (95% CI 0.42 to 0.85, p=0.004) was associated with exit from the labour market independent of age, sex, education, occupation and depression. The association of higher effort OR=1.32 (95% CI 1.01 to 1.73, p=0.045) with exit from the labour market was independent of age, sex and depression but attenuated to non-significance when additionally controlling for socioeconomic measures. Reward was not related to exit from the labour market. Stressful work conditions can be a risk for exiting the labour market before the age of 61 years. Neither socioeconomic position nor allostatic load and depressive symptoms seem to explain this association. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  20. Biological auctions with multiple rewards.

    Science.gov (United States)

    Reiter, Johannes G; Kanodia, Ayush; Gupta, Raghav; Nowak, Martin A; Chatterjee, Krishnendu

    2015-08-07

    The competition for resources among cells, individuals or species is a fundamental characteristic of evolution. Biological all-pay auctions have been used to model situations where multiple individuals compete for a single resource. However, in many situations multiple resources with various values exist and single reward auctions are not applicable. We generalize the model to multiple rewards and study the evolution of strategies. In biological all-pay auctions the bid of an individual corresponds to its strategy and is equivalent to its payment in the auction. The decreasingly ordered rewards are distributed according to the decreasingly ordered bids of the participating individuals. The reproductive success of an individual is proportional to its fitness given by the sum of the rewards won minus its payments. Hence, successful bidding strategies spread in the population. We find that the results for the multiple reward case are very different from the single reward case. While the mixed strategy equilibrium in the single reward case with more than two players consists of mostly low-bidding individuals, we show that the equilibrium can convert to many high-bidding individuals and a few low-bidding individuals in the multiple reward case. Some reward values lead to a specialization among the individuals where one subpopulation competes for the rewards and the other subpopulation largely avoids costly competitions. Whether the mixed strategy equilibrium is an evolutionarily stable strategy (ESS) depends on the specific values of the rewards. © 2015 The Author(s).

  1. The neural correlates of temporal reward discounting.

    Science.gov (United States)

    Scheres, Anouk; de Water, Erik; Mies, Gabry W

    2013-09-01

    Temporal reward discounting (TD) refers to the decrease in subjective value of a reward when the delay to that reward increases. In recent years, a growing number of studies on the neural correlates of temporal reward discounting have been conducted. This article focuses on functional magnetic resonance imaging (fMRI) studies on TD in humans. First, we describe the different types of tasks (also from behavioral studies) and the dependent variables. Subsequently, we discuss the evidence for three neurobiological models of TD: the dual-systems model, the single-system model and the self-control model. Further, studies in which nontraditional tasks (e.g., with nonmonetary rewards) were used to study TD are reviewed. Finally, we discuss the neural correlates of individual differences in discounting, and its development across the lifespan. We conclude that the evidence for each of the three neurobiological models of TD is mixed, in that all models receive (partial) support, and several studies provide support for multiple models. Because of large differences between studies in task design and analytical approach, it is difficult to draw a firm conclusion regarding which model provides the best explanation of the neural correlates of temporal discounting. We propose that some components of these models can complement each other, and future studies should test the predictions offered by different models against each other. Several future research directions are suggested, including studying the connectivity between brain regions in relation to discounting, and directly comparing the neural mechanisms involved in discounting of monetary and primary rewards. WIREs Cogn Sci 2013, 4:523-545. doi: 10.1002/wcs.1246 CONFLICT OF INTEREST: The authors have declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website. © 2013 John Wiley & Sons, Ltd.

  2. The impact of a total reward system of work engagement

    Directory of Open Access Journals (Sweden)

    Crystal Hoole

    2016-04-01

    Full Text Available Orientation: Work engagement is critical for both employees and employers. With the reported downward spiral of engagement levels worldwide, organisations are recognising that in order to address this, attract best talent and keep employees motivated, they need to shift their attention to total reward strategies.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

  3. Spontaneous Eye-Blink Rate as an Index of Reward Responsivity: Validation and Links to Bipolar Disorder

    Science.gov (United States)

    Peckham, Andrew D.; Johnson, Sheri L.

    2015-01-01

    Extensive research supports the role of striatal dopamine in pursuing and responding to reward, and that eye-blink rate is a valid indicator of striatal dopamine. This study tested whether phasic changes in blink rate could provide an index of reward pursuit. This hypothesis was tested in people with bipolar I disorder (BD; a population with aberrations in reward responsivity), and in those without BD. Thirty-one adults with BD and 28 control participants completed a laboratory task involving effort towards monetary reward. Blink rate was recorded using eye-tracking at baseline, reward anticipation, and post-reward. Those in the BD group completed self-report measures relating to reward and ambition. Results showed that across all participants, blink rates increased from reward anticipation to post-reward. In the BD group, reward-relevant measures were strongly correlated with variation in blink rate. These findings provide validation for phasic changes in blink rate as an index of reward response. PMID:27274949

  4. [Reward information encoded by power of local field potentials in the primate prefrontal cortex and striatum].

    Science.gov (United States)

    Chen, Yu-Ying; Pan, Xiao-Chuan; Wang, Ru-Bin; Sakagami, Masamichi

    2017-08-25

    Prefrontal cortex and striatum are two major areas in the brain. Some research reports suggest that both areas are involved in many advanced cognitive processes, such as learning and memory, reward processing, and behavioral decision. Single-unit recording experiments have found that neurons in the prefrontal cortex and striatum can represent reward information, but it remains elusive whether and how local field potentials (LFPs) in the two areas encode reward information. To investigate these issues, we recorded LFPs simultaneously in the prefrontal cortex and striatum of two monkeys by performing a reward prediction task (a large amount reward vs a small amount reward). Recorded LFP signals were transformed from the time domain to the time and frequency domain using the method of short-time Fourier transform (STFT). We calculated the power in each frequency and time, and examined whether they were different in the two reward conditions. The results showed that power of LFPs in both the prefrontal cortex and striatum distinguished one reward condition from the other one. And the power in small reward trials was greater than that in large reward trials. Furthermore, it was found that the LFPs better encoded reward information in the beta band (14-30 Hz) rather than other frequency bands. Our results suggest that the LFPs in the prefrontal cortex and striatum effectively represent reward information, which would help to further understand functional roles of LFPs in reward processing.

  5. Positive mood enhances reward-related neural activity.

    Science.gov (United States)

    Young, Christina B; Nusslock, Robin

    2016-06-01

    Although behavioral research has shown that positive mood leads to desired outcomes in nearly every major life domain, no studies have directly examined the effects of positive mood on the neural processes underlying reward-related affect and goal-directed behavior. To address this gap, participants in the present fMRI study experienced either a positive (n = 20) or neutral (n = 20) mood induction and subsequently completed a monetary incentive delay task that assessed reward and loss processing. Consistent with prediction, positive mood elevated activity specifically during reward anticipation in corticostriatal neural regions that have been implicated in reward processing and goal-directed behavior, including the nucleus accumbens, caudate, lateral orbitofrontal cortex and putamen, as well as related paralimbic regions, including the anterior insula and ventromedial prefrontal cortex. These effects were not observed during reward outcome, loss anticipation or loss outcome. Critically, this is the first study to report that positive mood enhances reward-related neural activity. Our findings have implications for uncovering the neural mechanisms by which positive mood enhances goal-directed behavior, understanding the malleability of reward-related neural activity, and developing targeted treatments for psychiatric disorders characterized by deficits in reward processing. © The Author (2016). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  6. Neural reward and punishment sensitivity in cigarette smokers.

    Science.gov (United States)

    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.

  7. Functions of Learning Rate in Adaptive Reward Learning.

    Science.gov (United States)

    Wu, Xi; Wang, Ting; Liu, Chang; Wu, Tao; Jiang, Jiefeng; Zhou, Dong; Zhou, Jiliu

    2017-01-01

    As a crucial cognitive function, learning applies prediction error (the discrepancy between the prediction from learning and the world state) to adjust predictions of the future. How much prediction error affects this adjustment also depends on the learning rate. Our understanding to the learning rate is still limited, in terms of (1) how it is modulated by other factors, and (2) the specific mechanisms of how learning rate interacts with prediction error to update learning. We applied computational modeling and functional magnetic resonance imaging to investigate these issues. We found that, when human participants performed a reward learning task, reward magnitude modulated learning rate. Modulation strength further predicted the difference in behavior following high vs. low reward across subjects. Imaging results further showed that this modulation was reflected in brain regions where the reward feedback is also encoded, such as the medial prefrontal cortex (MFC), precuneus, and posterior cingulate cortex. Furthermore, for the first time, we observed that the integration of the learning rate and the reward prediction error was represented in MFC activity. These findings extend our understanding of adaptive learning by demonstrating how it functions in a chain reaction of prediction updating.

  8. Functions of Learning Rate in Adaptive Reward Learning

    Directory of Open Access Journals (Sweden)

    Xi Wu

    2017-12-01

    Full Text Available As a crucial cognitive function, learning applies prediction error (the discrepancy between the prediction from learning and the world state to adjust predictions of the future. How much prediction error affects this adjustment also depends on the learning rate. Our understanding to the learning rate is still limited, in terms of (1 how it is modulated by other factors, and (2 the specific mechanisms of how learning rate interacts with prediction error to update learning. We applied computational modeling and functional magnetic resonance imaging to investigate these issues. We found that, when human participants performed a reward learning task, reward magnitude modulated learning rate. Modulation strength further predicted the difference in behavior following high vs. low reward across subjects. Imaging results further showed that this modulation was reflected in brain regions where the reward feedback is also encoded, such as the medial prefrontal cortex (MFC, precuneus, and posterior cingulate cortex. Furthermore, for the first time, we observed that the integration of the learning rate and the reward prediction error was represented in MFC activity. These findings extend our understanding of adaptive learning by demonstrating how it functions in a chain reaction of prediction updating.

  9. Neuron-type-specific signals for reward and punishment in the ventral tegmental area.

    Science.gov (United States)

    Cohen, Jeremiah Y; Haesler, Sebastian; Vong, Linh; Lowell, Bradford B; Uchida, Naoshige

    2012-01-18

    Dopamine has a central role in motivation and reward. Dopaminergic neurons in the ventral tegmental area (VTA) signal the discrepancy between expected and actual rewards (that is, reward prediction error), but how they compute such signals is unknown. We recorded the activity of VTA neurons while mice associated different odour cues with appetitive and aversive outcomes. We found three types of neuron based on responses to odours and outcomes: approximately half of the neurons (type I, 52%) showed phasic excitation after reward-predicting odours and rewards in a manner consistent with reward prediction error coding; the other half of neurons showed persistent activity during the delay between odour and outcome that was modulated positively (type II, 31%) or negatively (type III, 18%) by the value of outcomes. Whereas the activity of type I neurons was sensitive to actual outcomes (that is, when the reward was delivered as expected compared to when it was unexpectedly omitted), the activity of type II and type III neurons was determined predominantly by reward-predicting odours. We 'tagged' dopaminergic and GABAergic neurons with the light-sensitive protein channelrhodopsin-2 and identified them based on their responses to optical stimulation while recording. All identified dopaminergic neurons were of type I and all GABAergic neurons were of type II. These results show that VTA GABAergic neurons signal expected reward, a key variable for dopaminergic neurons to calculate reward prediction error.

  10. Neuronal Reward and Decision Signals: From Theories to Data

    Science.gov (United States)

    Schultz, Wolfram

    2015-01-01

    Rewards are crucial objects that induce learning, approach behavior, choices, and emotions. Whereas emotions are difficult to investigate in animals, the learning function is mediated by neuronal reward prediction error signals which implement basic constructs of reinforcement learning theory. These signals are found in dopamine neurons, which emit a global reward signal to striatum and frontal cortex, and in specific neurons in striatum, amygdala, and frontal cortex projecting to select neuronal populations. The approach and choice functions involve subjective value, which is objectively assessed by behavioral choices eliciting internal, subjective reward preferences. Utility is the formal mathematical characterization of subjective value and a prime decision variable in economic choice theory. It is coded as utility prediction error by phasic dopamine responses. Utility can incorporate various influences, including risk, delay, effort, and social interaction. Appropriate for formal decision mechanisms, rewards are coded as object value, action value, difference value, and chosen value by specific neurons. Although all reward, reinforcement, and decision variables are theoretical constructs, their neuronal signals constitute measurable physical implementations and as such confirm the validity of these concepts. The neuronal reward signals provide guidance for behavior while constraining the free will to act. PMID:26109341

  11. Neuronal Reward and Decision Signals: From Theories to Data.

    Science.gov (United States)

    Schultz, Wolfram

    2015-07-01

    Rewards are crucial objects that induce learning, approach behavior, choices, and emotions. Whereas emotions are difficult to investigate in animals, the learning function is mediated by neuronal reward prediction error signals which implement basic constructs of reinforcement learning theory. These signals are found in dopamine neurons, which emit a global reward signal to striatum and frontal cortex, and in specific neurons in striatum, amygdala, and frontal cortex projecting to select neuronal populations. The approach and choice functions involve subjective value, which is objectively assessed by behavioral choices eliciting internal, subjective reward preferences. Utility is the formal mathematical characterization of subjective value and a prime decision variable in economic choice theory. It is coded as utility prediction error by phasic dopamine responses. Utility can incorporate various influences, including risk, delay, effort, and social interaction. Appropriate for formal decision mechanisms, rewards are coded as object value, action value, difference value, and chosen value by specific neurons. Although all reward, reinforcement, and decision variables are theoretical constructs, their neuronal signals constitute measurable physical implementations and as such confirm the validity of these concepts. The neuronal reward signals provide guidance for behavior while constraining the free will to act. Copyright © 2015 the American Physiological Society.

  12. Rewarding the Multiplayer : How rewards and objectives influence Multiplayer games

    OpenAIRE

    Helin, Henry

    2014-01-01

    In this thesis I analyse the reward systems of cooperative and competitive Multiplayer games – the games I have chosen were built for a Single-player campaign with Multiplayer as additional content. My main focus is on the Multiplayer and the reward systems of that game mode. The reward systems are important to consider when designing a game for fans of Multiplayer games, as a faulty reward system might hinder the aspect which makes Multiplayer games special – to be playing together and go fo...

  13. Delaying rewards has greater effect on altruism when the beneficiary is socially distant.

    Science.gov (United States)

    Osiński, Jerzy; Karbowski, Adam

    2017-01-01

    Based on the assumption that social distance and time are dimensions of psychological distance important for altruistic choices it was predicted that enhancement of altruism due to delaying rewards when choosing between a reward for oneself and for another person would be more pronounced the greater the social distance between the subject and another person. In order to test this hypothesis, social discounting using hypothetical monetary rewards and manipulation of social distance and reward delay was measured in a group of 161 college students. The results indicate that delaying rewards increasingly enhances preference for altruistic choices as the social distance between subject and beneficiary grows.

  14. Dopamine signals for reward value and risk: basic and recent data

    Directory of Open Access Journals (Sweden)

    Schultz Wolfram

    2010-04-01

    Full Text Available Abstract Background Previous lesion, electrical self-stimulation and drug addiction studies suggest that the midbrain dopamine systems are parts of the reward system of the brain. This review provides an updated overview about the basic signals of dopamine neurons to environmental stimuli. Methods The described experiments used standard behavioral and neurophysiological methods to record the activity of single dopamine neurons in awake monkeys during specific behavioral tasks. Results Dopamine neurons show phasic activations to external stimuli. The signal reflects reward, physical salience, risk and punishment, in descending order of fractions of responding neurons. Expected reward value is a key decision variable for economic choices. The reward response codes reward value, probability and their summed product, expected value. The neurons code reward value as it differs from prediction, thus fulfilling the basic requirement for a bidirectional prediction error teaching signal postulated by learning theory. This response is scaled in units of standard deviation. By contrast, relatively few dopamine neurons show the phasic activation following punishers and conditioned aversive stimuli, suggesting a lack of relationship of the reward response to general attention and arousal. Large proportions of dopamine neurons are also activated by intense, physically salient stimuli. This response is enhanced when the stimuli are novel; it appears to be distinct from the reward value signal. Dopamine neurons show also unspecific activations to non-rewarding stimuli that are possibly due to generalization by similar stimuli and pseudoconditioning by primary rewards. These activations are shorter than reward responses and are often followed by depression of activity. A separate, slower dopamine signal informs about risk, another important decision variable. The prediction error response occurs only with reward; it is scaled by the risk of predicted reward

  15. Nutritional controls of food reward.

    Science.gov (United States)

    Fernandes, Maria F; Sharma, Sandeep; Hryhorczuk, Cecile; Auguste, Stephanie; Fulton, Stephanie

    2013-08-01

    The propensity to select and consume palatable nutrients is strongly influenced by the rewarding effects of food. Neural processes integrating reward, emotional states and decision-making can supersede satiety signals to promote excessive caloric intake and weight gain. While nutritional habits are influenced by reward-based neural mechanisms, nutrition and its impact on energy metabolism, in turn, plays an important role in the control of food reward. Feeding modulates the release of metabolic hormones that have an important influence on central controls of appetite. Nutrients themselves are also an essential source of energy fuel, while serving as key metabolites and acting as signalling molecules in the neural pathways that control feeding and food reward. Along these lines, this review discusses the impact of nutritionally regulated hormones and select macronutrients on the behavioural and neural processes underlying the rewarding effects of food. Copyright © 2013 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.

  16. Reward Industry for Innovative Outcomes

    Science.gov (United States)

    2015-08-01

    Defense AT&L: July–August 2015 34 Reward Industry for Innovative Outcomes RADM Allie Coetzee, USN Coetzee is Acting Director of Defense Procurement...away from the “best efforts” default and toward rational use of other techniques. Rather than reward compa- nies with contracts and funds to pursue...concepts advanced on paper in proposals, the DoD desires to reward companies that deliver demonstrable results through early prototypes that can be

  17. Reward processing in anorexia nervosa.

    Science.gov (United States)

    Keating, Charlotte; Tilbrook, Alan J; Rossell, Susan L; Enticott, Peter G; Fitzgerald, Paul B

    2012-04-01

    Individuals with anorexia nervosa (AN) demonstrate a relentless engagement in behaviors aimed to reduce their weight, which leads to severe underweight status, and occasionally death. Neurobiological abnormalities, as a consequence of starvation are controversial: evidence, however, demonstrates abnormalities in the reward system of patients, and recovered individuals. Despite this, a unifying explanation for reward abnormalities observed in AN and their relevance to symptoms of the illness, remains incompletely understood. Theories explaining reward dysfunction have conventionally focused on anhedonia, describing that patients have an impaired ability to experience reward or pleasure. We review taste reward literature and propose that patients' reduced responses to conventional taste-reward tasks may reflect a fear of weight gain associated with the caloric nature of the tasks, rather than an impaired ability to experience reward. Consistent with this, we propose that patients are capable of 'liking' hedonic taste stimuli (e.g., identifying them), however, they do not 'want' or feel motivated for the stimuli in the same way that healthy controls report. Recent brain imaging data on more complex reward processing tasks provide insights into fronto-striatal neural circuit dysfunction related to altered reward processing in AN that challenges the relevance of anhedonia in explaining reward dysfunction in AN. In this way, altered activity of the anterior cingulate cortex and striatum could explain patients' pathological engagement in behaviors they consider rewarding (e.g., self-starvation) that are otherwise aversive or punishing, to those without the eating disorder. Such evidence for altered patterns of brain activity associated with reward processing tasks in patients and recovered individuals may provide important information about mechanisms underlying symptoms of AN, their future investigation, and the development of treatment approaches. Copyright © 2012

  18. 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.

  19. 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.

  20. Value learning and arousal in the extinction of probabilistic rewards: the role of dopamine in a modified temporal difference model.

    Science.gov (United States)

    Song, Minryung R; Fellous, Jean-Marc

    2014-01-01

    Because most rewarding events are probabilistic and changing, the extinction of probabilistic rewards is important for survival. It has been proposed that the extinction of probabilistic rewards depends on arousal and the amount of learning of reward values. Midbrain dopamine neurons were suggested to play a role in both arousal and learning reward values. Despite extensive research on modeling dopaminergic activity in reward learning (e.g. temporal difference models), few studies have been done on modeling its role in arousal. Although temporal difference models capture key characteristics of dopaminergic activity during the extinction of deterministic rewards, they have been less successful at simulating the extinction of probabilistic rewards. By adding an arousal signal to a temporal difference model, we were able to simulate the extinction of probabilistic rewards and its dependence on the amount of learning. Our simulations propose that arousal allows the probability of reward to have lasting effects on the updating of reward value, which slows the extinction of low probability rewards. Using this model, we predicted that, by signaling the prediction error, dopamine determines the learned reward value that has to be extinguished during extinction and participates in regulating the size of the arousal signal that controls the learning rate. These predictions were supported by pharmacological experiments in rats.

  1. A universal role of the ventral striatum in reward-based learning: Evidence from human studies

    Science.gov (United States)

    Daniel, Reka; Pollmann, Stefan

    2014-01-01

    Reinforcement learning enables organisms to adjust their behavior in order to maximize rewards. Electrophysiological recordings of dopaminergic midbrain neurons have shown that they code the difference between actual and predicted rewards, i.e., the reward prediction error, in many species. This error signal is conveyed to both the striatum and cortical areas and is thought to play a central role in learning to optimize behavior. However, in human daily life rewards are diverse and often only indirect feedback is available. Here we explore the range of rewards that are processed by the dopaminergic system in human participants, and examine whether it is also involved in learning in the absence of explicit rewards. While results from electrophysiological recordings in humans are sparse, evidence linking dopaminergic activity to the metabolic signal recorded from the midbrain and striatum with functional magnetic resonance imaging (fMRI) is available. Results from fMRI studies suggest that the human ventral striatum (VS) receives valuation information for a diverse set of rewarding stimuli. These range from simple primary reinforcers such as juice rewards over abstract social rewards to internally generated signals on perceived correctness, suggesting that the VS is involved in learning from trial-and-error irrespective of the specific nature of provided rewards. In addition, we summarize evidence that the VS can also be implicated when learning from observing others, and in tasks that go beyond simple stimulus-action-outcome learning, indicating that the reward system is also recruited in more complex learning tasks. PMID:24825620

  2. Dopamine neurons learn to encode the long-term value of multiple future rewards

    Science.gov (United States)

    Enomoto, Kazuki; Matsumoto, Naoyuki; Nakai, Sadamu; Satoh, Takemasa; Sato, Tatsuo K.; Ueda, Yasumasa; Inokawa, Hitoshi; Haruno, Masahiko; Kimura, Minoru

    2011-01-01

    Midbrain dopamine neurons signal reward value, their prediction error, and the salience of events. If they play a critical role in achieving specific distant goals, long-term future rewards should also be encoded as suggested in reinforcement learning theories. Here, we address this experimentally untested issue. We recorded 185 dopamine neurons in three monkeys that performed a multistep choice task in which they explored a reward target among alternatives and then exploited that knowledge to receive one or two additional rewards by choosing the same target in a set of subsequent trials. An analysis of anticipatory licking for reward water indicated that the monkeys did not anticipate an immediately expected reward in individual trials; rather, they anticipated the sum of immediate and multiple future rewards. In accordance with this behavioral observation, the dopamine responses to the start cues and reinforcer beeps reflected the expected values of the multiple future rewards and their errors, respectively. More specifically, when monkeys learned the multistep choice task over the course of several weeks, the responses of dopamine neurons encoded the sum of the immediate and expected multiple future rewards. The dopamine responses were quantitatively predicted by theoretical descriptions of the value function with time discounting in reinforcement learning. These findings demonstrate that dopamine neurons learn to encode the long-term value of multiple future rewards with distant rewards discounted. PMID:21896766

  3. Intravascular food reward.

    Directory of Open Access Journals (Sweden)

    Albino J Oliveira-Maia

    Full Text Available Consumption of calorie-containing sugars elicits appetitive behavioral responses and dopamine release in the ventral striatum, even in the absence of sweet-taste transduction machinery. However, it is unclear if such reward-related postingestive effects reflect preabsorptive or postabsorptive events. In support of the importance of postabsorptive glucose detection, we found that, in rat behavioral tests, high concentration glucose solutions administered in the jugular vein were sufficient to condition a side-bias. Additionally, a lower concentration glucose solution conditioned robust behavioral responses when administered in the hepatic-portal, but not the jugular vein. Furthermore, enteric administration of glucose at a concentration that is sufficient to elicit behavioral conditioning resulted in a glycemic profile similar to that observed after administration of the low concentration glucose solution in the hepatic-portal, but not jugular vein. Finally using fast-scan cyclic voltammetry we found that, in accordance with behavioral findings, a low concentration glucose solution caused an increase in spontaneous dopamine release events in the nucleus accumbens shell when administered in the hepatic-portal, but not the jugular vein. These findings demonstrate that the postabsorptive effects of glucose are sufficient for the postingestive behavioral and dopaminergic reward-related responses that result from sugar consumption. Furthermore, glycemia levels in the hepatic-portal venous system contribute more significantly for this effect than systemic glycemia, arguing for the participation of an intra-abdominal visceral sensor for glucose.

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

    Science.gov (United States)

    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.

  5. 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.

  6. Rewards teach visual selective attention.

    Science.gov (United States)

    Chelazzi, Leonardo; Perlato, Andrea; Santandrea, Elisa; Della Libera, Chiara

    2013-06-07

    Visual selective attention is the brain function that modulates ongoing processing of retinal input in order for selected representations to gain privileged access to perceptual awareness and guide behavior. Enhanced analysis of currently relevant or otherwise salient information is often accompanied by suppressed processing of the less relevant or salient input. Recent findings indicate that rewards exert a powerful influence on the deployment of visual selective attention. Such influence takes different forms depending on the specific protocol adopted in the given study. In some cases, the prospect of earning a larger reward in relation to a specific stimulus or location biases attention accordingly in order to maximize overall gain. This is mediated by an effect of reward acting as a type of incentive motivation for the strategic control of attention. In contrast, reward delivery can directly alter the processing of specific stimuli by increasing their attentional priority, and this can be measured even when rewards are no longer involved, reflecting a form of reward-mediated attentional learning. As a further development, recent work demonstrates that rewards can affect attentional learning in dissociable ways depending on whether rewards are perceived as feedback on performance or instead are registered as random-like events occurring during task performance. Specifically, it appears that visual selective attention is shaped by two distinct reward-related learning mechanisms: one requiring active monitoring of performance and outcome, and a second one detecting the sheer association between objects in the environment (whether attended or ignored) and the more-or-less rewarding events that accompany them. Overall this emerging literature demonstrates unequivocally that rewards "teach" visual selective attention so that processing resources will be allocated to objects, features and locations which are likely to optimize the organism's interaction with the

  7. Spherical aberration in contact lens wear.

    Science.gov (United States)

    Lindskoog Pettersson, A; Jarkö, C; Alvin, A; Unsbo, P; Brautaset, R

    2008-08-01

    The aim of the present studies was to investigate the effect on spherical aberration of different non custom-made contact lenses, both with and without aberration control. A wavefront analyser (Zywave, Bausch & Lomb) was used to measure the aberrations in each subject's right eye uncorrected and with the different contact lenses. The first study evaluated residual spherical aberration with a standard lens (Focus Dailies Disposable, Ciba Vision) and with an aberration controlled contact lens (ACCL) (Definition AC, Optical Connection Inc.). The second study evaluated the residual spherical aberrations with a monthly disposable silicone hydrogel lens with aberration reduction (PureVision, Bausch & Lomb). Uncorrected spherical aberration was positive for all pupil sizes in both studies. In the first study, residual spherical aberration was close to zero with the standard lens for all pupil sizes whereas the ACCL over-corrected spherical aberration. The results of the second study showed that the monthly disposable lens also over-corrected the aberration making it negative. The changes in aberration were statistically significant (plenses. Since the amount of aberration varies individually we suggest that aberrations should be measured with lenses on the eye if the aim is to change spherical aberration in a certain direction.

  8. Low spirits keep rewards subdued: decreases in sensitivity to reward and vulnerability to dysphoria.

    Science.gov (United States)

    Hervas, Gonzalo; Vazquez, Carmelo

    2013-03-01

    Previous theories and research show clear divergences on the roles of the behavioral activation system (BAS) and the behavioral inhibition system (BIS) in depression. Across four studies, we examined the effects of a sad mood on the motivational pattern of sensitivity to reward and punishment. Psychological variables associated with such changes and implications for vulnerability to depression were also explored. For this purpose, we designed a state version of the extensively used BIS/BAS Scales (Carver & White, 1994). Using samples of undergraduate students, we found that both a natural (Study 1) and a laboratory-induced sad mood (Studies 2 and 3) generated a marked decrease in sensitivity to reward but did not alter sensitivity to punishment. Study 3a showed that participants' anxious attachment predicted larger decreases in sensitivity to reward after a sad mood induction. Study 3b extended these results by showing that sensitivity to reward, when assessed after the negative mood induction, predicted increases in dysphoria 7weeks later. Implications of the results for research on vulnerability to depression are discussed. Copyright © 2012. Published by Elsevier Ltd.

  9. Model Checking Multivariate State Rewards

    DEFF Research Database (Denmark)

    Nielsen, Bo Friis; Nielson, Flemming; Nielson, Hanne Riis

    2010-01-01

    We consider continuous stochastic logics with state rewards that are interpreted over continuous time Markov chains. We show how results from multivariate phase type distributions can be used to obtain higher-order moments for multivariate state rewards (including covariance). We also generalise ...

  10. Heightened reward learning under stress in generalized anxiety disorder: a predictor of depression resistance?

    Science.gov (United States)

    Morris, Bethany H; Rottenberg, Jonathan

    2015-02-01

    Stress-induced anhedonia is associated with depression vulnerability (Bogdan & Pizzagalli, 2006). We investigated stress-induced deficits in reward learning in a depression-vulnerable group with analogue generalized anxiety disorder (GAD, n = 34), and never-depressed healthy controls (n = 41). Utilizing a computerized signal detection task, reward learning was assessed under stressor and neutral conditions. Controls displayed intact reward learning in the neutral condition, and the expected stress-induced blunting. The GAD group as a whole also showed intact reward learning in the neutral condition. When GAD subjects were analyzed as a function of prior depression history, never-depressed GAD subjects showed heightened reward learning in the stressor condition. Better reward learning under stress among GAD subjects predicted lower depression symptoms 1 month later. Robust reward learning under stress may indicate depression resistance among anxious individuals. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  11. Chromosome Aberrations by Heavy Ions

    Science.gov (United States)

    Ballarini, Francesca; Ottolenghi, Andrea

    It is well known that mammalian cells exposed to ionizing radiation can show different types of chromosome aberrations (CAs) including dicentrics, translocations, rings, deletions and complex exchanges. Chromosome aberrations are a particularly relevant endpoint in radiobiology, because they play a fundamental role in the pathways leading either to cell death, or to cell conversion to malignancy. In particular, reciprocal translocations involving pairs of specific genes are strongly correlated (and probably also causally-related) with specific tumour types; a typical example is the BCR-ABL translocation for Chronic Myeloid Leukaemia. Furthermore, aberrations can be used for applications in biodosimetry and more generally as biomarkers of exposure and risk, that is the case for cancer patients monitored during Carbon-ion therapy and astronauts exposed to space radiation. Indeed hadron therapy and astronauts' exposure to space radiation represent two of the few scenarios where human beings can be exposed to heavy ions. After a brief introduction on the main general features of chromosome aberrations, in this work we will address key aspects of the current knowledge on chromosome aberration induction, both from an experimental and from a theoretical point of view. More specifically, in vitro data will be summarized and discussed, outlining important issues such as the role of interphase death/mitotic delay and that of complex-exchange scoring. Some available in vivo data on cancer patients and astronauts will be also reported, together with possible interpretation problems. Finally, two of the few available models of chromosome aberration induction by ionizing radiation (including heavy ions) will be described and compared, focusing on the different assumptions adopted by the authors and on how these models can deal with heavy ions.

  12. ATLAS rewards industry

    CERN Multimedia

    2006-01-01

    Showing excellence in mechanics, electronics and cryogenics, three industries are honoured for their contributions to the ATLAS experiment. Representatives of the three award-wining companies after the ceremony. For contributing vital pieces to the ATLAS puzzle, three industries were recognized on Friday 5 May during a supplier awards ceremony. After a welcome and overview of the ATLAS experiment by spokesperson Peter Jenni, CERN Secretary-General Maximilian Metzger stressed the importance of industry to CERN's scientific goals. Close interaction with CERN was a key factor in the selection of each rewarded company, in addition to the high-quality products they delivered to the experiment. Alu Menziken Industrie AG, of Switzerland, was honoured for the production of 380,000 aluminium tubes for the Monitored Drift Tube Chambers (MDT). As Giora Mikenberg, the Muon System Project Leader stressed, the aluminium tubes were delivered on time with an extraordinary quality and precision. Between October 2000 and Jan...

  13. Homeostatic reinforcement learning for integrating reward collection and physiological stability.

    Science.gov (United States)

    Keramati, Mehdi; Gutkin, Boris

    2014-12-02

    Efficient regulation of internal homeostasis and defending it against perturbations requires adaptive behavioral strategies. However, the computational principles mediating the interaction between homeostatic and associative learning processes remain undefined. Here we use a definition of primary rewards, as outcomes fulfilling physiological needs, to build a normative theory showing how learning motivated behaviors may be modulated by internal states. Within this framework, we mathematically prove that seeking rewards is equivalent to the fundamental objective of physiological stability, defining the notion of physiological rationality of behavior. We further suggest a formal basis for temporal discounting of rewards by showing that discounting motivates animals to follow the shortest path in the space of physiological variables toward the desired setpoint. We also explain how animals learn to act predictively to preclude prospective homeostatic challenges, and several other behavioral patterns. Finally, we suggest a computational role for interaction between hypothalamus and the brain reward system.

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

    Science.gov (United States)

    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.

  15. Serotonergic neurons signal reward and punishment on multiple timescales.

    Science.gov (United States)

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

    2015-02-25

    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.

  16. Adaptive Reward Pursuit: How Effort Requirements Affect Unconscious Reward Responses and Conscious Reward Decisions

    Science.gov (United States)

    Bijleveld, Erik; Custers, Ruud; Aarts, Henk

    2012-01-01

    When in pursuit of rewards, humans weigh the value of potential rewards against the amount of effort that is required to attain them. Although previous research has generally conceptualized this process as a deliberate calculation, recent work suggests that rudimentary mechanisms--operating without conscious intervention--play an important role as…

  17. Relief as a reward: hedonic and neural responses to safety from pain.

    Directory of Open Access Journals (Sweden)

    Siri Leknes

    2011-04-01

    Full Text Available Relief fits the definition of a reward. Unlike other reward types the pleasantness of relief depends on the violation of a negative expectation, yet this has not been investigated using neuroimaging approaches. We hypothesized that the degree of negative expectation depends on state (dread and trait (pessimism sensitivity. Of the brain regions that are involved in mediating pleasure, the nucleus accumbens also signals unexpected reward and positive prediction error. We hypothesized that accumbens activity reflects the level of negative expectation and subsequent pleasant relief. Using fMRI and two purpose-made tasks, we compared hedonic and BOLD responses to relief with responses during an appetitive reward task in 18 healthy volunteers. We expected some similarities in task responses, reflecting common neural substrates implicated across reward types. However, we also hypothesized that relief responses would differ from appetitive rewards in the nucleus accumbens, since only relief pleasantness depends on negative expectations. The results confirmed these hypotheses. Relief and appetitive reward task activity converged in the ventromedial prefrontal cortex, which also correlated with appetitive reward pleasantness ratings. In contrast, dread and pessimism scores correlated with relief but not with appetitive reward hedonics. Moreover, only relief pleasantness covaried with accumbens activation. Importantly, the accumbens signal appeared to specifically reflect individual differences in anticipation of the adverse event (dread, pessimism but was uncorrelated to appetitive reward hedonics. In conclusion, relief differs from appetitive rewards due to its reliance on negative expectations, the violation of which is reflected in relief-related accumbens activation.

  18. 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.

  19. The Art of Optical Aberrations

    Science.gov (United States)

    Wylde, Clarissa Eileen Kenney

    Art and optics are inseparable. Though seemingly opposite disciplines, the combination of art and optics has significantly impacted both culture and science as they are now known. As history has run its course, in the sciences, arts, and their fruitful combinations, optical aberrations have proved to be a problematic hindrance to progress. In an effort to eradicate aberrations the simple beauty of these aberrational forms has been labeled as undesirable and discarded. Here, rather than approach aberrations as erroneous, these beautiful forms are elevated to be the photographic subject in a new body of work, On the Bright Side. Though many recording methods could be utilized, this work was composed on classic, medium-format, photographic film using white-light, Michelson interferometry. The resulting images are both a representation of the true light rays that interacted on the distorted mirror surfaces (data) and the artist's compositional eye for what parts of the interferogram are chosen and displayed. A detailed description of the captivating interdisciplinary procedure is documented and presented alongside the final artwork, CCD digital reference images, and deformable mirror contour maps. This alluring marriage between the arts and sciences opens up a heretofore minimally explored aspect of the inextricable art-optics connection. It additionally provides a fascinating new conversation on the importance of light and optics in photographic composition.

  20. The role of aberrant salience and self-concept clarity in psychotic-like experiences.

    Science.gov (United States)

    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 cognitive mechanisms. The current research examined the relations between psychotic-like experiences and two 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 oversampled 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 a result of neuroticism. Additionally, aberrant salience and self-concept clarity did not interact to predict two other SPD criteria, social anhedonia or trait paranoia, which suggests the interaction is specific to psychotic-like experiences. Overall, our results are consistent with several cognitive models of psychosis suggesting that aberrant salience and self-concept clarity might be important mechanisms in the occurrence of psychotic-like symptoms.

  1. The link between callous-unemotional traits and neural mechanisms of reward processing : An fMRI study

    NARCIS (Netherlands)

    Veroude, Kim; von Rhein, Daniel; Chauvin, Roselyne J. M.; van Dongen, Eelco V.; Mennes, Maarten J. J.; Franke, Barbara; Heslenfeld, Dirk J.; Oosterlaan, Jaap; Hartman, Catharina A.; Hoekstra, Pieter J.; Glennon, Jeffrey C.; Buitelaar, Jan K.

    2016-01-01

    Callous-unemotional (CU) traits, i.e., unconcernedness and lack of prosocial feelings, may manifest in Conduct Disorder (CD), but also in Oppositional Defiant Disorder (ODD) and Attention Deficit Hyperactivity Disorder (ADHD). These disorders have been associated with aberrant reward processing,

  2. Reward expectation alters learning and memory: The impact of the amygdala on appetitive-driven behaviors

    OpenAIRE

    Savage, Lisa M.; Ramos, Raddy L.

    2008-01-01

    The capacity to seek and obtain rewards is essential for survival. Pavlovian conditioning is one mechanism by which organisms develop predictions about rewards and such anticipatory or expectancy states enable successful behavioral adaptations to environmental demands. Reward expectancies have both affective/motivational and discriminative properties that allow for the modulation of instrumental goal-directed behavior. Recent data provides evidence that different cognitive strategies (cue-out...

  3. Dissecting components of reward: ‘liking’, ‘wanting’, and learning

    OpenAIRE

    Berridge, Kent C.; Robinson, Terry E.; Aldridge, J. Wayne

    2009-01-01

    In recent years significant progress has been made delineating the psychological components of reward and their underlying neural mechanisms. Here we briefly highlight findings on three dissociable psychological components of reward: ‘liking’ (hedonic impact), ‘wanting’ (incentive salience), and learning (predictive associations and cognitions). A better understanding of the components of reward, and their neurobiological substrates, may help in devising improved treatments for disorders of m...

  4. Does general motivation energize financial reward-seeking behavior? Evidence from an effort task.

    Science.gov (United States)

    Chumbley, Justin; Fehr, Ernst

    2014-01-01

    We aimed to predict how hard subjects work for financial rewards from their general trait and state reward-motivation. We specifically asked 1) whether individuals high in general trait "reward responsiveness" work harder 2) whether task-irrelevant cues can make people work harder, by increasing general motivation. Each trial of our task contained a 1 second earning interval in which male subjects earned money for each button press. This was preceded by one of three predictive cues: an erotic picture of a woman, a man, or a geometric figure. We found that individuals high in trait "reward responsiveness" worked harder and earned more, irrespective of the predictive cue. Because female predictive cues are more rewarding, we expected them to increase general motivation in our male subjects and invigorate work, but found a more complex pattern.

  5. Modelling the effects of secondary spherical aberration on refractive error, image quality and depth of focus.

    Science.gov (United States)

    Xu, Renfeng; Bradley, Arthur; López Gil, Norberto; Thibos, Larry N

    2015-01-01

    To examine the role of Zernike secondary spherical aberration and its component terms on refraction, image quality and depth of focus. Computational methods were used to define wavefronts with controlled levels of r(6) , r(4) and r(2) terms, and image quality associated with these terms for a range of target vergences. Target vergences that generated maximum image quality were used as an objective measures of refractive error. Unlike primary Zernike spherical aberration, which generates peak image quality with a near paraxial focus, in the absence of other higher order aberrations, peak image quality with secondary spherical aberration is achieved with a near marginal focus. When alone, positive primary and secondary spherical aberration induce small hyperopic shifts in refraction, but in the presence of other higher order aberrations, secondary spherical aberration can induce significant myopic shifts in refractive error, as predicted by the combined lower order r(4) & r(2) component of Z60. The predicted expansion in depth of focus associated with increased primary or secondary spherical aberration is mostly absent if a strict image quality criterion is applied. The expansion of depth of focus observed with a low image quality criterion when opposite sign Z40 and Z60 are combined is primarily due to the elevated r(4) term. Secondary Zernike spherical aberration can have a significant impact on refractive error, image quality and depth of focus, but mostly due to the lower order components within this polynomial. Our analysis shows that the r(6) term that defines secondary spherical aberration actually narrows rather than expands depth of focus, when in the presence of the r(4) term within Z60. Therefore, a multifocal lens generated with exclusively primary spherical aberration is likely to be more effective than one that includes opposite sign of primary and secondary spherical aberration. © 2014 The Authors Ophthalmic & Physiological Optics © 2014 The College

  6. Reward Selectively Modulates the Lingering Neural Representation of Recently Attended Objects in Natural Scenes.

    Science.gov (United States)

    Hickey, Clayton; Peelen, Marius V

    2017-08-02

    Theories of reinforcement learning and approach behavior suggest that reward can increase the perceptual salience of environmental stimuli, ensuring that potential predictors of outcome are noticed in the future. However, outcome commonly follows visual processing of the environment, occurring even when potential reward cues have long disappeared. How can reward feedback retroactively cause now-absent stimuli to become attention-drawing in the future? One possibility is that reward and attention interact to prime lingering visual representations of attended stimuli that sustain through the interval separating stimulus and outcome. Here, we test this idea using multivariate pattern analysis of fMRI data collected from male and female humans. While in the scanner, participants searched for examples of target categories in briefly presented pictures of cityscapes and landscapes. Correct task performance was followed by reward feedback that could randomly have either high or low magnitude. Analysis showed that high-magnitude reward feedback boosted the lingering representation of target categories while reducing the representation of nontarget categories. The magnitude of this effect in each participant predicted the behavioral impact of reward on search performance in subsequent trials. Other analyses show that sensitivity to reward-as expressed in a personality questionnaire and in reactivity to reward feedback in the dopaminergic midbrain-predicted reward-elicited variance in lingering target and nontarget representations. Credit for rewarding outcome thus appears to be assigned to the target representation, causing the visual system to become sensitized for similar objects in the future. SIGNIFICANCE STATEMENT How do reward-predictive visual stimuli become salient and attention-drawing? In the real world, reward cues precede outcome and reward is commonly received long after potential predictors have disappeared. How can the representation of environmental stimuli

  7. 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

  8. Differences in reward processing between putative cell types in primate prefrontal cortex.

    Directory of Open Access Journals (Sweden)

    Hongwei Fan

    Full Text Available Single-unit studies in monkeys have demonstrated that neurons in the prefrontal cortex predict the reward type, reward amount or reward availability associated with a stimulus. To examine contributions of pyramidal cells and interneurons in reward processing, single-unit activity was extracellularly recorded in prefrontal cortices of four monkeys performing a reward prediction task. Based on their shapes of spike waveforms, prefrontal neurons were classified into broad-spike and narrow-spike units that represented putative pyramidal cells and interneurons, respectively. We mainly observed that narrow-spike neurons showed higher firing rates but less bursty discharges than did broad-spike neurons. Both narrow-spike and broad-spike cells selectively responded to the stimulus, reward and their interaction, and the proportions of each type of selective neurons were similar between the two cell classes. Moreover, the two types of cells displayed equal reliability of reward or stimulus discrimination. Furthermore, we found that broad-spike and narrow-spike cells showed distinct mechanisms for encoding reward or stimulus information. Broad-spike neurons raised their firing rate relative to the baseline rate to represent the preferred reward or stimulus information, whereas narrow-spike neurons inhibited their firing rate lower than the baseline rate to encode the non-preferred reward or stimulus information. Our results suggest that narrow-spike and broad-spike cells were equally involved in reward and stimulus processing in the prefrontal cortex. They utilized a binary strategy to complementarily represent reward or stimulus information, which was consistent with the task structure in which the monkeys were required to remember two reward conditions and two visual stimuli.

  9. 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.

  10. Managing Capacity Through Reward Programs

    OpenAIRE

    Byung-Do Kim; Mengze Shi; Kannan Srinivasan

    2004-01-01

    Rewarding customers with own products or services has become an increasingly popular practice across a spectrum of industries such as airlines, hotels, and telecommunication. In these service industries, firms face demand uncertainty and strict short-term capacity constraint. When the market demand is low, firms hold excess capacities that would lead to intense price competition. In this paper we study the adoption and design of reward programs in the context of capacity management. We demons...

  11. Floral reward in Ranunculaceae species

    OpenAIRE

    Bożena Denisow; Monika Strzałkowska-Abramek; Anna Jeżak

    2016-01-01

    Floral reward is important in ecological and evolutionary perspectives and essential in pollination biology. For example, floral traits, nectar and pollen features are essential for understanding the functional ecology, the dynamics of pollen transport, competition for pollinator services, and patterns of specialization and generalization in plant–pollinator interactions. We believe to present a synthetic description in the field of floral reward in Ranunculaceae family important in pollinati...

  12. Rewarding imperfect motor performance reduces adaptive changes

    NARCIS (Netherlands)

    van der Kooij, K.|info:eu-repo/dai/nl/304823406; Overvliet, K. E.

    2016-01-01

    Could a pat on the back affect motor adaptation? Recent studies indeed suggest that rewards can boost motor adaptation. However, the rewards used were typically reward gradients that carried quite detailed information about performance. We investigated whether simple binary rewards affected how

  13. Reducing starbursts in highly aberrated eyes with pupil miosis.

    Science.gov (United States)

    Xu, Renfeng; Kollbaum, Pete; Thibos, Larry; Lopez-Gil, Norberto; Bradley, Arthur

    2018-01-01

    To test the hypothesis that marginal ray deviations determine perceived starburst sizes, and to explore different strategies for decreasing starburst size in highly aberrated eyes. Perceived size of starburst images and visual acuities were measured psychophysically for eyes with varying levels of spherical aberration, pupil sizes, and defocus. Computationally, we use a polychromatic eye model including the typical levels of higher order aberrations (HOAs) for keratoconic and post-LASIK eyes to quantify the image quality (the visually weighted Strehl ratio derived from the optical transfer function, VSOTF) with different pupil sizes at both photopic and mesopic light levels. For distance corrected post-LASIK and keratoconic eyes with a night-time pupil (e.g., 7 mm), the starburst diameter is about 1.5 degrees (1 degree for normal presbyopic eyes), which can be reduced to ≤0.25 degrees with pupil sizes ≤3 mm. Starburst size is predicted from the magnitude of the longitudinal spherical aberration. Refracting the eye to focus the pupil margin also removed starbursts, but, unlike small pupils, significantly degraded visual acuity. Reducing pupil diameter to 3 mm improved image quality for these highly aberrated eyes by about 2.7 ×  to 1.7 ×  relative to the natural pupils when light levels were varied from 0.1 to 1000 cd m-2 , respectively. Subjects with highly aberrated eyes observed larger starbursts around bright lights at night predictable by the deviated marginal rays. These were effectively attenuated by reducing pupil diameters to ≤3 mm, which did not cause a drop in visual acuity or modelled image quality even at mesopic light levels. © 2017 The Authors Ophthalmic & Physiological Optics © 2017 The College of Optometrists.

  14. Phase Aberrations in Diffraction Microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Marchesini, S; Chapman, H N; Barty, A; Howells, M R; Spence, J H; Cui, C; Weierstall, U; Minor, A M

    2005-09-29

    In coherent X-ray diffraction microscopy the diffraction pattern generated by a sample illuminated with coherent x-rays is recorded, and a computer algorithm recovers the unmeasured phases to synthesize an image. By avoiding the use of a lens the resolution is limited, in principle, only by the largest scattering angles recorded. However, the imaging task is shifted from the experiment to the computer, and the algorithm's ability to recover meaningful images in the presence of noise and limited prior knowledge may produce aberrations in the reconstructed image. We analyze the low order aberrations produced by our phase retrieval algorithms. We present two methods to improve the accuracy and stability of reconstructions.

  15. Pathophysiology of MDS: genomic aberrations.

    Science.gov (United States)

    Ichikawa, Motoshi

    2016-01-01

    Myelodysplastic syndromes (MDS) are characterized by clonal proliferation of hematopoietic stem/progenitor cells and their apoptosis, and show a propensity to progress to acute myelogenous leukemia (AML). Although MDS are recognized as neoplastic diseases caused by genomic aberrations of hematopoietic cells, the details of the genetic abnormalities underlying disease development have not as yet been fully elucidated due to difficulties in analyzing chromosomal abnormalities. Recent advances in comprehensive analyses of disease genomes including whole-genome sequencing technologies have revealed the genomic abnormalities in MDS. Surprisingly, gene mutations were found in approximately 80-90% of cases with MDS, and the novel mutations discovered with these technologies included previously unknown, MDS-specific, mutations such as those of the genes in the RNA-splicing machinery. It is anticipated that these recent studies will shed new light on the pathophysiology of MDS due to genomic aberrations.

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

    Directory of Open Access Journals (Sweden)

    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.

  17. Renewal processes with costs and rewards

    OpenAIRE

    Vlasiou, Maria

    2014-01-01

    We review the theory of renewal reward processes, which describes renewal processes that have some cost or reward associated with each cycle. We present a new simplified proof of the renewal reward theorem that mimics the proof of the elementary renewal theorem and avoids the technicalities in the proof that is presented in most textbooks. Moreover, we mention briefly the extension of the theory to partial rewards, where it is assumed that rewards are not accrued only at renewal epochs but al...

  18. PER2 rs2304672 polymorphism moderates circadian-relevant reward circuitry activity in adolescents.

    Science.gov (United States)

    Forbes, Erika E; Dahl, Ronald E; Almeida, Jorge R C; Ferrell, Robert E; Nimgaonkar, Vishwajit L; Mansour, Hader; Sciarrillo, Samantha R; Holm, Stephanie M; Rodriguez, Eric E; Phillips, Mary L

    2012-03-01

    Reward behavior in animals is influenced by circadian genes, including clock-pathway genes such as Period2 (PER2). Several forms of psychiatric illness are associated with both altered reward function and disturbances in circadian function. The PER2 single nucleotide polymorphism (SNP) rs2304672 has been associated with psychiatric illnesses involving reward dysfunction. Associations among circadian genes, function in neural reward circuits, and circadian-influenced behavior have not yet been studied in humans, however. 90 healthy adolescents underwent functional magnetic resonance imaging during a guessing task with monetary reward, genotyping for two PER2 SNPs (rs2304672, rs2304674), and actigraphy to measure sleep in their home environments. Weekend sleep midpoint, a behavioral index of circadian function, was derived from actigraphy. Puberty was measured by physical exam. The rs2304672 SNP predicted blood oxygenation level-dependent response to monetary reward as constrained by sleep midpoint. Later sleep midpoint was associated with reduced activity in a key component of reward circuitry, medial prefrontal cortex (mPFC; Brodmann area 9/10/32), to reward outcome (p(corrected) circadian genes have a significant impact upon circadian-relevant reward circuitry in humans. These findings have the potential to elucidate gene-brain-behavior relationships underlying reward processing and psychopathology.

  19. 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,

  20. 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

  1. 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

  2. Reward expectation alters learning and memory: the impact of the amygdala on appetitive-driven behaviors.

    Science.gov (United States)

    Savage, Lisa M; Ramos, Raddy L

    2009-03-02

    The capacity to seek and obtain rewards is essential for survival. Pavlovian conditioning is one mechanism by which organisms develop predictions about rewards and such anticipatory or expectancy states enable successful behavioral adaptations to environmental demands. Reward expectancies have both affective/motivational and discriminative properties that allow for the modulation of instrumental goal-directed behavior. Recent data provide evidence that different cognitive strategies (cue-outcome associations) and neural systems (amygdala) are used when subjects are trained under conditions that allow Pavlovian-induced reward expectancies to guide instrumental behavioral choices. Furthermore, it has been demonstrated that impairments typically observed in a number of brain-damaged models are alleviated or eliminated by embedding unique reward expectancies into learning/memory tasks. These results suggest that Pavlovian-induced reward expectancies can change both behavioral and brain processes.

  3. Phasic mesolimbic dopamine release tracks reward seeking during expression of Pavlovian-to-instrumental transfer

    Science.gov (United States)

    Wassum, Kate M.; Ostlund, Sean B.; Loewinger, Gabriel C.; Maidment, Nigel T.

    2012-01-01

    Background Recent theories addressing mesolimbic dopamine’s role in reward processing emphasize two apparently distinct functions, one in reinforcement learning (i.e. prediction error) and another in incentive motivation (i.e. the invigoration of reward-seeking elicited by reward-paired cues). Here we evaluate the latter. Methods Using fast-scan cyclic voltammetry, we monitored, in real-time, dopamine release in the nucleus accumbens core of rats (n=9) during a Pavlovian-to-instrumental transfer task in which the effects of a reward-predictive cue on an independently-trained instrumental action were assessed. Voltammetric data were parsed into slow and phasic components to determine whether these forms of dopamine signaling were differentially related to task performance. Results We found that a reward-paired cue, which increased reward-seeking actions, induced an increase in phasic mesolimbic dopamine release and produced slower elevations in extracellular dopamine. Interestingly, phasic dopamine release was temporally-related to and positively correlated with lever-press activity, generally, while slow dopamine changes were not significantly related to such activity. Importantly, the propensity of the reward-paired cue to increase lever-pressing was predicted by the amplitude of phasic dopamine release events, indicating a possible mechanism through which cues initiate reward-seeking actions. Conclusions These data suggest that those phasic mesolimbic dopamine release events thought to signal reward prediction error may also be related to the incentive motivational impact of reward-paired cues on reward-seeking actions. PMID:23374641

  4. Specific genomic aberrations in primary colorectal cancer are associated with liver metastases

    NARCIS (Netherlands)

    Bruin, S.C.; Klijn, C.N.; Liefers, G.J.; Braaf, L.M.; Joosse, S.A.; Van Beers, E.H.; Verwaal, V.J.; Morreau, H.; Wessels, L.F.; Van Velthuysen, M.L.F.; Tollenaar, R.A.E.M.; Van 't Veer, L.J.

    2010-01-01

    Background: Accurate staging of colorectal cancer (CRC) with clinicopathological parameters is important for predicting prognosis and guiding treatment but provides no information about organ site of metastases. Patterns of genomic aberrations in primary colorectal tumors may reveal a chromosomal

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

    Science.gov (United States)

    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.

  6. Sensitivity of Locus Ceruleus Neurons to Reward Value for Goal-Directed Actions

    Science.gov (United States)

    Richmond, Barry J.

    2015-01-01

    The noradrenergic nucleus locus ceruleus (LC) is associated classically with arousal and attention. Recent data suggest that it might also play a role in motivation. To study how LC neuronal responses are related to motivational intensity, we recorded 121 single neurons from two monkeys while reward size (one, two, or four drops) and the manner of obtaining reward (passive vs active) were both manipulated. The monkeys received reward under three conditions: (1) releasing a bar when a visual target changed color; (2) passively holding a bar; or (3) touching and releasing a bar. In the first two conditions, a visual cue indicated the size of the upcoming reward, and, in the third, the reward was constant through each block of 25 trials. Performance levels and lipping intensity (an appetitive behavior) both showed that the monkeys' motivation in the task was related to the predicted reward size. In conditions 1 and 2, LC neurons were activated phasically in relation to cue onset, and this activation strengthened with increasing expected reward size. In conditions 1 and 3, LC neurons were activated before the bar-release action, and the activation weakened with increasing expected reward size but only in task 1. These effects evolved as monkeys progressed through behavioral sessions, because increasing fatigue and satiety presumably progressively decreased the value of the upcoming reward. These data indicate that LC neurons integrate motivationally relevant information: both external cues and internal drives. The LC might provide the impetus to act when the predicted outcome value is low. PMID:25740528

  7. 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.

  8. Learning and Stress Shape the Reward Response Patterns of Serotonin Neurons.

    Science.gov (United States)

    Zhong, Weixin; Li, Yi; Feng, Qiru; Luo, Minmin

    2017-09-13

    The ability to predict reward promotes animal survival. Both dopamine neurons in the ventral tegmental area and serotonin neurons in the dorsal raphe nucleus (DRN) participate in reward processing. Although the learning effects on dopamine neurons have been extensively characterized, it remains largely unknown how the response of serotonin neurons evolves during learning. Moreover, although stress is known to strongly influence reward-related behavior, we know very little about how stress modulates neuronal reward responses. By monitoring Ca 2+ signals during the entire process of Pavlovian conditioning, we here show that learning differentially shapes the response patterns of serotonin neurons and dopamine neurons in mice of either sex. Serotonin neurons gradually develop a slow ramp-up response to the reward-predicting cue, and ultimately remain responsive to the reward, whereas dopamine neurons increase their response to the cue but reduce their response to the reward. For both neuron types, the responses to the cue and the reward depend on reward value, are reversible when the reward is omitted, and are rapidly reinstated by restoring the reward. We also found that stressors including head restraint and fearful context substantially reduce the response strength of both neuron types, to both the cue and the reward. These results reveal the dynamic nature of the reward responses, support the hypothesis that DRN serotonin neurons signal the current likelihood of receiving a net benefit, and suggest that the inhibitory effect of stress on the reward responses of serotonin neurons and dopamine neurons may contribute to stress-induced anhedonia. SIGNIFICANCE STATEMENT Both serotonin neurons in the dorsal raphe and dopamine neurons in the ventral tegmental area are intimately involved in reward processing. Using long-term fiber photometry of Ca 2+ signals from freely behaving mice, we here show that learning produces a ramp-up activation pattern in serotonin neurons

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

    Directory of Open Access Journals (Sweden)

    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.

  10. Evolutionary advantages of adaptive rewarding

    Science.gov (United States)

    Szolnoki, Attila; Perc, Matjaž

    2012-09-01

    Our well-being depends on both our personal success and the success of our society. The realization of this fact makes cooperation an essential trait. Experiments have shown that rewards can elevate our readiness to cooperate, but since giving a reward inevitably entails paying a cost for it, the emergence and stability of such behavior remains elusive. Here we show that allowing for the act of rewarding to self-organize in dependence on the success of cooperation creates several evolutionary advantages that instill new ways through which collaborative efforts are promoted. Ranging from indirect territorial battle to the spontaneous emergence and destruction of coexistence, phase diagrams and the underlying spatial patterns reveal fascinatingly rich social dynamics that explain why this costly behavior has evolved and persevered. Comparisons with adaptive punishment, however, uncover an Achilles heel of adaptive rewarding, coming from over-aggression, which in turn hinders optimal utilization of network reciprocity. This may explain why, despite its success, rewarding is not as firmly embedded into our societal organization as punishment.

  11. 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.

  12. Increased neural processing of rewarding and aversive food stimuli in recovered anorexia nervosa.

    Science.gov (United States)

    Cowdrey, Felicity A; Park, Rebecca J; Harmer, Catherine J; McCabe, Ciara

    2011-10-15

    Recent evidence has shown that individuals with acute anorexia nervosa and those recovered have aberrant physiological responses to rewarding stimuli. We hypothesized that women recovered from anorexia nervosa would show aberrant neural responses to both rewarding and aversive disorder-relevant stimuli. Using functional magnetic resonance imaging (fMRI), the neural response to the sight and flavor of chocolate, and their combination, in 15 women recovered from restricting-type anorexia nervosa and 16 healthy control subjects matched for age and body mass index was investigated. The neural response to a control aversive condition, consisting of the sight of moldy strawberries and a corresponding unpleasant taste, was also measured. Participants simultaneously recorded subjective ratings of "pleasantness," "intensity," and "wanting." Despite no differences between the groups in subjective ratings, individuals recovered from anorexia nervosa showed increased neural response to the pleasant chocolate taste in the ventral striatum and pleasant chocolate sight in the occipital cortex. The recovered participants also showed increased neural response to the aversive strawberry taste in the insula and putamen and to the aversive strawberry sight in the anterior cingulate cortex and caudate. Individuals recovered from anorexia nervosa have increased neural responses to both rewarding and aversive food stimuli. These findings suggest that even after recovery, women with anorexia nervosa have increased salience attribution to food stimuli. These results aid our neurobiological understanding and support the view that the neural response to reward may constitute a neural biomarker for anorexia nervosa. Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.

  13. Ocular aberrations and wavefront aberrometry: A review

    Directory of Open Access Journals (Sweden)

    Holly A. Unterhorst

    2015-03-01

    Full Text Available Wavefront aberrations can be described as deviations of the wavefront exiting the eye froma reference wavefront that is aberration free and diffraction limited. Ocular aberrations canbe sub-categorised as lower and higher order aberrations. Ocular aberrations have promptedinterest amongst the ocular healthcare community owing to their influences on the visualfunctioning of patients as well as differences observed in ocular aberrations through the useof refractive surgery both pre- and post-operatively. Uncompensated refractive error remainsone of the most common reasons for which patients consult optometrists. Compensationof refractive error, or lower order aberrations, has become a routine procedure during anoptometric examination. However, there are some patients who experience visual symptomseven after their refractive errors have been compensated via spectacles or contact lenses.Higher-order aberrations may be the source of these visual disturbances. Refractive surgeryhas been found to influence and even induce various changes in higher-order aberrationspost-operatively, which in turn has led to increased interest in wavefront aberrations and howthe measurement of these aberrations can improve diagnosis and treatment within optometryand ophthalmology.

  14. Animal models of cannabinoid reward

    Science.gov (United States)

    Panlilio, Leigh V; Justinova, Zuzana; Goldberg, Steven R

    2010-01-01

    The endogenous cannabinoid system is involved in numerous physiological and neuropsychological functions. Medications that target this system hold promise for the treatment of a wide variety of disorders. However, as reward is one of the most prominent of these functions, medications that activate this system must be evaluated for abuse potential. Meanwhile, cannabis is already being used chronically by millions of people, many of whom eventually seek treatment for cannabis dependence. Therefore, there is a need for procedures that can be used to: (i) better understand the mechanisms of cannabinoid reward; (ii) evaluate the abuse potential of new medications; and (iii) evaluate the effectiveness of medications developed for treating cannabis dependence. Animal models of cannabinoid reward provide a means of accomplishing these goals. In this review, we briefly describe and evaluate these models, their advantages and their shortcomings. Special emphasis is placed on intravenous cannabinoid self-administration in squirrel monkeys, a valid, reliable and flexible model that we have developed over the past decade. Although the conditions under which cannabinoid drugs have rewarding effects may be more restricted than with other drugs of abuse such as cocaine and heroin, work with these models indicates that cannabinoid reward involves similar brain mechanisms and produces the same kinds of reward-related behaviour. By continuing to use these animal models as tools in the development of new medications, it should be possible to take advantage of the potential benefits provided by the endocannabinoid system while minimizing its potential for harm. This article is part of a themed issue on Cannabinoids. To view the editorial for this themed issue visit http://dx.doi.org/10.1111/j.1476-5381.2010.00831.x PMID:20590560

  15. Nanofocusing with aberration-corrected rotationally parabolic refractive X-ray lenses.

    Science.gov (United States)

    Seiboth, Frank; Wittwer, Felix; Scholz, Maria; Kahnt, Maik; Seyrich, Martin; Schropp, Andreas; Wagner, Ulrich; Rau, Christoph; Garrevoet, Jan; Falkenberg, Gerald; Schroer, Christian G

    2018-01-01

    Wavefront errors of rotationally parabolic refractive X-ray lenses made of beryllium (Be CRLs) have been recovered for various lens sets and X-ray beam configurations. Due to manufacturing via an embossing process, aberrations of individual lenses within the investigated ensemble are very similar. By deriving a mean single-lens deformation for the ensemble, aberrations of any arbitrary lens stack can be predicted from the ensemble with \\bar{\\sigma} = 0.034λ. Using these findings the expected focusing performance of current Be CRLs are modeled for relevant X-ray energies and bandwidths and it is shown that a correction of aberrations can be realised without prior lens characterization but simply based on the derived lens deformation. The performance of aberration-corrected Be CRLs is discussed and the applicability of aberration-correction demonstrated over wide X-ray energy ranges.

  16. Phase and birefringence aberration correction

    Science.gov (United States)

    Bowers, M.; Hankla, A.

    1996-07-09

    A Brillouin enhanced four wave mixing phase conjugate mirror corrects phase aberrations of a coherent electromagnetic beam and birefringence induced upon that beam. The stimulated Brillouin scattering (SBS) phase conjugation technique is augmented to include Brillouin enhanced four wave mixing (BEFWM). A seed beam is generated by a main oscillator which arrives at the phase conjugate cell before the signal beams in order to initiate the Brillouin effect. The signal beam which is being amplified through the amplifier chain is split into two perpendicularly polarized beams. One of the two beams is chosen to be the same polarization as some component of the seed beam, the other orthogonal to the first. The polarization of the orthogonal beam is then rotated 90{degree} such that it is parallel to the other signal beam. The three beams are then focused into cell containing a medium capable of Brillouin excitation. The two signal beams are focused such that they cross the seed beam path before their respective beam waists in order to achieve BEFWM or the two signal beams are focused to a point or points contained within the focused cone angle of the seed beam to achieve seeded SBS, and thus negate the effects of all birefringent and material aberrations in the system. 5 figs.

  17. Introduction: Addiction and Brain Reward and Anti-Reward Pathways

    Science.gov (United States)

    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

  18. Initial subjective reward to alcohol in Sprague-Dawley rats.

    Science.gov (United States)

    Nentwig, Todd B; Myers, Kevin P; Grisel, Judith E

    2017-02-01

    Initial subjective response to the rewarding properties of alcohol predicts voluntary consumption and the risk for alcohol use disorders. We assessed the initial subjective reward to alcohol in rats using a single exposure conditioned place preference (SE-CPP) paradigm. Sprague-Dawley rats demonstrate preference for a context paired with a single systemic injection of ethanol (1.0 g/kg, delivered intraperitoneally). However, expression of SE-CPP in males depended on pairing ethanol with the first exposure of two (ethanol; saline) to the conditioning apparatus and procedures, while conditioning day did not appreciably affect SE-CPP in females, consistent with the view that females experience heightened addiction vulnerability. This model offers researchers a high throughput assay for investigating factors that influence alcohol reward and may point the way toward more effective prevention and treatment efforts. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Aberrations of magnetooptical system of SALO recirculator

    Science.gov (United States)

    Guk, I. S.; Dovbnya, A. N.; Kononenko, S. G.; Peev, F. A.; Tarasenko, A. S.

    2010-12-01

    The influence of spatial and chromatic aberrations on the parameters of the 730 MeV beam extracted from a SALO recirculator is studied using numerical simulation. The influence of fringing fields and the heterogeneity of the guide field of dipole magnets on the beam parameters at the extraction point is studied for different orders and types of aberrations. Estimates of the contributions of the different types of aberrations to the extracted beam emittance are presented.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. Temporal dynamics of reward anticipation in the human brain.

    Science.gov (United States)

    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.

  5. Effects of Material and Non-Material Rewards on Remembering to Do Things for Others.

    Science.gov (United States)

    Brandimonte, Maria A; Ferrante, Donatella

    2015-01-01

    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 et al., 2010). Extending research on this general topic, in two activity-based prospective memory (PM) 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 PM action. In Experiment 2, their pro-social PM performance could be rewarded or not with an image reward (disclosure of their altruistic behavior). Results revealed that introducing a small material reward (Experiment 1) or a non-material reward (Experiment 2) impaired pro-social PM. 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.

  6. Observation of reward delivery to a conspecific modulates dopamine release in ventral striatum.

    Science.gov (United States)

    Kashtelyan, Vadim; Lichtenberg, Nina T; Chen, Mindy L; Cheer, Joseph F; Roesch, Matthew R

    2014-11-03

    Dopamine (DA) neurons increase and decrease firing for rewards that are better and worse than expected, respectively. These correlates have been observed at the level of single-unit firing and in measurements of phasic DA release in ventral striatum (VS). Here, we ask whether DA release is modulated by delivery of reward, not to oneself, but to a conspecific. It is unknown what, if anything, DA release encodes during social situations in which one animal witnesses another animal receive reward. It might be predicted that DA release will increase, suggesting that watching a conspecific receive reward is a favorable outcome. Conversely, DA release may be entirely dependent on personal experience, or perhaps observation of receipt of reward might be experienced as a negative outcome because another individual, rather than oneself, receives the reward. Our data show that animals display a mixture of affective states during observation of conspecific reward, first exhibiting increases in appetitive calls (50 kHz), then exhibiting increases in aversive calls (22 kHz). Like ultrasonic vocalizations (USVs), DA signals were modulated by delivery of reward to the conspecific. We show stronger DA release during observation of the conspecific receiving reward relative to observation of reward delivered to an empty box, but only on the first trial. During the following trials, this relationship reversed: DA release was reduced during observation of the conspecific receiving reward. These findings suggest that positive and negative states associated with conspecific reward delivery modulate DA signals related to learning in social situations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. 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.

  8. Reward Expectations Lead to Smoking Uptake among Depressed Adolescents

    Science.gov (United States)

    Audrain-McGovern, Janet; Rodriguez, Daniel; Rodgers, Kelli; Cuevas, Jocelyn; Sass, Joseph; Riley, Tennisha

    2011-01-01

    Aims While the comorbidity between adolescent depression and smoking has been well documented, less is known about why smoking is disproportionately higher among depressed adolescents. Emerging research suggests that reward-related mechanisms may be important to consider. This study sought to determine whether adolescents with higher depression symptoms have greater smoking reward expectations, which in turn, influence smoking progression. Participants The sample was composed of 1,393 adolescents participating in a longitudinal survey study of adolescent health behaviors. Design and Measurements In this prospective cohort study, variables were measured via self-report every six months from age 14 to age 17 resulting in six waves of data. Findings Parallel processes latent growth curve modeling indicated that higher depression symptoms across mid to late adolescence predicted a 17% increase in smoking reward expectations (β = 3.50, z=2.85, p=.004), which in turn predicted a 23% increase in the odds of smoking progression (β= .206, z=3.29, p=.001). The indirect effect was significant with delta method (βindirect = .72, z= 3.09, p=.002; 95% CI= .26, 1.18) and bootstrap (βindirect = .72, z= 2.10, p=.03; 95% CI= .05, 1.39) standard errors. Conclusions The study provides novel evidence that expectations of smoking reward facilitate smoking uptake among depressed adolescents. Smoking reward expectations may identify depressed adolescents at risk of smoking. Addressing alternative ways to meet the reward expectations rather than smoking may be an important component to consider in the preventing smoking and promoting smoking cessation among adolescents with elevated depression symptoms. PMID:21855235

  9. Studying Food Reward and Motivation in Humans

    National Research Council Canada - National Science Library

    Ziauddeen, Hisham; Subramaniam, Naresh; Cambridge, Victoria C; Medic, Nenad; Farooqi, Ismaa Sadaf; Fletcher, Paul C

    2014-01-01

    A key challenge in studying reward processing in humans is to go beyond subjective self-report measures and quantify different aspects of reward such as hedonics, motivation, and goal value in more objective ways...

  10. 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...... 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...

  11. Adolescent development of the reward system

    National Research Council Canada - National Science Library

    Galvan, Adriana

    2010-01-01

    .... Investigators have used functional magnetic resonance imaging (fMRI) in conjunction with reward paradigms to test two opposing hypotheses about adolescent developmental changes in the striatum, a region implicated in reward processing...

  12. A universal role of the ventral striatum in reward-based learning: evidence from human studies.

    Science.gov (United States)

    Daniel, Reka; Pollmann, Stefan

    2014-10-01

    Reinforcement learning enables organisms to adjust their behavior in order to maximize rewards. Electrophysiological recordings of dopaminergic midbrain neurons have shown that they code the difference between actual and predicted rewards, i.e., the reward prediction error, in many species. This error signal is conveyed to both the striatum and cortical areas and is thought to play a central role in learning to optimize behavior. However, in human daily life rewards are diverse and often only indirect feedback is available. Here we explore the range of rewards that are processed by the dopaminergic system in human participants, and examine whether it is also involved in learning in the absence of explicit rewards. While results from electrophysiological recordings in humans are sparse, evidence linking dopaminergic activity to the metabolic signal recorded from the midbrain and striatum with functional magnetic resonance imaging (fMRI) is available. Results from fMRI studies suggest that the human ventral striatum (VS) receives valuation information for a diverse set of rewarding stimuli. These range from simple primary reinforcers such as juice rewards over abstract social rewards to internally generated signals on perceived correctness, suggesting that the VS is involved in learning from trial-and-error irrespective of the specific nature of provided rewards. In addition, we summarize evidence that the VS can also be implicated when learning from observing others, and in tasks that go beyond simple stimulus-action-outcome learning, indicating that the reward system is also recruited in more complex learning tasks. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Addiction: Beyond dopamine reward circuitry

    Energy Technology Data Exchange (ETDEWEB)

    Volkow, N.D.; Wang, G.; Volkow, N.D.; Wang, G.-J.; Fowler, J.S.; Tomasi, D.; Telang, F.

    2011-09-13

    Dopamine (DA) is considered crucial for the rewarding effects of drugs of abuse, but its role in addiction is much less clear. This review focuses on studies that used PET to characterize the brain DA system in addicted subjects. These studies have corroborated in humans the relevance of drug-induced fast DA increases in striatum [including nucleus accumbens (NAc)] in their rewarding effects but have unexpectedly shown that in addicted subjects, drug-induced DA increases (as well as their subjective reinforcing effects) are markedly blunted compared with controls. In contrast, addicted subjects show significant DA increases in striatum in response to drug-conditioned cues that are associated with self-reports of drug craving and appear to be of a greater magnitude than the DA responses to the drug. We postulate that the discrepancy between the expectation for the drug effects (conditioned responses) and the blunted pharmacological effects maintains drug taking in an attempt to achieve the expected reward. Also, whether tested during early or protracted withdrawal, addicted subjects show lower levels of D2 receptors in striatum (including NAc), which are associated with decreases in baseline activity in frontal brain regions implicated in salience attribution (orbitofrontal cortex) and inhibitory control (anterior cingulate gyrus), whose disruption results in compulsivity and impulsivity. These results point to an imbalance between dopaminergic circuits that underlie reward and conditioning and those that underlie executive function (emotional control and decision making), which we postulate contributes to the compulsive drug use and loss of control in addiction.

  14. Rewarding Community-Engaged Scholarship

    Science.gov (United States)

    Saltmarsh, John; Giles, Dwight E., Jr.; Ward, Elaine; Buglione, Suzanne M.

    2009-01-01

    Higher education leaders seeking to reshape institutional identity and establish community engagement as a core institutional value ultimately have to address how to embed the values of community engagement in the institutional reward policies that define the faculty roles of teaching, scholarship, and service. Furthermore, since the research…

  15. Food reward, hyperphagia, and obesity.

    Science.gov (United States)

    Berthoud, Hans-Rudolf; Lenard, Natalie R; Shin, Andrew C

    2011-06-01

    Given the unabated obesity problem, there is increasing appreciation of expressions like "my eyes are bigger than my stomach," and recent studies in rodents and humans suggest that dysregulated brain reward pathways may be contributing not only to drug addiction but also to increased intake of palatable foods and ultimately obesity. After describing recent progress in revealing the neural pathways and mechanisms underlying food reward and the attribution of incentive salience by internal state signals, we analyze the potentially circular relationship between palatable food intake, hyperphagia, and obesity. Are there preexisting individual differences in reward functions at an early age, and could they be responsible for development of obesity later in life? Does repeated exposure to palatable foods set off a cascade of sensitization as in drug and alcohol addiction? Are reward functions altered by secondary effects of the obese state, such as increased signaling through inflammatory, oxidative, and mitochondrial stress pathways? Answering these questions will significantly impact prevention and treatment of obesity and its ensuing comorbidities as well as eating disorders and drug and alcohol addiction.

  16. Addiction: beyond dopamine reward circuitry.

    Science.gov (United States)

    Volkow, Nora D; Wang, Gene-Jack; Fowler, Joanna S; Tomasi, Dardo; Telang, Frank

    2011-09-13

    Dopamine (DA) is considered crucial for the rewarding effects of drugs of abuse, but its role in addiction is much less clear. This review focuses on studies that used PET to characterize the brain DA system in addicted subjects. These studies have corroborated in humans the relevance of drug-induced fast DA increases in striatum [including nucleus accumbens (NAc)] in their rewarding effects but have unexpectedly shown that in addicted subjects, drug-induced DA increases (as well as their subjective reinforcing effects) are markedly blunted compared with controls. In contrast, addicted subjects show significant DA increases in striatum in response to drug-conditioned cues that are associated with self-reports of drug craving and appear to be of a greater magnitude than the DA responses to the drug. We postulate that the discrepancy between the expectation for the drug effects (conditioned responses) and the blunted pharmacological effects maintains drug taking in an attempt to achieve the expected reward. Also, whether tested during early or protracted withdrawal, addicted subjects show lower levels of D2 receptors in striatum (including NAc), which are associated with decreases in baseline activity in frontal brain regions implicated in salience attribution (orbitofrontal cortex) and inhibitory control (anterior cingulate gyrus), whose disruption results in compulsivity and impulsivity. These results point to an imbalance between dopaminergic circuits that underlie reward and conditioning and those that underlie executive function (emotional control and decision making), which we postulate contributes to the compulsive drug use and loss of control in addiction.

  17. Delay discounting as impaired valuation: Delayed rewards in an animal obesity model.

    Science.gov (United States)

    Jarmolowicz, David P; Hudnall, Jennifer L; Hale, Luanne; Fowler, Stephen C; Bortolato, Marco; Lemley, Shea M; Sofis, Michael J

    2017-09-01

    Obesity is a major public health problem, which, like many forms of addiction, is associated with an elevated tendency to choose smaller immediate rather than larger delayed rewards, a response pattern often referred to as excessive delay discounting. Although some accounts of delay discounting conceptualize this process as impulsivity (placing the emphasis on overvaluing the smaller immediate reward), others have conceptualized delay discounting as an executive function (placing the emphasis on delayed rewards failing to retain their value). The present experiments used a popular animal model of obesity that has been shown to discount delayed rewards at elevated rates (i.e., obese Zucker rats) to test two predictions that conceptualize delay discounting as executive function. In the first experiment, acquisition of lever pressing with delayed rewards was compared in obese versus lean Zucker rats. Contrary to predictions based on delay discounting as executive function, obese Zucker rats learned to press the lever more quickly than controls. In the second experiment, progressive ratio breakpoints (a measure of reward efficacy) with delayed rewards were compared in obese versus lean Zucker rats. Contrary to the notion that obese rats fail to value delayed rewards, the obese Zucker rats' breakpoints were (at least) as high as those of the lean Zucker rats. © 2017 Society for the Experimental Analysis of Behavior.

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

    Science.gov (United States)

    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.

  19. 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|info:eu-repo/dai/nl/304817740

    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

  20. 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

  1. Remembering with gains and losses: effects of monetary reward and punishment on successful encoding activation of source memories.

    Science.gov (United States)

    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.

  2. What can the monetary incentive delay task tell us about the neural processing of reward and punishment?

    Directory of Open Access Journals (Sweden)

    Lutz K

    2014-04-01

    Full Text Available Kai Lutz,1–3 Mario Widmer1,2,41Department of Neurology, University Hospital Zürich, Zürich, 2Cereneo, Center for Neurology and Rehabilitation, Vitznau, 3Division of Neuropsychology, Institute of Psychology, University of Zürich, Zürich, 4Neural Control of Movement Lab, ETH Zürich, Zürich, SwitzerlandAbstract: Since its introduction in 2000, the monetary incentive delay (MID task has been used extensively to investigate changes in neural activity in response to the processing of reward and punishment in healthy, but also in clinical populations. Typically, the MID task requires an individual to react to a target stimulus presented after an incentive cue to win or to avoid losing the indicated reward. In doing so, this paradigm allows the detailed examination of different stages of reward processing like reward prediction, anticipation, outcome processing, and consumption as well as the processing of tasks under different reward conditions. This review gives an overview of different utilizations of the MID task by outlining the neuronal processes involved in distinct aspects of human reward processing, such as anticipation versus consumption, reward versus punishment, and, with a special focus, reward-based learning processes. Furthermore, literature on specific influences on reward processing like behavioral, clinical and developmental influences, is reviewed, describing current findings and possible future directions.Keywords: reward, punishment, dopamine, reward system

  3. 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.

  4. Basolateral Amygdala to Orbitofrontal Cortex Projections Enable Cue-Triggered Reward Expectations.

    Science.gov (United States)

    Lichtenberg, Nina T; Pennington, Zachary T; Holley, Sandra M; Greenfield, Venuz Y; Cepeda, Carlos; Levine, Michael S; Wassum, Kate M

    2017-08-30

    required for expectations of specific available rewards to influence reward seeking and decision making. The necessity of these projections was limited to situations in which expectations were elicited by reward-predictive cues. These projections therefore facilitate adaptive behavior by enabling the orbitofrontal cortex to use environmental stimuli to generate expectations of potential future rewarding events. Copyright © 2017 the authors 0270-6474/17/378374-11$15.00/0.

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

    Science.gov (United States)

    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.

  6. Housing conditions affect rat responses to two types of ambiguity in a reward-reward discrimination cognitive bias task.

    Science.gov (United States)

    Parker, Richard M A; Paul, Elizabeth S; Burman, Oliver H P; Browne, William J; Mendl, Michael

    2014-11-01

    Decision-making under ambiguity in cognitive bias tasks is a promising new indicator of affective valence in animals. Rat studies support the hypothesis that animals in a negative affective state evaluate ambiguous cues negatively. Prior automated operant go/go judgement bias tasks have involved training rats that an auditory cue of one frequency predicts a Reward and a cue of a different frequency predicts a Punisher (RP task), and then measuring whether ambiguous cues of intermediate frequency are judged as predicting reward ('optimism') or punishment ('pessimism'). We investigated whether an automated Reward-Reward (RR) task yielded similar results to, and was faster to train than, RP tasks. We also introduced a new ambiguity test (simultaneous presentation of the two training cues) alongside the standard single ambiguous cue test. Half of the rats experienced an unpredictable housing treatment (UHT) designed to induce a negative state. Control rats were relatively 'pessimistic', whilst UHT rats were quicker, but no less accurate, in their responses in the RR test, and showed less anxiety-like behaviour in independent tests. A possible reason for these findings is that rats adapted to and were stimulated by UHT, whilst control rats in a predictable environment were more sensitive to novelty and change. Responses in the new ambiguity test correlated positively with those in single ambiguous cue tests, and may provide a measure of attention bias. The RR task was quicker to train than previous automated RP tasks. Together, they could be used to disentangle how reward and punishment processes underpin affect-induced cognitive biases. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

  7. Antisocial behavior, psychopathic features and abnormalities in reward and punishment processing in youth.

    Science.gov (United States)

    Byrd, Amy L; Loeber, Rolf; Pardini, Dustin A

    2014-06-01

    A better understanding of what leads youth to initially engage in antisocial behavior (ASB) and more importantly persist with such behaviors into adulthood has significant implications for prevention and intervention efforts. A considerable number of studies using behavioral and neuroimaging techniques have investigated abnormalities in reward and punishment processing as potential causal mechanisms underlying ASB. However, this literature has yet to be critically evaluated, and there are no comprehensive reviews that systematically examine and synthesize these findings. The goal of the present review is twofold. The first aim is to examine the extent to which youth with ASB are characterized by abnormalities in (1) reward processing; (2) punishment processing; or (3) both reward and punishment processing. The second aim is to evaluate whether aberrant reward and/or punishment processing is specific to or most pronounced in a subgroup of antisocial youth with psychopathic features. Studies utilizing behavioral methods are first reviewed, followed by studies using functional magnetic resonance imaging. An integration of theory and research across multiple levels of analysis is presented in order to provide a more comprehensive understanding of reward and punishment processing in antisocial youth. Findings are discussed in terms of developmental and contextual considerations, proposed future directions and implications for intervention.

  8. Rewards are not always bad for fun: Undermining the Undermining Effect Using Task-Congruent Rewards

    OpenAIRE

    Steiner, Susanne

    2013-01-01

    Currently, researchers on the undermining effect agree: Tangible rewards could harm intrinsic motivation. The aim of the present research was to search for tangible rewards that do not harm intrinsic motivation. Guided by ideas of a recent model on motivation, I tested the assumptions that task-congruent rewards do not undermine intrinsic motivation, while task-incongruent rewards do. Furthermore, task-congruent rewards should even enhance intrinsic motivation. Three experiments confirmed the...

  9. Emotional arousal predicts intertemporal choice.

    Science.gov (United States)

    Lempert, Karolina M; Johnson, Eli; Phelps, Elizabeth A

    2016-08-01

    People generally prefer immediate rewards to rewards received after a delay, often even when the delayed reward is larger. This phenomenon is known as temporal discounting. It has been suggested that preferences for immediate rewards may be due to their being more concrete than delayed rewards. This concreteness may evoke an enhanced emotional response. Indeed, manipulating the representation of a future reward to make it more concrete has been shown to heighten the reward's subjective emotional intensity, making people more likely to choose it. Here the authors use an objective measure of arousal-pupil dilation-to investigate if emotional arousal mediates the influence of delayed reward concreteness on choice. They recorded pupil dilation responses while participants made choices between immediate and delayed rewards. They manipulated concreteness through time interval framing: delayed rewards were presented either with the date on which they would be received (e.g., "$30, May 3"; DATE condition, more concrete) or in terms of delay to receipt (e.g., "$30, 7 days; DAYS condition, less concrete). Contrary to prior work, participants were not overall more patient in the DATE condition. However, there was individual variability in response to time framing, and this variability was predicted by differences in pupil dilation between conditions. Emotional arousal increased as the subjective value of delayed rewards increased, and predicted choice of the delayed reward on each trial. This study advances our understanding of the role of emotion in temporal discounting. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  10. Serotonergic modulation of reward and punishment

    DEFF Research Database (Denmark)

    Macoveanu, Julian

    2014-01-01

    of evidence on the key role serotonin plays in reward processing. The reviewed research has revealed how central serotonin availability and receptor specific transmission modulates the neural response to both appetitive (rewarding) and aversive (punishing) stimuli in putative reward-related brain regions....... Thus, serotonin is suggested to be involved in behavioral control when there is a prospect of reward or punishment. The new findings may have implications in understanding psychiatric disorders such as major depression which is characterized by abnormal serotonergic function and reward...

  11. Aberrant Radial Artery Causing Carpal Tunnel Syndrome

    Directory of Open Access Journals (Sweden)

    Zinon T. Kokkalis

    2016-07-01

    Full Text Available Anatomical vascular variations are rare causes of carpal tunnel syndrome. An aberrant medial artery is the most common vascular variation, while an aberrant radial artery causing carpal tunnel syndrome is even more rare, with an incidence ranging less than 3%. This article reports a patient with compression of the median nerve at the carpal tunnel by an aberrant superficial branch of the radial artery. An 80- year- old man presented with a 5-year history of right hand carpal tunnel syndrome; Tinel sign, Phalen test and neurophysiological studies were positive. Open carpal tunnel release showed an aberrant superficial branch of the radial artery with its accompanying veins running from radially to medially, almost parallel to the median nerve, ending at the superficial palmar arterial arch. The median nerve was decompressed without ligating the aberrant artery. At the last follow-up, 2 years after diagnosis and treatment the patient is asymptomatic.

  12. Aberrant Radial Artery Causing Carpal Tunnel Syndrome.

    Science.gov (United States)

    Kokkalis, Zinon T; Tolis, Konstantinos E; Megaloikonomos, Panayiotis D; Panagopoulos, Georgios N; Igoumenou, Vasilios G; Mavrogenis, Andreas F

    2016-06-01

    Anatomical vascular variations are rare causes of carpal tunnel syndrome. An aberrant medial artery is the most common vascular variation, while an aberrant radial artery causing carpal tunnel syndrome is even more rare, with an incidence ranging less than 3%. This article reports a patient with compression of the median nerve at the carpal tunnel by an aberrant superficial branch of the radial artery. An 80- year- old man presented with a 5-year history of right hand carpal tunnel syndrome; Tinel sign, Phalen test and neurophysiological studies were positive. Open carpal tunnel release showed an aberrant superficial branch of the radial artery with its accompanying veins running from radially to medially, almost parallel to the median nerve, ending at the superficial palmar arterial arch. The median nerve was decompressed without ligating the aberrant artery. At the last follow-up, 2 years after diagnosis and treatment the patient is asymptomatic.

  13. Conjunctive encoding of movement and reward by ventral tegmental area neurons in the freely navigating rodent

    Science.gov (United States)

    Puryear, Corey B.; Kim, Min Jung; Mizumori, Sheri J.Y.

    2010-01-01

    As one of the two main sources of brain dopamine, the ventral tegmental area (VTA) is important for several complex functions, including motivation, reward prediction, and contextual learning. Although many studies have identified the potential neural substrate of VTA dopaminergic activity in reward prediction functions during Pavlovian and operant conditioning tasks, less is understood about the role of VTA neuronal activity in motivated behaviors and more naturalistic forms of context-dependent learning. Therefore, VTA neural activity was recorded as rats performed a spatial memory task under varying context conditions. In addition to reward- and reward predicting cue-related firing commonly observed during conditioning tasks, the activity of a large proportion of VTA neurons was also related to the velocity and/or acceleration of the animal’s movement. Importantly, movement-related activity was strongest when rats displayed more motivation to obtain reward. Furthermore, many cells displayed a dual code of movement- and reward-related activity. These two modes of firing, however, were differentially regulated by context information, suggesting that movement- and reward-related firing are two independently regulated modes of VTA neuronal activity and may serve separate functions. PMID:20364883

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

    Science.gov (United States)

    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

  15. An Upside to Reward Sensitivity: The Hippocampus Supports Enhanced Reinforcement Learning in Adolescence.

    Science.gov (United States)

    Davidow, Juliet Y; Foerde, Karin; Galván, Adriana; Shohamy, Daphna

    2016-10-05

    Adolescents are notorious for engaging in reward-seeking behaviors, a tendency attributed to heightened activity in the brain's reward systems during adolescence. It has been suggested that reward sensitivity in adolescence might be adaptive, but evidence of an adaptive role has been scarce. Using a probabilistic reinforcement learning task combined with reinforcement learning models and fMRI, we found that adolescents showed better reinforcement learning and a stronger link between reinforcement learning and episodic memory for rewarding outcomes. This behavioral benefit was related to heightened prediction error-related BOLD activity in the hippocampus and to stronger functional connectivity between the hippocampus and the striatum at the time of reinforcement. These findings reveal an important role for the hippocampus in reinforcement learning in adolescence and suggest that reward sensitivity in adolescence is related to adaptive differences in how adolescents learn from experience. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Ventral pallidum roles in reward and motivation.

    Science.gov (United States)

    Smith, Kyle S; Tindell, Amy J; Aldridge, J Wayne; Berridge, Kent C

    2009-01-23

    In recent years the ventral pallidum has become a focus of great research interest as a mechanism of reward and incentive motivation. As a major output for limbic signals, the ventral pallidum was once associated primarily with motor functions rather than regarded as a reward structure in its own right. However, ample evidence now suggests that ventral pallidum function is a major mechanism of reward in the brain. We review data indicating that (1) an intact ventral pallidum is necessary for normal reward and motivation, (2) stimulated activation of ventral pallidum is sufficient to cause reward and motivation enhancements, and (3) activation patterns in ventral pallidum neurons specifically encode reward and motivation signals via phasic bursts of excitation to incentive and hedonic stimuli. We conclude that the ventral pallidum may serve as an important 'limbic final common pathway' for mesocorticolimbic processing of many rewards.

  17. Reward alters the perception of time.

    Science.gov (United States)

    Failing, Michel; Theeuwes, Jan

    2016-03-01

    Recent findings indicate that monetary rewards have a powerful effect on cognitive performance. In order to maximize overall gain, the prospect of earning reward biases visual attention to specific locations or stimulus features improving perceptual sensitivity and processing. The question we addressed in this study is whether the prospect of reward also affects the subjective perception of time. Here, participants performed a prospective timing task using temporal oddballs. The results show that temporal oddballs, displayed for varying durations, presented in a sequence of standard stimuli were perceived to last longer when they signaled a relatively high reward compared to when they signaled no or low reward. When instead of the oddball the standards signaled reward, the perception of the temporal oddball remained unaffected. We argue that by signaling reward, a stimulus becomes subjectively more salient thereby modulating its attentional deployment and distorting how it is perceived in time. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Adolescent development of the reward system

    Directory of Open Access Journals (Sweden)

    Adriana Galván

    2010-02-01

    Full Text Available Adolescence is a developmental period characterized by increased reward-seeking behavior. Investigators have used functional magnetic resonance imaging (fMRI in conjunction with reward paradigms to test two opposing hypotheses about adolescent developmental changes in the striatum, a region implicated in reward processing. One hypothesis posits that the striatum is relatively hypo-responsive to rewards during adolescence, such that heightened reward-seeking behavior is necessary to achieve the same activation as adults. Another view suggests that during adolescence the striatal reward system is hyper-responsive, which subsequently results in greater reward-seeking. While evidence for both hypotheses has been reported, the field has generally converged on this latter hypothesis based on compelling evidence. In this review, I describe the evidence to support this notion, speculate on the disparate fMRI findings and conclude with future areas of inquiry to this fascinating question.

  19. The effect of probability discounting on reward seeking: a three-dimensional perspective

    Directory of Open Access Journals (Sweden)

    Yannick-Andre eBreton

    2014-08-01

    Full Text Available Rats will work for electrical stimulation pulses of the medial forebrain bundle. The rewarding effect arises from the volleys of action potentials fired by the stimulation and subsequent spatio-temporal integration of their post-synpatic impact. The proportion of time allocated to self-stimulation depends on the intensity of the rewarding effect as well as on other key determinants of decision-making, such as subjective opportunity costs and reward probability. We have proposed that a 3D model relating time allocation to the intensity and cost of reward can distinguish manipulations acting prior to the output of the spatio-temporal integrator from those acting at or beyond it. Here, we test this proposition by varying reward probability, a variable that influences the computation of payoff in the 3D model downstream from the output of the integrator. On riskless trials, reward was delivered on every occasion that the rat held down the lever for a cumulative duration called the ``price,'' whereas on risky trials, reward was delivered with probability 0.75 or 0.50. According to the model, the 3D structure relating time allocation to reward intensity and price is shifted leftward along the price axis by reductions in reward probability; the magnitude of the shift estimates the change in subjective probability. The predictions were borne out: reducing reward probability shifted the 3D structure systematically along the price axis while producing only small, inconsistent displacements along the pulse-frequency axis. The results confirm that the model can accurately distinguish manipulations acting at or beyond the spatio-temporal integrator and strengthen the conclusions of previous studies showing similar shifts following dopaminergic manipulations. Subjective and objective reward probabilities appeared indistinguishable over the range of 0.5 <= p <= 1.0.

  20. Reward, Addiction, Withdrawal to Nicotine

    Science.gov (United States)

    De Biasi, Mariella; Dani, John A.

    2011-01-01

    Nicotine is the principle addictive component that drives continued tobacco use despite users’ knowledge of the harmful consequences. The initiation of addiction involves the mesocorticolimbic dopamine system, which contributes to the processing of rewarding sensory stimuli during the overall shaping of successful behaviors. Acting mainly through nicotinic receptors containing the α4 and β2 subunits, often in combination with the α6 subunit, nicotine increases the firing rate and the phasic bursts by midbrain dopamine neurons. Neuroadaptations arise during chronic exposure to nicotine, producing an altered brain condition that requires the continued presence of nicotine to be maintained. When nicotine is removed, a withdrawal syndrome develops. The expression of somatic withdrawal symptoms depends mainly on the α5, α2, and β4 nicotinic subunits involving the epithalamic habenular complex and its targets. Thus, nicotine taps into diverse neural systems and an array of nicotinic acetylcholine receptor (nAChR) subtypes to influence reward, addiction, and withdrawal. PMID:21438686

  1. Ocular Chromatic Aberrations and Their Effects on Polychromatic Retinal Image Quality

    Science.gov (United States)

    Zhang, Xiaoxiao

    Previous studies of ocular chromatic aberrations have concentrated on chromatic difference of focus (CDF). Less is known about the chromatic difference of image position (CDP) in the peripheral retina and no experimental attempt has been made to measure the ocular chromatic difference of magnification (CDM). Consequently, theoretical modelling of human eyes is incomplete. The insufficient knowledge of ocular chromatic aberrations is partially responsible for two unsolved applied vision problems: (1) how to improve vision by correcting ocular chromatic aberration? (2) what is the impact of ocular chromatic aberration on the use of isoluminance gratings as a tool in spatial-color vision?. Using optical ray tracing methods, MTF analysis methods of image quality, and psychophysical methods, I have developed a more complete model of ocular chromatic aberrations and their effects on vision. The ocular CDM was determined psychophysically by measuring the tilt in the apparent frontal parallel plane (AFPP) induced by interocular difference in image wavelength. This experimental result was then used to verify a theoretical relationship between the ocular CDM, the ocular CDF and the entrance pupil of the eye. In the retinal image after correcting the ocular CDF with existing achromatizing methods, two forms of chromatic aberration (CDM and chromatic parallax) were examined. The CDM was predicted by theoretical ray tracing and measured with the same method used to determine ocular CDM. The chromatic parallax was predicted with a nodal ray model and measured with the two-color vernier alignment method. The influence of these two aberrations on polychromatic MTF were calculated. Using this improved model of ocular chromatic aberration, luminance artifacts in the images of isoluminance gratings were calculated. The predicted luminance artifacts were then compared with experimental data from previous investigators. The results show that: (1) A simple relationship exists between

  2. [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

  3. NEURAL REACTIVITY TO REWARD AS A PREDICTOR OF COGNITIVE BEHAVIORAL THERAPY RESPONSE IN ANXIETY AND DEPRESSION.

    Science.gov (United States)

    Burkhouse, Katie L; Kujawa, Autumn; Kennedy, Amy E; Shankman, Stewart A; Langenecker, Scott A; Phan, K Luan; Klumpp, Heide

    2016-04-01

    Cognitive behavioral therapy (CBT) is a well-established treatment for anxiety and depression; however, response to CBT is heterogeneous across patients and many remain symptomatic after therapy, raising the need to identify prospective predictors for treatment planning. Altered neural processing of reward has been implicated in both depression and anxiety, and improving hedonic capacity is a goal of CBT. However, little is known about how neural response to reward relates to CBT outcomes in depression and anxiety. The current study used the reward positivity (RewP) event-related potential (ERP) component to examine whether neural reactivity to reward would predict CBT response in a sample of patients with anxiety without depression (n = 30) and comorbid anxiety and depression (CAD, n = 22). Participants completed a guessing reward ERP paradigm before completing 12 weeks of standard CBT. The majority of the sample (68%; 35 out of 52 patients) responded to treatment, and those with a reduced RewP at baseline were more likely to respond to treatment. A reduced RewP was also associated with a greater pre-to-post CBT reduction in depressive symptoms among individuals with CAD, but not among individuals with pure anxiety. CBT may be most beneficial in reducing depressive symptoms for individuals who demonstrate decreased reward reactivity prior to treatment. CBT may target reward brain function, leading to greater improvement in symptoms. These effects may be strongest, and therefore most meaningful, for individuals with reward-processing deficits prior to treatment. © 2016 Wiley Periodicals, Inc.

  4. Sharing a context with other rewarding events increases the probability that neutral events will be recollected

    Directory of Open Access Journals (Sweden)

    Eleanor eLoh

    2016-01-01

    Full Text Available Although reward is known to enhance memory for reward-predicting events, the extent to which such memory effects spread to associated (neutral events is unclear. Using a between-subject design, we examined how sharing a background context with rewarding events influenced memory for motivationally neutral events (tested after a five day delay. We found that sharing a visually rich context with rewarding objects during encoding increased the probability that neutral objects would be successfully recollected during memory test, as opposed to merely being recognized without any recall of associative detail. In contrast, such an effect was not seen when the context was not explicitly demarcated and objects were presented against a blank black background. These qualitative changes in memory were observed in the absence of any effects on overall recognition (as measured by d’. Additionally, a follow-up study failed to find any evidence to suggest that the mere presence of a context picture in the background during encoding (i.e. without the reward manipulation produced any such qualitative changes in memory. These results suggest that reward enhances recollection for rewarding objects as well as other non-rewarding events that are representationally linked to the same context.

  5. 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.

  6. Chromosome aberration assays in Allium

    Energy Technology Data Exchange (ETDEWEB)

    Grant, W.F.

    1982-01-01

    The common onion (Allium cepa) is an excellent plant for the assay of chromosome aberrations after chemical treatment. Other species of Allium (A. cepa var. proliferum, A. carinatum, A. fistulosum and A. sativum) have also been used but to a much lesser extent. Protocols have been given for using root tips from either bulbs or seeds of Allium cepa to study the cytological end-points, such as chromosome breaks and exchanges, which follow the testing of chemicals in somatic cells. It is considered that both mitotic and meiotic end-points should be used to a greater extent in assaying the cytogenetic effects of a chemical. From a literature survey, 148 chemicals are tabulated that have been assayed in 164 Allium tests for their clastogenic effect. Of the 164 assays which have been carried out, 75 are reported as giving a positive reaction, 49 positive and with a dose response, 1 positive and temperature-related, 9 borderline positive, and 30 negative; 76% of the chemicals gave a definite positive response. It is proposed that the Allium test be included among those tests routinely used for assessing chromosomal damage induced by chemicals.

  7. Impact of astigmatism and high-order aberrations on subjective best focus.

    Science.gov (United States)

    Marcos, Susana; Velasco-Ocana, Miriam; Dorronsoro, Carlos; Sawides, Lucie; Hernandez, Martha; Marin, Gildas

    2015-08-01

    We studied the role of native astigmatism and ocular aberrations on best-focus setting and its shift upon induction of astigmatism in 42 subjects (emmetropes, myopes, hyperopes, with-the-rule [WTR] and against-the-rule [ATR] myopic astigmats). Stimuli were presented in a custom-developed adaptive optics simulator, allowing correction for native aberrations and astigmatism induction (+1 D; 6-mm pupil). Best-focus search consisted on randomized-step interleaved staircase method. Each subject searched best focus for four different images, and four different conditions (with/without aberration correction, with/without astigmatism induction). The presence of aberrations induced a significant shift in subjective best focus (0.4 D; p < 0.01), significantly correlated (p = 0.005) with the best-focus shift predicted from optical simulations. The induction of astigmatism produced a statistically significant shift of the best-focus setting in all groups under natural aberrations (p = 0.001), and in emmetropes and in WTR astigmats under corrected aberrations (p < 0.0001). Best-focus shift upon induced astigmatism was significantly different across groups, both for natural aberrations and AO-correction (p < 0.0001). Best focus shifted in opposite directions in WTR and ATR astigmats upon induction of astigmatism, symmetrically with respect to the best-focus shift in nonastigmatic myopes. The shifts are consistent with a bias towards vertical and horizontal retinal blur in WTR and ATR astigmats, respectively, indicating adaptation to native astigmatism.

  8. Are optical aberrations during accommodation a significant problem for refractive surgery?

    Science.gov (United States)

    Artal, Pablo; Fernández, Enrique J; Manzanera, Silvestre

    2002-01-01

    To study the limits to a perfect ideal customized wavefront correction due to the change of aberrations during accommodation. METHODS. We measured the dynamic changes of ocular aberrations during accommodation in normal eyes with a real-time Hartmann-Shack wavefront sensor. Those results were used in computer simulations to predict the benefit of a perfect customized correction. Due to the continuous changes of the aberrations over time, an ideal perfect static correction will not provide stable aberration-free optics. For example, when the eye accommodates to near objects, due to the changing aberrations, the eye will become aberrated again. An alternative correction using the aberration pattern for a slightly accommodated condition could provide a better-correction in a larger accommodative range, although at the cost of non-perfect correction for far vision. Due to the dynamic nature of ocular optics, a static perfect correction, for instance performed in customized refractive surgery, would not remain perfect for every condition occurring during normal accommodation.

  9. Neural and personality correlates of individual differences related to the effects of acute tryptophan depletion on future reward evaluation.

    Science.gov (United States)

    Demoto, Yoshihiko; Okada, Go; Okamoto, Yasumasa; Kunisato, Yoshihiko; Aoyama, Shiori; Onoda, Keiichi; Munakata, Ayumi; Nomura, Michio; Tanaka, Saori C; Schweighofer, Nicolas; Doya, Kenji; Yamawaki, Shigeto

    2012-01-01

    In general, humans tend to discount the value of delayed reward. An increase in the rate of discounting leads to an inability to select a delayed reward over a smaller immediate reward (reward-delay impulsivity). Although deficits in the serotonergic system are implicated in this reward-delay impulsivity, there is individual variation in response to serotonin depletion. The aim of the present study was to investigate whether the effects of serotonin depletion on the ability to evaluate future reward are affected by individual personality traits or brain activation. Personality traits were assessed using the NEO-Five Factor Inventory and Temperament and Character Inventory. The central serotonergic levels of 16 healthy volunteers were manipulated by dietary tryptophan depletion. Subjects performed a delayed reward choice task that required the continuous estimation of reward value during functional magnetic resonance imaging scanning. Discounting rates were increased in 9 participants, but were unchanged or decreased in 7 participants in response to tryptophan depletion. Participants whose discounting rate was increased by tryptophan depletion had significantly higher neuroticism and lower self-directedness. Furthermore, tryptophan depletion differentially affected the groups in terms of hemodynamic responses to the value of predicted future reward in the right insula. These results suggest that individuals who have high neuroticism and low self-directedness as personality traits are particularly vulnerable to the effect of low serotonin on future reward evaluation accompanied by altered brain activation patterns. Copyright © 2012 S. Karger AG, Basel.

  10. The roles of the reward system in sleep and dreaming.

    Science.gov (United States)

    Perogamvros, Lampros; Schwartz, Sophie

    2012-09-01

    The mesolimbic dopaminergic system (ML-DA) allows adapted interactions with the environment and is therefore of critical significance for the individual's survival. The ML-DA system is implicated in reward and emotional functions, and it is perturbed in schizophrenia, addiction, and depression. The ML-DA reward system is not only recruited during wakeful behaviors, it is also active during sleep. Here, we introduce the Reward Activation Model (RAM) for sleep and dreaming, according to which activation of the ML-DA reward system during sleep contributes to memory processes, to the regulation of rapid-eye movement (REM) sleep, and to the generation and motivational content of dreams. In particular, the engagement of ML-DA and associated limbic structures prioritizes information with high emotional or motivational relevance for (re)processing during sleep and dreaming. The RAM provides testable predictions and has clinical implications for our understanding of the pathogenesis of major depression and addiction. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Homeostatic reinforcement learning for integrating reward collection and physiological stability

    Science.gov (United States)

    Keramati, Mehdi; Gutkin, Boris

    2014-01-01

    Efficient regulation of internal homeostasis and defending it against perturbations requires adaptive behavioral strategies. However, the computational principles mediating the interaction between homeostatic and associative learning processes remain undefined. Here we use a definition of primary rewards, as outcomes fulfilling physiological needs, to build a normative theory showing how learning motivated behaviors may be modulated by internal states. Within this framework, we mathematically prove that seeking rewards is equivalent to the fundamental objective of physiological stability, defining the notion of physiological rationality of behavior. We further suggest a formal basis for temporal discounting of rewards by showing that discounting motivates animals to follow the shortest path in the space of physiological variables toward the desired setpoint. We also explain how animals learn to act predictively to preclude prospective homeostatic challenges, and several other behavioral patterns. Finally, we suggest a computational role for interaction between hypothalamus and the brain reward system. DOI: http://dx.doi.org/10.7554/eLife.04811.001 PMID:25457346

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

    Science.gov (United States)

    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

  13. On being attracted to the possibility of a win: reward sensitivity (via gambling motives) undermines treatment seeking among pathological gamblers.

    Science.gov (United States)

    Sztainert, Travis; Wohl, Michael J A; McManus, Justin F; Stead, John D H

    2014-12-01

    Unfortunately, only a small percent of pathological gamblers seek the professional help they need. In the current study, we test the idea that individual differences in reward sensitivity should predict whether a pathological gambler has sought treatment-the odds of treatment seeking should decrease as reward sensitivity increases. This hypothesis rests on the proposition that reward sensitive pathological gamblers should find treatment seeking aversive because doing so would remove a route to reward. We also tested those motivations to gamble that are positively reinforcing (social affliction and self-enhancement) as a possible mechanism by which reward sensitivity undermines treatment seeking-we did not anticipate negatively reinforcing motivations (e.g., coping) to be a mechanistic variable. Ninety-two pathological gamblers completed a large-scale survey that contained the variables of interest. As predicted, pathological gamblers were less likely to have sought treatment as reward sensitivity increased. Moreover, this relationship was mediated by social affiliation motivations to gamble, but not self-enhancement or coping motives. Reward sensitive gamblers did not wish to seek treatment to the extent that they were motivated to gamble for the social interactions it provides-seeking treatment would cut this avenue of affiliation with others. In light of these results, we suggest health care professionals take reward sensitivity into account when trying to promote treatment seeking, to say nothing of the social affiliation motives that underlie the reward sensitivity-treatment seeking link.

  14. Aberrations in square pore micro-channel optics used for x-ray lobster eye telescopes

    Science.gov (United States)

    Willingale, R.; Pearson, J. F.; Martindale, A.; Feldman, C. H.; Fairbend, R.; Schyns, E.; Petit, S.; Osborne, J. P.; O'Brien, P. T.

    2016-07-01

    We identify all the significant aberrations that limit the performance of square pore micro-channel plate optics (MPOs) used as an X-ray lobster eye. These include aberrations intrinsic to the geometry, intrinsic errors associated with the slumping process used to introduce a spherical form to the plates and imperfections associated with the plate manufacturing process. The aberrations are incorporated into a comprehensive software model of the X-ray response of the optics and the predicted imaging response is compared with the measured X-ray performance obtained from a breadboard lobster eye. The results reveal the manufacturing tolerances which limit the current performance of MPOs and enable us to identify particular intrinsic aberrations which will limit the ultimate performance we can expect from MPO-lobster eye telescopes.

  15. Chromosomal aberrations in uranium and coal miners

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, G.; Arndt, D.; Kotschy-Lang, N.; Obe, G. [Robert Koch Inst., Berlin (Germany)

    2004-02-01

    Peripheral lymphocytes from 66 Wismut uranium miners (WUM) and 29 Ruhr coal miners (RGM) were cultured and analysed for structural chromosomal aberrations in Giemsa-stained M1 metaphases. Cytogenetic data from 23 male white-collar workers from public services were used as a historical control group. The frequencies of chromosomal aberrations and sister chromatid exchanges in WUM and RCM were quite similar. Compared with public services workers, WUM and RCM had significantly higher frequencies of chromosomal aberrations. It is concluded that chromosomal aberrations in WUM are not induced by radioactive particles inhaled during underground mining but as in RCM rather result from factors such as age, lifestyle, illnesses, medications and diagnostic irradiations.

  16. Aberration corrected Lorentz scanning transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    McVitie, S., E-mail: stephen.mcvitie@glasgow.ac.uk; McGrouther, D.; McFadzean, S.; MacLaren, D.A.; O’Shea, K.J.; Benitez, M.J.

    2015-05-15

    We present results from an aberration corrected scanning transmission electron microscope which has been customised for high resolution quantitative Lorentz microscopy with the sample located in a magnetic field free or low field environment. We discuss the innovations in microscope instrumentation and additional hardware that underpin the imaging improvements in resolution and detection with a focus on developments in differential phase contrast microscopy. Examples from materials possessing nanometre scale variations in magnetisation illustrate the potential for aberration corrected Lorentz imaging as a tool to further our understanding of magnetism on this lengthscale. - Highlights: • Demonstration of nanometre scale resolution in magnetic field free environment using aberration correction in the scanning transmission electron microscope (STEM). • Implementation of differential phase contrast mode of Lorentz microscopy in aberration corrected STEM with improved sensitivity. • Quantitative imaging of magnetic induction of nanostructures in amorphous and cross-section samples.

  17. Epigenetic aberrations in myeloid malignancies (Review).

    Science.gov (United States)

    Takahashi, Shinichiro

    2013-09-01

    The development of novel technologies, such as massively parallel DNA sequencing, has led to the identification of several novel recurrent gene mutations, such as DNA methyltransferase (Dnmt)3a, ten-eleven-translocation oncogene family member 2 (TET2), isocitrate dehydrogenase (IDH)1/2, additional sex comb-like 1 (ASXL1), enhancer of zeste homolog 2 (EZH2) and ubiquitously transcribed tetratricopeptide repeat X chromosome (UTX) mutations in acute myeloid leukemia (AML) and other myeloid malignancies. These findings strongly suggest a link between recurrent genetic alterations and aberrant epigenetic regulations, resulting from an abnormal DNA methylation and histone modification status. This review focuses on the current findings of aberrant epigenetic signatures by these newly described genetic alterations. Moreover, epigenetic aberrations resulting from transcription factor aberrations, such as mixed lineage leukemia (MLL) rearrangement, ecotropic viral integration site 1 (Evi1) overexpression, chromosomal translocations and the downregulation of PU.1 are also described.

  18. Linking reward processing to behavioral output: motor and motivational integration in the primate subthalamic nucleus

    Directory of Open Access Journals (Sweden)

    Juan-Francisco eEspinosa-Parrilla

    2013-12-01

    Full Text Available The expectation and detection of motivationally relevant events is a major determinant of goal-directed behavior and there is a strong interest in the contribution of basal ganglia in the integration of motivational processes into behavioral output. Recent research has focused on the role of the subthalamic nucleus (STN in the motivational control of action, but it remains to be determined how information about reward is encoded in this nucleus. We recorded the activity of single neurons in the STN of two behaving monkeys to examine whether activity was influenced by the delivery of reward in an instrumental task, a Pavlovian stimulus-reward association, or outside of a task context. We confirmed preliminary findings indicating that STN neurons were sensitive not only to rewards obtained during task performance, but also to the expectation of reward when its delivery was delayed in time. Most of the modulations at the onset of reaching movement were combined with modulations following reward delivery, suggesting the convergence of signals related to the animal’s movement and its outcome in the same neurons. Some neurons were also influenced by the visuomotor contingencies of the task, i.e., target location and/or movement direction. In addition, modulations were observed under conditions where reward delivery was not contingent on an instrumental response, even in the absence of a reward predictive cue. Taken as a whole, these results demonstrate a potential contribution of the STN to motivational control of behavior in the non-human primate, although problems in distinguishing neuronal signals related to reward from those related to motor behavior should be considered. Characterizing the specificity of reward processing in the STN remains challenging and could have important implications for understanding the influence of this key component of basal ganglia circuitry on emotional and motivated behaviors under normal and pathological

  19. The rewarding nature of social interactions

    Directory of Open Access Journals (Sweden)

    Sören Krach

    2010-05-01

    Full Text Available The objective of this short review is to highlight rewarding aspects of social interactions for humans and discuss their neural basis. Thereby we report recent research findings to illustrate how social stimuli in general are processed in the reward system and highlight the role of Theory of Mind (ToM as one mediating process for experiencing social reward during social interactions. In conclusion we discuss clinical implications for psychiatry and psychotherapy.

  20. Reward disrupts reactivated human skill memory

    OpenAIRE

    Eran Dayan; Rony Laor-Maayany; Nitzan Censor

    2016-01-01

    Accumulating evidence across species and memory domains shows that when an existing memory is reactivated, it becomes susceptible to modifications. However, the potential role of reward signals in these mechanisms underlying human memory dynamics is unknown. Leaning on a wealth of findings on the role of reward in reinforcing memory, we tested the impact of reinforcing a skill memory trace with monetary reward following memory reactivation, on strengthening of the memory trace. Reinforcing re...

  1. Willing to Wait: Elevated Reward-Processing EEG Activity Associated with a Greater Preference for Larger-But-Delayed Rewards

    OpenAIRE

    Pornpattananangkul, Narun; Nusslock, Robin

    2016-01-01

    While almost everyone discounts the value of future rewards over immediate rewards, people differ in their so-called delay-discounting. One of the several factors that may explain individual differences in delay-discounting is reward-processing. To study individual-differences in reward-processing, however, one needs to consider the heterogeneity of neural-activity at each reward-processing stage. Here using EEG, we separated reward-related neural activity into distinct reward-anticipation an...

  2. Diminished choice effect on anticipating improbable rewards.

    Science.gov (United States)

    Chen, Weiran; Li, Qi; Mei, Shuting; Yi, Wei; Yang, Guochun; Zhou, Shiyu; Liu, Xun; Zheng, Ya

    2018-02-01

    Previous research found that the neural substrates underlying perceived control highly overlap those of reward system, especially during reward anticipation stage. The current event-related potential study examined whether the experience of choice by which individuals exercise control is modulated by reward probability during reward anticipation stage as indexed by the stimulus-preceding negativity (SPN). Thirty participants performed a cued gambling task during which choices could be made either by themselves (a choice condition) or by a computer (a no-choice condition) with three levels of reward probability (low, medium, and high) while their EEG was recording. As expected, the participants perceived higher control during the choice compared to no-choice condition. Correspondingly, the SPN was enhanced in the choice condition than the no-choice condition. Critically, the SPN choice effect was present when reward probability was high and medium, but was diminished when reward probability was low. These findings suggest that the perceived control as exercised by choice is associated with reward anticipation, which may be sensitive to the fundamental properties of reward. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Neural processing of reward in adolescent rodents

    Directory of Open Access Journals (Sweden)

    Nicholas W. Simon

    2015-02-01

    Full Text Available Immaturities in adolescent reward processing are thought to contribute to poor decision making and increased susceptibility to develop addictive and psychiatric disorders. Very little is known; however, about how the adolescent brain processes reward. The current mechanistic theories of reward processing are derived from adult models. Here we review recent research focused on understanding of how the adolescent brain responds to rewards and reward-associated events. A critical aspect of this work is that age-related differences are evident in neuronal processing of reward-related events across multiple brain regions even when adolescent rats demonstrate behavior similar to adults. These include differences in reward processing between adolescent and adult rats in orbitofrontal cortex and dorsal striatum. Surprisingly, minimal age related differences are observed in ventral striatum, which has been a focal point of developmental studies. We go on to discuss the implications of these differences for behavioral traits affected in adolescence, such as impulsivity, risk-taking, and behavioral flexibility. Collectively, this work suggests that reward-evoked neural activity differs as a function of age and that regions such as the dorsal striatum that are not traditionally associated with affective processing in adults may be critical for reward processing and psychiatric vulnerability in adolescents.

  4. Hedging Your Bets by Learning Reward Correlations in the Human Brain

    OpenAIRE

    Wunderlich, K.; Symmonds, M.; Bossaerts, P.; Dolan, R.J.

    2011-01-01

    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 outco...

  5. Hedging Your Bets by Learning Reward Correlations in the Human Brain

    OpenAIRE

    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 associat...

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

    OpenAIRE

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

    2015-01-01

    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 ven...

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

    OpenAIRE

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

    2015-01-01

    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 v...

  8. Rewarding Honest Taxpayers? Evidence on the Impact of Rewards from Field Experiments

    OpenAIRE

    Feld, Lars P.; Frey, Bruno S; Benno Torgler

    2006-01-01

    This paper analyzes the impact of rewards on tax compliance as an additional instrument to take into account. While social psychologists and neuroscientists have emphasized the importance of rewards, the tax compliance literature has strongly disregarded the possibilities of rewards. The use of field experiments presents an alternative ?carrot? strategy for tax policy. Design mechanisms to conduct a field experiments focusing on the impact of rewards on tax compliance are discussed.

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

    Science.gov (United States)

    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.

  10. Pulse compressor with aberration correction

    Energy Technology Data Exchange (ETDEWEB)

    Mankos, Marian [Electron Optica, Inc., Palo Alto, CA (United States)

    2015-11-30

    In this SBIR project, Electron Optica, Inc. (EOI) is developing an electron mirror-based pulse compressor attachment to new and retrofitted dynamic transmission electron microscopes (DTEMs) and ultrafast electron diffraction (UED) cameras for improving the temporal resolution of these instruments from the characteristic range of a few picoseconds to a few nanoseconds and beyond, into the sub-100 femtosecond range. The improvement will enable electron microscopes and diffraction cameras to better resolve the dynamics of reactions in the areas of solid state physics, chemistry, and biology. EOI’s pulse compressor technology utilizes the combination of electron mirror optics and a magnetic beam separator to compress the electron pulse. The design exploits the symmetry inherent in reversing the electron trajectory in the mirror in order to compress the temporally broadened beam. This system also simultaneously corrects the chromatic and spherical aberration of the objective lens for improved spatial resolution. This correction will be found valuable as the source size is reduced with laser-triggered point source emitters. With such emitters, it might be possible to significantly reduce the illuminated area and carry out ultrafast diffraction experiments from small regions of the sample, e.g. from individual grains or nanoparticles. During phase I, EOI drafted a set of candidate pulse compressor architectures and evaluated the trade-offs between temporal resolution and electron bunch size to achieve the optimum design for two particular applications with market potential: increasing the temporal and spatial resolution of UEDs, and increasing the temporal and spatial resolution of DTEMs. Specialized software packages that have been developed by MEBS, Ltd. were used to calculate the electron optical properties of the key pulse compressor components: namely, the magnetic prism, the electron mirror, and the electron lenses. In the final step, these results were folded

  11. 21 CFR 203.70 - Application for a reward.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Application for a reward. 203.70 Section 203.70...: GENERAL PRESCRIPTION DRUG MARKETING Rewards § 203.70 Application for a reward. (a) Reward for providing... not more than $125,000. (b) Procedure for making application for a reward for providing information...

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

    Science.gov (United States)

    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.

  13. Reward and non-reward learning of flower colours in the butterfly Byasa alcinous (Lepidoptera: Papilionidae)

    Science.gov (United States)

    Kandori, Ikuo; Yamaki, Takafumi

    2012-09-01

    Learning plays an important role in food acquisition for a wide range of insects. To increase their foraging efficiency, flower-visiting insects may learn to associate floral cues with the presence (so-called reward learning) or the absence (so-called non-reward learning) of a reward. Reward learning whilst foraging for flowers has been demonstrated in many insect taxa, whilst non-reward learning in flower-visiting insects has been demonstrated only in honeybees, bumblebees and hawkmoths. This study examined both reward and non-reward learning abilities in the butterfly Byasa alcinous whilst foraging among artificial flowers of different colours. This butterfly showed both types of learning, although butterflies of both sexes learned faster via reward learning. In addition, females learned via reward learning faster than males. To the best of our knowledge, these are the first empirical data on the learning speed of both reward and non-reward learning in insects. We discuss the adaptive significance of a lower learning speed for non-reward learning when foraging on flowers.

  14. Study of ocular aberrations with age.

    Science.gov (United States)

    Athaide, Helaine Vinche Zampar; Campos, Mauro; Costa, Charles

    2009-01-01

    Aging has various effects on visual system. Vision deteriorate, contrast sensitivity decreases and ocular aberrations apparently make the optical quality worse across the years. To prospective evaluate ocular aberrations along the ages. Three hundred and fifteen patients were examined, 155 were male (39.36%) and 160 were female (60.63%). Ages ranged from 5 to 64 year-old, the study was performed from February to November, 2004. Patients were divided into 4 age-groups according to IBGE (Instituto Brasileiro de Geografia e Estatística) classification: 68 patients from 5 to 14 year-old, 55 patients from 15 to 24 year-old, 116 from 25 to 44 year-old and 76 from 45 to 67 year-old. All patients had the following characteristics: best corrected visual acuity > 20/25, emmetropia or spherical equivalent < 3.50 SD, refractive astigmatism < 1.75 CD on cycloplegic refraction, normal ophthalmologic exam and no previous ocular surgeries. This protocol was approved by Federal University of São Paulo Institutional Review Board. Total optical aberrations were measured by H-S sensor LadarWave Custom Cornea Wavefront System (Alcon Laboratories Inc, Orlando, FLA, USA) and were statistically analysed. Corneal aberrations were calculated using CT-View software Version 6.89 (Sarver and Associates, Celebration, FL, USA). Lens aberrations were calculated by subtraction. High-order (0.32 e 0.48 microm) and ocular spherical aberrations (0.02 e 0.26 microm) increased respectively in child and middle age groups. High order (0.27 microm) and corneal spherical aberrations (0.05 microm) did not show changes with age. Lens showed a statistically significant spherical aberration increase (from -0.02 to 0.22 microm). Vertical (from 0.10 to -0.07 microm) and horizontal coma (from 0.01 to -0.12 microm) presented progressively negative values with aging. High-order and spherical aberrations increased with age due to lens contribution. The cornea did not affect significantly changes observed on ocular

  15. Chromosomal aberrations and SCEs as biomarkers of cancer risk

    DEFF Research Database (Denmark)

    Norppa, H; Bonassi, S; Hansteen, I-L

    2006-01-01

    Previous studies have suggested that the frequency of chromosomal aberrations (CAs), but not of sister chromatid exchanges (SCEs), predicts cancer risk. We have further examined this relationship in European cohorts comprising altogether almost 22,000 subjects, in the framework of a European...... collaborative project (CancerRiskBiomarkers). The present paper gives an overview of some of the results of the project, especially as regards CAs and SCEs. The results confirm that a high level of CAs is associated with an increased risk of cancer and indicate that this association does not depend on the time...

  16. Covert expectation-of-reward in rat ventral striatum at decision points

    Directory of Open Access Journals (Sweden)

    Matthijs A A Van Der Meer

    2009-02-01

    Full Text Available Flexible decision-making strategies (such as planning are a key component of adaptive behavior, yet their neural mechanisms have remained resistant to experimental analysis. Theories of planning require prediction and evaluation of potential future rewards, suggesting that reward signals may covertly appear at decision points. To test this idea, we recorded ensembles of ventral striatal neurons on a spatial decision task, in which hippocampal ensembles are known to represent future possibilities at decision points. We found representations of reward which were not only activated at actual reward delivery sites, but also at a high-cost choice point and before error correction. This expectation-of-reward signal at decision points was apparent at both the single cell and the ensemble level, and vanished with behavioral automation. We conclude that ventral striatal representations of reward are more dynamic than suggested by previous reports of reward- and cue-responsive cells, and may provide the necessary signal for evaluation of internally generated possibilities considered during flexible decision-making.

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

    Science.gov (United States)

    2017-01-01

    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. PMID:28961245

  18. Neural signal during immediate reward anticipation in schizophrenia: Relationship to real-world motivation and function.

    Science.gov (United States)

    Subramaniam, Karuna; Hooker, Christine I; Biagianti, Bruno; Fisher, Melissa; Nagarajan, Srikantan; Vinogradov, Sophia

    2015-01-01

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  20. Neural signal during immediate reward anticipation in schizophrenia: Relationship to real-world motivation and function

    Directory of Open Access Journals (Sweden)

    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.

  1. Neural signal during immediate reward anticipation in schizophrenia: Relationship to real-world motivation and function

    Science.gov (United States)

    Subramaniam, Karuna; Hooker, Christine I.; Biagianti, Bruno; Fisher, Melissa; Nagarajan, Srikantan; Vinogradov, Sophia

    2015-01-01

    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. PMID:26413478

  2. MONITORING EXTRACELLULAR PH, OXYGEN, AND DOPAMINE DURING REWARD DELIVERY IN THE STRIATUM OF PRIMATES

    Directory of Open Access Journals (Sweden)

    Jennifer L Ariansen

    2012-07-01

    Full Text Available Dopamine projections that extend from the ventral tegmental area to the striatum have been implicated in the biological basis for behaviors associated with reward and addiction. Until recently, it has been difficult to evaluate the complex balance of energy utilization and neural activity in the striatum. Many techniques such as electrophysiology, functional magnetic resonance imaging (fMRI, and fast-scan cyclic voltammetry have been employed to monitor these neurochemical and neurophysiological changes. In this brain region, physiological responses to cues and rewards cause local, transient pH changes. Oxygen and pH are coupled in the brain through a complex system of blood flow and metabolism as a result of transient neural activity. Indeed, this balance is at the heart of imaging studies such as fMRI. To this end, we measured pH and O2 changes with fast-scan cyclic voltammetry in the striatum as indices of changes in metabolism and blood flow in vivo in three Macaca mulatta monkeys. The animals were presented with Pavlovian conditioned cues that predicted different probabilities of liquid reward. They also received free reward without predictive cues. The primary change consisted of pH shifts in the striatal extracellular environment following the reward predicting cues or the free reward. We observed three types of cue responses which consisted of purely basic pH shifts, basic pH shifts followed by acidic pH shifts, and purely acidic pH shifts. These responses increased with reward probability. The pH changes were accompanied by increases in extracellular O2. The changes in pH and extracellular O2 are consistent with current theories of metabolism and blood flow. The findings suggest a role of these chemical responses in neuronal reward processing

  3. Self-rewards and personal motivation

    NARCIS (Netherlands)

    Koch, A.K.; Nafziger, J.; Suvorov, A.; van de Ven, J.

    2014-01-01

    Self-administered rewards are ubiquitous. They serve as incentives for personal accomplishments and are widely recommended to increase personal motivation. We show that in a model with time-inconsistent and reference-dependent preferences, self-rewards can be a credible and effective tool to

  4. Reward Magnitude Effects on Temporal Discrimination

    Science.gov (United States)

    Galtress, Tiffany; Kirkpatrick, Kimberly

    2010-01-01

    Changes in reward magnitude or value have been reported to produce effects on timing behavior, which have been attributed to changes in the speed of an internal pacemaker in some instances and to attentional factors in other cases. The present experiments therefore aimed to clarify the effects of reward magnitude on timing processes. In Experiment…

  5. Video Game Training and the Reward System

    Directory of Open Access Journals (Sweden)

    Robert C. Lorenz

    2015-02-01

    Full Text Available Video games contain elaborate reinforcement and reward schedules that have the potential to maximize motivation. Neuroimaging studies suggest that video games might have an influence on the reward system. However, it is not clear whether reward-related properties represent a precondition, which biases an individual towards playing video games, or if these changes are the result of playing video games. Therefore, we conducted a longitudinal study to explore reward-related functional predictors in relation to video gaming experience as well as functional changes in the brain in response to video game training.Fifty healthy participants were randomly assigned to a video game training (TG or control group (CG. Before and after training/control period, functional magnetic resonance imaging (fMRI was conducted using a non-video game related reward task.At pretest, both groups showed strongest activation in ventral striatum (VS during reward anticipation. At posttest, the TG showed very similar VS activity compared to pretest. In the CG, the VS activity was significantly attenuated.This longitudinal study revealed that video game training may preserve reward responsiveness in the ventral striatum in a retest situation over time. We suggest that video games are able to keep striatal responses to reward flexible, a mechanism which might be of critical value for applications such as therapeutic cognitive training.

  6. Self-Rewards and Personal Motivation

    DEFF Research Database (Denmark)

    Koch, Alexander Karl; Nafziger, Julia; Suvorov, Anton

    Self-administered rewards are ubiquitous. They serve as incentives for personal accomplishments and are widely recommended to increase personal motivation. We show that in a model with time-inconsistent and reference-dependent preferences, self-rewards can be a credible and effective tool to over...

  7. Self-rewards and personal motivation

    DEFF Research Database (Denmark)

    Koch, Alexander Karl; Nafziger, Julia; Suvorov, Anton

    2014-01-01

    Self-administered rewards are ubiquitous. They serve as incentives for personal accomplishments and are widely recommended to increase personal motivation. We show that in a model with time-inconsistent and reference-dependent preferences, self-rewards can be a credible and effective tool to over...

  8. Neural correlates of reward in autism

    NARCIS (Netherlands)

    Schmitz, Nicole; Rubia, Katya; van Amelsvoort, Therese; Daly, Eileen; Smith, Anna; Murphy, Declan G. M.

    2008-01-01

    BACKGROUND: Lack of social interaction, which is characteristically seen in people with autistic-spectrum disorder, may be caused by malfunctioning of the frontostriatal reward systems. However, no reported in vivo brain imaging studies have investigated reward mechanisms in autistic-spectrum

  9. Social Reward Questionnaire (SRQ): development and validation.

    Science.gov (United States)

    Foulkes, Lucy; Viding, Essi; McCrory, Eamon; Neumann, Craig S

    2014-01-01

    Human beings seek out social interactions as a source of reward. To date, there have been limited attempts to identify different forms of social reward, and little is known about how the value of social rewards might vary between individuals. This study aimed to address both these issues by developing the Social Reward Questionnaire (SRQ), a measure of individual differences in the value of different social rewards. Exploratory factor analysis (EFA) was run on an initial set of 75 items (N = 305). Based on this analysis, confirmatory factor analysis (CFA) was then conducted on a second sample (N = 505) with a refined 23-item scale. This analysis was used to test a six-factor structure, which resulted in good model fit (CFI = 0.96, RSMEA = 0.07). The factors represent six subscales of social reward defined as follows: Admiration; Negative Social Potency; Passivity; Prosocial Interactions; Sexual Reward; and Sociability. All subscales demonstrated good test-retest reliability and internal consistency. Each subscale also showed a distinct pattern of associations with external correlates measuring personality traits, attitudes, and goals, thus demonstrating construct validity. Taken together, the findings suggest that the SRQ is a reliable, valid measure that can be used to assess individual differences in the value experienced from different social rewards.

  10. Discretionary rewards as a feedback mechanism

    NARCIS (Netherlands)

    Suvorov, A.; van de Ven, J.

    2009-01-01

    This paper studies the use of discretionary rewards in a finitely repeated principal-agent relationship with moral hazard. The key aspect is that rewards have informational content. When the principal obtains a private subjective signal about the agent's performance, she may pay discretionary

  11. Video game training and the reward system.

    Science.gov (United States)

    Lorenz, Robert C; Gleich, Tobias; Gallinat, Jürgen; Kühn, Simone

    2015-01-01

    Video games contain elaborate reinforcement and reward schedules that have the potential to maximize motivation. Neuroimaging studies suggest that video games might have an influence on the reward system. However, it is not clear whether reward-related properties represent a precondition, which biases an individual toward playing video games, or if these changes are the result of playing video games. Therefore, we conducted a longitudinal study to explore reward-related functional predictors in relation to video gaming experience as well as functional changes in the brain in response to video game training. Fifty healthy participants were randomly assigned to a video game training (TG) or control group (CG). Before and after training/control period, functional magnetic resonance imaging (fMRI) was conducted using a non-video game related reward task. At pretest, both groups showed strongest activation in ventral striatum (VS) during reward anticipation. At posttest, the TG showed very similar VS activity compared to pretest. In the CG, the VS activity was significantly attenuated. This longitudinal study revealed that video game training may preserve reward responsiveness in the VS in a retest situation over time. We suggest that video games are able to keep striatal responses to reward flexible, a mechanism which might be of critical value for applications such as therapeutic cognitive training.

  12. Performance-Based Rewards and Work Stress

    Science.gov (United States)

    Ganster, Daniel C.; Kiersch, Christa E.; Marsh, Rachel E.; Bowen, Angela

    2011-01-01

    Even though reward systems play a central role in the management of organizations, their impact on stress and the well-being of workers is not well understood. We review the literature linking performance-based reward systems to various indicators of employee stress and well-being. Well-controlled experiments in field settings suggest that certain…

  13. Social Reward Questionnaire (SRQ: Development and validation

    Directory of Open Access Journals (Sweden)

    Lucy eFoulkes

    2014-03-01

    Full Text Available Human beings seek out social interactions as a source of reward. To date, there have been limited attempts to identify different forms of social reward, and little is known about how the value of social rewards might vary between individuals. This study aimed to address both these issues by developing the Social Reward Questionnaire (SRQ, a measure of individual differences in the value of different social rewards. Exploratory factor analysis (EFA was run on an initial set of 75 items (N=305. Based on this analysis, confirmatory factor analysis (CFA was then conducted on a second sample (N=505 with a refined 23-item scale. This analysis was used to test a six-factor structure, which resulted in good model fit (CFI=.96, RSMEA=.07. The factors represent six subscales of social reward defined as follows: Admiration; Negative Social Potency; Passivity; Prosocial Interactions; Sexual Reward; and Sociability. All subscales demonstrated good test-retest reliability and internal consistency. Each subscale also showed a distinct pattern of associations with external correlates measuring personality traits, attitudes and goals, thus demonstrating construct validity. Taken together, the findings suggest that the SRQ is a reliable, valid measure that can be used to assess individual differences in the value experienced from different social rewards.

  14. Resource Allocation Problems with Concave Reward Functions

    NARCIS (Netherlands)

    Grundel, S.; Borm, P.E.M.; Hamers, H.J.M.

    2013-01-01

    Abstract: In a resource allocation problem there is a common-pool resource, which has to be divided among agents. Each agent is characterized by a claim on this pool and an individual concave reward function on assigned resources. An assignment of resources is optimal if the total joint reward is

  15. Intelligence moderates neural responses to monetary reward and punishment.

    Science.gov (United States)

    Hawes, Daniel R; DeYoung, Colin G; Gray, Jeremy R; Rustichini, Aldo

    2014-05-01

    The relations between intelligence (IQ) and neural responses to monetary gains and losses were investigated in a simple decision task. In 94 healthy adults, typical responses of striatal blood oxygen level-dependent (BOLD) signal after monetary reward and punishment were weaker for subjects with higher IQ. IQ-moderated differential responses to gains and losses were also found for regions in the medial prefrontal cortex, posterior cingulate cortex, and left inferior frontal cortex. These regions have previously been identified with the subjective utility of monetary outcomes. Analysis of subjects' behavior revealed a correlation between IQ and the extent to which choices were related to experienced decision outcomes in preceding trials. Specifically, higher IQ predicted behavior to be more strongly correlated with an extended period of previously experienced decision outcomes, whereas lower IQ predicted behavior to be correlated exclusively to the most recent decision outcomes. We link these behavioral and imaging findings to a theoretical model capable of describing a role for intelligence during the evaluation of rewards generated by unknown probabilistic processes. Our results demonstrate neural differences in how people of different intelligence respond to experienced monetary rewards and punishments. Our theoretical discussion offers a functional description for how these individual differences may be linked to choice behavior. Together, our results and model support the hypothesis that observed correlations between intelligence and preferences may be rooted in the way decision outcomes are experienced ex post, rather than deriving exclusively from how choices are evaluated ex ante.

  16. Extending Markov Automata with State and Action Rewards

    NARCIS (Netherlands)

    Guck, Dennis; Timmer, Mark; Blom, Stefan; Bertrand, N.; Bortolussi, L.

    This presentation introduces the Markov Reward Automaton (MRA), an extension of the Markov automaton that allows the modelling of systems incorporating rewards in addition to nondeterminism, discrete probabilistic choice and continuous stochastic timing. Our models support both rewards that are

  17. Calculation of aberration coefficients by ray tracing.

    Science.gov (United States)

    Oral, M; Lencová, B

    2009-10-01

    In this paper we present an approach for the calculation of aberration coefficients using accurate ray tracing. For a given optical system, intersections of a large number of trajectories with a given plane are computed. In the Gaussian image plane the imaging with the selected optical system can be described by paraxial and aberration coefficients (geometric and chromatic) that can be calculated by least-squares fitting of the analytical model on the computed trajectory positions. An advantage of such a way of computing the aberration coefficients is that, in comparison with the aberration integrals and the differential algebra method, it is relatively easy to use and its complexity stays almost constant with the growing complexity of the optical system. This paper shows a tested procedure for choosing proper initial conditions and computing the coefficients of the fifth-order geometrical and third-order, first-degree chromatic aberrations by ray tracing on an example of a weak electrostatic lens. The results are compared with the values for the same lens from a paper Liu [Ultramicroscopy 106 (2006) 220-232].

  18. Describing ocular aberrations with wavefront vergence maps.

    Science.gov (United States)

    Nam, Jayoung; Thibos, Larry N; Iskander, D Robert

    2009-05-01

    A common optometric problem is to specify the eye's ocular aberrations in terms of Zernike coefficients and to reduce that specification to a prescription for the optimum sphero-cylindrical correcting lens. The typical approach is first to reconstruct wavefront phase errors from measurements of wavefront slopes obtained by a wavefront aberrometer. This paper applies a new method to this clinical problem that does not require wavefront reconstruction. Instead, we base our analysis of axial wavefront vergence as inferred directly from wavefront slopes. The result is a wavefront vergence map that is similar to the axial power maps in corneal topography and hence has a potential to be favoured by clinicians. We use our new set of orthogonal Zernike slope polynomials to systematically analyse details of the vergence map analogous to Zernike analysis of wavefront maps. The result is a vector of slope coefficients that describe fundamental aberration components. Three different methods for reducing slope coefficients to a spherocylindrical prescription in power vector forms are compared and contrasted. When the original wavefront contains only second order aberrations, the vergence map is a function of meridian only and the power vectors from all three methods are identical. The differences in the methods begin to appear as we include higher order aberrations, in which case the wavefront vergence map is more complicated. Finally, we discuss the advantages and limitations of vergence map representation of ocular aberrations.

  19. Effects of chalazion excision on ocular aberrations.

    Science.gov (United States)

    Sabermoghaddam, Ali A; Zarei-Ghanavati, Siamak; Abrishami, Mojtaba

    2013-06-01

    The goal of this study was to compare higher-order aberrations before and after upper lid chalazion excision. Fourteen eyes from 12 patients (8 females, mean age: 28.7 ± 2.7 years) with upper lid chalazion were enrolled in this prospective interventional case series. Chalazia were excised by standard transconjunctival vertical incision. Ocular aberrations were evaluated by aberrometry (ZyWave) before and 2 months after chalazion excision. Root mean square of total higher-order aberrations decreased from 0.67 ± 0.12 to 0.43 ± 0.15 μm (P = 0.012) after excision. The root mean square of Zernike orders in the vertical and horizontal trefoil and horizontal coma were decreased after excision. Orbscan IIz tomography showed a statistically significant decrease in 5 mm zone irregularity (P = 0.027) and an increase in minimum simulated keratometry after surgery (P = 0.046). Chalazion increases higher-order aberrations, as measured by the Hartmann-Shack aberrometer, which could affect the preoperative evaluation and results of refractive surgery, especially wavefront-guided approaches. Chalazion excision could reduce ocular aberrations and is recommended before refractive surgeries.

  20. Floral reward in Ranunculaceae species

    Directory of Open Access Journals (Sweden)

    Bożena Denisow

    2016-04-01

    Full Text Available Floral reward is important in ecological and evolutionary perspectives and essential in pollination biology. For example, floral traits, nectar and pollen features are essential for understanding the functional ecology, the dynamics of pollen transport, competition for pollinator services, and patterns of specialization and generalization in plant–pollinator interactions. We believe to present a synthetic description in the field of floral reward in Ranunculaceae family important in pollination biology and indicating connections between ecological and evolutionary approaches. The links between insect visitors’ behaviour and floral reward type and characteristics exist. Ranunculaceae is a family of aboot 1700 species (aboot 60 genera, distributed worldwide, however the most abundant representatives are in temperate and cool regions of the northern and southern hemispheres. The flowers are usually radially symmetric (zygomorphic and bisexual, but in Aconitum, Aquilegia are bilaterally symmetric (zygomorphic. Most Ranunculaceae flowers offer no nectar, only pollen (e.g., Ranunculus, Adonis vernalis, Thalictrum, but numerous species create trophic niches for different wild pollinators (e.g. Osmia, Megachile, Bombus, Andrena (Denisow et al. 2008. Pollen is a source of protein, vitamins, mineral salts, organic acids and hormones, but the nutritional value varies greatly between different plant species. The pollen production can differ significantly between Ranunculacea species. The mass of pollen produced in anthers differ due to variations in the number of developed anthers. For example, interspecies differences are considerable, 49 anthers are noted in Aquilegia vulgaris, 70 anthers in Ranunculus lanuginosus, 120 in Adonis vernalis. A significant intra-species differences’ in the number of anthers are also noted (e.g. 41 to 61 in Aquilegia vulgaris, 23-45 in Ranunculus cassubicus. Pollen production can be up to 62 kg per ha for Ranunculus acer

  1. Touch massage, a rewarding experience.

    Science.gov (United States)

    Lindgren, Lenita; Jacobsson, Maritha; Lämås, Kristina

    2014-12-01

    This study aims to describe and analyze healthy individuals' expressed experiences of touch massage (TM). Fifteen healthy participants received whole body touch massage during 60 minutes for two separate occasions. Interviews were analyzed by narrative analysis. Four identifiable storyline was found, Touch massage as an essential need, in this storyline the participants talked about a desire and need for human touch and TM. Another storyline was about, Touch massage as a pleasurable experience and the participants talked about the pleasure of having had TM. In the third storyline Touch massage as a dynamic experience, the informants talked about things that could modulate the experience of receiving TM. In the last storyline, Touch massage influences self-awareness, the participants described how TM affected some of their psychological and physical experiences. Experiences of touch massage was in general described as pleasant sensations and the different storylines could be seen in the light of rewarding experiences. © The Author(s) 2014.

  2. Orbitofrontal cortex volume and brain reward response in obesity.

    Science.gov (United States)

    Shott, M E; Cornier, M-A; Mittal, V A; Pryor, T L; Orr, J M; Brown, M S; Frank, G K W

    2015-02-01

    What drives overconsumption of food is poorly understood. Alterations in brain structure and function could contribute to increased food seeking. Recently, brain orbitofrontal cortex (OFC) volume has been implicated in dysregulated eating but little is known how brain structure relates to function. We examined obese (n=18, age=28.7±8.3 years) and healthy control women (n=24, age=27.4±6.3 years) using a multimodal brain imaging approach. We applied magnetic resonance and diffusion tensor imaging to study brain gray and white matter volume as well as white matter (WM) integrity, and tested whether orbitofrontal cortex volume predicts brain reward circuitry activation in a taste reinforcement-learning paradigm that has been associated with dopamine function. Obese individuals displayed lower gray and associated white matter volumes (Pobese individuals in fiber tracts including the external capsule, corona radiata, sagittal stratum, and the uncinate, inferior fronto-occipital, and inferior longitudinal fasciculi. Gray matter volume of the gyrus rectus at the medial edge of the orbitofrontal cortex predicted functional taste reward-learning response in frontal cortex, insula, basal ganglia, amygdala, hypothalamus and anterior cingulate cortex in control but not obese individuals. This study indicates a strong association between medial orbitofrontal cortex volume and taste reinforcement-learning activation in the brain in control but not in obese women. Lower brain volumes in the orbitofrontal cortex and other brain regions associated with taste reward function as well as lower integrity of connecting pathways in obesity (OB) may support a more widespread disruption of reward pathways. The medial orbitofrontal cortex is an important structure in the termination of food intake and disturbances in this and related structures could contribute to overconsumption of food in obesity.

  3. Stress and reward processing in bipolar disorder: a functional magnetic resonance imaging study.

    Science.gov (United States)

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

    2016-11-01

    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. Thirteen euthymic or mildly depressed individuals with BD and 15 controls performed a Monetary Incentive Delay (MID) 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. In hypothesis-driven region-of-interest 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 in response to rewards in participants with BD during stress, but an opposite pattern in controls. 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. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Low RPS14 expression in MDS without 5q - aberration confers higher apoptosis rate of nucleated erythrocytes and predicts prolonged survival and possible response to lenalidomide in lower risk non-5q- patients.

    Science.gov (United States)

    Wu, Lingyun; Li, Xiao; Xu, Feng; Zhang, Zheng; Chang, Chunkang; He, Qi

    2013-06-01

    Haploinsufficiency of the ribosomal protein S14 (RPS14) has been identified as a causal factor in myelodysplastic syndrome (MDS) with isolated del (5q). This study was carried out to investigate RPS14 expression in MDS without 5q deletion and the role of lower expressed RPS14 plays in pathogenesis and the prognosis and lenalidomide-response predicting of non-5q-MDS. The expression level of RPS14 transcription was detected in 156 MDS patients without 5q-. The apoptosis of bone marrow (BM) nucleated erythrocytes was also analyzed. Furthermore, patient prognosis with lower or normal RPS14 expression was analyzed, and the role of RPS14 expression in lenalidomide-response prediction was evaluated. The reduced RPS14 expression occurred in 83 of 156 (53.2%) non-5q-patients. Patients with RPS14 lower expression presented higher platelet counts in the peripheral blood compared with RPS14 normal patients (P = 0.012). The lower RPS14 expression status was inversely correlated with increased apoptosis ratio in nucleated erythrocytes from BM (r = -0.54, P = 0.013). Patients with lower RPS14 expression have a higher 2-yr survival probability than normal RPS14 cases in the international prognosis scoring system (IPSS) lower risk group (90.8% vs. 71.7%; P = 0.018). A multivariate analysis showed RPS14 expression status was an independent predictor for survival in lower risk MDS patients without 5q deletion. Twelve patients were treated with lenalidomide. Five of seven patients achieved an erythroid response in the lower RPS14 expression group (5/7, 71.4%), compared with zero responses in the five normal RPS14 patients (P = 0.018). Lower RPS14 expression in MDS patients without 5q deletion is associated with increased apoptosis of nucleated erythrocytes in lower risk MDS. Additionally, lower RPS14 predicts prolonged survival and possible response to lenalidomide in lower risk MDS patients. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Perceptual Competition Promotes Suppression of Reward Salience in Behavioral Selection and Neural Representation.

    Science.gov (United States)

    Gong, Mengyuan; Jia, Ke; Li, Sheng

    2017-06-28

    Visual attentional selection is influenced by the value of objects. Previous studies have demonstrated that reward-associated items lead to rapid distraction and associated behavioral costs, which are difficult to override with top-down control. However, it has not been determined whether a perceptually competitive environment could render the reward-driven distraction more susceptible to top-down suppression. Here, we trained both genders of human subjects to associate two orientations with high and low magnitudes of reward. After training, we collected fMRI data while the subjects performed a categorical visual search task. The item in the reward-associated orientation served as the distractor, and the relative physical salience between the target and distractor was carefully controlled to modulate the degree of perceptual competition. The behavioral results showed faster searches in the presence of high, relative to low, reward-associated distractors. However, this effect was evident only if the physical salience of the distractor was higher than that of the target, indicating a context-dependent suppression effect of reward salience that relied on high perceptual competition. By analyzing the fMRI data in primary visual cortex, we found that the behavioral pattern of results could be predicted by the suppressed channel responses tuned to the reward-associated orientation in the distractor location, accompanied by increased responses in the midbrain dopaminergic region. Our results suggest that the learned salience of a reward plays a flexible role in solving perceptual competition, enabling the neural system to adaptively modulate the perceptual representation for behavioral optimization.SIGNIFICANCE STATEMENT The predictiveness principle in learning theory suggests that the stimulus with high predictability of reward receives priority in attentional selection. This selection bias leads to difficulties in changing approach behaviors, and thus becomes an

  6. 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.

  7. Amygdala neural activity reflects spatial attention towards stimuli promising reward or threatening punishment.

    Science.gov (United States)

    Peck, Christopher J; Salzman, C Daniel

    2014-10-30

    Humans and other animals routinely identify and attend to sensory stimuli so as to rapidly acquire rewards or avoid aversive experiences. Emotional arousal, a process mediated by the amygdala, can enhance attention to stimuli in a non-spatial manner. However, amygdala neural activity was recently shown to encode spatial information about reward-predictive stimuli, and to correlate with spatial attention allocation. If representing the motivational significance of sensory stimuli within a spatial framework reflects a general principle of amygdala function, then spatially selective neural responses should also be elicited by sensory stimuli threatening aversive events. Recordings from amygdala neurons were therefore obtained while monkeys directed spatial attention towards stimuli promising reward or threatening punishment. Neural responses encoded spatial information similarly for stimuli associated with both valences of reinforcement, and responses reflected spatial attention allocation. The amygdala therefore may act to enhance spatial attention to sensory stimuli associated with rewarding or aversive experiences.

  8. 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.

  9. Refractive surgery, optical aberrations, and visual performance.

    Science.gov (United States)

    Applegate, R A; Howland, H C

    1997-01-01

    Visual optics is taking on new clinical significance. Given that current refractive procedures can and do induce large amounts of higher order ocular aberration that often affects the patient's daily visual function and quality of life, we can no longer relegate the considerations of ocular aberrations to academic discussions. Instead, we need to move toward minimizing (not increasing) the eye's aberrations at the same time we are correcting the eye's spherical and cylindrical refractive error. These are exciting times in refractive surgery, which need to be tempered by the fact that after all the research, clinical, and marketing dust settles, the level to which we improve the quality of the retinal image will be guided by the trade-off between cost and the improvement in the quality of life that refractive surgery offers.

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

    Science.gov (United States)

    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.

  11. Optical aberrations in professional baseball players.

    Science.gov (United States)

    Kirschen, David G; Laby, Daniel M; Kirschen, Matthew P; Applegate, Raymond; Thibos, Larry N

    2010-03-01

    To determine the presence, type, and size of optical higher-order aberrations (HOAs) in professional athletes with superior visual acuity and to compare them with those in an age-matched population of nonathletes. Vero Beach and Fort Myers, Florida, USA. Players from 2 professional baseball teams were studied. Each player's optical aberrations were measured with a naturally dilated 4.0 mm pupil using a Z-Wave aberrometer and a LADARWave aberrometer. One hundred sixty-two players (316 eyes) were evaluated. The HOAs were less than 0.026 mum in all cases. Spherical aberration C(4,0) was the largest aberration with both aberrometers. There were small but statistically significant differences between the aberrometers in mean values for trefoil C(3,3) and C(3,-3) and secondary astigmatism C(4,2). Although statistically significant, the differences were clinically insignificant, being similar at approximately 0.031 diopter (D) of spherical power. A statistically significant difference was found between the professional baseball players and the control population in trefoil C(3,-3). These differences were clinically insignificant, similar to 0.071 D of spherical power. Professional baseball players have small higher-order optical aberrations when tested with naturally dilated pupils. No clinically significant differences were found between the 2 aberrometers. Statistically significant differences in trefoil were found between the players and the control population; however, the difference was clinically insignificant. It seems as though the visual system of professional baseball players is limited by lower-order aberrations and that the smaller HOAs do not enhance visual function over that in a control population. Copyright 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  12. Developmental trends of communicative skills in children with chromosome 14 aberrations.

    Science.gov (United States)

    Zampini, Laura; Zanchi, Paola; Rinaldi, Berardo; Novara, Francesca; Zuffardi, Orsetta

    2017-04-01

    Children with chromosome 14 aberrations usually show developmental delays, intellectual disability, neurological disorders and behaviour problems. The aim of the present study is to describe the developmental trajectories of the communicative skills of children with chromosome 14 aberrations, considering the possible relationships between the patterns of language development and the children's clinical characteristics (e.g., intellectual disability or autistic traits). Longitudinal data on five children (four with linear deletions and one with ring 14 syndrome) followed for 3 years are presented. Four out of five children showed profound intellectual disability, and three out of five showed autistic traits. A high individual variability was found in both vocal and gestural productions. However, only a modest increase in the children's communicative and symbolic skills was detected over time (e.g., in the quality of preverbal productions). The increase of communicative skills in children with chromosome 14 aberration is very slow. We need to consider the children's characteristics, in terms of type of chromosome aberration, level of intellectual disability and presence/absence of autistic traits, to predict their possible linguistic outcomes and to give a more realistic expectation to their parents. What is known: • The communicative skills of children with chromosome 14 aberrations are usually impaired. • The presence of autistic traits is frequent in these children. What is new: • The increase of communicative skills in children with chromosome 14 aberrations is very slow. • The level of intellectual disability and the presence/absence of autistic traits appeared to have a role in predicting the possible linguistic outcomes in children with chromosome 14 aberrations.

  13. Multiple Mechanisms for Processing Reward Uncertainty in the Primate Basal Forebrain.

    Science.gov (United States)

    Ledbetter, Noah M; Chen, Charles D; Monosov, Ilya E

    2016-07-27

    The ability to use information about the uncertainty of future outcomes is critical for adaptive behavior in an uncertain world. We show that the basal forebrain (BF) contains at least two distinct neural-coding strategies to support this capacity. The dorsal-lateral BF, including the ventral pallidum (VP), contains reward-sensitive neurons, some of which are selectively suppressed by uncertain-reward predictions (U(-)). In contrast, the medial BF (mBF) contains reward-sensitive neurons, some of which are selectively enhanced (U(+)) by uncertain-reward predictions. In a two-alternative choice-task, U(-) neurons were selectively suppressed while monkeys chose uncertain options over certain options. During the same choice-epoch, U(+) neurons signaled the subjective reward value of the choice options. Additionally, after the choice was reported, U(+) neurons signaled reward uncertainty until the choice outcome. We suggest that uncertainty-related suppression of VP may participate in the mediation of uncertainty-seeking actions, whereas uncertainty-related enhancement of the mBF may direct cognitive resources to monitor and learn from uncertain-outcomes. To survive in an uncertain world, we must approach uncertainty and learn from it. Here we provide evidence for two mostly distinct mechanisms for processing uncertainty about rewards within different subregions of the primate basal forebrain (BF). We found that uncertainty suppressed the representation of certain (or safe) reward values by some neurons in the dorsal-lateral BF, in regions occupied by the ventral pallidum. This uncertainty-related suppression was evident as monkeys made risky choices. We also found that uncertainty-enhanced the activity of many medial BF neurons, most prominently after the monkeys' choices were completed (as they awaited uncertain outcomes). Based on these findings, we propose that different subregions of the BF could support action and learning under uncertainty in distinct but

  14. The influence of organisational rewards on workplace trust and work engagement

    Directory of Open Access Journals (Sweden)

    Janine Victor

    2017-01-01

    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

  15. Prosocial reward learning in children and adolescents

    Directory of Open Access Journals (Sweden)

    Youngbin Kwak

    2016-10-01

    Full Text Available Adolescence is a period of increased sensitivity to social contexts. To evaluate how social context sensitivity changes over development – and influences reward learning – we investigated how children and adolescents perceive and integrate rewards for oneself and others during a dynamic risky-decision-making task. Children and adolescents (N=75, 8-16 yrs performed the Social Gambling Task (SGT, (Kwak et al., 2014 and completed a set of questionnaires measuring other-regarding behavior. In the SGT, participants choose amongst four card decks that have different payout structures for oneself and for a charity. We examined patterns of choices, overall decision strategies, and how reward outcomes led to trial-by-trial adjustments in behavior, as estimated using a reinforcement-learning model. Performance of children and adolescents was compared to data from a previously collected sample of adults (N=102 performing the identical task. We found that that children/adolescents were not only more sensitive to rewards directed to the charity than self but also showed greater prosocial tendencies on independent measures of other-regarding behavior. Children and adolescents also showed less use of a strategy that prioritizes rewards for self at the expense of rewards for others. These results support the conclusion that, compared to adults, children and adolescents show greater sensitivity to outcomes for others when making decisions and learning about potential rewards.

  16. Acute stress selectively reduces reward sensitivity

    Directory of Open Access Journals (Sweden)

    Lisa H Berghorst

    2013-04-01

    Full Text Available Stress may promote the onset of psychopathology by disrupting reward processing. However, the extent to which stress impairs reward processing, rather than incentive processing more generally, is unclear. To evaluate the specificity of stress-induced reward processing disruption, 100 psychiatrically healthy females were administered a probabilistic stimulus selection task enabling comparison of sensitivity to reward-driven (Go and punishment-driven (NoGo learning under either ‘no stress’ or ‘stress’ (threat-of-shock conditions. Cortisol samples and self-report measures were collected. Contrary to hypotheses, the groups did not differ significantly in task performance or cortisol reactivity. However, further analyses focusing only on individuals under ‘stress’ who were high responders with regard to both cortisol reactivity and self-reported negative affect revealed reduced reward sensitivity relative to individuals tested in the ‘no stress’ condition; importantly, these deficits were reward-specific. Overall, findings provide preliminary evidence that stress-reactive individuals show diminished sensitivity to reward but not punishment under stress. While such results highlight the possibility that stress-induced anhedonia might be an important mechanism linking stress to affective disorders, future studies are necessary to confirm this conjecture.

  17. Acute stress selectively reduces reward sensitivity

    Science.gov (United States)

    Berghorst, Lisa H.; Bogdan, Ryan; Frank, Michael J.; Pizzagalli, Diego A.

    2013-01-01

    Stress may promote the onset of psychopathology by disrupting reward processing. However, the extent to which stress impairs reward processing, rather than incentive processing more generally, is unclear. To evaluate the specificity of stress-induced reward processing disruption, 100 psychiatrically healthy females were administered a probabilistic stimulus selection task (PSST) that enabled comparison of sensitivity to reward-driven (Go) and punishment-driven (NoGo) learning under either “no stress” or “stress” (threat-of-shock) conditions. Cortisol samples and self-report measures were collected. Contrary to hypotheses, the groups did not differ significantly in task performance or cortisol reactivity. However, further analyses focusing only on individuals under “stress” who were high responders with regard to both cortisol reactivity and self-reported negative affect revealed reduced reward sensitivity relative to individuals tested in the “no stress” condition; importantly, these deficits were reward-specific. Overall, findings provide preliminary evidence that stress-reactive individuals show diminished sensitivity to reward, but not punishment, under stress. While such results highlight the possibility that stress-induced anhedonia might be an important mechanism linking stress to affective disorders, future studies are necessary to confirm this conjecture. PMID:23596406

  18. Opposing BOLD responses to reciprocated and unreciprocated altruism in putative reward pathways.

    Science.gov (United States)

    Rilling, James K; Sanfey, Alan G; Aronson, Jessica A; Nystrom, Leigh E; Cohen, Jonathan D

    2004-11-15

    Mesencephalic dopamine neurons are believed to facilitate reward-dependent learning by computing errors in reward predictions. We used fMRI to test whether this system was activated as expected in response to errors in predictions about whether a social partner would reciprocate an act of altruism. Nineteen subjects received fMRI scans as they played a series of single-shot Prisoner's Dilemma games with partners who were outside the scanner. In both ventromedial prefrontal cortex and ventral striatum, reciprocated and unreciprocated cooperation were associated with positive and negative BOLD responses, respectively. Our results are consistent with the hypothesis that mesencephalic dopamine projection sites carry information about errors in reward prediction that allow us to learn who can and cannot be trusted to reciprocate favors.

  19. Dorsolateral prefrontal cortex modulates striatal reward encoding during reappraisal of reward anticipation.

    Science.gov (United States)

    Staudinger, Markus R; Erk, Susanne; Walter, Henrik

    2011-11-01

    Recent research showed that cognitive emotion regulation (ER) both increases activity in the dorsolateral prefrontal cortex (DLPFC) and decreases striatal responsivity to monetary rewards. Using a mixed monetary incentive delay/memory task as well as functional magnetic resonance imaging, we tested in healthy subjects whether ER effectively attenuates striatal reward encoding during the anticipation of reward (€1.00 vs. €0.05 reward cues) as well as subsequent target reaction times (RTs), which are an indicator of motivation to obtain reward. ER significantly diminished feelings of pleasant anticipation and slowed down €1.00 target RT. At the neural level, ER increased activity in the DLPFC and attenuated reward encoding in the left putamen. Analyses of psychophysiological interaction revealed that DLPFC activity correlated more positively with putamen activity during €0.05 than during €1.00 reward trials. Furthermore, parametric modulations showed that anticipatory left putamen activity correlated with target RT during nonregulation. No such correlation could be observed during ER, suggesting that ER had abolished preparatory target RT encoding. Our results provide evidence that ER can attenuate behavioral and striatal measures of reward-related motivation and motor preparation. Furthermore, the present findings suggest that the DLPFC might contribute to successful regulation of reward via increased promotion of low-reward responses.

  20. 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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  3. Endocannabinoid signaling in reward and addiction

    Science.gov (United States)

    Parsons, Loren H.; Hurd, Yasmin L.

    2015-01-01

    Brain endocannabinoid signaling influences the motivation for natural rewards (such as palatable food, sexual activity and social interaction) and modulates the rewarding effects of addictive drugs. Pathological forms of natural and drug-induced reward are associated with dysregulated endocannabinoid signaling that may derive from pre-existing genetic factors or from prolonged drug exposure. Impaired endocannabinoid signaling contributes to dysregulated synaptic plasticity, increased stress responsivity, negative emotional states, and craving that propel addiction. Understanding the contributions of endocannabinoid disruptions to behavioral and physiological traits provides insight into the endocannabinoid influence on addiction vulnerability. PMID:26373473

  4. The correction of electron lens aberrations

    Energy Technology Data Exchange (ETDEWEB)

    Hawkes, P.W., E-mail: peter.hawkes@cemes.fr

    2015-09-15

    The progress of electron lens aberration correction from about 1990 onwards is chronicled. Reasonably complete lists of publications on this and related topics are appended. A present for Max Haider and Ondrej Krivanek in the year of their 65th birthdays. By a happy coincidence, this review was completed in the year that both Max Haider and Ondrej Krivanek reached the age of 65. It is a pleasure to dedicate it to the two leading actors in the saga of aberration corrector design and construction. They would both wish to associate their colleagues with such a tribute but it is the names of Haider and Krivanek (not forgetting Joachim Zach) that will remain in the annals of electron optics, next to that of Harald Rose. I am proud to know that both regard me as a friend as well as a colleague. - Highlights: • Geometrical aberration correction. • Chromatic aberration correction. • 50 pm resolution. • High-resolution electron energy-loss spectroscopy. • Extensive bibliographies.

  5. Chromosomal aberrations induced by Markhamia tomentosa (Benth ...

    African Journals Online (AJOL)

    Markhamia tomentosa (Benth.) K. Schum. Ex Engl. (Bignoniaceae) is used traditionally in the treatment of pain, oedema, pulmonary troubles and cancer. The genotoxic and cytotoxic effects of the ethanolic extract of the leaves of M. tomentosa was investigated using the Allium cepa root chromosomal aberration assay.

  6. Anti-forensics of chromatic aberration

    Science.gov (United States)

    Mayer, Owen; Stamm, Matthew C.

    2015-03-01

    Over the past decade, a number of information forensic techniques have been developed to identify digital image manipulation and falsification. Recent research has shown, however, that an intelligent forger can use anti-forensic countermeasures to disguise their forgeries. In this paper, an anti-forensic technique is proposed to falsify the lateral chromatic aberration present in a digital image. Lateral chromatic aberration corresponds to the relative contraction or expansion between an image's color channels that occurs due to a lens's inability to focus all wavelengths of light on the same point. Previous work has used localized inconsistencies in an image's chromatic aberration to expose cut-and-paste image forgeries. The anti-forensic technique presented in this paper operates by estimating the expected lateral chromatic aberration at an image location, then removing deviations from this estimate caused by tampering or falsification. Experimental results are presented that demonstrate that our anti-forensic technique can be used to effectively disguise evidence of an image forgery.

  7. Heightened sensitivity to punishment and reward in anorexia nervosa.

    Science.gov (United States)

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

    2014-04-01

    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 validity of PS and RS was examined for AN symptoms one year later. In total, 165 female adolescents admitted for treatment of AN or eating disorder not otherwise specified resembling AN and 72 controls participated in the study. Participants completed measurements for eating disorder severity and the Sensitivity to Punishment/Sensitivity to Reward Questionnaire (SPSRQ). Percentage of underweight and severity of AN symptoms were measured again after one year in individuals with AN. Individuals with AN scored higher on PS and RS than controls. In addition, the AN purging type showed higher PS than the AN restrictive type, whereas there were no differences in RS between AN-subtypes. Regression analyses indicated that PS and RS were independently associated with the degree of eating disorder symptoms, whereas only PS was related to percentage underweight. Yet, neither RS nor PS were related to percentage of underweight and AN symptoms after one year. Although the present study clearly demonstrated that heightened punishment and reward sensitivity are both linked to AN, there was no evidence that these characteristics are also involved in the course of AN symptoms. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Getting to the heart of the matter: Does aberrant interoceptive processing contribute towards emotional eating?

    National Research Council Canada - National Science Library

    Hayley A Young; Claire Williams; Aimee E Pink; Gary Freegard; Amy Owens; David Benton

    2017-01-01

    ...’. No longer viewed as a ‘bottom up’ process, new interoceptive facets based on ‘top down’ predictions have been proposed, although at present it is unclear which aspects of interoception contribute to aberrant eating behaviour and obesity...

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

    Science.gov (United States)

    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.

  10. Higher-order aberrations and anisometropia.

    Science.gov (United States)

    Hartwig, Andreas; Atchison, David A; Radhakrishnan, Hema

    2013-01-01

    Myopia incidence is increasing around the world. Myopization is considered to be caused by a variety of factors. One consideration is whether higher-order aberrations (HOA) influence myopization. More knowledge of optics in anisometropic eyes might give further insight into the development of refractive error. To analyze the possible influence of HOA on refractive error development, we compared HOA between anisometropes and isometropes. We analyzed HOA up to the 4th order for both eyes of 20 anisometropes (mean age: 43 ± 17 years) and 20 isometropes (mean age: 33 ± 17 years). HOA were measured with the Shack-Hartman i.Profiler (Carl Zeiss, Germany) and were recalculated for a 4 mm pupil. Mean spherical equivalent (MSE) was based on the subjective refraction. Anisometropia was defined as ≥1 D interocular difference in MSE. The mean absolute differences between right and left eyes in spherical equivalent were 0.28 ± 0.21 D in the isometropic group and 2.81 ± 2.04 D in the anisometropic group. Interocular differences in HOA were compared with the interocular difference in MSE using correlations. For isometropes oblique trefoil, vertical coma, horizontal coma and spherical aberration showed significant correlations between the two eyes. In anisometropes, all analyzed higher-order aberrations correlated significantly between the two eyes except oblique secondary astigmatism and secondary astigmatism. When analyzing anisometropes and isometropes separately, no significant correlations were found between interocular differences of higher-order aberrations and MSE. For isometropes and anisometropes combined, tetrafoil correlated significantly with MSE in left eyes. The present study could not show that interocular differences of higher-order aberrations increase with increasing interocular difference in MSE.

  11. Learning, Reward, and Decision Making.

    Science.gov (United States)

    O'Doherty, John P; Cockburn, Jeffrey; Pauli, Wolfgang M

    2017-01-03

    In this review, we summarize findings supporting the existence of multiple behavioral strategies for controlling reward-related behavior, including a dichotomy between the goal-directed or model-based system and the habitual or model-free system in the domain of instrumental conditioning and a similar dichotomy in the realm of Pavlovian conditioning. We evaluate evidence from neuroscience supporting the existence of at least partly distinct neuronal substrates contributing to the key computations necessary for the function of these different control systems. We consider the nature of the interactions between these systems and show how these interactions can lead to either adaptive or maladaptive behavioral outcomes. We then review evidence that an additional system guides inference concerning the hidden states of other agents, such as their beliefs, preferences, and intentions, in a social context. We also describe emerging evidence for an arbitration mechanism between model-based and model-free reinforcement learning, placing such a mechanism within the broader context of the hierarchical control of behavior.

  12. Perceived control increases the reward positivity and stimulus preceding negativity.

    Science.gov (United States)

    Mühlberger, Christina; Angus, Douglas Jozef; Jonas, Eva; Harmon-Jones, Cindy; Harmon-Jones, Eddie

    2017-02-01

    The reward positivity (RewP) and the stimulus preceding negativity (SPN), two ERPs associated with reward delivery and reward anticipation, are modulated by motivational intensity. Motivational intensity is the effort organisms would make to exert behaviors, and it varies with the difficulty of exerting that behavior. If a task is perceived as impossible, which means that one does not have control over own outcomes, motivational intensity is low. In the current study, we tested the prediction that perceiving control over one's outcomes increases both the RewP to feedback and the SPN prior to feedback compared to perceiving no control. We also examined whether P300 and LPP amplitudes to reward and nonreward images were similarly modulated. Twenty-five female participants completed a gambling task in which correct choices were followed by pictures of attractive men and incorrect choices were followed by pictures of rocks. To manipulate perceived control, participants were told that, in one block of trials, they could learn a mouse-click rule in order to see only pictures of men (high perceived control condition), while in the other block, the pictures would appear randomly (low perceived control condition). However, in both conditions, feedback appeared randomly. Although the RewP was elicited in both blocks, the RewP and SPN were higher in the high perceived control condition (i.e., when participants thought that they could influence their outcomes). Perceived control did not modulate the P300 and LPP to pictures. The results suggest that approach motivation and its intensity modulate the processing of performance feedback. © 2016 Society for Psychophysiological Research.

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

    Science.gov (United States)

    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.

  14. Relative changes from prior reward contingencies can constrain brain correlates of outcome monitoring.

    Science.gov (United States)

    Mushtaq, Faisal; Stoet, Gijsbert; Bland, Amy Rachel; Schaefer, Alexandre

    2013-01-01

    It is well-known that the affective value of an environment can be relative to whether it reflects an improvement or a worsening from a previous state. A potential explanation for this phenomenon suggests that relative changes from previous reward contingencies can constrain how brain monitoring systems form predictions about future events. In support of this idea, we found that changes per se relative to previous states of learned reward contingencies modulated the Feedback-Related Negativity (FRN), a human brain potential known to index discrepancies between predictions and affective outcomes. Specifically, we observed that environments with a 50% reward probability yielded different FRN patterns according to whether they reflected an improvement or a worsening from a previous environment. Further, we also found that this pattern of results was driven mainly by variations in the amplitude of ERPs to positive outcomes. Overall, these results suggest that relative changes in reward probability from previous learned environments can constrain how neural systems of outcome monitoring formulate predictions about the likelihood of future rewards and nonrewards.

  15. Mood congruent tuning of reward expectation in positive mood: evidence from FRN and theta modulations.

    Science.gov (United States)

    Paul, Katharina; Pourtois, Gilles

    2017-05-01

    Positive mood broadens attention and builds additional mental resources. However, its effect on performance monitoring and reward prediction errors remain unclear. To examine this issue, we used a standard mood induction procedure (based on guided imagery) and asked 45 participants to complete a gambling task suited to study reward prediction errors by means of the feedback-related negativity (FRN) and mid-frontal theta band power. Results showed a larger FRN for negative feedback as well as a lack of reward expectation modulation for positive feedback at the theta level with positive mood, relative to a neutral mood condition. A control analysis showed that this latter result could not be explained by the mere superposition of the event-related brain potential component on the theta oscillations. Moreover, these neurophysiological effects were evidenced in the absence of impairments at the behavioral level or increase in autonomic arousal with positive mood, suggesting that this mood state reliably altered brain mechanisms of reward prediction errors during performance monitoring. We interpret these new results as reflecting a genuine mood congruency effect, whereby reward is anticipated as the default outcome with positive mood and therefore processed as unsurprising (even when it is unlikely), while negative feedback is perceived as unexpected. © The Author (2017). Published by Oxford University Press.

  16. Relative Changes from Prior Reward Contingencies Can Constrain Brain Correlates of Outcome Monitoring

    Science.gov (United States)

    Mushtaq, Faisal; Stoet, Gijsbert; Bland, Amy Rachel; Schaefer, Alexandre

    2013-01-01

    It is well-known that the affective value of an environment can be relative to whether it reflects an improvement or a worsening from a previous state. A potential explanation for this phenomenon suggests that relative changes from previous reward contingencies can constrain how brain monitoring systems form predictions about future events. In support of this idea, we found that changes per se relative to previous states of learned reward contingencies modulated the Feedback-Related Negativity (FRN), a human brain potential known to index discrepancies between predictions and affective outcomes. Specifically, we observed that environments with a 50% reward probability yielded different FRN patterns according to whether they reflected an improvement or a worsening from a previous environment. Further, we also found that this pattern of results was driven mainly by variations in the amplitude of ERPs to positive outcomes. Overall, these results suggest that relative changes in reward probability from previous learned environments can constrain how neural systems of outcome monitoring formulate predictions about the likelihood of future rewards and nonrewards. PMID:23840446

  17. TOTAL REWARDS MODEL IN ROMANIAN COMPANIES

    Directory of Open Access Journals (Sweden)

    Elena-Sabina HODOR

    2014-04-01

    Full Text Available Total Rewards Management is a subject of major importance for companies, because, by using models for this, firms can achieve their objectives of high performance. In order to analyse a validated total rewards model in Romanian Accounting and Consulting Companies, it is used The WorldatWork Total Rewards Model, which depict what contributes to applicant attraction and employee motivation and retention. Thus, the methodology of the previous survey is adjusted to the local context. The conclusions for the methodological aspects illustrate that the present research involves three strategic steps in order to achieve the objectives presented: the analysis of organizational environment of the companies from the sample, checking if Total Rewards Model proposed in the previous research is applicable for the same romanian companies from the previous survey, the analysing of the differences between results, and, if necessary, the adaptation of the model for Romania.

  18. Analysis of Bitcoin Pooled Mining Reward Systems

    OpenAIRE

    Rosenfeld, Meni

    2011-01-01

    In this paper we describe the various scoring systems used to calculate rewards of participants in Bitcoin pooled mining, explain the problems each were designed to solve and analyze their respective advantages and disadvantages.

  19. Rewards and Opportunities for Successful Entrepreneurs.

    Science.gov (United States)

    Longenecker, Justin G.

    1983-01-01

    Among the rewards for entrepreneurs are money, independence, and a satisfying way of life. A variety of opportunities exist for those with the vision, ingenuity, and courage to exploit the potential of the market place. (SK)

  20. EuroPlus+ Reward / Alar Hammer

    Index Scriptorium Estoniae

    Hammer, Alar

    2000-01-01

    EuroPlus+ Reward on mitmes versioonis ilmunud inglise keele õppeprogramm, milles on ühendatud multimeedia võimalused ning distantsõpe ning mis loob täiesti uued võimalused keele omandamiseks arvuti abil

  1. Dopamine Signaling in reward-related behaviors

    Directory of Open Access Journals (Sweden)

    Ja-Hyun eBaik

    2013-10-01

    Full Text Available Dopamine (DA regulates emotional and motivational behavior through the mesolimbic dopaminergic pathway. Changes in DAmesolimbic neurotransmission have been found to modify behavioral responses to various environmental stimuli associated with reward behaviors. Psychostimulants, drugs of abuse, and natural rewards such as food can cause substantial synaptic modifications to the mesolimbic DA system. Recent studies using optogenetics and DREADDs, together with neuron-specific or circuit-specific genetic manipulations have improved our understanding of DA signaling in the reward circuit, and provided a means to identify the neural substrates of complex behaviors such as drug addiction and eating disorders. This review focuses on the role of the DA system in drug addiction and food motivation, with an overview of the role of D1 and D2 receptors in the control of reward-associated behaviors.

  2. The electrocortical response to rewarding and aversive feedback: The reward positivity does not reflect salience in simple gambling tasks.

    Science.gov (United States)

    Mulligan, Elizabeth M; Hajcak, Greg

    2017-11-26

    The Reward Positivity (RewP) is an event-related potential (ERP) potentiated to monetary gains and reduced to monetary losses. Recently, competing data suggest that more salient outcomes elicit a positivity relative to less salient outcomes, regardless of valence. However, all previous work testing the impact of salience on the RewP have examined expected versus unexpected outcomes. In the current study, participants completed the same gambling task twice in which feedback was equally probable: in one condition, feedback indicated monetary gain or loss-and in the other condition, feedback indicated either safety or punishment from subsequent electric shock. Traditional ERP and principal component analysis (PCA)-derived measures confirmed that the RewP was more positive to feedback signaling monetary gain and safety from shock compared to feedback signaling monetary loss and punishment with shock. These results align with models in which the RewP indexes reward-related processes, including reward prediction error models. Potential explanations for salience-based effects on the RewP are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Individual differences in sensitivity to reward and punishment and neural activity during reward and avoidance learning.

    Science.gov (United States)

    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.

  4. EEG indices of reward motivation and target detectability in a rapid visual detection task.

    Science.gov (United States)

    Hughes, Gethin; Mathan, Santosh; Yeung, Nick

    2013-01-01

    A large corpus of data has demonstrated the sensitivity of behavioral and neural measures to variation in the availability of reward. The present study aimed to extend this work by exploring reward motivation in an RSVP task using complex satellite imagery. We found that reward motivation significantly influenced neural activity both in the preparatory period and in response to target images. Pre-stimulus alpha activity and, to a lesser degree, P3 and CNV amplitude were found to be significantly predictive of reward condition on single trials. Target-locked P3 amplitude was modulated both by reward condition and by variation in target detectability inherent to our task. We further quantified this exogenous influence, showing that P3 differences reflected single-trial variation in P3 amplitude for different targets. These findings provide theoretical insight into the neural indices of reward in an RSVP task, and have important applications in the field of satellite imagery analysis. Copyright © 2012 Elsevier Inc. All rights reserved.

  5. 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.

  6. Neuroelectric signatures of reward learning and decision-making in the human nucleus accumbens.

    Science.gov (United States)

    Cohen, Michael X; Axmacher, Nikolai; Lenartz, Doris; Elger, Christian E; Sturm, Volker; Schlaepfer, Thomas E

    2009-06-01

    Learning that certain actions lead to risky rewards is critical for biological, social, and economic survival, but the precise neural mechanisms of such reward-guided learning remain unclear. Here, we show that the human nucleus accumbens plays a key role in learning about risks by representing reward value. We recorded electrophysiological activity directly from the nucleus accumbens of five patients undergoing deep brain stimulation for treatment of refractory major depression. Patients engaged in a simple reward-learning task in which they first learned stimulus-outcome associations (learning task), and then were able to choose from among the learned stimuli (choosing task). During the learning task, nucleus accumbens activity reflected potential and received reward values both during the cue stimulus and during the feedback. During the choosing task, there was no nucleus accumbens activity during the cue stimulus, but feedback-related activity was pronounced and similar to that during the learning task. This pattern of results is inconsistent with a prediction error response. Finally, analyses of cross-correlations between the accumbens and simultaneous recordings of medial frontal cortex suggest a dynamic interaction between these structures. The high spatial and temporal resolution of these recordings provides novel insights into the timing of activity in the human nucleus accumbens, its functions during reward-guided learning and decision-making, and its interactions with medial frontal cortex.

  7. Nucleus Accumbens Mediates Relative Motivation for Rewards in the Absence of Choice

    Science.gov (United States)

    Clithero, John A.; Reeck, Crystal; Carter, R. McKell; Smith, David V.; Huettel, Scott A.

    2011-01-01

    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 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. PMID:21941472

  8. 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.

  9. Coexistence of reward and unsupervised learning during the operant conditioning of neural firing rates.

    Directory of Open Access Journals (Sweden)

    Robert R Kerr

    Full Text Available A fundamental goal of neuroscience is to understand how cognitive processes, such as operant conditioning, are performed by the brain. Typical and well studied examples of operant conditioning, in which the firing rates of individual cortical neurons in monkeys are increased using rewards, provide an opportunity for insight into this. Studies of reward-modulated spike-timing-dependent plasticity (RSTDP, and of other models such as R-max, have reproduced this learning behavior, but they have assumed that no unsupervised learning is present (i.e., no learning occurs without, or independent of, rewards. We show that these models cannot elicit firing rate reinforcement while exhibiting both reward learning and ongoing, stable unsupervised learning. To fix this issue, we propose a new RSTDP model of synaptic plasticity based upon the observed effects that dopamine has on long-term potentiation and depression (LTP and LTD. We show, both analytically and through simulations, that our new model can exhibit unsupervised learning and lead to firing rate reinforcement. This requires that the strengthening of LTP by the reward signal is greater than the strengthening of LTD and that the reinforced neuron exhibits irregular firing. We show the robustness of our findings to spike-timing correlations, to the synaptic weight dependence that is assumed, and to changes in the mean reward. We also consider our model in the differential reinforcement of two nearby neurons. Our model aligns more strongly with experimental studies than previous models and makes testable predictions for future experiments.

  10. Neural sensitivity to social reward and punishment anticipation in Social Anxiety Disorder.

    Directory of Open Access Journals (Sweden)

    Henk eCremers

    2015-01-01

    Full Text Available 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 Social Incentive Delay task to measure the anticipation of social reward and punishment. The left putamen (part of the striatum showed a valence-specific interaction with group after correcting for medication use and comorbidity. The control group showed a relatively stronger activation for reward vs. punishment trials, compared to the social anxiety group. However, post-hoc pairwise comparisons were not significant, indicating that the effect is driven by a relative difference. A connectivity analysis (Psychophysiological interaction further revealed a general salience effect: SAD patients showed decreased putamen-ACC connectivity compared to controls for both reward and punishment trials. Together these results suggest that the usual motivational preference for social reward is absent in SAD. In addition, cortical control processes during social incentive anticipation may be disrupted in SAD. These results provide initial evidence for altered striatal involvement in both valence-specific and valence nonspecific processing of social incentives, and stress the relevance of taking motivational processes into account when studying social anxiety.

  11. The circadian clock, reward and memory

    Directory of Open Access Journals (Sweden)

    Urs eAlbrecht

    2011-11-01

    Full Text Available During our daily activities, we experience variations in our cognitive performance, which is often accompanied by cravings for small rewards, such as consuming coffee or chocolate. This indicates that the time of day, cognitive performance and reward may be related to one another. This review will summarize data that describes the influence of the circadian clock on addiction and mood-related behavior and put the data into perspective in relation to memory processes.

  12. The circadian clock, reward, and memory.

    Science.gov (United States)

    Albrecht, Urs

    2011-01-01

    During our daily activities, we experience variations in our cognitive performance, which is often accompanied by cravings for small rewards, such as consuming coffee or chocolate. This indicates that the time of day, cognitive performance, and reward may be related to one another. This review will summarize data that describe the influence of the circadian clock on addiction and mood-related behavior and put the data into perspective in relation to memory processes.

  13. Classroom Reward Structures and Academic Performance. Report No. 186.

    Science.gov (United States)

    Michaels, James W.

    The general shortcomings of the traditional classroom reward structure are discussed in light of performance-reward principles of demonstrable effectiveness. Four alternative general reward structures are analyzed, and studies comparing their effectiveness are reviewed. Although none of the reward structures was found to be consistently superior…

  14. 28 CFR 7.4 - Procedure for claiming reward.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Procedure for claiming reward. 7.4 Section 7.4 Judicial Administration DEPARTMENT OF JUSTICE REWARDS FOR CAPTURE OF ESCAPED FEDERAL PRISONERS § 7.4 Procedure for claiming reward. A person claiming a reward under this part shall present his...

  15. 28 CFR 7.3 - Eligibility for reward.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Eligibility for reward. 7.3 Section 7.3 Judicial Administration DEPARTMENT OF JUSTICE REWARDS FOR CAPTURE OF ESCAPED FEDERAL PRISONERS § 7.3 Eligibility for reward. A reward may be paid to any person, except an official or employee of the Department...

  16. 28 CFR 7.2 - Amount of reward.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Amount of reward. 7.2 Section 7.2 Judicial Administration DEPARTMENT OF JUSTICE REWARDS FOR CAPTURE OF ESCAPED FEDERAL PRISONERS § 7.2 Amount of reward. Within the discretion of the Warden or U.S. Marshal concerned, a reward not in excess of...

  17. 28 CFR 7.1 - Standing offer of reward.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Standing offer of reward. 7.1 Section 7.1 Judicial Administration DEPARTMENT OF JUSTICE REWARDS FOR CAPTURE OF ESCAPED FEDERAL PRISONERS § 7.1 Standing offer of reward. A standing offer of reward is made for the capture, or for assisting in, or...

  18. Wave aberration of human eyes and new descriptors of image optical quality and visual performance.

    Science.gov (United States)

    Lombardo, Marco; Lombardo, Giuseppe

    2010-02-01

    The expansion of wavefront-sensing techniques redefined the meaning of refractive error in clinical ophthalmology. Clinical aberrometers provide detailed measurements of the eye's wavefront aberration. The distribution and contribution of each higher-order aberration to the overall wavefront aberration in the individual eye can now be accurately determined and predicted. Using corneal or ocular wavefront sensors, studies have measured the interindividual and age-related changes in the wavefront aberration in the normal population with the goal of optimizing refractive surgery outcomes for the individual. New objective optical-quality metrics would lead to better use and interpretation of newly available information on aberrations in the eye. However, the first metrics introduced, based on sets of Zernike polynomials, is not completely suitable to depict visual quality because they do not directly relate to the quality of the retinal image. Thus, several approaches to describe the real, complex optical performance of human eyes have been implemented. These include objective metrics that quantify the quality of the optical wavefront in the plane of the pupil (ie, pupil-plane metrics) and others that quantify the quality of the retinal image (ie, image-plane metrics). These metrics are derived by wavefront aberration information from the individual eye. This paper reviews the more recent knowledge of the wavefront aberration in human eyes and discusses the image-quality and optical-quality metrics and predictors that are now routinely calculated by wavefront-sensor software to describe the optical and image quality in the individual eye. Copyright 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  19. Musical pleasure and reward: mechanisms and dysfunction.

    Science.gov (United States)

    Zatorre, Robert J

    2015-03-01

    Most people derive pleasure from music. Neuroimaging studies show that the reward system of the human brain is central to this experience. Specifically, the dorsal and ventral striatum release dopamine when listening to pleasurable music, and activity in these structures also codes the reward value of musical excerpts. Moreover, the striatum interacts with cortical mechanisms involved in perception and valuation of musical stimuli. Recent studies have begun to explore individual differences in the way that this complex system functions. Development of a questionnaire for music reward experiences has allowed the identification of separable factors associated with musical pleasure, described as music-seeking, emotion-evocation, mood regulation, sensorimotor, and social factors. Applying this questionnaire to a large sample uncovered approximately 5% of the population with low sensitivity to musical reward in the absence of generalized anhedonia or depression. Further study of this group revealed that there are individuals who respond normally both behaviorally and psychophysiologically to rewards other than music (e.g., monetary value) but do not experience pleasure from music despite normal music perception ability and preserved ability to identify intended emotions in musical passages. This specific music anhedonia bears further study, as it may shed light on the function and dysfunction of the reward system. © 2014 New York Academy of Sciences.

  20. Reward sensitivity deficits modulated by dopamine are associated with apathy in Parkinson’s disease

    Science.gov (United States)

    Manohar, Sanjay; Ben Yehuda, Michael; Chong, Trevor T.-J.; Tofaris, George; Lennox, Graham; Bogdanovic, Marko; Hu, Michele; Husain, Masud

    2016-01-01

    Apathy is a debilitating and under-recognized condition that has a significant impact in many neurodegenerative disorders. In Parkinson’s disease, it is now known to contribute to worse outcomes and a reduced quality of life for patients and carers, adding to health costs and extending disease burden. However, despite its clinical importance, there remains limited understanding of mechanisms underlying apathy. Here we investigated if insensitivity to reward might be a contributory factor and examined how this relates to severity of clinical symptoms. To do this we created novel ocular measures that indexed motivation level using pupillary and saccadic response to monetary incentives, allowing reward sensitivity to be evaluated objectively. This approach was tested in 40 patients with Parkinson’s disease, 31 elderly age-matched control participants and 20 young healthy volunteers. Thirty patients were examined ON and OFF their dopaminergic medication in two counterbalanced sessions, so that the effect of dopamine on reward sensitivity could be assessed. Pupillary dilation to increasing levels of monetary reward on offer provided quantifiable metrics of motivation in healthy subjects as well as patients. Moreover, pupillary reward sensitivity declined with age. In Parkinson’s disease, reduced pupillary modulation by incentives was predictive of apathy severity, and independent of motor impairment and autonomic dysfunction as assessed using overnight heart rate variability measures. Reward sensitivity was further modulated by dopaminergic state, with blunted sensitivity when patients were OFF dopaminergic drugs, both in pupillary response and saccadic peak velocity response to reward. These findings suggest that reward insensitivity may be a contributory mechanism to apathy and provide potential new clinical measures for improved diagnosis and monitoring of apathy. PMID:27452600

  1. Neural reactivity to reward in school-age offspring of depressed mothers.

    Science.gov (United States)

    Wiggins, Jillian Lee; Schwartz, Karen T G; Kryza-Lacombe, Maria; Spechler, Philip A; Blankenship, Sarah L; Dougherty, Lea R

    2017-05-01

    Identifying neural profiles predictive of future psychopathology in at-risk individuals is important to efficiently direct preventive care. Alterations in reward processing may be a risk factor for depression. The current study characterized neural substrates of reward processing in children at low- and high-risk for psychopathology due to maternal depression status. Children with (n=27) and without (n=19) maternal depression (ages 5.9-9.6 years) performed a monetary incentive delay task in which they received rewards, if they successfully hit a target, or no reward regardless of performance, during fMRI acquisition. Multiple dorsal prefrontal, temporal, and striatal regions showed significant Group (high- vs. low-risk)×Performance (hit vs. miss)×Condition (no reward vs. reward) interactions in a whole-brain analysis. All regions exhibited similar patterns, whereby the high-risk group showed blunted activation differences between trials with vs. without rewards when participants hit the target. Moreover, high-risk children showed activation differences between trials with vs. without rewards in the opposite direction, compared to the low-risk group, when they missed the target. This study had a modest sample size, though larger than existing studies. Children with maternal depression are at elevated risk for future psychopathology, yet not all experience clinically significant symptoms; longitudinal research is necessary to fully track the pathway from risk to disorder. Children of depressed mothers exhibited attenuated neural activation differences and activation patterns opposite to children without depressed mothers. Our findings may provide targets for hypothesis-driven preventive interventions and lead to earlier identification of individuals at risk. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Striatal dopamine transmission in healthy humans during a passive monetary reward task.

    Science.gov (United States)

    Hakyemez, Hélène S; Dagher, Alain; Smith, Stephen D; Zald, David H

    2008-02-15

    Research on dopamine (DA) transmission has emphasized the importance of increased phasic DA cell firing in the presence of unpredictable rewards. Using [(11)C]raclopride PET, we previously reported that DA transmission was both suppressed and enhanced in different regions of the striatum during an unpredictable reward task [Zald, D.H., Boileau, I., El Dearedy, W., Gunn, R., McGlone, F., Dichter, G.S. et al. (2004). Dopamine transmission in the human striatum during monetary reward tasks. J. Neurosci. 24, 4105-4112]. However, it was unclear if reductions in DA release during this task reflected a response to the high proportion of nonrewarding trials, and whether the behavioral demands of the task influenced the observed response. To test these issues, we presented 10 healthy subjects with an automated (passive) roulette wheel game in which the amount of reward and its timing were unpredictable and the rewarding trials greatly outnumbered the nonrewarding ones. As in the previous study, DA transmission in the putamen was significantly suppressed relative to a predictable control condition. A similar suppression occurred when subjects were presented with temporally unpredictable novel pictures and sounds. At present, models of DA functioning during reward do not account for this suppression, but given that it has been observed in two different studies using different reward paradigms, this phenomenon warrants attention. Neither the unpredictable reward nor the novelty conditions produced consistent increases in striatal DA transmission. These data suggest that active behavioral engagement may be necessary to observe robust statewise increases in DA release in the striatum.

  3. Theoretical investigation of aberrations upon ametropic human eyes

    Science.gov (United States)

    Tan, Bo; Chen, Ying-Ling; Lewis, J. W. L.; Baker, Kevin

    2003-11-01

    The human eye aberrations are important for visual acuity and ophthalmic diagnostics and surgical procedures. Reported monochromatic aberration data of the normal 20/20 human eyes are scarce. There exist even fewer reports of the relation between ametropic conditions and aberrations. We theoretically investigate the monochromatic and chromatic aberrations of human eyes for refractive errors of -10 to +10 diopters. Schematic human eye models are employed using optical design software for axial, index, and refractive types of ametropia.

  4. 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

  5. Hedging your bets by learning reward correlations in the human brain.

    Science.gov (United States)

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

    2011-09-22

    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. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Spherical aberration from trajectories in real and hard-edge ...

    Indian Academy of Sciences (India)

    (3)–(4) by comparing with spherical aberration obtained from the ensemble of particle trajectories. The scaled field gives the same focal length. 3. Particle trajectory. 3.1 Ray equation with aberration. The particle trajectory in a solenoid magnet with aberrations is governed by the third-order paraxial ray equation given in eq.

  7. Generalized beam quality factor of aberrated truncated Gaussian laser beams

    CSIR Research Space (South Africa)

    Mafusire, C

    2011-07-01

    Full Text Available The authors outline a theory for the calculation of the beam quality factor of an aberrated laser beam. They provide closed form equations that show that the beam quality factor of an aberrated Gaussian beam depends on all primary aberrations except...

  8. Dose-Response Curve of Chromosome Aberrations in Human Lymphocytes Induced by Gamma-Rays

    Directory of Open Access Journals (Sweden)

    Y. Lusiyanti

    2013-12-01

    Full Text Available Chromosome aberration is a biomarker to predict the level of cell damage caused by exposure to ionizing radiation on human body. Dicentric chromosome is a specific chromosome aberration caused by ionizing radiation and is used as a gold standard biodosimetry of individuals over exposed to ionizing radiation. In radiation accident the dicentric assays has been applied as biological dosimetry to estimate radiation absorbed dose and also to confirm the radiation dose received to radiation workers.The purpose of this study was to generate a dose response curve of chromosome aberration (dicentric in human lymphocyte induced by gamma radiation. Peripheral blood samples from three non smoking healthy volunteers aged between 25-48 years old with informed consent were irradiated with dose between 0.1-4.0 Gy and a control using gamma teletherapy source. The culture procedure was conducted following the IAEA standard procedures with slight modifications. Analysis of dose-response curves used was LQ model Y = a + αD + βD2. The result showed that α and β values of the curve obtained were 0.018 ± 0.006 and 0.013 ± 0.002, respectively. Dose response calibration curve for dicentric chromosome aberrations in human lymphocytes induced by gamma-radiation fitted to linear quadratic model. In order to apply the dose response curve of chromosome aberration disentric for biodosimetry, this standar curve still need to be validated.

  9. Strain-dependent differences in corticolimbic processing of aversive or rewarding stimuli

    Directory of Open Access Journals (Sweden)

    Diego eAndolina

    2015-02-01

    Full Text Available Aberrations in the elaboration of both aversive and rewarding stimuli characterize several psychopathologies including anxiety, depression and addiction. Several studies suggest that different neurotrasmitters, within the corticolimbic system, are critically involved in the processing of positive and negative stimuli. Individual differences in this system, depending on genotype, have been shown to act as a liability factor for different psychopathologies. Inbred mouse strains are commonly used in preclinical studies of normal and pathological behaviors. In particular, C57BL/6J (C57 and DBA/2J (DBA strains have permitted to disclose the impact of different genetic backgrounds over the corticolimbic system functions. Here, we summarize the main findings collected over the years in our laboratory, showing how the genetic background plays a critical role in modulating amminergic and GABAergic neurotransmission in prefrontal-accumbal-amygdala system response to different rewarding and aversive experiences, as well as to stress response. Finally, we propose a top-down model for the response to rewarding and aversive stimuli in which amminergic transmission in PFC controls accumbal and amygdala neurotransmitter response.

  10. Reward sensitivity for a palatable food reward peaks during pubertal developmental in rats

    Directory of Open Access Journals (Sweden)

    Chris M Friemel

    2010-07-01

    Full Text Available Puberty is a critical period for the initiation of drug use and abuse. Because early drug use onset often accounts for a more severe progression of addiction, it is of importance to understand the underlying mechanisms and neurodevelopmental changes during puberty that are contributing to enhanced reward processing in teenagers. The present study investigated the progression of reward sensitivity towards a natural food reward over the whole course of adolescence in male rats (postnatal days 30–90 by monitoring consummatory, motivational behavior and neurobiological correlates of reward. Using a limited-free intake paradigm, consumption of sweetened condensed milk (SCM was measured repeatedly in adolescent and adult rats. Additionally, early- and mid-pubertal animals were tested in Progressive Ratio responding for SCM and c-fos protein expression in reward-associated brain structures was examined after odor-conditioning for SCM. We found a transient increase in SCM consumption and motivational incentive for SCM during puberty. This increased reward sensitivity was most pronounced around mid-puberty. The behavioral findings are paralleled by enhanced c-fos staining in reward-related structures revealing an intensified neuronal response after reward-cue presentation, distinctive for pubertal animals. Taken together, these data indicate an increase in reward sensitivity during adolescence accompanied by enhanced responsiveness of reward associated brain structures to incentive stimuli, and it seems that both is strongly pronounced around mid-puberty. Therefore, higher reward sensitivity during pubertal maturation might contribute to the enhanced vulnerability of teenagers for the initiation of experimental drug use.

  11. Timing and expectation of reward: a neuro-computational model of the afferents to the ventral tegmental area

    Directory of Open Access Journals (Sweden)

    Julien eVitay

    2014-01-01

    Full Text Available Neural activity in dopaminergic areas such as the ventral tegmental area is influenced by timing processes, in particular by the temporal expectation of rewards during Pavlovian conditioning. Receipt of a reward at the expected time allows to compute reward-prediction errors which can drive learning in motor or cognitive structures. Reciprocally, dopamine plays an important role in the timing of external events. Several models of the dopaminergic system exist, but the substrate of temporal learning is rather unclear. In this article, we propose a neuro-computational model of the afferent network to the ventral tegmental area, including the lateral hypothalamus, the pedunculopontine nucleus, the amygdala, the ventromedial prefrontal cortex, the ventral basal ganglia (including the nucleus accumbens and the ventral pallidum, as well as the lateral habenula and the rostromedial tegmental nucleus. Based on a plausible connectivity and realistic learning rules, this neuro-computational model reproduces several experimental observations, such as the progressive cancellation of dopaminergic bursts at reward delivery, the appearance of bursts at the onset of reward-predicting cues or the influence of reward magnitude on activity in the amygdala and ventral tegmental area. While associative learning occurs primarily in the amygdala, learning of the temporal relationship between the cue and the associated reward is implemented as a dopamine-modulated coincidence detection mechanism in the nucleus accumbens.

  12. Visual sexual stimuli – cue or reward? A key for interpreting brain imaging studies on human sexual behaviors

    Directory of Open Access Journals (Sweden)

    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.

  13. Nucleus accumbens response to rewards and testosterone levels are related to alcohol use in adolescents and young adults

    Directory of Open Access Journals (Sweden)

    Barbara R. Braams

    2016-02-01

    Full Text Available During adolescence there is a normative increase in risk-taking behavior, which is reflected in, for example, increases in alcohol consumption. Prior research has demonstrated a link between testosterone and alcohol consumption, and between testosterone and neural responses to rewards. Yet, no study to date tested how testosterone levels and neural responses to rewards relate to and predict individual differences in alcohol use. The current study aimed to investigate this by assessing alcohol use, testosterone levels and neural responses to rewards in adolescents (12–17 years old and young adults (18–26 years old. Participants were measured twice with a two-year interval between testing sessions. Cross-sectional analysis showed that at the second time point higher neural activity to rewards, but not testosterone levels, explained significant variance above age in reported alcohol use. Predictive analyses showed that, higher testosterone level at the first time point, but not neural activity to rewards at the first time point, was predictive of more alcohol use at the second time point. These results suggest that neural responses to rewards are correlated with current alcohol consumption, and that testosterone level is predictive of future alcohol consumption. These results are interpreted in the context of trajectory models of adolescent development.

  14. The correction of electron lens aberrations.

    Science.gov (United States)

    Hawkes, P W

    2015-09-01

    The progress of electron lens aberration correction from about 1990 onwards is chronicled. Reasonably complete lists of publications on this and related topics are appended. A present for Max Haider and Ondrej Krivanek in the year of their 65th birthdays. By a happy coincidence, this review was completed in the year that both Max Haider and Ondrej Krivanek reached the age of 65. It is a pleasure to dedicate it to the two leading actors in the saga of aberration corrector design and construction. They would both wish to associate their colleagues with such a tribute but it is the names of Haider and Krivanek (not forgetting Joachim Zach) that will remain in the annals of electron optics, next to that of Harald Rose. I am proud to know that both regard me as a friend as well as a colleague. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Reward-related attentional bias and adolescent substance use: a prognostic relationship?

    Science.gov (United States)

    van Hemel-Ruiter, Madelon E; de Jong, Peter J; Ostafin, Brian D; Oldehinkel, Albertine J

    2015-01-01

    Current cognitive-motivational addiction theories propose that prioritizing appetitive, reward-related information (attentional bias) plays a vital role in substance abuse behavior. Previous cross-sectional research has shown that adolescent substance use is related to reward-related attentional biases. The present study was designed to extend these findings by testing whether these reward biases have predictive value for adolescent substance use at three-year follow-up. Participants (N = 657, mean age = 16.2 yrs at baseline) were a sub-sample of Tracking Adolescents' Individual Lives Survey (TRAILS), a large longitudinal community cohort study. We used a spatial orienting task as a behavioral index of appetitive-related attentional processes at baseline and a substance use questionnaire at both baseline and three years follow-up. Bivariate correlational analyses showed that enhanced attentional engagement with cues that predicted potential reward and nonpunishment was positively associated with substance use (alcohol, tobacco, and cannabis) three years later. However, reward bias was not predictive of changes in substance use. A post-hoc analysis in a selection of adolescents who started using illicit drugs (other than cannabis) in the follow-up period demonstrated that stronger baseline attentional engagement toward cues of nonpunishment was related to a higher level of illicit drug use three years later. The finding that reward bias was not predictive for the increase in substance use in adolescents who already started using substances at baseline, but did show prognostic value in adolescents who initiated drug use in between baseline and follow-up suggests that appetitive bias might be especially important in the initiation stages of adolescent substance use.

  16. The aberrant retroesophageal right subclavian artery.

    Science.gov (United States)

    Seres-Sturm, M; Maros, T N; Seres-Sturm, L

    1985-01-01

    Two cases with arteria lusoria were found at 278 routine dissections. These arteria arise as the last branches of the aortic arch and have a retroesophageal position. At the crossing point, the esophagus narrows due to the groove caused by the artery. The appearance of this malposition is the consequence of the perturbation in the organo-genesis of the right dorsal aorta and fourth branchial artery. The aberration can lead to disphagia lusoria.

  17. Retrotracheal aberrant left brachiocephalic vein: CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Yigit, Adalet E.; Haliloglu, Mithat; Karcaaltincaba, Musturay; Ariyurek, Macit O. [Hacettepe University Faculty of Medicine, Department of Radiology, Ankara (Turkey)

    2008-03-15

    We present a child with double aberrant left brachiocephalic vein (ALBCV) that was an incidental finding on CT. The anterior and thin branch was above the aortic arch and behind the truncus brachiocephalicus and drained into the superior vena cava (SVC). The posterior and thick branch of the ALBCV coursed posterior to the trachea and oesophagus and joined with the azygos vein before draining into the SVC. To our knowledge, retrotracheal ALBCV has not been previously described. (orig.)

  18. Aberrant attachment of orbicularis oculi: Case report

    Directory of Open Access Journals (Sweden)

    Sehgal Ritu

    2005-01-01

    Full Text Available A morphological peculiarity was observed in the form of an aberrant lateral bony attachment of the orbital part of the Orbicularis oculi muscle on the zygomatic bone, during routine dissection of a cadaver of an adult male of Indian origin. Fibers of this part of the muscle are not known to show any lateral attachment on bone. This paper discusses the presentation, probable embryological cause and clinical implications of this unusual finding.

  19. Reward sensitivity, decisional bias, and metacognitive deficits in cocaine drug addiction.

    Science.gov (United States)

    Balconi, Michela; Finocchiaro, Roberta; Campanella, Salvatore

    2014-01-01

    The present research explored the effect of reward sensitivity bias and metacognitive deficits on substance use disorder (SUD) in the decision-making process. The behavioral activation system (BAS) was used as a predictive marker of dysfunctional behavior during the Iowa gambling task (IGT). We also tried to relate this motivational system bias to self-reported metacognitive measures (self-knowledge, strategic planning, flexibility, and efficacy) in the decision processes. Thirty-four SUD participants (cocaine dependent) and 39 participants in the control group underwent the IGT. The SUD group was associated with a poorer performance on the IGT and a dysfunctional metacognition ability (unrealistic representation). An increase in the reward sensitivity (higher BAS, BAS reward responsiveness, and BAS reward) was observed in the SUD group compared with the control group and explained (through a regression analysis) the main behavioral deficits. More generally, an increase in the BAS reward responsiveness may be considered a predictive measure of risk-taking and dysfunctional behavior, not only in pathological (SUD) individuals, but also in subclinical individuals (controls). We discuss the likely cognitive, brain, and neurotransmitter contributions to this phenomenon.

  20. On Being Imitated: Effects on Reward and Reward Value of the Imitator

    Science.gov (United States)

    Thelen, Mark H.; And Others

    1977-01-01

    This study extends the research on being imitated by assessing its impact on the model's reward of the imitator and on the imitator's reward value relative to a juxtaposed nonimitating confederate. 48 first grade students of primarily middle socio-economic class served as subjects. (Author/RK)

  1. 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

  2. Neural sensitivity to absolute and relative anticipated reward in adolescents.

    Science.gov (United States)

    Vaidya, Jatin G; Knutson, Brian; O'Leary, Daniel S; Block, Robert I; Magnotta, Vincent

    2013-01-01

    Adolescence is associated with a dramatic increase in risky and impulsive behaviors that have been attributed to developmental differences in neural processing of rewards. In the present study, we sought to identify age differences in anticipation of absolute and relative rewards. To do so, we modified a commonly used monetary incentive delay (MID) task in order to examine brain activity to relative anticipated reward value (neural sensitivity to the value of a reward as a function of other available rewards). This design also made it possible to examine developmental differences in brain activation to absolute anticipated reward magnitude (the degree to which neural activity increases with increasing reward magnitude). While undergoing fMRI, 18 adolescents and 18 adult participants were presented with cues associated with different reward magnitudes. After the cue, participants responded to a target to win money on that trial. Presentation of cues was blocked such that two reward cues associated with $.20, $1.00, or $5.00 were in play on a given block. Thus, the relative value of the $1.00 reward varied depending on whether it was paired with a smaller or larger reward. Reflecting age differences in neural responses to relative anticipated reward (i.e., reference dependent processing), adults, but not adolescents, demonstrated greater activity to a $1 reward when it was the larger of the two available rewards. Adults also demonstrated a more linear increase in ventral striatal activity as a function of increasing absolute reward magnitude compared to adolescents. Additionally, reduced ventral striatal sensitivity to absolute anticipated reward (i.e., the difference in activity to medium versus small rewards) correlated with higher levels of trait Impulsivity. Thus, ventral striatal activity in anticipation of absolute and relative rewards develops with age. Absolute reward processing is also linked to individual differences in Impulsivity.

  3. Neural sensitivity to absolute and relative anticipated reward in adolescents.

    Directory of Open Access Journals (Sweden)

    Jatin G Vaidya

    Full Text Available Adolescence is associated with a dramatic increase in risky and impulsive behaviors that have been attributed to developmental differences in neural processing of rewards. In the present study, we sought to identify age differences in anticipation of absolute and relative rewards. To do so, we modified a commonly used monetary incentive delay (MID task in order to examine brain activity to relative anticipated reward value (neural sensitivity to the value of a reward as a function of other available rewards. This design also made it possible to examine developmental differences in brain activation to absolute anticipated reward magnitude (the degree to which neural activity increases with increasing reward magnitude. While undergoing fMRI, 18 adolescents and 18 adult participants were presented with cues associated with different reward magnitudes. After the cue, participants responded to a target to win money on that trial. Presentation of cues was blocked such that two reward cues associated with $.20, $1.00, or $5.00 were in play on a given block. Thus, the relative value of the $1.00 reward varied depending on whether it was paired with a smaller or larger reward. Reflecting age differences in neural responses to relative anticipated reward (i.e., reference dependent processing, adults, but not adolescents, demonstrated greater activity to a $1 reward when it was the larger of the two available rewards. Adults also demonstrated a more linear increase in ventral striatal activity as a function of increasing absolute reward magnitude compared to adolescents. Additionally, reduced ventral striatal sensitivity to absolute anticipated reward (i.e., the difference in activity to medium versus small rewards correlated with higher levels of trait Impulsivity. Thus, ventral striatal activity in anticipation of absolute and relative rewards develops with age. Absolute reward processing is also linked to individual differences in Impulsivity.

  4. Necessary Contributions of Human Frontal Lobe Subregions to Reward Learning in a Dynamic, Multidimensional Environment.

    Science.gov (United States)

    Vaidya, Avinash R; Fellows, Lesley K

    2016-09-21

    Real-world decisions are typically made between options that vary along multiple dimensions, requiring prioritization of the important dimensions to support optimal choice. Learning in this setting depends on attributing decision outcomes to the dimensions with predictive relevance rather than to dimensions that are irrelevant and nonpredictive. This attribution problem is computationally challenging, and likely requires an interplay between selective attention and reward learning. Both these processes have been separately linked to the prefrontal cortex, but little is known about how they combine to support learning the reward value of multidimensional stimuli. Here, we examined the necessary contributions of frontal lobe subregions in attributing feedback to relevant and irrelevant dimensions on a trial-by-trial basis in humans. Patients with focal frontal lobe damage completed a demanding reward learning task where options varied on three dimensions, only one of which predicted reward. Participants with left lateral frontal lobe damage attributed rewards to irrelevant dimensions, rather than the relevant dimension. Damage to the ventromedial frontal lobe also impaired learning about the relevant dimension, but did not increase reward attribution to irrelevant dimensions. The results argue for distinct roles for these two regions in learning the value of multidimensional decision options under dynamic conditions, with the lateral frontal lobe required for selecting the relevant dimension to associate with reward, and the ventromedial frontal lobe required to learn the reward association itself. The real world is complex and multidimensional; how do we attribute rewards to predictive features when surrounded by competing cues? Here, we tested the critical involvement of human frontal lobe subregions in a probabilistic, multidimensional learning environment, asking whether focal lesions affected trial-by-trial attribution of feedback to relevant and irrelevant

  5. DNA Repair Defects and Chromosomal Aberrations

    Science.gov (United States)

    Hada, Megumi; George, K. A.; Huff, J. L.; Pluth, J. M.; Cucinotta, F. A.

    2009-01-01

    Yields of chromosome aberrations were assessed in cells deficient in DNA doublestrand break (DSB) repair, after exposure to acute or to low-dose-rate (0.018 Gy/hr) gamma rays or acute high LET iron nuclei. We studied several cell lines including fibroblasts deficient in ATM (ataxia telangiectasia mutated; product of the gene that is mutated in ataxia telangiectasia patients) or NBS (nibrin; product of the gene mutated in the Nijmegen breakage syndrome), and gliomablastoma cells that are proficient or lacking in DNA-dependent protein kinase (DNA-PK) activity. Chromosomes were analyzed using the fluorescence in situ hybridization (FISH) chromosome painting method in cells at the first division post irradiation, and chromosome aberrations were identified as either simple exchanges (translocations and dicentrics) or complex exchanges (involving >2 breaks in 2 or more chromosomes). Gamma irradiation induced greater yields of both simple and complex exchanges in the DSB repair-defective cells than in the normal cells. The quadratic dose-response terms for both simple and complex chromosome exchanges were significantly higher for the ATM- and NBS-deficient lines than for normal fibroblasts. However, in the NBS cells the linear dose-response term was significantly higher only for simple exchanges. The large increases in the quadratic dose-response terms in these repair-defective cell lines points the importance of the functions of ATM and NBS in chromatin modifications to facilitate correct DSB repair and minimize the formation of aberrations. The differences found between ATM- and NBS-deficient cells at low doses suggest that important questions should with regard to applying observations of radiation sensitivity at high dose to low-dose exposures. For aberrations induced by iron nuclei, regression models preferred purely linear dose responses for simple exchanges and quadratic dose responses for complex exchanges. Relative biological effectiveness (RBE) factors of all of

  6. Genetic variation in dopaminergic reward in humans.

    Science.gov (United States)

    Stice, Eric; Dagher, Alain

    2010-01-01

    Dopamine-based reward circuitry appears to play a role in encoding reward from eating and incentive sensitization, whereby cues associated with food reward acquire motivational value. Data suggest that low levels of dopamine D2 receptors and attenuated responsivity of dopamine-target regions (e.g. the striatum) to food and food cues are associated with elevated weight. There is mixed evidence that genotypes that appear to be associated with reduced signaling of dopamine circuitry, including DRD2, DRD4 and DAT, are correlated with obesity. In addition, there is emerging fMRI evidence that reduced responsivity in brain regions implicated in food reward increase risk for future weight gain among individuals who appear to be at genetic risk for attenuated dopamine signaling by virtue of DRD2 and DRD4 genotypes. However, it is vital for these relations to be replicated in larger, independent prospective studies and to use positron emission tomography to better characterize parameters of dopamine signaling, including dopamine receptor density, basal dopamine levels, and phasic dopamine release. Improved understanding of the role of dopamine-based reward circuitry and genotypes that influence the functioning of this circuitry may inform the design of more effective preventive and treatment interventions for obesity. Copyright (c) 2010 S. Karger AG, Basel.

  7. Reward modulation of cognitive function in adult attention-deficit/hyperactivity disorder: a pilot study on the role of striatal dopamine.

    Science.gov (United States)

    Aarts, Esther; van Holstein, Mieke; Hoogman, Martine; Onnink, Marten; Kan, Cornelis; Franke, Barbara; Buitelaar, Jan; Cools, Roshan

    2015-02-01

    Attention-deficit/hyperactivity disorder (ADHD) is accompanied by impairments in cognitive control, such as task-switching deficits. We investigated whether such problems, and their remediation by medication, reflect abnormal reward motivation and associated striatal dopamine transmission in ADHD. We used functional genetic neuroimaging to assess the effects of dopaminergic medication and reward motivation on task-switching and striatal BOLD signal in 23 adults with ADHD, ON and OFF methylphenidate, and 26 healthy controls. Critically, we took into account interindividual variability in striatal dopamine by exploiting a common genetic polymorphism (3'-UTR VNTR) in the DAT1 gene coding for the dopamine transporter. The results showed a highly significant group by genotype interaction in the striatum. This was because a subgroup of patients with ADHD showed markedly exaggerated effects of reward on the striatal BOLD signal during task-switching when they were OFF their dopaminergic medication. Specifically, patients carrying the 9R allele showed a greater striatal signal than healthy controls carrying this allele, whereas no effect of diagnosis was observed in 10R homozygotes. Aberrant striatal responses were normalized when 9R-carrying patients with ADHD were ON medication. These pilot data indicate an important role for aberrant reward motivation, striatal dopamine and interindividual genetic differences in cognitive processes in adult ADHD.

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

    Science.gov (United States)

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

    2014-09-01

    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. 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. 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). 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. 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.

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

    Science.gov (United States)

    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

  10. Electrophysiological Evidence of Atypical Motivation and Reward Processing in Children with Attention-Deficit Hyperactivity Disorder

    Science.gov (United States)

    Holroyd, Clay B.; Baker, Travis E.; Kerns, Kimberly A.; Muller, Ulrich

    2008-01-01

    Behavioral and neurophysiological evidence suggest that attention-deficit hyperactivity disorder (ADHD) is characterized by the impact of abnormal reward prediction error signals carried by the midbrain dopamine system on frontal brain areas that implement cognitive control. To investigate this issue, we recorded the event-related brain potential…

  11. 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

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  14. A Tribute to Charlie Chaplin: Induced Positive Affect Improves Reward-Based Decision-Learning in Parkinson’s Disease

    Science.gov (United States)

    Ridderinkhof, K. Richard; van Wouwe, Nelleke C.; Band, Guido P. H.; Wylie, Scott A.; Van der Stigchel, Stefan; van Hees, Pieter; Buitenweg, Jessika; van de Vijver, Irene; van den Wildenberg, Wery P. M.

    2012-01-01

    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 associated with frontostriatal circuitry and, consequently, learning to predict which actions will yield reward. PMID:22707944

  15. A tribute to charlie chaplin: induced positive affect improves reward-based decision-learning in Parkinson's disease.

    Science.gov (United States)

    Ridderinkhof, K Richard; van Wouwe, Nelleke C; Band, Guido P H; Wylie, Scott A; Van der Stigchel, Stefan; van Hees, Pieter; Buitenweg, Jessika; van de Vijver, Irene; van den Wildenberg, Wery P M

    2012-01-01

    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 associated with frontostriatal circuitry and, consequently, learning to predict which actions will yield reward.

  16. The Effects of Rewarding User Engagement

    DEFF Research Database (Denmark)

    Claussen, Jörg; Kretschmer, Tobias; Mayrhofer, Philip

    2013-01-01

    We study the market for apps on Facebook, the dominant social networking platform, and make use of a rule change by Facebook by which highly engaging apps were rewarded with further opportunities to engage users. The rule change led to new applications with significantly higher user ratings being...... declined less rapidly with age. Our results show that social media channels do not necessarily have to be managed through hard exclusion of participants but can also be steered through “softer” changes in reward and incentive systems.......We study the market for apps on Facebook, the dominant social networking platform, and make use of a rule change by Facebook by which highly engaging apps were rewarded with further opportunities to engage users. The rule change led to new applications with significantly higher user ratings being...

  17. Willing to wait: Elevated reward-processing EEG activity associated with a greater preference for larger-but-delayed rewards.

    Science.gov (United States)

    Pornpattananangkul, Narun; Nusslock, Robin

    2016-10-01

    While almost everyone discounts the value of future rewards over immediate rewards, people differ in their so-called delay-discounting. One of the several factors that may explain individual differences in delay-discounting is reward-processing. To study individual-differences in reward-processing, however, one needs to consider the heterogeneity of neural-activity at each reward-processing stage. Here using EEG, we separated reward-related neural activity into distinct reward-anticipation and reward-outcome stages using time-frequency characteristics. Thirty-seven individuals first completed a behavioral delay-discounting task. Then reward-processing EEG activity was assessed using a separate reward-learning task, called a reward time-estimation task. During this EEG task, participants were instructed to estimate time duration and were provided performance feedback on a trial-by-trial basis. Participants received monetary-reward for accurate-performance on Reward trials, but not on No-Reward trials. Reward trials, relative to No-Reward trials, enhanced EEG activity during both reward-anticipation (including, cued-locked delta power during cue-evaluation and pre-feedback alpha suppression during feedback-anticipation) and reward-outcome (including, feedback-locked delta, theta and beta power) stages. Moreover, all of these EEG indices correlated with behavioral performance in the time-estimation task, suggesting their essential roles in learning and adjusting performance to maximize winnings in a reward-learning situation. Importantly, enhanced EEG power during Reward trials, as reflected by stronger 1) pre-feedback alpha suppression, 2) feedback-locked theta and 3) feedback-locked beta, was associated with a greater preference for larger-but-delayed rewards in a separate, behavioral delay-discounting task. Results highlight the association between a stronger preference toward larger-but-delayed rewards and enhanced reward-processing. Moreover, our reward

  18. A framework for guiding efforts to reward value instead of volume.

    Science.gov (United States)

    Christensen, Taylor J

    2016-06-01

    The U.S. healthcare system is in the midst of a major shift from fee-for-service to value-based reimbursement models. To date, these new reimbursement models have been focused on quality-contingent bonuses and cost-of-care risk sharing for providers, both of which have yielded only modest success.An analysis of health policy and business strategy literature was performed to identify the mechanisms of how value is rewarded in other industries and to understand the barriers to those mechanisms operating in the healthcare industry. A framework was developed to organize these findings. Rewarding healthcare providers for delivering value can only be achieved by enabling profitability to increase as value increases relative to competitors. Four variables determine a provider's profitability, each of which is considered as a potential lever to reward value with profit. The lever that offers the greatest potential is quantity (i.e., market share). Ironically, this means rewarding value with volume. The major barriers to value improvements being rewarded with market share are identified, and the profound impact of minimizing or removing those barriers is illustrated using a variety of examples from our healthcare system. Trending reforms that rely on quality-contingent bonuses and cost-of-care risk sharing are limited in the degree of value improvement they will stimulate because they rely on ineffective levers to reward value; instead, reform efforts must focus on removing barriers to rewarding value with market share. The framework presented can be used to predict the impact of any proposed reform.

  19. Optimization of rewards in single machine scheduling in the rewards-driven systems

    Directory of Open Access Journals (Sweden)

    Abolfazl Gharaei

    2015-06-01

    Full Text Available The single machine scheduling problem aims at obtaining the best sequence for a set of jobs in a manufacturing system with a single machine. In this paper, we optimize rewards in single machine scheduling in rewards-driven systems such that total reward is maximized while the constraints contains of limitation in total rewards for earliness and learning, independent of earliness and learning and etc. are satisfied. In mentioned systems as for earliness and learning the bonus is awarded to operators, we consider only rewards in mentioned systems and it will not be penalized under any circumstances. Our objective is to optimize total rewards in mentioned system by taking the rewards in the form of quadratic for both learning and earliness. The recently-developed sequential quadratic programming (SQP, is used by solve the problem. Results show that SQP had satisfactory performance in terms of optimum solutions, number of iterations, infeasibility and optimality error. Finally, a sensitivity analysis is performed on the change rate of the objective function obtained based on the change rate of the “amount of earliness for jobs (Ei parameter”.

  20. [Influences on the amount of the reward: how five-year-old children distribute rewards].

    Science.gov (United States)

    Tsutsu, Kiyomi

    2010-08-01

    Five-year-old children were presented two stories in which each of two characters made different numbers of Origami stars; the total number of stars was 16 in one story and 12 in the other. The children allocated rewards to the characters and justified their allocations. There were three conditions in which the total number of rewards was equal to (Middle-N), less than (Small-N), or more than (Large-N) the total number of stars in each story. Most children allocated the rewards equally to the two characters in the Small-N condition, while almost half of the children did not employ an equal allocation in the Middle-N and Large-N conditions. This suggests that in the Small-N condition, if an equity-like allocation were employed, children would feel sorry for the character given very few rewards, and therefore they distributed the rewards equally. On the other hand, in the Middle-N and Large-N conditions, even when one character received fewer rewards than the other, the children did not feel that the fewer rewards were too few.

  1. Long-term voluntary wheel running is rewarding and produces plasticity in the mesolimbic reward pathway.

    Science.gov (United States)

    Greenwood, Benjamin N; Foley, Teresa E; Le, Tony V; Strong, Paul V; Loughridge, Alice B; Day, Heidi E W; Fleshner, Monika

    2011-03-01

    The mesolimbic reward pathway is implicated in stress-related psychiatric disorders and is a potential target of plasticity underlying the stress resistance produced by repeated voluntary exercise. It is unknown, however, whether rats find long-term access to running wheels rewarding, or if repeated voluntary exercise reward produces plastic changes in mesolimbic reward neurocircuitry. In the current studies, young adult, male Fischer 344 rats allowed voluntary access to running wheels for 6 weeks, but not 2 weeks, found wheel running rewarding, as measured by conditioned place preference (CPP). Consistent with prior reports and the behavioral data, 6 weeks of wheel running increased ΔFosB/FosB immunoreactivity in the nucleus accumbens (Acb). In addition, semi quantitative in situ hybridization revealed that 6 weeks of wheel running, compared to sedentary housing, increased tyrosine hydroxylase (TH) mRNA levels in the ventral tegmental area (VTA), increased delta opioid receptor (DOR) mRNA levels in the Acb shell, and reduced levels of dopamine receptor (DR)-D2 mRNA in the Acb core. Results indicate that repeated voluntary exercise is rewarding and alters gene transcription in mesolimbic reward neurocircuitry. The duration-dependent effects of wheel running on CPP suggest that as the weeks of wheel running progress, the rewarding effects of a night of voluntary wheel running might linger longer into the inactive cycle thus providing stronger support for CPP. The observed plasticity could contribute to the mechanisms by which exercise reduces the incidence and severity of substance abuse disorders, changes the rewarding properties of drugs of abuse, and facilitates successful coping with stress. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. Long term voluntary wheel running is rewarding and produces plasticity in the mesolimbic reward pathway

    Science.gov (United States)

    Greenwood, Benjamin N.; Foley, Teresa E.; Le, Tony V.; Strong, Paul V.; Loughridge, Alice B.; Day, Heidi E.W.; Fleshner, Monika

    2011-01-01

    The mesolimbic reward pathway is implicated in stress-related psychiatric disorders and is a potential target of plasticity underlying the stress resistance produced by repeated voluntary exercise. It is unknown, however, whether rats find long-term access to running wheels rewarding, or if repeated voluntary exercise reward produces plastic changes in mesolimbic reward neurocircuitry. In the current studies, young adult, male Fischer 344 rats allowed voluntary access to running wheels for 6 weeks, but not 2 weeks, found wheel running rewarding, as measured by conditioned place preference (CPP). Consistent with prior reports and the behavioral data, 6 weeks of wheel running increased ΔFosB/FosB immunoreactivity in the nucleus accumbens (Acb). In addition, semi quantitative in situ hybridization revealed that 6 weeks of wheel running, compared to sedentary housing, increased tyrosine hydroxylase (TH) mRNA levels in the ventral tegmental area (VTA), increased delta opioid receptor (DOR) mRNA levels in the Acb shell, and reduced levels of dopamine receptor (DR)-D2 mRNA in the Acb core. Results indicate that repeated voluntary exercise is rewarding and alters gene transcription in mesolimbic reward neurocircuitry. The duration-dependent effects of wheel running on CPP suggest that as the weeks of wheel running progress, the rewarding effects of a night of voluntary wheel running might linger longer into the inactive cycle thus providing stronger support for CPP. The observed plasticity could contribute to the mechanisms by which exercise reduces the incidence and severity of substance abuse disorders, changes the rewarding properties of drugs of abuse, and facilitates successful coping with stress. PMID:21070820

  3. Mental Imagery Training Increases Wanting of Rewards and Reward Sensitivity and Reduces Depressive Symptoms.

    Science.gov (United States)

    Linke, Julia; Wessa, Michèle

    2017-09-01

    High reward sensitivity and wanting of rewarding stimuli help to identify and motivate repetition of pleasant activities. This behavioral activation is thought to increase positive emotions. Therefore, both mechanisms are highly relevant for resilience against depressive symptoms. Yet, these mechanisms have not been targeted by psychotherapeutic interventions. In the present study, we tested a mental imagery training comprising eight 10-minute sessions every second day and delivered via the Internet to healthy volunteers (N = 30, 21 female, mean age of 23.8 years, Caucasian) who were preselected for low reward sensitivity. Participants were paired according to age, sex, reward sensitivity, and mental imagery ability. Then, members of each pair were randomly assigned to either the intervention or wait condition. Ratings of wanting and response bias toward probabilistic reward cues (Probabilistic Reward Task) served as primary outcomes. We further tested whether training effects extended to approach behavior (Approach Avoidance Task) and depressive symptoms (Beck Depression Inventory). The intervention led to an increase in wanting (p reward sensitivity (p = .004, η2p= .27). Further, the training group displayed faster approach toward positive edibles and activities (p = .025, η2p= .18) and reductions in depressive symptoms (p = .028, η2p= .16). Results extend existing literature by showing that mental imagery training can increase wanting of rewarding stimuli and reward sensitivity. Further, the training appears to reduce depressive symptoms and thus may foster the successful implementation of exsiting treatments for depression such as behavioral activation and could also increase resilience against depressive symptoms. Copyright © 2017. Published by Elsevier Ltd.

  4. Genomic aberrations in borderline ovarian tumors

    Directory of Open Access Journals (Sweden)

    Davidson Ben

    2010-02-01

    Full Text Available Abstract Background According to the scientific literature, less than 30 borderline ovarian tumors have been karyotyped and less than 100 analyzed for genomic imbalances by CGH. Methods We report a series of borderline ovarian tumors (n = 23 analyzed by G-banding and karyotyping as well as high resolution CGH; in addition, the tumors were analyzed for microsatellite stability status and by FISH for possible 6q deletion. Results All informative tumors were microsatellite stable and none had a deletion in 6q27. All cases with an abnormal karyotype had simple chromosomal aberrations with +7 and +12 as the most common. In three tumors with single structural rearrangements, a common breakpoint in 3q13 was detected. The major copy number changes detected in the borderline tumors were gains from chromosome arms 2q, 6q, 8q, 9p, and 13q and losses from 1p, 12q, 14q, 15q, 16p, 17p, 17q, 19p, 19q, and 22q. The series included five pairs of bilateral tumors and, in two of these pairs, informative data were obtained as to their clonal relationship. In both pairs, similarities were found between the tumors from the right and left side, strongly indicating that bilaterality had occurred via a metastatic process. The bilateral tumors as a group showed more aberrations than did the unilateral ones, consistent with the view that bilaterality is a sign of more advanced disease. Conclusion Because some of the imbalances found in borderline ovarian tumors seem to be similar to imbalances already known from the more extensively studied overt ovarian carcinomas, we speculate that the subset of borderline tumors with detectable imbalances or karyotypic aberrations may contain a smaller subset of tumors with a tendency to develop a more malignant phenotype. The group of borderline tumors with no imbalances would, in this line of thinking, have less or no propensity for clonal evolution and development to full-blown carcinomas.

  5. Wavefront aberrations of x-ray dynamical diffraction beams.

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    Liao, Keliang; Hong, Youli; Sheng, Weifan

    2014-10-01

    The effects of dynamical diffraction in x-ray diffractive optics with large numerical aperture render the wavefront aberrations difficult to describe using the aberration polynomials, yet knowledge of them plays an important role in a vast variety of scientific problems ranging from optical testing to adaptive optics. Although the diffraction theory of optical aberrations was established decades ago, its application in the area of x-ray dynamical diffraction theory (DDT) is still lacking. Here, we conduct a theoretical study on the aberration properties of x-ray dynamical diffraction beams. By treating the modulus of the complex envelope as the amplitude weight function in the orthogonalization procedure, we generalize the nonrecursive matrix method for the determination of orthonormal aberration polynomials, wherein Zernike DDT and Legendre DDT polynomials are proposed. As an example, we investigate the aberration evolution inside a tilted multilayer Laue lens. The corresponding Legendre DDT polynomials are obtained numerically, which represent balanced aberrations yielding minimum variance of the classical aberrations of an anamorphic optical system. The balancing of classical aberrations and their standard deviations are discussed. We also present the Strehl ratio of the primary and secondary balanced aberrations.

  6. When "Your" reward is the same as "My" reward: self-construal priming shifts neural responses to own vs. friends' rewards.

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    Varnum, Michael E W; Shi, Zhenhao; Chen, Antao; Qiu, Jiang; Han, Shihui

    2014-02-15

    Is it possible for neural responses to others' rewards to be as strong as those for the self? Although prior fMRI studies have demonstrated that watching others get rewards can activate one's own reward centers, such vicarious reward activation has always been less strong than responses to rewards for oneself. In the present study we manipulated participants' self-construal (independent vs. interdependent) and found that, when an independent self-construal was primed, subjects showed greater activation in the bilateral ventral striatum in response to winning money for the self (vs. for a friend) during a gambling game. However, priming an interdependent self-construal resulted in comparable activation in these regions in response to winning money for the self and for a friend. Our findings suggest that interdependence may cause people to experience rewards for a close other as strongly as they experience rewards for the self. © 2013 Elsevier Inc. All rights reserved.

  7. Impaired learning of social compared to monetary rewards in autism

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    Alice eLin

    2012-10-01

    Full Text Available A leading hypothesis to explain the social dysfunction in people with autism spectrum disorders (ASD is that they exhibit a deficit in reward processing and motivation specific to social stimuli.  However, there have been few direct tests of this hypothesis to date.  Here we used an instrumental reward learning task that contrasted learning with social rewards (pictures of positive and negative faces against learning with monetary reward (winning and losing money. The two tasks were structurally identical except for the type of reward, permitting direct comparisons.  We tested ten high-functioning people with ASD (7M, 3F and ten healthy controls who were matched on gender, age and education.  We found no significant differences between the two groups in terms of overall ability behaviorally to discriminate positive from negative slot machines, reaction-times, and valence ratings,  However, there was a specific impairment in the ASD group in learning to choose social rewards, compared to monetary rewards: they had a significantly lower cumulative number of choices of the most rewarding social slot machine, and had a significantly slower initial learning rate for the socially rewarding slot machine, compared to the controls.  The findings show a deficit in reward learning in ASD that is greater for social rewards than for monetary rewards, and support the hypothesis of a disproportionate impairment in social reward processing in ASD.

  8. Ocular aberrations in barn owl eyes.

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    Harmening, Wolf M; Vobig, Michael A; Walter, Peter; Wagner, Hermann

    2007-10-01

    Optical quality in barn owl eyes is presented in terms of measuring the ocular wavefront aberrations with a standard Tscherning-type wavefront aberrometer under natural viewing conditions. While accommodative state was uncontrolled, all eyes were focused within 0.4D with respect to the plane of the aberrometer. Total RMS wavefront error was between 0.06 and 0.15 microm (mean: 0.10 microm, STD: 0.03 microm, defocus cancelled) for a 6 mm pupil. The results suggest that image quality in barn owl eyes is excellent.

  9. The relationship between personality types and reward preferences

    Directory of Open Access Journals (Sweden)

    R. Nienaber

    2011-12-01

    Full Text Available Orientation: Research has shown that total rewards models structured according to individual preferences, positively influence efforts to attract, retain and motivate key employees. Yet, this is seldom done. Structuring total rewards models according to the preferences of employee segments is a viable alternative to accommodate individual preferences. Research purpose: The primary aim of the study was to determine the relationship between personality types and reward preferences. The secondary aim was to determine the reward preferences for different demographic groups. Motivation for the study: An enhanced understanding of reward preferences for different employee segments will enable employers to offer more competitive reward options to their employees. This may, in turn, have a positive impact on retention. Research design, approach and method: Two measuring instruments, the MBTI® Form GRV and the Rewards Preferences Questionnaire, were distributed electronically to 5 000 potential respondents. The results from 589 sets of questionnaires were used in the data analyses. Primary and secondary factor analyses were done on the items in the Rewards Preferences Questionnaire. Main findings/results: The study confirmed that individuals with certain personality types and personality preferences, have different preferences for certain reward categories. There was a stronger relationship between reward preferences and personality preferences than for reward preferences and personality types. Preferences for reward categories by different demographic groups were confirmed. The significant difference in reward preferences between Black and White respondents in particular was noteworthy, with Black respondents indicating significantly higher mean scores for all reward categories than White respondents. Finally, a total rewards framework influenced by the most prominent preferences for reward categories, was designed. Practical/Managerial implications

  10. Reward-related attentional biases and adolescent substance use: the TRAILS study.

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    van Hemel-Ruiter, Madelon E; de Jong, Peter J; Oldehinkel, Albertine J; Ostafin, Brian D

    2013-03-01

    Current cognitive-motivational theories of addiction propose that prioritizing appetitive, reward-related information (attentional bias) plays a vital role in the development and maintenance of substance abuse. This study focused on reward-related attentional processes that might be involved in young-adolescent substance use. Participants were young adolescents (N = 682, mean age = 16.14), who completed a motivated game in the format of a spatial orienting task as a behavioral index of appetitive-related attentional processes and a questionnaire to index substance (alcohol, tobacco, and cannabis) use. Correlational analysis showed a positive relationship between substance use and enhanced attentional engagement, with cues that predicted potential reward and nonpunishment. These results are consistent with the view that adolescents who show a generally enhanced appetitive bias might be at increased risk for developing heavier substance use. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

  11. Anticipation of Monetary Reward Can Attenuate the Vigilance Decrement.

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    Michael Esterman

    Full Text Available Motivation and reward can have differential effects on separate aspects