Reward Salience Research Articles

Disruption of maternal parenting circuitry by addictive process: rewiring of reward and stress systems.

Addiction represents a complex interaction between the reward and stress neural circuits, with increasing drug use reflecting a shift from positive reinforcement to negative reinforcement mechanisms in sustaining drug dependence. Preclinical studies have indicated the involvement of regions within the extended amygdala as subserving this transition, especially under stressful conditions. In the addictive situation, the reward system serves to maintain habitual behaviors that are associated with the relief of negative affect, at the cost of attenuating the salience of other rewards. Therefore, addiction reflects the dysregulation between core reward systems, including the prefrontal cortex (PFC), ventral tegmental area (VTA), and nucleus accumbens (NAc), as well as the hypothalamic–pituitary–adrenal axis and extended amygdala of the stress system. Here, we consider the consequences of changes in neural function during or following addiction on parenting, an inherently rewarding process that may be disrupted by addiction. Specifically, we outline the preclinical and human studies that support the dysregulation of reward and stress systems by addiction and the contribution of these systems to parenting. Increasing evidence suggests an important role for the hypothalamus, PFC, VTA, and NAc in parenting, with these same regions being those dysregulated in addiction. Moreover, in addicted adults, we propose that parenting cues trigger stress reactivity rather than reward salience, and this may heighten negative affect states, eliciting both addictive behaviors and the potential for child neglect and abuse.

Multiple Timescales of Memory in Lateral Habenula and Dopamine Neurons

Midbrain 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 input, the lateral habenula, while animals predicted upcoming rewards based on the past reward history. We found that lateral habenula and dopamine neurons accessed two distinct reward memories: a short-timescale memory expressed at the start of the task and a near-optimal long-timescale memory expressed when a future reward outcome was revealed. The short- and long-timescale memories were expressed in different forms of reward-oriented eye movements. Our data show that the habenula-dopamine pathway contains multiple timescales of memory and provide evidence for their role in motivated behavior.

‘Cue reward salience’ predicts craving in response to alcohol cues

Many studies have shown that regular drinkers react to alcohol-related stimuli (i.e., cue reactivity) with a variety of appetitive responses, in particular, increased urge to drink. Recent research has focused on accounting for variability in responses to alcohol-related stimuli by examining drinking histories and personality. The aim of the current study was to extend this line of work by investigating the role of reinforcement expectancies (‘cue reward salience’) in alcohol cue reactivity research. In this study, ‘cue reward salience’ refers to the notion that appetitive responses will only ensue if the individual finds the stimulus to be equal to or more rewarding than initial expectations. Sixty-one regular drinkers completed a standard cue reactivity assessment whereby reactions (i.e., urge to drink and affect) to the sight, smell and taste of alcohol are measured and compared to a control condition. Results indicated significant increases in positive urge to drink but no changes in affect. Analyses revealed that drinking level and trait reward sensitivity were significant predictors of the urge to drink response. In addition, ‘cue reward salience’ accounted for significant additional variance in predicting urge to drink alcohol. Discussion focuses on the importance of measuring reinforcement expectancies when conducting cue reactivity studies.

Disruption of Orbitofrontal Cortex Laterality in Offspring from Multiplex Alcohol Dependence Families

Increased susceptibility for developing alcohol dependence (AD) might be related to structural differences in brain circuits that influence the salience of rewards and/or modify the efficiency of information processing. The role of the orbitofrontal cortex (OFC) in regulating emotional processing is increasingly being recognized along with its association with impulsive behavior. Magnetic resonance imaging was used to measure the OFC in 107 high- and low-risk offspring (mean age 17.6 +/- 4.69 years) from either multiplex AD families or control families. Region of interest measures including segmented values were obtained by reliable raters using BRAINS2 software. Statistical analyses were adjusted for intracranial volume, age, socioeconomic status (SES), IQ, and handedness. The Multidimensional Personality Questionnaire (MPQ) was administered to determine scale scores for Control. Genotyping was performed for the serotonin transporter (5-HTT) gene and the brain-derived neurotrophic factor (BDNF) gene. High-risk offspring from multiplex for AD families showed decreased right/left OFC volumes in comparison with control subjects. Smaller volume in the right hemisphere was significantly associated with variation in the 5-HTT and BDNF genes. White matter (WM) ratios showed a positive correlation with MPQ Control scale scores, indicating that reduced OFC WM is related to greater impulsivity. Offspring from multiplex families for AD manifest genetic susceptibility by exhibiting disruption in the laterality of the OFC volume that is related to greater impulsivity (lower Control scale scores). This disruption in OFC laterality is related to variation in genes associated with neuronal growth.

Cortical activation during delay discounting in abstinent methamphetamine dependent individuals

Methamphetamine (MA)-dependent individuals prefer smaller immediate over larger delayed rewards in delay discounting (DD) tasks. Human and animal data implicate ventral (amygdala, ventral striatum, ventrolateral prefrontal cortex insula) and dorsal (dorsolateral prefrontal cortex, dorsal anterior cingulate cortex and posterior parietal cortex) systems in DD decisions. The ventral system is hypothesized to respond to the salience and immediacy of rewards while the dorsal system is implicated in the process of comparison and choice. We used functional Magnetic Resonance Imaging to probe the neural correlates of DD in 19 recently abstinent MA-dependent patients and 17 age- and gender-matched controls. Hard DD choices were associated with greatest activation in bilateral middle cingulate, posterior parietal cortex (PPC), and the right rostral insula. Control subjects showed more activation than MA patients bilaterally in the precuneus and in the right caudate nucleus, anterior cingulate cortex (ACC), and dorsolateral prefrontal cortex (DLPFC). Magnitude of discounting was correlated with activity in the amygdala, DLPFC, posterior cingulate cortex and PPC. Our findings were consistent with a model wherein dorsal cognitive systems modulate the neural response of ventral regions. Patients addicted to MA, who strongly prefer smaller immediate over larger delayed rewards, activate the dorsal cognitive control system in order to overcome their preference. Activation of the amygdala during choice of delayed rewards was associated with a greater degree of discounting, suggesting that heavily discounting MA-dependent individuals may be more responsive to the negative salience of delayed rewards than controls.

Experiment timing and preferences for fairness

Classroom experiments examining fairness preferences [Andreoni, J., Miller, J., 2002. Giving according to GARP: an experimental test of the consistency of preferences for Altruism. Econometrica 70 (2), 737–753] were conducted to examine two issues: first, are classroom points a salient reward medium (comparable to cash in research experiments)? Secondly, does experiment timing during the semester influence results. Subject choices are consistent with the existence of well-behaved utility functions, indicating that points experiments can be valid. Secondly, subjects are more likely to be “selfish” when the experiment is conducted early rather than late in the academic semester. This result has behavioral implications for environments where nonmonetary incentives prevail, as well as implications for the growing number of instructors using experiments and follow-up discussion in the classroom.

Electrophysiological evidence of atypical motivation and reward processing in children with attention-deficit hyperactivity disorder

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) from typical children and children with ADHD as they navigated a “virtual maze” to find monetary rewards, and physically gave them their accumulated rewards halfway through the task and at the end of the experiment. We found that the amplitude of a reward-related ERP component decreased somewhat for typical children after they received their first payment, but increased for children with ADHD following the payment. This result indicates that children with ADHD are unusually sensitive to the salience of reward and suggests that such sensitivity may be mediated in part by the midbrain dopamine system.

Realistic synaptic inputs applied to coupled oscillator model of the dopamine neuron

Midbrain dopamine neurons are involved in motivation and the control of movement, and have been implicated in various pathologies such as Parkinson's disease, schizophrenia and drug abuse. Dopamine neurons in the presence of their afferent inputs in vivo can exhibit one of several firing modes: silence, regular single-spike firing, irregular single-spike firing, and bursting. Bursts in dopamine neurons are thought to convey the reward prediction and salience signals. Dopamine neurons in a slice preparation fire spontaneously in a regular, pacemaker-like manner at a low frequency (~2–3 Hz). This regular firing appears to be driven by a subthreshold oscillation caused by interaction of a low voltage threshold, noninactivating Ca2+ current and a Ca2+-activated small conductance K+ current. Somatic injection of depolarizing bias current can increase the frequency of sustained firing only up to 10 Hz before the neurons go into depolarization block. Bursts observed in vivo have higher instantaneous frequencies. Two theories have been advanced for how higher frequencies are achieved in vivo. One is that during pacemaking, the natural frequencies of the soma and proximal dendrites drive the subthreshold oscillation, whereas during bursting the NMDA input to the dendrites amplifies the current associated with the distal dendritic oscillation, and drives the soma, resulting in high-frequency spiking. The other hypothesis is that the rapidly varying synaptic input (particularly the AMPA component) is not equivalent to a constant depolarizing pulse but this rapid variation can drive faster spiking that can be observed in response to a constant pulse. We have constructed a realistic multicompartmental model to test the contribution of intrinsic and synaptic currents in the dendrites to the firing pattern. The oscillatory dendrites regularize the firing pattern, decrease the frequency compared to a model in which the subthreshold oscillation is confined to the soma, and contribute to grouping of spikes into bursts.

To Do or Not To Do? The Complexities of Addiction, Motivation, Self-Control, and Impulsivity

To Do or Not To Do? The Complexities of Addiction, Motivation, Self-Control, and Impulsivity

Cerebellar Volume in Offspring From Multiplex Alcohol Dependence Families

Increased susceptibility for developing alcohol dependence (AD) might be related to structural differences in brain circuits that influence the salience of rewards and/or modify the efficiency of information processing. The role of the cerebellum in regulating cognitive functions is being increasingly recognized along with its well-known influence on motor performance. Additionally, developmental changes in cerebellar volume during adolescence have been reported. Magnetic resonance imaging was used to measure the cerebellum in 17 high-risk adolescent and young adult offspring from multiplex alcohol dependence families and 16 control subjects matched for gender, age, and IQ. High-risk (HR) adolescents/young adults showed increased total cerebellum volume and total grey in comparison with control subjects. Age-related decreases in total grey volume were seen with age, a pattern that was not seen in HR offspring. Offspring from multiplex families for AD manifest genetic susceptibility by having larger cerebellar volume, which seems to be related to lesser grey matter pruning for age. Larger cerebellar volumes in adult obsessive compulsive disorder (OCD) patients have been reported. This suggests a possible similarity in structural underpinnings for alcohol dependence and OCD.

Plasma cocaine levels, metabolites, and locomotor activity after subcutaneous cocaine injection are stable across the postpartum period in rats

Plasma levels of cocaine (COC) and two of its principle metabolites, benzoylecgonine (BE) and ecgonine methyl ester (EME) were determined by liquid chromatography–tandem mass spectrometry (LC/MS/MS) in samples collected up to 3 h after a subcutaneous injection of cocaine (10 mg/kg) on six different days between days 4 and 24 postpartum, a period of dramatic change in the endocrine state of the female rat. Locomotor activity was measured in the same animals during this period using automated animal activity monitors. Additional measures in males provide a link to existing literature. We found that plasma levels of cocaine and its metabolites, as well as their respective time courses, are remarkably uniform across the postpartum period in female rats, as are the effects of cocaine on locomotor activity. Data from males show accord with prior published values. COC and BE, but not EME levels, were higher in males, and the time courses of COC and BE levels after injection varied somewhat between postpartum females and males; however, neither baseline nor cocaine-induced locomotor activity differed between postpartum females and males. We conclude that in the postpartum rat, there are no significant differences in the peripheral processing or general accessibility of cocaine to the brain to activate motor systems across the postpartum period. These data are critical to our understanding of differences in the reward salience of cocaine across the postpartum period and in other adult rat models [Mattson BJ, Williams S, Rosenblatt JS, Morrell JI. Comparison of two positive reinforcing stimuli: pups and cocaine throughout the postpartum period. Behav Neurosci 2001;115:683–94, Mattson BJ, Williams SE, Rosenblatt JS, Morrell JI. Preferences for cocaine- or pup-associated chambers differentiate otherwise behaviorally identical postpartum maternal rats. Psychopharmacology (Berl) 2003;167:1–8].

Inspiration: Core Characteristics, Component Processes, Antecedents, and Function.

The authors examined the core characteristics, component processes, antecedents, and function of state inspiration. In Studies 1 and 2, inspiration was contrasted with baseline experience and activated positive affect (PA) using a vivid recall methodology. Results supported the tripartite conceptualization of inspiration. Confirmatory factor analysis indicated that inspiration may be decomposed into separate processes related to being inspired "by" and being inspired "to." Study 3 found that daily inspiration is triggered by illumination among individuals high in receptive engagement, whereas activated PA is triggered by reward salience among individuals high in approach temperament. Approach temperament was also implicated in being inspired "to." Inspiration and activated PA appear to serve different functions: transmission and acquisition, respectively.

Intra-Accumbens Amphetamine Increases the Conditioned Incentive Salience of Sucrose Reward: Enhancement of Reward “Wanting” without Enhanced “Liking” or Response Reinforcement

Amphetamine microinjection into the nucleus accumbens shell enhanced the ability of a Pavlovian reward cue to trigger increased instrumental performance for sucrose reward in a pure conditioned incentive paradigm. Rats were first trained to press one of two levers to obtain sucrose pellets. They were separately conditioned to associate a Pavlovian cue (30 sec light) with free sucrose pellets. On test days, the rats received bilateral microinjection of intra-accumbens vehicle or amphetamine (0.0, 2.0, 10.0, or 20.0 microgram/0.5 microliter), and lever pressing was tested in the absence of any reinforcement contingency, while the Pavlovian cue alone was freely presented at intervals throughout the session. Amphetamine microinjection selectively potentiated the cue-elicited increase in sucrose-associated lever pressing, although instrumental responding was not reinforced by either sucrose or the cue during the test. Intra-accumbens amphetamine can therefore potentiate cue-triggered incentive motivation for reward in the absence of primary or secondary reinforcement. Using the taste reactivity measure of hedonic impact, it was shown that intra-accumbens amphetamine failed to increase positive hedonic reaction patterns elicited by sucrose (i.e., sucrose "liking") at doses that effectively increase sucrose "wanting." We conclude that nucleus accumbens dopamine specifically mediates the ability of reward cues to trigger "wanting" (incentive salience) for their associated rewards, independent of both hedonic impact and response reinforcement.

Can salient reward increase creative performance without reducing intrinsic creative interest?

Can salient reward increase creative performance without reducing intrinsic creative interest?

The impact of ethnic origin and gender on image of occupations and salience of work rewards: A multicultural approach

The study examined the impact of ethnic culture and gender on attitudes toward work and occupations among Soviet immigrant and Israeli students. The research focused on image of occupations (sex-typing and prestige of occupations), as well as on perceived salience of work rewards.

Disincentives to Teaching: Teacher Reactions to Legislated Learning

Legislated learning describes accurately the assumptions underlying educational legislation in Florida from 1976 to 1985. This study explores the failure of teachers to accept models of legislated learning imposed on them. While 86.7% of teachers surveyed identified "the times I know I have `reached' a student or group of students and they have learned" as the most salient intrinsic reward in teaching, 74% of teachers interviewed found legislated learning as questioning competency, limiting the scope of teachers' work and/or political interference. Instead of creating an incentive of a better educational environment, legislated learning, according to interviewees, functioned as a disincentive to these teachers.

Reward Salience, Assessment of Success, and Critical Attitudes Among Tutors

Results from a questionnaire administered to 1,353 college students, who were to receive a tuition rebate for tutoring disadvantaged elementary school children, indicated that external rewards were not equally salient for all tutors. Tutors could be classified into 4 motivational groups on the basis of their primary reasons for tutoring. Extrinsically motivated tutors reported less change in their tutees, and were more critical of the tutoring experience than tutors professing differing degrees of intrinsic motivation. When tutors claimed both extrinsic and intrinsic motives, their other assessments were, unexpectedly, similar to those of internally motivated tutors.

Intrinsic motivation and delay of gratification in preschoolers: The variables of reward salience and length of expected delay

The undermining effect of reward on the intrinsic motivation of 100 preschool children was tested under six reward conditions and a control. The reward conditions varied the children's attention to rewards (salience) and length of expected reward delay to test predictions derived from the delay of gratification hypothesis. The results disconfirmed the prediction of greater decrements in intrinsic interest with increases in length of expected reward delay and, in fact, showed the opposite trend. The pattern of significant effects supported the role of reward salience. Cognitive script theory is discussed as an explanation of these results and elaborated to incorporate developmental changes in cognitive processes. The combination of attribution theory and the elaborated version of cognitive scripts is proposed to account for the undermining effect in young children and adults.

Sex, Costs, and Helping Behavior

Summary A field experiment in an American university library setting examined the effects of perceived costs on helping behavior. Males and females (N = 192) requested either 10 cents or 30 cents from male or female subjects. Overall, subjects helped more often in response to a request for 10 cents than to a request for 30 cents and gave assistance more frequently to female requestors than to male requestors. As predicted on the basis of research indicating that increasing costs decrease the relative salience of potential rewards, cross-sex helping was mediated by the level of costs for helping. The cross-sex helping interaction occurred in the 10-cents requests conditions, but not in the 30-cents request conditions.

Effects of salience of extrinsic rewards on liking and loving.

Effects of salience of extrinsic rewards on liking and loving.