Anticipatory pleasure predicts effective connectivity in the mesolimbic system

Convergent evidence suggests the important role of the mesolimbic pathway in anticipating monetary rewards. However, the underlying mechanism of how the sub-regions interact with each other is still not clearly understood. Using dynamic causal modeling, we constructed a reward-related network for anticipating monetary reward using the Monetary Incentive Delay Task. Twenty-six healthy adolescents (Female/Male = 11/15; age = 18.69 +/- 1.35 years; education = 12 +/- 1.58 years) participated in the present study. The best-fit network involved the right substantia nigra/ventral tegmental area (SN/VTA), the right nucleus accumbens (NAcc) and the right thalamus, which were all activated during anticipation of monetary gain and loss. The SN/VTA directly activates the NAcc and the thalamus. More importantly, monetary gain modulated the connectivity from the SN/VTA to the NAcc and this was significantly correlated with subjective anticipatory pleasure (r = 0.649, p < 0.001). Our findings suggest that activity in the mesolimbic pathway during the anticipation of monetary reward could to some extent be predicted by subjective anticipatory pleasure

Ventral striatum connectivity during reward anticipation in adolescent smokers

Substance misusers, including adolescent smokers, often have reduced reward system activity during processing of non-drug rewards. Using a psychophysiological interaction approach, we examined functional connectivity with the ventral striatum during reward anticipation in a large (N = 206) sample of adolescent smokers. Increased smoking frequency was associated with (1) increased connectivity with regions involved in saliency and valuation, including the orbitofrontal cortex and (2) reduced connectivity between the ventral striatum and regions associated with inhibition and risk aversion, including the right inferior frontal gyrus. These results demonstrate that functional connectivity during reward processing is relevant to adolescent addiction

How Gains and Losses Influence the Brain and Behavior: Relations to Age, Risk for Depression, and Individual Differences

Behavioral and neural response to rewards and punishments has been the subject of a growing literature with particular interest within developmental, psychopathology, and individual difference domains. There is now mounting evidence suggesting that adolescents show heightened response to reward relative to adults, and that adolescents with Major Depressive Disorder (MDD), elevated depressive symptoms, or at high-risk for depression show reduced response to reward. However, it is unclear whether similar relations between response to incentives and development/psychopathology are observed during childhood. Here we examine behavioral, neural (functional magnetic resonance imaging - fMRI), and self-reported responsiveness to gain and loss of rewards within healthy children and young adults. We relate observed neural/behavioral incentive responsiveness to 1) developmental stage, 2) risk for depression, and 3) self-reported incentive sensitivity. First, studies investigating developmental stage indicated that responsiveness to gain and loss of reward feedback show differing relations with age. Specifically, while children show elevated behavioral and neural (dorsal/posterior insula) response to loss of reward relative to adults, response to reward was similar across age groups. Second, we observed similar levels of both gain approach and loss avoidance behavior between healthy children at relatively high and low-risk for MDD, based on a positive/negative maternal history of MDD respectively. Third, across several studies both elevated gain approach and elevated loss avoidance behavior related to elevated self-reported incentive sensitivity as assessed via different questionnaire types (i.e. hedonic capacity, Behavioral Inhibition System/Behavioral Activation System, and anhedonic depressive scales). Interestingly, gain approach and loss avoidance behavior predicted unique variance in self-reported incentive sensitivity (BAS drive) and relations between incentive sensitivity and behavior did not differ based on age or depression risk status. Together these results highlight the importance of responsiveness to feedback signaling the loss of reward from both developmental and incentive sensitivity perspectives. Future work is needed to examine how gain and loss responsiveness during childhood prospectively predicts changes in incentive responsiveness over development and incidence of depression/changes in depressive symptoms

Association between the oxytocin receptor (OXTR) gene and mesolimbic responses to rewards

10.1186/2040-2392-5-7Molecular Autism51

Processing of primary and secondary rewards: A quantitative meta-analysis and review of human functional neuroimaging studies

One fundamental question concerning brain reward mechanisms is to determine how reward-related activity is influenced by the nature of rewards. Here, we review the neuroimaging literature and explicitly assess to what extent the representations of primary and secondary rewards overlap in the human brain. To achieve this goal, we performed an activation likelihood estimation (ALE) meta-analysis of 87 studies (1452 subjects) comparing the brain responses to monetary, erotic and food reward outcomes. Those three rewards robustly engaged a common brain network including the ventromedial prefrontal cortex, ventral striatum, amygdala, anterior insula and mediodorsal thalamus, although with some variations in the intensity and location of peak activity. Money-specific responses were further observed in the most anterior portion of the orbitofrontal cortex, supporting the idea that abstract secondary rewards are represented in evolutionary more recent brain regions. In contrast, food and erotic (i.e. primary) rewards were more strongly represented in the anterior insula, while erotic stimuli elicited particularly robust responses in the amygdala. Together, these results indicate that the computation of experienced reward value does not only recruit a core "reward system" but also reward type-dependent brain structures

Μελέτη της επίδρασης της ανταμοιβής στους νοητικούς μηχανισμούς λήψης απόφασης σε ασθενείς με σχιζοφρένεια και χρήστες κάνναβης

Η χρόνια χρήση κάνναβης και η σχιζοφρένεια πιστεύεται ότι επηρεάζουν τη διεργασία ανταμοιβής. Ενώ έχουν μελετηθεί και για τις δύο περιπτώσεις οι συμπεριφορικές και νευρικές επιδράσεις στη διεργασία κινήτρων, δεν έχει μελετηθεί η αλληλεπίδρασή τους, αν και η χρόνια χρήση κάνναβης είνα κοινή στους ασθενείς με σχιζοφρένεια. Στην παρούσα μελέτη ογδόντα εννέα συμμετέχοντες χωρισμένοι σε τέσσερις ομάδες (δείγμα χρόνιων χρηστών κάνναβης και μη χρηστών· ασθενείς με σχιζοφρένεια χρήστες κάνναβης και μη χρήστες) εξετέλεσαν μια άσκηση αποφάσεων διπλής επιλογής, αφού είχαν προηγηθεί σήματα κινήτρων (υψηλή/χαμηλή ανταμοιβή/τιμωρία ή ουδέτερο), ενώ παράλληλα σαρώνονταν με τη χρήση Λειτουργικού Μαγνητικού Συντονισμού (fMRI). Η αναμονή ανταμοιβής και τιμωρίας είχε ως αποτέλεσμα την ενεργοποίηση περιοχών ενδιαφέροντος, όπως του θαλάμου, των βασικών γαγγλίων, της αμυγδαλής και του νησιωτικού φλοιού. Η χρόνια χρήση κάνναβης και η σχιζοφρένεια είχαν αντίθετα αποτελέσματα αναφορικά με την ευαισθησία αναμονής ανταμοιβής. Ειδικότερα, οι χρήστες του δείγματος και οι ασθενείς μη χρήστες παρουσίασαν ταχύτερη συμπεριφορική απόκριση και αυξημένη δραστηριότητα στον πρόσθιο/οπίσθιο νησιωτικό φλοιό στα σήματα υψηλού μεγέθους σε σύγκριση με το δείγμα μη χρηστών και ασθενών χρηστών. Το ίδιο μοτίβο αλληλεπίδρασης παρατηρήθηκε στην ενεργοποίηση του δεξιού θαλάμου όσον αφορά στην ανταμοιβή έναντι των σημάτων τιμωρίας. Η μελέτη αυτή παρείχε αποδείξεις για την αλληλεπίδραση της χρόνιας χρήσης κάνναβης και σχιζοφρένειας στη διεργασία ανταμοιβής και τιμωρίας και αναδεικνύει την ανάγκη περαιτέρω μελλοντικής έρευνας λόγω της σπουδαιότητας αυτής της αλληλεπίδρασης στην παθοφυσιολογία αυτών των καταστάσεων και των κλινικών συνεπειών τους.Chronic cannabis use and schizophrenia are both thought to affect reward processing. While behavioural and neural effects on incentive processing have been investigated in both populations, their interaction has not been studied, although chronic cannabis use is common among schizophrenia patients. In the present study eighty-nine participants divided into four groups (control chronic cannabis users and non-users; schizophrenia patient cannabis users and non-users) performed a two-choice decision task, preceded by incentive cues (high/low reward/punishment or neutral), while being scanned using functional magnetic resonance imaging. Reward and punishment anticipation resulted in activation of regions of interest including the thalamus, striatum, amygdala and insula. Chronic cannabis use and schizophrenia had opposing effects on reward anticipation sensitivity. More specifically control users and patient non-users showed faster behavioural responses and increased activity in anterior/posterior insula for high magnitude cues compared to control non-users and patient users. The same interaction pattern was observed in the activation of the right thalamus for reward versus punishment cues. This study provided evidence for the interaction of chronic cannabis use and schizophrenia on reward and punishment processing and highlights the need for future research addressing the significance of this interaction for the pathophysiology of these conditions and its clinical consequences

Reward Processing in Autism Spectrum Disorder: Behavioral Indicators, Neural Correlates, and Mechanisms of Treatment Response

This integrative dissertation broadly explores reward processing differences in autism spectrum disorder (ASD) using neuroimaging and eye tracking technologies. Study 1 investigated prediction error responses, one aspect of reward processing, in individuals with ASD using an outcome expectancy eye tracking task. The findings corroborate previous reports of aberrant responses to prediction errors in ASD, but did not find that this effect was impacted by reward type (e.g., social vs. nonsocial). Study 2 is the first published neuroimaging study to examine neural responses of individuals with ASD as they win money for others (i.e., vicarious reward). As hypothesized, participants with ASD showed decreased neural activation in key vicarious reward regions when earning rewards for others, potentially shedding light on mechanisms behind social difficulties in ASD. Finally, Study 3 evaluated neural reward responses following intranasal oxytocin administration, and the results showed heightened neural reward circuitry activation in response to non-social rewards following oxytocin administration. Taken together, these studies provide a greater depth of understanding regarding various aspects of reward processing differences in ASD.Doctor of Philosoph

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

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