SEARCH · PubMed Health

Results for “Reward”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed1977

Reward versus performance in self-stimulation: electrode-specific effects of alpha-methyl-p-tyrosine on reward in the rat.

The hypothesis that alpha-methyl-p-tyrosine (AMPT), an inhibitor of catecholamine synthesis, reduces brain stimulation reward was tested, using a measure of reward previously shown to be relatively unaffected by variables that alter performance but not reward. The rewarding effectiveness of stimulation was determined by the location of the sharp rise in the function relating running speed in an alley to the number of pulses received as a reward. For some electrodes, AMPT depressed self-stimulation performance (speed of running) without producing any sizable effect on the measure of reward (location of rise). For other electrodes, the rewarding effectiveness of the stimulation was greatly reduced by AMPT and restored by L-dopa. These opposing results could be repeatedly demonstrated on different electrodes in the same rat. The electrode-specific differential sensitivity to AMPT suggests neurochemically disparate substrates for reward.

Animals↗

PubMed2025

Multi-Locus Pro-Dopaminergic Restoration of Reward Brain Circuitry in Reward Deficiency Rescinds Mono-Pharmaceutical Targeting.

Dopaminergic dysfunction in reward circuitry is well-documented as a contributor to addictive behaviors. Evidence indicates that changes in synchronous neural activity between brain regions mediating reward and cognitive functions may significantly contribute to substance-related disorders. In this commentary we highlight findings showing that the pro-dopaminergic nutraceutical (KB220) enhances functional connectivity between reward and cognitive brain areas in both animal and human studies. Animal studies demonstrate that KB220 activates important brain reward-related regions, including the nucleus accumbens, anterior cingulate gyrus, anterior thalamic nuclei, hippocampus, and prelimbic and infralimbic loci. Kb220 induced significant functional connectivity, enhanced neuroplasticity, and improved dopaminergic functionality within the brain reward circuitry with effects localized to these regions rather than broader distributed across the brain. In abstinent heroin-dependent individuals, acute KB220 administration significantly induced BOLD activation in caudate-accumbens dopaminergic pathways relative to placebo. Furthermore, data from 36 clinical trials and preclinical studies encompassing over 1,000 subjects, demonstrate that KB220 supports "dopamine homeostasis" across various reward deficiency behaviors. Clinical outcomes and quantitative electroencephalogy (qEEG) results underscore KB220's potential anti-craving/anti-relapse effects in addiction and other psychiatric disorders through direct or indirect dopaminergic modulation. Based on a review of the existing knowledge and further intensive investigation, we propose that instead of relying on mono-pharmaceutical approaches, the scientific community should endorse multi-loci dopaminergic restoration of reward brain circuitry as a fundamental paradigm for addressing mental illness.

Alcohol Use Disorder (AUD)↗

PubMed1991

Measuring the subjective magnitude of brain stimulation reward by titration with rate of reward.

The magnitude of experienced reward as a function of the pulse frequency and current in trains of fixed duration delivered to the medial forebrain bundle of the rat was measured using a new psychophysical method in which the parameters of the brain stimulation reward on one lever are adjusted to offset the effect of changing the rate of reward on a competing lever. Subjective reward magnitude is a steep sigmoidal function of both pulse frequency and current. The growth of reward to its half-maximal level was approximated by a power function with an exponent that varied from 2 to 10. Within a subject, the exponent was the same for both current and pulse frequency, which supports the hypothesis that the magnitude of reward from a train of fixed duration is determined by the rate at which action potentials are generated in the population of reward-relevant axons (the counter hypothesis). This rate is proportional to Current x Pulse Frequency.

Animals↗

PubMed1991

Olfactory associative conditioning in infant rats with brain stimulation as reward: II. Norepinephrine mediates a specific component of the bulb response to reward.

One of the circuits modified by early olfactory learning is in the olfactory bulb. Specifically, response patterns of mitral-tufted cells are modified by associative conditioning during the early postnatal period. In addition, previous work has demonstrated that mitral-tufted cell single units respond to both olfactory conditioned stimuli and rewarding stimulation of the medial forebrain bundle-lateral hypothalamus (MFB-LH). The present study suggests that norepinephrine beta-receptor activation is required for early olfactory learning using MFB-LH stimulation as reward. Propranolol injected before odor-MFB-LH pairings blocks the acquisition of conditioned behavioral responses and their neural correlates to the conditioned odor. Furthermore, propranolol blocks a specific class of the mitral-tufted cell responses to MFB-LH reward stimulation. The relationship of this response to reward and early learning is discussed.

Aging↗

PubMed1992

Brain-stimulation reward: a model for the study of the rewarding effects of abused drugs.

The robustness of the findings of the BSR effects of abused substances indicates that almost any technique used to measure these effects will be useful. The simplest procedure, however, of selecting a single intensity of stimulation and determining the effects of drugs on the rate of response for that selected intensity is fraught with difficulty in interpretation. More than 25 years ago the interpretation of changes in response rate as a reflection of changes in the reward value of the stimulation was challenged (Hodos and Valenstein 1962). Today it is rare to see a single stimulation intensity used in a published manuscript. However, most studies still use procedures of which rate of response is an integral part. Because animals will press a lever more than 80 times per minute and--on a continuous reinforcement schedule--receive as many as 80 stimulations a minute, conclusions about the specificity of the effects of drugs are difficult. The results of BSR experiments on mechanisms of action of abused substances clearly indicate that the reinforcing effect of most, if not all, such substances is probably the result of activation of a reward system that originates in the cell bodies of the ventral tegmental area and courses rostrally to the limbic and frontal projection sites of the mesocortical system. Thus, we believe, the technique has clearly fulfilled its promise as a "window on the brain" (Olds 1977).

Animals↗

PubMed2026

The effect of monetary versus point-based rewards on effort-cost decision making in individuals at clinical high risk for psychosis.

OBJECTIVE: The dissemination of inexpensive computerized behavioral tasks indexing amotivation may enhance the assessment of clinical high risk (CHR) across settings. However, the impact of varying reward value in such tasks is unclear. If point-based rewards engage participants, this could improve the scalability of computerized assessments. We tested how point-based rewards versus money impacted effort-cost decision-making in CHR individuals. We further assessed how negative symptom severity and household income interacted with reward-type to impact behavior. METHODS: Participants completed the Effort Expenditure for Reward Task (EEfRT). Participants were randomly assigned to receive either money or points for their performance during the EEfRT. Data from a large sample of CHR (N = 233) individuals and healthy controls (HC; N = 157) were collected. RESULTS: Across diagnostic groups, we observed heightened effort expenditure when money was used as a reward (b = 0.13, p = 0.018). We did not find an interaction of CHR status (b = 0.07, p = 0.845) or negative symptoms (b = 0.01, p = 0.429) with reward-type. Within CHR individuals, heightened negative symptom severity was associated with reduced expended effort (b = -0.03, p = 0.016), regardless of reward type. In an exploratory analysis, we found that individuals in the money condition with relatively high household income expended less effort during high reward, high probability trials (b = -0.24, p = 0.046). CONCLUSIONS: Across CHR and HC individuals, individuals pursuing money expended greater effort. While we did not find a group by reward type interaction, CHR individuals with heightened negative symptom severity expended less effort across trials, replicating prior work. Present findings support further study of point-based rewards in tasks indexing amotivation.

Humans↗

PubMed2026

Targeting distinct facets of anhedonia via transcutaneous auricular vagus nerve stimulation: Effects on heart rate variability and reward-based behavior.

Anhedonia, a core feature of major depressive disorder, is associated with disrupted reward processing and may represent a mechanistically relevant target for neuromodulation. This study examined the effects of transcutaneous auricular vagus nerve stimulation (taVNS) on reward-related behavior and autonomic regulation in individuals with higher (n = 34) and lower (n = 34) depressive symptomatology. In a randomized, within-subject crossover design, participants received active taVNS and sham stimulation on two separate days. During each session, incentive motivation and reward learning were assessed using the Effort Expenditure for Rewards Task and the Probabilistic Reward Task (PRT), respectively, with stimulation condition and task order counterbalanced. Findings revealed that taVNS effects on heart rate variability (HRV) were modulated by baseline HRV levels and depressive status; specifically, they enhanced HRV at low baseline levels and reduced it at high baseline levels in participants with lower depressive symptomatology, with opposite patterns in individuals with higher symptoms. Moreover, compared to sham, taVNS enhanced the willingness to exert effort for rewards, particularly at low reward probabilities, with a more pronounced effect in the group characterized by higher depressive symptoms. No significant effects were observed on reward learning, as indexed by the PRT. Additionally, taVNS reduced self-reported anxiety across groups. Despite the limitation of a single stimulation session, these findings suggest that taVNS modulates motivational effort allocation in individuals with higher depressive symptoms, supporting its potential relevance for targeting reward-related dysfunctions in mood disorders.

Anhedonia↗

PubMed1992

Construct validity of a self-stimulation threshold paradigm: effects of reward and performance manipulations.

A discrete-trial current-threshold intracranial self-stimulation (ICSS) paradigm has been used extensively to examine the effects of drugs on reward thresholds. However, there is little work to date validating that this specific procedure measures reward. The purpose of the present study was to establish the construct validity of this procedure by testing the procedure's ability to measure reward effects and to discriminate these reward effects from performance effects. The discrete-trial ICSS procedure provides four measures: current thresholds, response latency, extra responses and time-out responses. The effects of a performance manipulation (variations in the force required to operate the manipulandum) and of a reward manipulation (variations in the train duration of the electrical stimulation) were evaluated on the four measures. Reward effects were reflected primarily in changes in thresholds, with no effect on any of the other three measures. Conversely, performance effects were reflected primarily in changes in response latency, extra responses and time-out responses, with only a small effect on thresholds. Finally, the paradigm's potential as a useful tool in the elucidation of the neurobiological basis of reward was demonstrated by investigating the effects of two pharmacological agents, cocaine and curare, on the four measures derived from the discrete-trial current-threshold ICSS procedure. The results suggest that the discrete-trial current-threshold procedure can readily discriminate reward from performance treatments.

Animals↗

PubMed1992

Neuronal activity in monkey ventral striatum related to the expectation of reward.

Projections from cortical and subcortical limbic structures to the basal ganglia are predominantly directed to the ventral striatum. The present study investigated how the expectation of external events with behavioral significance is reflected in the activity of ventral striatal neurons. A total of 420 neurons were studied in macaque monkeys performing in a delayed go-no-go task. Lights of different colors instructed the animal to do an arm-reaching movement or refrain from moving, respectively, when a trigger light was illuminated a few seconds later. Task performance was reinforced by liquid reward in both situations. A total of 60 ventral striatal neurons showed sustained increases of activity before the occurrence of individual task events. In 43 of these neurons, activations specifically preceded the delivery of reward, independent of the movement or no-movement reaction. In a series of additional tests, these activations were time locked to the subsequent reward, disappeared within a few trials when reward was omitted, and were temporally unrelated to mouth movements. Changes in the appetitive value of the reward liquid modified the magnitude of activations, suggesting a possible relationship to the hedonic properties of the expected event. Activations also occurred when reward was delivered in a predictable manner outside of any behavioral task. These data suggest that neurons in the ventral striatum are activated during states of expectation of individual environmental events that are predictable to the subject through its past experience. The prevalence of activations related to the expectation of reward suggests that ventral striatal neurons have access to central representations of reward and thereby participate in the processing of information underlying the motivational control of goal-directed behavior.

Amygdala↗

PubMed2025

Histone Arginine Methylation Regulates Neuropeptide Y Expression in the Basolateral Amygdala to Promote Reward-Seeking Behaviour.

The basolateral amygdala (BLA) serves in the evaluation of reward. However, the causal molecular substrates in the BLA necessary for reward seeking behaviour are largely unknown. Reward conditioning induces long-lasting changes in epienzymes in limbic areas, including the amygdala. The current study probed the role of histone arginine methylation as a novel epigenetic mechanism in neuropeptide Y (NPY) gene regulation in the BLA during reward and reinforcement. For reward conditioning, adult Wistar rats were trained to self-administer sucrose pellets in a nose-poke operant chamber. Reward conditioning increased protein arginine methyltransferase 4 (PRMT4) and NPY in the BLA. Moreover, after operant conditioning, histone arginine methylation (H3R17me2a) and PRMT4 occupancy at the NPY promoter were heightened. PRMT4 was predominantly colocalised in the nucleus of the NPY-expressing cells in the BLA. Intra-BLA administration of specific siRNA or inhibitor of PRMT4 after conditioning waned the nose-poke activity, which was further reinstated during the subsequent 5 days. These effects of PRMT4 repression were correlated with the NPY expression and H3R17me2a levels at the NPY promoter. Furthermore, NPY peptide administration after PRMT4 siRNA or inhibitor infusion in BLA restored the nose-poke activity. PRMT4 is known to interact with CREB-binding protein (CBP). Therefore, co-occupancy of PRMT4 and CBP resulted in heightened histone acetylation (H3K14ac) in the conditioned rats. The current study suggests a pivotal role of PRMT4-mediated histone arginine methylation in NPY gene expression in the amygdala necessary for the reward-seeking behaviour.

Animals↗

PubMed2026

Smoking Cue Reactivity in Relation to Uncertain-Threat and Reward-Anticipation Networks: A Coordinate-Based fMRI Meta-Analysis.

BACKGROUND: Smoking is a concerning medical and social problem, yet how the brain links stress to continued smoking is still not well understood. This coordinate-based meta-analysis identified convergent activations for smoking cues, uncertain threat, and reward anticipation, and examined co-activation patterns to clarify whether smoking-cue activity in smokers relates to threat and reward activity in non-addicted controls. METHODS: We conducted a coordinate-based activation likelihood estimation (ALE) meta-analysis of 102 fMRI studies (N = 3,068), including 30 studies on smoking cue reactivity (n = 945), 48 on reward anticipation (n = 1,413), and 24 on uncertain threat processing (n = 1,621). We performed single, conjunction, and contrast analyses, followed by meta-analytic connectivity modeling (MACM) of key regions. RESULTS: Single analysis revealed smoking engaged bilateral ACC (-1.1, 46.2, -1.1), uncertain threat engaged bilateral insula (left = -33.6, 22, 4.3, right = 41.3, 22, 1), reward anticipation activated thalamus (0.9, 1.3, -3.1) and medial frontal gyrus (2.7, 6.6, 52.1). Conjunction and contrast analyses showed shared or unique activation for each task in its respective regions. MACM showed ACC co-activation with thalamus and medial frontal gyrus, while insula co-activated with ACC and inferior frontal gyrus. CONCLUSIONS: Each process converged in a separate region, with no overlap between the smoking-cue map and either the threat or reward map. The ACC nonetheless co-activated with reward-related regions and shared network membership with the threat-related insula. On this basis we hypothesize a shift in motivation from stress-driven reward toward cue-driven craving, to be tested within subjects, and identify candidate neuromodulation targets for preventing stress-precipitated relapse.

fMRI↗

PubMed1992

Visual responses to reward-related cues in inferior parietal lobule.

A sample of 263 neurones was recorded in area 7a of the parietal lobe, in a monkey performing a reach task to visual targets displayed on a touch-sensitive videomonitor. The task had been operantly conditioned on food or juice rewards, and 78 (30%) of the units showed activity changes linked in some way to the reward. For most of these cells, the response was to the approach of the trainer's hand with the food reward. This specific visual response was similar irrespective of the direction of approach. Six cells increased discharge as soon as the task was completed in apparent anticipation of the reward. Another two neurones responded to missing a reward: they fired vigorously if the videoscreen was blanked in mid-trial because a target was not correctly touched. In many cases (40/78) the same cells responding to some aspect of the reward also responded to visual cues given during the task, especially the presentation of the target location. Reward-related activity in area 7a probably results from an integration of the visual and limbic inputs to this region, such that visual information which foretells behaviourally important events is emphasized.

Animals↗

PubMed2026

Effects of acute inflammatory challenge on anhedonia and social reward processing: A randomized controlled trial of endotoxin.

Anhedonia is a core feature of depression that reflects reward system dysfunction. Acute inflammatory challenge has been shown to induce transient anhedonia and reward processing deficits, but its effects on distinct components of social reward processes remain poorly understood. This randomized, double-blind, placebo-controlled study evaluated anhedonia and social reward responsivity following acute inflammatory challenge. Low-dose endotoxin (0.8 ng/kg body weight; n = 18) or placebo (same volume of 0.9% saline; n = 22) was administered to female adults (ages 25-44). Anhedonia (Snaith-Hamilton Pleasure Questionnaire) and blood samples for cytokine assessment were collected pre-infusion and 2 and 4 h post-infusion. Social reward motivation (wanting to engage in a social task) was assessed at a baseline eligibility visit and 2 h post-infusion. Sensitivity to positive social cues (attentional bias toward and recognition of happy faces) was assessed pre-infusion and 2 h post-infusion. Results showed that endotoxin increased anhedonic symptoms (p = .005) and decreased social motivation by 2 h post-infusion (p = .001); within the endotoxin condition, changes in both outcomes were associated with increases in TNF-α (p's < .04). A significant condition-by-time interaction for happy-face recognition (p = .011) was driven by increased accuracy in the placebo (p = .04) but not endotoxin (p = .43) condition. Endotoxin administration did not affect attentional bias toward happy faces. Findings suggest that acute inflammatory challenge induces anhedonia and reduces social motivation, with more limited effects on sensitivity to positive social cues, highlighting specific reward-related pathways through which immune activation may contribute to inflammation-associated depression. Future work could examine whether immune-related changes in social motivation contribute to motivational deficits in depression.

Humans↗

PubMed1976

Modulation of reward and aversion processes in the rat diencephalon by neuroleptics: differential effects of clozapine and haloperidol.

The effects of clozapine and haloperidol on self-stimulation in rats were investigated in a shuttle-box that provides concurrent rate-independent indexes of the rewarding and aversive components of intracranial stimulation. The use of two concurrent measures of performance permits the differentiation of specific reward modulation effects from the variety of nonspecific performance decrements that these drugs may produce. Clozapine produced a dose-dependent reduction in reward that could be clearly dissociated from its nonspecific effects. In contrast, the apparent reduction in reward produced by haloperidol could not be dissociated from a nonspecific performance decrement. Consequently, the attenuation of self-stimulation produced by haloperidol does not indicate a direct role for dopamine in modulating reward. It is suggested that the attenuation of reward produced by neuroleptics reflects a reduction in noradrenergic transmission, whereas their nonspecific effects reflect their blockade of dopamine receptors.

Animals↗

PubMed1992

Chronic morphine fails to enhance the reward value of prefrontal cortex self-stimulation.

Dopamine (DA) plays an important role in the rewarding effects of drugs of abuse and intracranial self-stimulation (ICSS). We previously reported that ICSS derived from the prefrontal cortex appears insensitive to the reward-enhancing effects of amphetamine, a drug that increases DA release and reward at other ICSS sites. In the present study, rats with prefrontal electrodes were tested to see if morphine (7.5 or 10.0 mg/kg, IP) given once per day for 10 days enhanced prefrontal reward as assessed with the curve-shift method. Morphine initially produced sedation; however, after 3-4 days response rates increased sharply while frequency thresholds were unaffected. These results demonstrate that morphine does not enhance prefrontal ICSS reward and provide further evidence that prefrontal brain stimulation reward does not display the same characteristics as other ICSS sites.

Animals↗

PubMed1992

Effects of nicotine on the threshold for rewarding brain stimulation in rats.

The rewarding effects of nicotine alone and nicotine challenged with mecamylamine, a nicotine receptor blocker, or naloxone were determined using a rate-independent discrete-trial threshold measure of brain-stimulation reward in rats. If nicotine acts as other drugs of abuse, it would be expected to lower the reward threshold, that is, increase an animal's sensitivity to rewarding brain stimulation, and naloxone would be expected to block this effect, as it does other stimulants in this paradigm. Nicotine was found to significantly lower the reward threshold and mecamylamine blocked this effect. However, although naloxone increased the variability of nicotine's effect on the reward threshold, it failed to dose dependently block nicotine's threshold-lowering effect.

Animals↗

PubMed1992

The function relating the subjective magnitude of brain stimulation reward to stimulation strength varies with site of stimulation.

A two-lever choice paradigm with concurrent variable interval schedules of reward was used to measure the growth in the subjective magnitude of reward as a function of current, by finding the adjustment in the stimulating current required to offset a given difference in the rates at which two rewards were received. Increasing current by a factor of 2 increased subjective reward magnitude by a factor ranging from as little as 3 to as much as 4,000. This range was about as great between electrodes within one rat as between electrodes and rats. In the light of earlier findings regarding the equivalent effects of increments is current and pulse frequency, these large differences cannot readily be explained by differing fiber densities at the site of stimulation. It is suggested that the medial forebrain bundle terminates in more than one spatio-temporal integration mechanism. The magnitude of the spatio-temporally integrated effect of a barrage of action potentials in the reward-relevant axons depends on which subset of reward-relevant axons is excited by the stimulation.

Action Potentials↗

PubMed1976

Effects of self-esteem and expected duration of interaction on liking for a highly rewarding partner.

Psychological theories predicated on the assumption of human selfishness and theories based on principles of equity may lead to conflicting predictions about when a person will like his partner. Of special interest are a person's reactions to receiving uncommonly high rewards. The present study addressed this issue by examing the development of same-sex liking in 40 female college students. It was hypothesized that subjects with lowered self-esteem, having a great need for interpersonal rewards, would react favorably to the receipt of such rewards, even if underserved. Subjects with raised self-esteem, on the other hand, having had their need for rewards met, should respond unfavorably to the receipt of high rewards, desiring a more equitable distribution of reward. These effects should be strong only when continuing dyadic interaction is expected (i.e., as issues of stability and reciprocity become salient). The predictions were confirmed.

Adult↗