AbstractTheories of the positive symptoms of schizophrenia hypothesize a role for aberrant reinforcement signaling driven by dysregulated dopamine transmission. Recently, we provided evidence of aberrant reward learning in symptomatic, but not asymptomatic patients with schizophrenia, using a novel paradigm, the Salience Attribution ...
PubMed Central
A dysregulation of the mesolimbic dopamine system in schizophrenia patients may lead to aberrant attribution of incentive salience and contribute to the emergence of psychopathological symptoms like delusions. The dopaminergic signal has been conceptualized to represent a prediction error that indicates the difference between received and ...
Obese humans, compared with normal-weight humans, have less striatal D2 receptors and striatal response to food intake; weaker striatal response to food predicts weight gain for individuals at genetic risk for reduced dopamine (DA) signaling, consistent with the reward-deficit theory of obesity. Yet these may not be initial vulnerability factors, as ...
PubMed
... Accession Number : ADA438496. Title : Prediction of Breast Cancer Risk by Aberrant Methylation in Mammary Duct Lavage. ...
DTIC Science & Technology
Prediction about outcomes constitutes a basic mechanism underlying informed economic decision making. A stimulus constitutes a reward predictor when it provides more information about the reward than the environmental background. Reward prediction can be manipulated in two ways, by varying the ...
INTRODUCTION Midbrain dopamine neurons are activated by unpredicted rewards and reward-predicting stimuli, are not influenced by fully predicted rewards, and are depressed by omitted rewards. Thus, they appear to report an error in the prediction of ...
E-print Network
Animals learn not only about stimuli that predict reward but also about those that signal the omission of an expected reward. We used a conditioned inhibition paradigm derived from animal learning theory to train a discrimination between a visual stimulus that predicted reward (conditioned ...
It was hypothesized that rewards, as perceived by an individual in an organization, are important in that perceived reward forms one identifiable factor in attempting to predict the rate of movement of ideas within an organization. Various concepts and mo...
National Technical Information Service (NTIS)
The dopamine system has been linked to anhedonia in depression and both the positive and negative symptoms of schizophrenia, but it remains unclear how dopamine dysfunction could mechanistically relate to observed symptoms. There is considerable evidence that phasic dopamine signals encode prediction error (differences between expected and actual outcomes), with reinforcement ...
Page 1. AD_____ AWARD NUMBER: DAMD17-01-1-0421 TITLE: Prediction of Breast Cancer Risk by Aberrant ...
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 ...
Previous work has demonstrated that human adolescents may be hypersensitive to rewards; it is unknown which aspect of reward processing this reflects. We separated decision value and prediction error signals and found that neural prediction error signals in the striatum peaked in adolescence, whereas neural ...
... Title : Person-Situation Effects in the Prediction of Performance: An Investigation of Ability, Self-Esteem, and Reward Contingencies. ...
Young, novice drivers constitute a disproportionate percentage of fatalities and injuries in road traffic accidents around the world. This study, attempts to identify motivational factors behind risky driving behavior, and examines the role of personality, especially sensation seeking, impulsivity and sensitivity to punishment/reward in predicting negative ...
Understanding how organisms deal with probabilistic stimulus-reward associations has been advanced by a convergence between reinforcement learning models and primate physiology, which demonstrated that the brain encodes a reward prediction error signal. However, organisms must also predict the level of risk ...
Although positive reward prediction error, a key element in learning that is signaled by dopamine cells, has been extensively studied, little is known about negative reward prediction errors in humans. Detailed animal electrophysiology shows that the habenula, an integrative region involved in many processes ...
s of this method as well as the relevance of the results for dopamine involvement in reward processing are discussed. 2002 Elsevier Science (USA) Key Words: positron emission tomography; endogenous dopamine release; dopamine receptors; reward; raclopride; statistical parametric mapping; kinetic model; activation studies. INTRODUCTION Mesolimbic ...
How do addictive drugs hijack the brain's reward system? This review speculates how normal, physiological reward processes may be affected by addictive drugs. Addictive drugs affect acute responses and plasticity in dopamine neurons and postsynaptic structures. These effects reduce reward discrimination, increase the effects of ...
This study examined whether ventral frontostriatal regions differentially code expected and unexpected reward outcomes. We parametrically manipulated the probability of reward and examined the neural response to reward and nonreward for each probability condition in the ventral striatum and the orbitofrontal cortex (OFC). By late ...
SUMMARYMidbrain dopamine neurons are thought to signal predictions about future rewards based on the memory of past rewarding experience. Little is known about the source of their reward memory and the factors that control its timescale. Here we recorded from dopamine neurons, as well as one of their sources of ...
Subregions of prefrontal cortex are important for estimating reward values and using these values to guide behavior. The present studies directly tested whether orbital prefrontal cortex (O-PFC) and lateral prefrontal cortex (L-PFC) are necessary for evaluating trial-to-trial changes in the reward values predicted by visual cues. We ...
Different Cortico-Basal Ganglia Loops Specialize in Reward Prediction on Different Time Scales suggests that different cortico-basal ganglia loops are specialized for reward prediction on different time of prediction time scale with in the cortico-basal ganglia loops. 2 Methods 2.1 Markov ...
Midbrain dopamine neurons respond to reward-predictive stimuli. In the natural environment reward-predictive stimuli are often perceptually complicated. Thus, to discriminate one stimulus from another, elaborate sensory processing is necessary. Given that previous studies have used simpler types of reward-predictive stimuli, it has yet ...
Medial frontal event-related potentials (ERPs) following rewarding feedback index outcome evaluation. The majority of studies examining the feedback related medial frontal negativity (MFN) employ active tasks during which participants' responses impact their feedback, however, the MFN has been elicited during passive tasks. Many of the studies examining the MFN show enhanced ...
ERIC Educational Resources Information Center
Interactional psychology is concerned with the identification of situational characteristics that enhance the prediction of behavior from knowledge of individual characteristics. Ability, self-esteem, and reward contingencies were examined as predictors o...
Learning Working Memory Tasks by Reward Prediction in the Basal Ganglia Bryan Loughry Department- served by the basal ganglia and prefrontal cortex. The model expands on our previous work is in- formed via a detailed consideration of the basal ganglia anatomy and physiology. This mechanism
General functioning predicts reward and punishment learning in schizophrenia Zsuzsanna Somlai-driven reinforcement learning in patients with schizophrenia have provided mixed results. In this study, we explored. Patients with schizophrenia (n=40) performed similarly to healthy controls (n=30) on the classification
... pressed attitudes of non-MW peers if they ... MWs sonic basic training and understanding of the ... of motivation for predicting and modifying the work ...
... the system of subspecialty opportunities and rewards. ... Track in this research) emphasizes diversification ... the Warrior Track maximizes the prestige of ...
The orbitofrontal cortex (OBFc) has been suggested to code the motivational value of environmental stimuli and to use this information for the flexible guidance of goal-directed behavior. To examine whether information regarding reward prediction is quantitatively represented in the rat OBFc, neural activity was recorded during an olfactory discrimination ...
The serotonergic system plays a key role in the control of impulsive behaviors. Forebrain serotonin depletion leads to premature actions and steepens discounting of delayed rewards. However, there has been no direct evidence for serotonin neuron activity in relation to actions for delayed rewards. Here we show that serotonin neurons increase their tonic ...
Two studies examined whether the detrimental effects of attention to rewards on delay of gratification in waiting situations holds-or reverses-in working situations. In Study 1, preschoolers waited or worked for desired delayed rewards. Delay times increased when children worked in the presence of rewards but, as ...
During reinforcement learning, dopamine release shifts from the moment of reward consumption to the time point when the reward can be predicted. Previous studies provide consistent evidence that reward-predicting cues enhance long-term memory (LTM) formation of these items via dopaminergic projections to the ...
Certain classes of stimuli, such as food and drugs, are highly effective in activating reward regions. We show in humans that activity in these regions can be modulated by the predictability of the sequenced delivery of two mildly pleasurable stimuli, orally delivered fruit juice and water. Using functional magnetic resonance imaging, the activity for ...
Disorders. A Neural Substrate of Prediction and Reward Wolfram Schultz, Peter Dayan, P. Read Montague rewards. In these latter experiments (17), dopa- mine neurons respond with short, phasic activations when by reward, dopamine neurons change the time of their phasic activation from just after the time of ...
Physiologic studies revealed that neurons in the dopaminergic midbrain of non-human primates encode reward prediction errors. It was furthermore shown that reward prediction errors are adaptively scaled with respect to the range of possible outcomes, enabling sensitive encoding for a large range of ...
The study of Mastery Approach Orientation as an achievement goal is central to the understanding of basic motivational processes though controversy surrounds its impact. This research extends the literature regarding this goal orientation by investigating the interaction between Mastery Approach Orientation and Rewarding Climate in the prediction of self ...
Animals depend on a large variety of rewards but their brains have a limited dynamic coding range. When rewards are uncertain, neuronal coding needs to cover a wide range of possible rewards. However, when reward is likely to occur within a specific range, focusing the sensitivity on the ...
It is commonly accepted that reward is an effective motivator of behavior, but little is known about potential costs resulting from reward associations. Here, we used functional magnetic resonance imaging (fMRI) to investigate the neural underpinnings of such reward-related performance-disrupting effects in a ...
... can predict the majority of clonal aberrations among Chernobyl workers who were examined 5�6 years after ... bomb) survivors (4�7), Thorotrast patients (8, 9), Chernobyl nuclear power plant accident victi...
NBII National Biological Information Infrastructure
BackgroundPrevious 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.MethodsThe described experiments used standard behavioral and neurophysiological methods to record ...
Performance in a behavioral task can be facilitated by associating stimulus properties with reward. In contrast, conflicting information is known to impede task performance. Here we investigated how reward associations influence the within-trial processing of conflicting information using a color-naming Stroop task in which a subset of ink colors ...
Risk-sensitive foraging theory (RSFT) was developed to explain a choice between a variable (risk-prone) or constant (risk-averse) option. In the RSFT literature, qualitative shifts in risk-sensitivity have been explained by fluctuations in daily caloric energy budget (DEB). The DEB rule describes foragers' choices as being based on fitness and rate of gain. If the DEB rule is correct, ...
Reward-related mesolimbic dopamine steers animal behavior, creating automatic approach toward reward-associated objects and avoidance of objects unlikely to be beneficial. Theories of dopamine suggest that this reflects underlying biases in perception and attention, with reward enhancing the representation of ...
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 ...
We hypothesized that novel stimuli represent salient learning signals that can motivate "exploration" in search for potential rewards. In computational theories of reinforcement learning, this is referred to as the novelty "exploration bonus" for rewards. If true, stimulus novelty should enhance the reward anticipation signals in brain ...
Dopamine neurons appear to code an error in the prediction of reward. They are activated by unpredicted rewards, are not influenced by predicted rewards, and are depressed when a predicted reward is omitted. After conditioning, they respond to ...
Employers seeking to motivate and encourage healthy behaviors among their employees are increasingly turning to incentive rewards. In fact, a recent Buck Consultants survey of 555 employers, titled Working Well: A Global Survey of Health Promotion and Workplace Wellness Strategies, predicts the use of such rewards to more than double ...
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 ...
A geometrical-optical analysis is developed to predict the reflex observed in retinoscopy. The analysis can be expanded to explain the reflex for an eye with aberrations. The succession of reflexes across the pupil for each position of the retinoscope is represented in a contour plot. The plots demonstrate that retinoscopy can be considered a measure of ...
Neural circuits implicated in drug conditioning, craving and relapse overlap extensively with those involved in natural reward and reinforcement like food. Exposure to drug-related cues in human addicts results in drug craving and localized activation of central circuits that are known to mediate cue-induced reinstatement of drug-seeking behavior in animal models of relapse. ...
and reinforce- ment. Whereas the phasic response of dopamine neurons to reward prediction error fits remark and reinforcing properties. Indeed, gambling be- havior is defined by reward uncertainty and is prevalent response after prediction error could mediate the more dominant reinforcement of ...
It has been suggested that septal nuclei are important in the control of behavior during various reward and non-reward situations. In the present study, neuronal activity was recorded from rat septal nuclei during discrimination of conditioned sensory stimuli (CSs) of the medial forebrain bundle associated with or without a reward ...
The theoretical framework that motivates our research program predicts a three-way interaction between global incentives, local rewards, and task structure, such that the optimal combination of incentives and rewards depends on the factors that govern opt...
Delay discounting is the process by which the value of an expected reward decreases as the delay to obtaining that reward increases. Individuals with higher discounting rates tend to prefer smaller immediate rewards over larger delayed rewards. Previous research has indicated that personality can influence an ...
The influence of radiation upon the structure of the cell nucleus and on cytoplasm and resulting chromosome changes are described. Reversible damage to cells was stu died. The formation of gigantic cells is discussed. (OTS) Chromosome aberrations after irradiation were studied on mice. A connection between the number of spontaneous aberrations ...
Energy Citations Database
Schultz, Wolfram. Predictive reward signal of dopamine neurons. is called rewards, which elicit and reinforce approach behav-J. Neurophysiol. 80: 1�27, 1998. The effects of lesions, receptor ior. The functions of rewards were developed further during blocking, electrical self-stimulation, and drugs of abuse ...
Although reward probability is an important factor that shapes animal's behavior, it is not well understood how the brain translates reward expectation into the vigor of movement [reaction time (RT) and speed]. To address this question, we trained two monkeys in a RT task that required wrist movements in response to vibrotactile and visual stimuli, with a ...
Individuals make choices and prioritize goals using complex processes that assign value to rewards and associated stimuli. During Pavlovian learning, previously neutral stimuli that predict rewards can acquire motivational properties, becoming attractive and desirable incentive stimuli. However, whether a cue acts solely as a predictor ...
Reward representation in ventral striatum is boosted by perceptual novelty, although the mechanism of this effect remains elusive. Animal studies indicate a functional loop (Lisman and Grace, 2005) that includes hippocampus, ventral striatum and midbrain as important in regulating salience attribution within the context of novel stimuli. According to this model, ...
Recently, computational models of reinforcement learning have been applied for the analysis of neuroimaging data. It has been clarified that the striatum plays a key role in decision making. We review the reinforcement learning theory and the biological structures such as the brain and signals such as neuromodulators associated with reinforcement learning. We also investigated the function of the ...
Dopaminergic neurons in the mammalian substantia nigra display characteristic phasic responses to stimuli which reliably predict the receipt of primary rewards. These responses have been suggested to encode reward prediction-errors similar to those used in reinforcement learning. Here, we propose a model of ...
Clinical investigators have long theorized about the role of reward processing and positive affect in depression. One theory posits that compared to nonmelancholic depressives, melancholic depressives experience less consummatory (i.e., post-reward), but comparably low anticipatory (prior to reward), positive affect. We tested whether ...
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 ...
The anterior cingulate cortex (ACC) is implicated in performance monitoring and cognitive control. Non-human primate studies of ACC show prominent reward signals, but these are elusive in human studies, which instead show mainly conflict and error effects. Here we demonstrate distinct appetitive and aversive activity in human ACC. The error likelihood hypothesis suggests that ...
Our ability to selectively engage with our environment enables us to guide our learning and to take advantage of its benefits. When facing multiple possible actions, our choices are a critical aspect of learning. In the case of learning from rewarding feedback, there has been substantial theoretical and empirical progress in elucidating the associated behavioral and neural ...
MicroRNAs (miRNAs) are small RNAs that modulate gene expression by binding target mRNAs. The hundreds of miRNAs expressed in the brain are critical for synaptic development and plasticity. Drugs of abuse cause lasting changes in the limbic regions of the brain that process reward, and addiction is viewed as a form of aberrant neuroplasticity. Using ...
of patients with eyes implanted with different IOLs. In these patients, corneal wave- front aberrations were. 1). Because corneal SA is normally positive, implanting this lens should generate a significantPredicting the Optical Performance of Eyes Implanted with IOLs to Correct Spherical Aberration Juan
In this paper we investigate tradeoffs between speed and accuracy that are produced by humans when confronted with a sequence of choices between two alternatives. We assume that the choice process is described by the drift diffusion model, in which the speed-accuracy tradeoff is primarily controlled by the value of the decision threshold. We test the hypothesis that participants choose the ...
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 (ERP) ...
What happens to others profoundly influences our own behavior. Such other-regarding outcomes can drive observational learning, as well as motivate cooperation, charity, empathy, and even spite. Vicarious reinforcement may serve as one of the critical mechanisms mediating the influence of other-regarding outcomes on behavior and decision-making in groups. Here we show that rhesus macaques ...
The detection of differences between predictions and actual outcomes is important for associative learning and for selecting actions according to their potential future reward. There are reports that tonically active neurons (TANs) in the primate striatum may carry information about errors in the prediction of ...
Social interaction deficits and restricted repetitive behaviors and interests that characterize autism spectrum disorders (ASDs) may both reflect aberrant functioning of brain reward circuits. However, no neuroimaging study to date has investigated the integrity of reward circuits using an incentive delay paradigm in individuals with ...
We investigated the interaction of motivation and timing by manipulating the expected reward magnitude during a peak procedure. Four pigeons were tested with three different reward magnitudes, operationalized as duration of food access. Each stimulus predicted a different reward magnitude on a 5s fixed-interval ...
Using original survey data, this paper examines whether monetary rewards and image reward encourage blood donation or discourage it by damping the intrinsic motivation. On monetary rewards, we find that i) the overall sample�s response to monetary rewards is positive; ii) people who volunteer more frequently, ...
Recent functional imaging studies link reward-related activation of the midbrain substantia nigra-ventral tegmental area (SN/VTA), the site of origin of ascending dopaminergic projections, with improved long-term episodic memory. Here, we investigated in two behavioral experiments how (1) the contingency between item properties and reward, (2) the ...
Individuals make choices and prioritize goals using complex processes that assign value to rewards and associated stimuli. During Pavlovian learning, previously neutral stimuli that predict rewards can acquire motivational properties, whereby they themselves become attractive and desirable incentive stimuli. But individuals differ in ...
Distinct psychological processes have been proposed to unfold in decision-making. The time course of neural mechanisms supporting these processes has not been fully identified. The present MEG study examined spatio-temporal activity related to components of decision-making proposed to support reward valuation, reward prediction, and ...
We investigated how rapidly the reward-predicting properties of visual cues are signaled in the human brain and the extent these reward prediction signals are contextually modifiable. In a magnetoencephalography study, we presented participants with fractal visual cues that predicted monetary ...
errors. This form of learning had a distinct signature: as motor commands adapted, the subjects altered their predictions regarding sensory consequences of motor commands, and generalized this learning broadly of motor commands, leaving behind a sensory remapping, whereas learning from reward prediction error
Delayed rewards lose their value for economic decisions and constitute weaker reinforcers for learning. Temporal discounting of reward value already occurs within a few seconds in animals, which allows investigations of the underlying neurophysiological mechanisms. However, it is difficult to relate these mechanisms to human discounting behavior, which is ...
Humans and animals have the ability to predict future events, which they cultivate by continuously searching their environment for sources of predictive information. However, little is known about the neural systems that motivate this behavior. We hypothesized that information-seeking is assigned value by the same circuits that support ...
In general, humans tend to devalue a delayed reward. Such delay discounting is a theoretical and computational concept in which the discount factor influences the time scale of the trade-off between delay of reward and amount of reward. The discount factor relies on the individual's ability to evaluate the future ...
The lens system of the Melbourne Proton Microprobe, MP, consists of four magnetic quadrupole lenses arranged in a configuration known as a Russian antisymmetric quadruplet. The resolution of the microprobe is degraded by spherical aberration of the lens system. The aim of the present work was to correct the spherical aberration and improve the resolution ...
NASA Astrophysics Data System (ADS)
Disordered dopamine neurotransmission is implicated in mediating impulsiveness across a range of behaviors and disorders including addiction, compulsive gambling, attention-deficit/hyperactivity disorder, and dopamine dysregulation syndrome. Whereas existing theories of dopamine function highlight mechanisms based on aberrant reward learning or behavioral ...
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 ...
The discovery that dopamine neurons signal errors in reward prediction has demonstrated that concepts empirically-derived from the study of animal behavior, can be used to understand the neural implementation of reward learning. Yet the learning theory models linked to phasic dopamine activity treat attention to events such as cues and ...
Lateral habenula (LHb) neurons signal negative "reward-prediction errors" and inhibit midbrain dopamine (DA) neurons. Yet LHb neurons are largely glutamatergic, indicating that this inhibition may occur through an intermediate structure. Recent studies in rats have suggested a candidate for this role, the GABAergic rostromedial tegmental nucleus (RMTg), but this neural pathway ...
Sub-regions of prefrontal cortex are important for estimating reward values and using these values to guide behavior. The present studies directly tested whether orbital (O-PFC) and lateral (L-PFC) prefrontal cortex are necessary for evaluating trial-to-trial changes in the reward values predicted by visual cues. We have compared ...
In this longitudinal study, the authors provide support for the validity of the claim that differences in the nature of the reinforcement that adolescent girls expect from eating contribute to the development of different forms of maladaptive eating. The learned expectancy that eating is pleasurable and rewarding predicted higher levels of ...
Many aspects of human behavior are driven by rewards, yet different people are differentially sensitive to rewards and punishment. In this study, we show that white matter microstructure in the uncinate/inferior fronto-occipital fasciculus, defined by fractional anisotropy values derived from diffusion tensor magnetic resonance images, correlates with both ...
Real-world decision-making often involves social considerations. Consequently, the social value of stimuli can induce preferences in choice behavior. However, it is unknown how financial and social values are integrated in the brain. Here, we investigated how smiling and angry face stimuli interacted with financial reward feedback in a stochastically ...
The anterior cingulate cortex (ACC) is involved in performance monitoring and in learning from performance feedback. Recent research suggests that the feedback-related negativity (FRN), an event-related potentials (ERP) component reflecting neural activity in the ACC, codes the size of a negative prediction error when reward probabilities are varied. There ...
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 ...
Appraisal theories of emotion predict that the relevance of a stimulus to a person's needs and goals influences attentional allocation. We used a modified visual probe task to examine the influence of hunger and trait reward drive on food-related attentional bias. Both hunger and trait reward drive predicted degree ...
The subjective effects of intravenous cocaine are felt almost immediately, and this immediacy plays an important part in the drug�s rewarding impact. The primary rewarding effect of cocaine involves blockade of dopamine reuptake; however, the onset of this action is too late to account for the drug�s initial effects. Recent studies suggest that ...
The present experiment tested the prediction of Redish's (2004) computational model of addiction that drug reward expectation continues to grow even when the received drug reward is smaller than expected. Initially, rats were trained to press two levers, each associated with a large dose of cocaine. Then, the dose associated with one ...
Experimental approaches can help disentangle the impacts of policies from the effects of individual characteristics, but the heterogeneity of implementation inherent in studies with complex program designs may mask average treatment impacts (Morris & Hendra, 2009). In the case of the Opportunity NYC-Family Rewards (ONYC-Family Rewards), families earned ...
Correlation between the level of somatic pathology and cytogenetic characteristics of blood was analyzed in a group of liquidators of the accident at the Chernobyl Nuclear Power Plant (ChNPP). A statistically significant correlation was found between the occurrence of cardiovascular diseases and the level of chromosome aberrations (total frequency of chromosome ...
The shape of the surfaces of ex-vivo human crystalline lenses was measured using a shadow photography technique. From these data, the back-focal distance and the contribution of each surface to the main optical aberrations of the lenses were estimated. The aberrations of the lenses were measured separately with two complementary techniques: a ...
Chromosomal aberration frequency in peripheral lymphocytes of healthy individuals has been found to be predictive of future cancer risk. The variability of chromosomal aberrations over time, which is largely unknown, should be clarified to interpret the strength of this association and to determine its use in cancer ...
SummaryDrugs of abuse acquire different degrees of control over thoughts and actions based not only on the effects of drugs themselves, but also on predispositions of the individual. Those individuals who become addicted are unable to shift their thoughts and actions away from drugs and drug-associated stimuli. Thus in addicts, exposure to places or things (cues) that have been previously ...
BackgroundTo compare the predictive validity of the demand/control and reward/imbalance models, alone and in combination with each other, for self-reported health status and the self-reported presence of any chronic disease condition.MethodsSelf-reports for psychosocial work conditions were obtained in a sample of sawmill workers using the demand/control ...
... and HIN-1. Time and financial constraints dictate ... Gail model [2]. The -> 1.7% five-year Gail risk ... when balanced against the risks of thromboembolic ...
... Promoter region methylation of Cyclin D2, APC, HIN1, RASSF1A, and RAR 2 was measured in NDL samples by quantitative methylation-specific ...
... We have shown previously that methylation of RASSF1A or APC in benign breast epithelium correlates with calculated breast cancer risk and the ...
... We have shown previously that methylation of RASSFlA of APC in benign breast epithelium correlates with calculated breast cancer risk and the ...
... have identified five genes namely APC, Cyclin D2, RARbeta, RASSFlA and TMSl, that are frequently methylated in tumors. Methylation analysis of ...
Adult male mallards (Anas platyrhynchos ) were banded in summer 1987 with reward bands of different dollar values (0-$400) to determine the lowest dollar value that would yield a reporting rate approaching 1.0. During the 1987-88 and 1988-89 hunting seasons, rewards of between 50 and $100 were required to yield a reporting rate near 1.0. We estimated ...
USGS Publications Warehouse
How Do Computational Models of the Role of Dopamine as a Reward Prediction Error Map on to Current Dopamine Theories of Schizophrenia? Angela J. Thurnham* (a.j.thurnham@herts.ac.uk), D. John Done** (d United Kingdom Abstract A review of the current dopamine theories of schizophrenia reveals a likely
A time-of-flight concept that dynamically corrects for chromatic aberration effects in scanning electron microscopes (SEMs) is presented. The method is predicted to reduce the microscope's chromatic aberration by an order of magnitude. The scheme should significantly improve the spatial resolution of low-voltage scanning electron ...
Previous research suggests that discrepancies between work values and rewards are indicators of dissonance that induce change in both to reduce such dissonance over time. The present study elaborates this model to suggest parallels with the first phase of the extension- and-strain curve. Small discrepancies or small increases in extension are presumed to be almost ...
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 ...
Behavioral decisions and actions are directed to achieve specific goals and to obtain rewards and escape punishments. Previous studies involving the recording of neuronal activity suggest the involvement of the cerebral cortex, basal ganglia, and midbrain dopamine system in these processes. The value signal of the action options is represented in the striatum, updated by ...
The anterior cingulate cortex (ACC) plays a critical role in stimulus-reinforcement learning and reward-guided selection of actions. Here we conducted a series of experiments to further elucidate the role of the ACC in instrumental behavior involving effort-based decision-making and instrumental learning guided by reward-predictive stimuli. In Experiment ...
Optimal performance in two-alternative, free response decision making tasks can be achieved by the drift-diffusion model of decision making - which can be implemented in a neural network - as long as the threshold parameter of that model can be adapted to different task conditions. Evidence exists that people seek to maximize reward in such tasks by modulating response ...
Voluntary motor commands produce two kinds of consequences. Initially, a sensory consequence is observed in terms of activity in our primary sensory organs (e.g., vision, proprioception). Subsequently, the brain evaluates the sensory feedback and produces a subjective measure of utility or usefulness of the motor commands (e.g., reward). As a result, comparisons between ...
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 ...
Human society is strongly rooted in people's experiences of agency; that is, the pervasive feeling that one engages in voluntary behavior and causes one's own actions and resulting outcomes. Rewards and positive affect play an important role in the control of voluntary action. However, the role of positive reward signals in the sense of agency is poorly ...
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 ...
The aim of this study was to test whether honeybees develop reward expectations. In our experiment, bees first learned to associate colors with a sugar reward in a setting closely resembling a natural foraging situation. We then evaluated whether and how the sequence of the animals' experiences with different reward magnitudes changed ...
The maxim "no pain, no gain" summarizes scenarios in which an action leading to reward also entails a cost. Although we know a substantial amount about how the brain represents pain and reward separately, we know little about how they are integrated during goal-directed behavior. Two theoretical models might account for the integration of ...
The maxim �no pain, no gain� summarises scenarios where an action leading to reward also entails a cost. Although we know a substantial amount about how the brain represents pain and reward separately, we know little about how they are integrated during goal directed behaviour. Two theoretical models might account for the integration of ...
We tested the risk-sensitive foraging preferences of wild rufous hummingbirds, Selasphorus rufus, with three types of artificial flowers. All three flower types provided the same mean volume of 30 �l of sucrose, but differed in terms of variability of the reward: constant, low variance and high variance. In trinary comparisons, subjects preferred the low-variance ...
Dysfunctional social reward and social attention are present in a variety of neuropsychiatric disorders including autism, schizophrenia, and social anxiety. Here we show that similar social reward and attention dysfunction are present in anorexia nervosa (AN), a disorder defined by avoidance of food and extreme weight loss. We measured the implicit ...
Analyzed are thermally induced aberrations in optical beams propagating through solid-state laser media. Several geometrical configurations are considered: cylindrical rod, thin disk and slab. Predicted are thermally-induced optical effects in the temperature range of 77 - 770K. The analysis is based on an analytical solution to the problems of nonlinear ...
In this study, we examined whether the feedback-related negativity (FRN) is associated with both subjective and objective (model-estimated) reward prediction errors (RPE) per trial in a reinforcement learning task in healthy adults (n=25). The level of RPE was assessed by 1) subjective ratings per trial and by 2) a computational model of reinforcement ...
According to modern reinforcement learning theories, midbrain dopamine (DA) neurons are part of an adaptive system within which learned expectations filter reward-related signals to enable computation of reward prediction errors (RPEs). Recent electrophysiological data on DA neuron responses to probabilistic reward ...
Schematic eye models have typically been used to explain the average monochromatic and chromatic imaging properties of the eye. Both monochromatic aberrations and transverse chromatic aberration are known to vary widely across subjects. However, to our knowledge, the ability of schematic eye models to predict these individual ...
We compared experimental wave aberrations in pseudophakic eyes with aspheric intraocular lenses (IOLs) to simulate aberrations from numerical ray tracing on customized computer eye models using corneal topography, angle lambda, ocular biometry, IOL geometry, and IOL tilt and decentration measured on the same eyes. We found high correlations between real ...
Sexual behavior is a natural reward for many rodent species, and it often includes chemosensory-directed components. Chemosensory stimuli themselves may also be rewarding. Conditioned place preference (CPP) is one paradigm frequently used to test the rewarding properties of a range of stimuli. Males and females of several rodent ...
Psychopathy is a personality disorder that is strongly linked to criminal behavior. Using [18F]fallypride PET and BOLD fMRI, we show that impulsive-antisocial psychopathic traits selectively predict nucleus accumbens dopamine release and reward anticipation-related neural activity in response to pharmacological and monetary ...
Reward-modulated spike-timing-dependent plasticity (STDP) has recently emerged as a candidate for a learning rule that could explain how behaviorally relevant adaptive changes in complex networks of spiking neurons could be achieved in a self-organizing manner through local synaptic plasticity. However, the capabilities and limitations of this learning rule could so far only ...
Reward and novelty are potent learning signals that critically rely on dopaminergic midbrain responses. Recent findings suggest that although reward and novelty are likely to interact, both functions may be subserved by distinct neuronal clusters. We used high-resolution functional magnetic resonance imaging (fMRI) to isolate neural responses to ...
Several theories of self-control [including intertemporal bargaining (Ainslie, 1992) and self-signaling (Bodner and Prelec, 2001)] imply that intertemporal decisions can be more farsighted than would be predicted by the incentive associated with rewards outside a decision context. We examined this hypothesis using behavior and functional neuroimaging. ...
Several theories of self-control (including intertemporal bargaining Ainslie (1992) and self-signaling Bodner and Prelec (2001)) imply that intertemporal decisions can be more farsighted than would be predicted by the incentive associated with rewards outside a decision context. We examined this hypothesis using behavior and functional neuroimaging. First, ...
A telecentric confocal optical arrangement is presented that greatly reduces the diffraction aberrations of the acousto-optic tunable filter (AOTF). Analytical expressions for the aberrations were identified based on the fundamental properties of Bragg diffraction, and additional aberrations due to focusing through the AOTF were also ...
Alterations of both central and peripheral feeding regulatory substances occur in the acute phases of anorexia nervosa (AN) and bulimia nervosa (BN) and, generally, reverse after recovery. Some of these alterations are believed not only to sustain the altered eating behavior but also to contribute to certain psychopathological aspects and/or etiopathogenetic processes of eating disorders (EDs). It ...
The drift-diffusion model (DDM) describes decision making in simple, two-alternative forced choice (2AFC) tasks. It accurately fits response-time distributions and implements an optimal decision procedure for stationary 2AFC tasks: for a given accuracy, no other model achieves faster average response times. The value of a decision threshold applied to accumulated information also determines a ...
The drift-diffusion model (DDM) implements an optimal decision procedure for stationary, 2-alternative forced-choice tasks. The height of a decision threshold applied to accumulating information on each trial determines a speed-accuracy tradeoff (SAT) for the DDM, thereby accounting for a ubiquitous feature of human performance in speeded response tasks. However, little is known about how ...
Termination of a painful or unpleasant event can be rewarding. However, whether the brain treats relief in a similar way as it treats natural reward is unclear, and the neural processes that underlie its representation as a motivational goal remain poorly understood. We used fMRI (functional magnetic resonance imaging) to investigate how humans learn to ...
The orbitofrontal cortex appears to be involved in the control of voluntary, goal-directed behavior by motivational outcomes. This study investigated how orbitofrontal neurons process information about rewards in a task that depends on intact orbitofrontal functions. In a delayed go-nogo task, animals executed or withheld a reaching movement and obtained liquid or a ...
This study investigated whether a behavioral economic index of the value of rewards available over different time horizons improved prediction of drinking outcomes beyond established biopsychosocial predictors. Preferences for immediate drinking versus more delayed rewards made possible by saving money were determined from expenditures ...