The present study aimed to: (1) Characterize markers of reward sensitivity during periods of social stress using a well validated social feedback paradigm; (2) Evaluate clinical relations between reward markers and anhedonia; and (3) Investigate if elevated levels of baseline prior exposure to stress (i.e., peer victimization) are associated with the degree of ventral striatum suppression and anhedonia symptoms in a social stress context. A total of 29 adolescents between the ages of 13 and 17 years old (Mage = 15.31; SD = 1.51; 55.2% cisgender girls) participated in the present study. Participants were asked to complete a semi-structured interview; fill out self-report questionnaires regarding social anxiety, stress, depression, and anhedonia; and complete a magnetic resonance imaging scan while playing the Island Getaway task. Ventral striatum (VS) BOLD signal activation estimates were then extracted during discrete phases of the game (e.g., anticipation of social feedback and outcome of social feedback) and statistically compared within-subjects via paired samples t-tests and correlated to social anxiety measures. Additionally, regression analyses assessed the effect of VS activation on anhedonia as well as the associative effect of peer victimization on VS activation and anhedonia. Results revealed that when in the presence of social stress (defined as the potential for negative feedback), socially anxious adolescents demonstrated significantly suppressed VS activation relative to baseline when anticipating feedback. Additionally, results indicated that the degree of reduced VS activation during anticipation was correlated to total changes in anhedonia severity across the task. Lastly, results demonstrated that overt peer victimization is a significant predictor of suppressed VS activation during anticipation of social feedback, but not during social outcomes. Taken together, these results identify potentially novel mechanisms associated with anhedonia and blunted reward processing in socially anxious youth that could be improved via interventions that target positive-valence systems. / Doctor of Philosophy / Socially anxious teens may be at a heightened risk for developing anhedonia – which means that they are showing a significant lack of interest in things they used to find interesting or rewarding. This is problematic, because the presence of anhedonia is associated with not doing as well in therapy and even with higher rates of suicide attempt. One area that may be linked to the development of anhedonia in socially anxious teens is social stress induced disrupted reward processing in certain regions of the brain that generally activate when people anticipate a reward. Despite this, there is very little research on the development of anhedonia is socially anxious teens and even less that focuses on biological and behavioral experiences of reward processing when under social stress. This study examines this potential stress-to-anhedonia pipeline by looking at a key region of the brain, called the ventral striatum, to see if social stress does disrupt reward processing in socially anxious teens, and, if so, if this disrupted reward processing is related to anhedonia. Through evaluating a total of 29 socially anxious teens who underwent a social stress task while completing brain scanning, the present study demonstrated evidence for diminished brain activation in the ventral striatum when anticipating rewards. Additionally, the present study showed that reduced brain activation in the ventral striatum was associated with changes in anhedonia severity. Lastly, results from this study indicated that peer victimization (or bullying) was a significant predictor of diminished brain activation in the ventral striatum. Taken together, these results identify potentially new markers associated with anhedonia and blunted reward processing in socially anxious youth that could be improved via interventions.

Breast cancer is associated with significant disruption in social support, social cognition, and depression. This study seeks to explore social and emotional factors using the integrative model for social reward processing. To better understand these relationships, 103 women with breast cancer (e.g., stage I – IV; mean age = 58.74, SD = 11.48; range 25 - 82) completed the Anticipatory and Consummatory Interpersonal Pleasure Scale, Patient Reported Outcomes Measurement Information System - Depression Scale, Medical Outcomes Study- Social Support Survey, and the Reading the Mind in the Eyes Test. Path analysis, controlling for current breast cancer stage and history of a depressive disorder, was used to examine relationships between social pleasure, social support, social cognition, and depression severity. A significant moderated mediation was found with reduced social pleasure related to increased depression severity through (i.e., mediated by) reduced social support. Further, analyses revealed the relationship between reduced social pleasure and reduced social support was moderated by reduced social cognition. Findings suggest unique relationships between reduced social pleasure and social support as they relate to depression severity. Further, reduced social cognition may serve as a risk factor for increased depression severity though its influence on social pleasure and social support. Additionally, findings suggest high social cognition may serve as a protective factor in the relationships between depression severity through its influence on social pleasure and social support. The current study suggests the need for future research focused on integrating strategies for improving social cognition into the treatment of depression in individuals with breast cancer. Future research is needed to explore other domains as potential mechanisms of social reward processing such as social skills, effort, and motivation.

<p>  </p> <p>Social withdrawal is a disabling feature of schizophrenia. To understand its development, researchers have focused on social anhedonia— diminished pleasure from social interactions. Discrepancies in anticipated versus consummatory pleasure for non-social stimuli are well-documented in schizophrenia. Thus, a similar emotional paradox may underlie social anhedonia. If so, our understanding of social anhedonia—including how to treat it in schizophrenia—could be enhanced. This project used a 5-day experience sampling method (ESM) to measure discrepancies between anticipated and consummatory pleasure for real-world social activities in people with schizophrenia and healthy controls (<em>n=</em>30/group). Results suggest people with schizophrenia exhibited similar levels of anticipated and consummatory social pleasure as controls, and both groups were accurate in their short-term predictions of pleasure. Yet, healthy control participants were somewhat more precise in their short-term pleasure predictions, and clinical interviews revealed those with schizophrenia showed moderate deficits in long-term social pleasure prediction. Negative symptoms and cognitive impairment in schizophrenia were related to anticipated, but not consummatory, social pleasure, suggesting anhedonia is driven by deficits in thinking about pleasure, rather than inability to experience pleasure. Clinical implications include focusing on building upon short-term ability to predict pleasure in therapy in order to increase social motivation in schizophrenia. Moreover, exploratory analyses revealed differences in qualitative aspects of social activities such as level of engagement may lead to social anhedonia in schizophrenia and are a promising treatment target for addressing social dysfunction.</p>

No description available.

Experiential avoidance (EA), or the evasion of unpleasant internal experiences, is key to changes in emotional responsivity in Posttraumatic Stress Disorder (PTSD). EA has been linked to altered negative emotional reactivity in PTSD, but it remains unclear whether EA is linked to altered positive reactivity in PTSD, i.e. anhedonia. Therefore the study examined how manipulating EA influences emotional responsiveness in a non-clinical adult population (N=74). Positive emotion reactivity (self-report and psychophysiology) was measured before and after viewing a laboratory analogue trauma induction, with half of participants instructed to adopt the detached protector (DP) mode as an example of EA during trauma viewing and half of participants in an uninstructed control condition. Following the DP mode instructions reduced negative emotion experience during the trauma induction, relative to the control condition. However counter to prediction, there was no carry over onto blunted positive emotion experience or psychophysiological response in the experimental condition (relative to the control condition) when recalling positive memories and imagining positive future events. No significant relationships were identified between trait EA levels and anhedonia symptoms or pre-manipulation positive emotional responsiveness in the laboratory. Overall, the current findings offer no support for the hypothesis that EA contributes to anhedonia.

Literature Review: Anhedonia, the loss of interest or pleasure in usually pleasurable activities, is a core symptom of depression and is associated with a reduction in positive affect (PA). Repetitive negative thought (RNT) is implicated in the development and maintenance of psychiatric disorders. It has been hypothesised that RNT causally contributes to anhedonia. The aim of this review was to explore this relationship to answer two questions: Is there a relationship between RNT and anhedonia? Does RNT causally contribute to anhedonia? Review inclusion criteria were: studies using standardised measures to report a relationship between RNT and anhedonia or reduced PA. Results suggest that cross-sectional and longitudinal studies identify a relationship between RNT and anhedonia. Preliminary evidence from experimental studies shows that RNT causally contributes to anhedonia. Limitations within the field are that anhedonia is rarely measured directly or behaviourally. Future research is warranted to explore the relationship between RNT and anhedonia with a particular focus on direct and behavioural measures of anhedonia. Empirical Paper: It is hypothesised that repetitive negative thought (RNT) causally contributes to anhedonia. There is cross-sectional and longitudinal evidence of this relationship, but it has not previously been investigated directly using experimental methods. In the present study, student participants were randomly assigned to an unresolved goal (RNT) manipulation (n = 43) or resolved goal (control) manipulation (n =41) prior to completing a reward sensitivity task. This task has been reliably found to train a response bias towards the stimuli that is differentially positively reinforced, with both depression and self-reported anhedonia associated with a reduced response bias. The unresolved goal versus resolved goal manipulation was effective, with the unresolved condition producing significantly higher levels of RNT during the reward sensitivity task relative to the resolved condition. Inconsistent with study predictions, there was no significant difference between the conditions on response bias, although there were trend findings, which tentatively suggest that RNT may influence anhedonia. Potential accounts for the null findings and future research are discussed.

Chronic Mild Stress (CMS) é um modelo animal de depressão no qual ratos são submetidos a um protocolo de estressores moderados de forma crônica. Em função disso, o consumo e preferência por água com sacarose diminuem. Tal redução costuma ser considerada uma medida de anedonia, sintoma central da depressão em humanos. Três estudos realizados no Laboratório do Programa de Estudos Pós- Graduados em Psicologia Experimental da PUC-SP demonstraram que esse efeito é atenuado pela exposição a uma condição operante em esquema concorrente FR água FR sacarose. O presente estudo teve por objetivo investigar se a submissão a uma condição operante que envolvesse diferentes estímulos reforçadores teria o mesmo efeito. Para isso, as seguintes condições experimentais foram propostas: 1) exposição a um protocolo de estressores por seis semanas; 2) testes semanais de consumo de água e água + 2% sacarose; 3) sessões operantes. Dos nove sujeitos utilizados, quatroforam expostos também a uma condição na qual a resposta de pressão à barra foi consequenciada com acesso à roda de atividades, dois a uma condição na qual a resposta de pressão à barra foi consequenciada com uma pelota de alimento em FR6 e dois em FR12. Como resultado, observou-se que no sujeito submetido somente aos estressores (sujeito 09) foi replicado mais uma vez o efeito de redução no consumo de solução de sacarose. Esse efeito não pode ser observado em nenhum dos sujeitos submetidos às sessões operantes durante a exposição. Observou-se uma queda somente no primeiro teste após o término dessa, indicando que possivelmente a submissão a essas afetou o efeito tradicionalmente observado em decorrência da exposição ao protocolo de estressores. Tais resultados corroboram e ampliam os estudos anteriores. Nas sessões operantes, observou-se redução na taxa de respostas na quinta semana de exposição para os sujeitos em FR12 (02 e 03) e na quinta ou sexta para o sujeitos em FR6 (01 e 04). O desempenho na roda de atividades pareceu ficar sob controle da alteração no peso corporal (sujeitos 05 a 09). É possível que a exposição à condição operante tenha atenuado os efeitos do protocolo de estressores e a redução no valor reforçador dos estímulos tenha sido retardada e/ou observada em condições com maior custo de resposta. / Chronic Mild Stress (CMS) is an animal model of depression. Chronic exposure of rats to a protocol of mild stressors produces decrease in sucrose intake and reduction in the preference for sucrose over water, which is considered as a measure of anhedonia, a core symptom of depression. Three Brazilian studies from PUC-SP showed that the additional exposure of rats to operant sessions using FR water FR sucrose concurrent schedule of reinforcement attenuates this effect. The objective of this study was to investigate if the submission to operant conditions that involves other reinforcers would also attenuate the decrease in sucrose consumption. Three experimental conditions were proposed: 1) exposure to a protocol of mild stressors for six weeks; 2) weekly tests of water and water + 2% sucrose intake; 3) operant sessions. Subject 09 was exposed only to conditions (1) and (2). Eight subjects were submitted to conditions (1), (2) and (3): access to a running-wheel served as reinforcer, in CRF, for subjects 05, 06, 07 and 08 and food was the reinforcer for other four subjects: 01 and 04 were submitted to a FR6 schedule of reinforcement and 02 and 03 to a FR12 schedule of reinforcement. It was observed that the subject 09, that was submitted only to stressors showed, again, a decrease in sucrose consumption and preference. The other eight subjects did not show this effect. A decrease in sucrose consumption was noted only in the first test after exposure to the protocol. These results suggest that submission to these operant conditions affected the traditional effect of the exposure to mild stressors and it corroborates and amplifies previous studies. During operant conditions, it was observed that lever presses decreased during fifth week of exposure to stressors for subjects responding on FR12 and during fifth or sixth week for subjects responding on FR6. Performance on running wheel changed according to body weight. It is possible that exposure to these operant conditions diminished the stressors effects and that the decrease in the reinforcing value of these stimuli was delayed and/ or observed under conditions with higher response cost.

Made available in DSpace on 2016-04-29T13:17:55Z (GMT). No. of bitstreams: 1 Paulo Eduardo da Silva.pdf: 1304608 bytes, checksum: 120f5cf5c36c91fabfb9829aab88df3f (MD5) Previous issue date: 2015-07-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Chronic Mild Stress (CMS) has been described in the literature as an experimental model of anhedonia, central symptom of depression in humans. The anhedonia has been studied in this model looking for a decrease of water with sucrose consumption in rats. This result is usually observed after the animal had been subjected to a set of stressful stimuli in a moderated and chronical way, for six weeks in average. The present study aimed to investigate the effects of the Stressors Protocol in rats subjected to a continuous water deprivation regimen. Eleven male rats of Wistar lineage were studie,. All the rats were subjected to a water deprivation schedule until reaching 85% of their ad lib weights, and they were maintained at these weights for the whole study. Thirteen water and water with sucrose consumption tests were used for all the subjects, while S7 was exposed only to the liquids consumption tests. S3 subject was submitted only to the Stressors Protocol. S5 was exposed to the same conditions of S3, except that the Stressors Protocol involved only the grouping stressor. For the other eight subjects, first they had the bar press response to the two bars modeled, using water as reinforcement. Then these eight animals were subjected to a Conc VI 5 sec VI 5 sec reinforcement, each bar being associated to water or water with sucrose reinforcements (one for each bar). After four weeks in this reinforcement schedule these animals were subjected to the Stressors Protocol for six consecutive and uninterrupted weeks in their living cages. During the protocol, four subjects (S2, S6, S8 and S10) also had their bar press responses reinforced in a Conc VI 5 sec VI 5 sec schedule (group before, during and after). The other four rats (S1, S4, S9 and S11- group before and after) were not submitted to operant sessions as long as the Stressors Protocol was available. At the end of the phase when the Stressors Protocol was available, these eight subjects were again subjected to the base line condition. The main results were: (a) a weight stability for the animals subjected to the protocol, (b) a high alternation of water and water with sucrose consumption in the tests for the only subject submitted to the tests and to the protocol, not demonstrating anhedonia, (c) a reduction in the animal s food consumption and an increase of water consumption in the living cage during the protocol for seven subjects, (d) the stressors protocol was not followed by a modification of the distribution of water and water with sucrose reinforced responses by Conc VI 5sVI5s, neither during the protocol, nor after its cessation, and (e) it seems that the reinforcement value of the liquids alternated for some subjects over major of the sessions. The role of continuous water deprivation and the measures used as anhedonia indicators are discussed / O Chronic Mild Stress (CMS) tem sido descrito na literatura como um modelo experimental de anedonia, sintoma central na depressão em humanos. A anedonia tem sido estudada dentro desse modelo a partir do decréscimo no consumo de água com sacarose em ratos. Este resultado é geralmente observado após o animal ser submetido a um conjunto de estímulos estressores de forma moderada e crônica, durante seis semanas em média, O presente estudo teve como objetivo investigar os efeitos do Protocolo de Estressores em ratos submetidos a um regime contínuo de privação de água. Foram empregados 11 ratos machos, da linhagem Wistar. Todos os sujeitos foram submetidos a um esquema de privação de água até atingir 85% dos seus pesos ad lib. e foram mantidos nesses pesos durante todo o estudo. Foram empregados 13 testes de consumo de água e de água com sacarose, sendo que o Sujeito S7 só passou pelos testes de consumo dos líquidos. O Sujeito S3 foi submetido ao Protocolo de Estressores. O sujeito S5 passou pelas mesmas condições que o S3, exceto que o Protocolo de Estressores envolveu apenas o estressor agrupamento. Para os outros 8 sujeitos, primeiramente foram modeladas as respostas de pressão às duas barras, usando água como reforçador. Depois, esses 8 animais foram submetidos a um esquema Conc VI 5 seg VI 5 seg associado aos reforços água e água com sacarose (um para cada barra). Após quatro semanas nesse esquema de reforçamento esses animais foram submetidos ao Protocolo de Estressores por seis semanas consecutivas e ininterruptas nas suas gaiolas-viveiro. Durante o Protocolo, 4 sujeitos (S2, S6, S8, S10) também tiveram suas respostas de pressão à barra reforçadas num esquema Conc VI 5 seg VI 5 seg (grupo antes, durante e depois) e os outros 4 (S1, S4, S9, S11) não (grupo antes e depois). Ao término do Protocolo de estressores, esses 8 sujeitos foram submetidos novamente à condição de linha de base. Os principais resultados encontrados foram: (a) estabilidade nos pesos dos animais submetidos ao protocolo, (b) maior oscilação em relação ao consumo de água e de água com sacarose para o sujeito submetido apenas aos testes e ao protocolo, não demonstrando anedonia, (c) redução no consumo de ração e aumento no consumo de água na gaiola-viveiro durante o protocolo (d) o protocolo de estressores não foi acompanhada por uma alteração na distribuição de respostas reforçadas com água e água com sacarose, nem durante e nem após a suspensão do mesmo, e (e) o valor reforçador dos líquidos parece ter se alternado para alguns sujeitos ao longo da maioria das sessões. Discute-se o papel da privação contínua de água e as medidas utilizadas como indicativas a de anedonia

Research on addictive behavior has traditionally emphasized the role that primary reinforcing effects of drugs of abuse plays in the development and maintenance of dependence. However, contemporary behavioral economic theory and animal models of nicotine dependence suggest the need for greater attention to the impact that response to alternative rewards may have on smoking behavior. The present study sought to investigate the impact of nicotine withdrawal on self-report, behavioral and neural indices of motivation, immediate response to rewards and the capacity to learn and modify behavior in response to positive and negative feedback. Heavy smokers (n = 48) completed two laboratory sessions following overnight deprivation, during which they smoked either nicotinized or denicotinized cigarettes. At each session, they completed a reward prediction and feedback learning task while electro-encephalographic recordings were obtained, as well as resting state recordings which were used to extract global indices of motivational state. Results confirmed that nicotine withdrawal produced an avoidant motivational state. This effect was strongly related to numerous indices of smoking motivation. Exploratory analyses also revealed numerous moderators of these effects. Behavioral data from tasks provided some support for the impact of nicotine withdrawal on reward and feedback processing, though minimal impact was observed for neural indices. Together, results confirm the manifestation of a broad-spanning impact of nicotine withdrawal on motivational state, but effects on specific reward systems remains unknown. Future research should examine the impact of nicotine withdrawal on other reward-related constructs to better delineate these effects.

This thesis examines potential associations between trait approach motivation and related measures, the everyday experience of affect and goal pursuit, and reward-related neural responses. The Behavioural Activation System (BAS) is a core motivational system, subserved by the neural reward circuitry, eliciting approach-type behaviour and positive emotion when activated by appetitive stimuli. Deficits in BAS sensitivity are thought to underlie the lack of motivation and positive affect (PA) that characterise anhedonia, whilst hyperactivation of the BAS has been linked to the increased goal-directed behaviour and positive affectivity associated with hypomania. In order to explore relationships between BAS sensitivity, goal pursuit, and reward processing, young participants, recruited from the student population (N = 65), and older participants, from the community (N = 63), underwent a 7-day period of experience sampling (ESM) to provide a naturalistic measure of momentary affect and goal-focused motivation. Functional Magnetic Resonance Imaging (fMRI; in a subset of n = 28 and n = 31 respectively) was then used to investigate individual differences in sensitivity of brain reward-related systems to various social and non-social rewards. Limited support was found for the relationship between BAS traits and the more motivational aspects of goal pursuit and reward processing, whilst anhedonia seemed to pertain more to reward consumption, with few links to everyday goal pursuit. This would indicate that anhedonia might not be as closely related to BAS sensitivity as was initially anticipated. Finally, in order to examine real-world correlates of neural activation, the data from the naturalistic measure were correlated with reward-related activation. Everyday PA correlated with striatal activation when viewing pleasant images, but no other associations emerged. This would suggest that the basic measures of brain function in relation to the particular reward-related stimuli used might be of limited relevance to everyday affective experience and goal pursuit.