No neuroimaging investigation to date has considered the effects of social context on self-referential processing, despite the fact that the hypothesis that people engage different selves in different contexts has been with psychology for more than a century. To address this gap in the empirical record, a suite of three functional magnetic resonance imaging (fMRI) experiments was conducted in order to assess patterns of neural activity associated with self-referential (compared to non-self-referential) processes (Experiment 1), computational models of reinforcement-learning processes (Experiment 2), and social context modulation of personally relevant cognition (Experiment 3). I demonstrate that distinct patterns of neural activity in cortical midline structures and the mesial ventral striatum are associated with thinking about the self privately, sharing information about the self with a parent, and sharing with a friend. These differentiated disclosure responses (Experiment 3) are evident at the whole brain level and in regions of interest defined by functional activity in independent tasks of self (Experiment 1) and reward (Experiment 2). In addition to providing empirical evidence for contextually differentiated self-representations in the brain, this dissertation validates the use of fMRI paradigms designed to functionally localize self-referential and reward-related activity either independently or in conjunction, as well as distinguish components of ventral striatal activity unique to each task. Finally, I consider strategies for approaching future investigations of self and social cognition in terms of reinforcement learning.

Estudos em neurociência aplicada ao exercício tem demonstrado que a gustação do carboidrato pode estimular áreas cerebrais de recompensa e postergar a exaustão em atletas humanos. O presente estudo tem por objetivo investigar o efeito do enxague oral com maltodextrina sobre o desempenho de cavalos em teste incremental de esforço máximo a campo. Sete equinos da raça Mangalarga Marchador foram avaliados após enxague oral com maltodextrina a 6,4% (teste C) e placebo (teste P). Tempo até a exaustão (TAE), frequência cardíaca, glicose e lactato plasmáticos, e a atividade plasmática de creatinoquinase foram avaliados durante e após os testes. O TAE do teste C foi em média 31 segundos superior ao P. O valor pico de lactato do teste C foi 5,97 mg/dl superior ao teste P. O enxague oral com maltodextrina aumentou a capacidade de resistência dos animais avaliados neste estudo / Ergogenic effect of carbohydrate mouth rinse has been widely described in human runner and cyclists. This effect seems to be mediated by the activation of brain areas related to reward and motivation. The aim of the present study is to investigate the effect of maltodextrin mouth rinse on field maximal exercise test. Seven MM breed horses were evaluated after mouth rinse with maltodextrin 6, 4% (test C) and placebo (test P). Time to exhaustion, heart rate, plasmatic glucose and lactate, and serum creatinokinase were measured during and after tests. Time to exhaustion of the test C was 31 second higher than test P. Plasmatic lactate peak was 5,97 mmol/l higher in test C. No differences were observed in glucose and CK levels. Maltodextrin mouth rinse improved performance in maximal field test

D.Com. (Leadership in Performance and Change) / Against the background of the continuously increasing need of employers to attract and retain key employees and the utilisation of the rewards offering in this process, the aim of this study was firstly to determine the relationship between personality types and reward preferences. In addition, the relationship between different reward categories and underlying reward components in a total rewards framework was identified, the relationships between identified demographic variables and reward preferences were confirmed and the reward categories that contribute most to the attraction, retention and motivation of employees were identified. From the research constructs it can be seen that personality types, personality preferences and motivational theories influence the design of a total rewards framework, which, in tum, enhances the total rewards strategy and employee value proposition (EVP) of an organisation.

Objective: Childhood abuse (CA) is commonly associated with increased frequency of high-risk behaviours (HRB) in adolescence. Similarly, research has highlighted links between CA and blunted responses to reward. To date, little attention has been devoted to examine if altered reward processes may also be linked to increased engagement in HRB. To explore this hypothesis, this systematic review collated research that investigated the relationship among CA, reward processes and HRB. Specifically, the review addressed the question: Are HRB associated with altered reward processes in children and adults with a history of CA? Method: Behavioural and neurobiological studies on CA, reward processing and HRB in children and adults were selected from multidisciplinary and subject-specific databases published prior to the 1st of March 2016. The systematic literature search yielded 271 records with 198 non-duplicated results. Screening of 14 full-text publications led to five eligible studies synthesized in this review. Results: Results confirmed impaired reward learning and increased HRB in those with a history of CA. Associations of blunted anticipatory or consummatory reward processing and HRB in individuals with CA remained inconclusive. Conclusions: Reward learning appears to be associated with CA. Further research is required to explore the relationship between reward processes and HRB. Understanding CA from a neurodevelopment perspective is a critical step to developing effective intervention strategies to reduce HRB. Empirical Paper: Abstract Objective: Following childhood abuse (CA), adolescence often sees the onset of depression and high-risk behaviour (HRB). Despite the prevalence, little is known about underlying neurobiological factors linking CA and HRB. To address this gap, I examined if anticipatory and consummatory reward processing in adolescents with CA predict frequency of HRB, irrespective of depressive symptoms. Methods: Thirty-seven adolescents (M=17.08 years; SD = 1.86) participated in the study: 13 females with CA and current major depressive disorder (MDD), eight females with MDD and no CA, and 16 individuals with no CA and no MDD for comparison (control group). Adolescents completed the Card-Guessing paradigm to assess reward processing, while undergoing a magnetic resonance imaging scan. Neural region-of-interest responses in the striatum and pallidum were assessed during anticipatory and consummatory reward phases. Hierarchical regression models investigated if neural responses to reward were altered based on exposure to CA and if altered neural responses predicted higher use of HRB. Results: Data showed that (1) depressed adolescents engaged more frequently in HRB irrespective of history of CA, (2) anticipatory and consummatory reward processes were not altered based on a history of CA, and (3) blunted activation in right pallidum in anticipation of rewards predicted HRB irrespective of depressive symptoms. Conclusion: Although the current study did not confirm changes in reward processing following CA, blunted reward ‘wanting’ was linked to more frequent HRB. Findings are relevant to theories highlighting the critical role of the pallidum in perceiving cues as rewarding and in initiating goal-directed actions to obtain rewards.

No description available.

Individuals who display high levels of reward sensitivity are motivated by and respond to reward related cues, thus exhibiting more approach-motivated behaviors. A majority of the research on physiological indices of reward sensitivity in relation to self-regulatory abilities has focused on adults or adolescents, with relatively little work examining these associations in children. Thus, the current study sought to examine whether a common neural measure of reward sensitivity, left frontal electroencephalogram (EEG) asymmetry, assessed in early childhood was predictive of children’s later self-regulation abilities in the context of reward delay. Emerging inhibitory control skills were also examined as a potential moderator of the association between reward sensitivity and self-regulation. The frontal asymmetry measure of reward sensitivity was assessed at Time 1, when children were between the ages of 4 and 7 years old. The Time 2 visit occurred 18-24 months later, at which point children completed a flanker task to assess inhibitory control and a lock-box task to measure two components of self-regulation: behavioral control (i.e., task effort and attentional focus) and emotion regulation (i.e., expressions of anger). Children with average levels of reward sensitivity showed the highest levels of overall effort (collapsed across low, moderate, and high effort scores) and the lowest levels of weak effort. Additionally, inhibitory control iv moderated the relation between reward sensitivity and effort such that children with low reward sensitivity and strong inhibitory control showed the highest levels of overall and moderate effort as well as the lowest levels of weak effort. There were no significant associations between reward sensitivity, inhibitory control, and attentional focus or anger expression. These results suggest that EEG frontal asymmetry is a useful physiological marker of reward sensitivity when predicting specific types of regulatory abilities in children.

OBJECTIVE: The overlap in literature on stress and human reward processing is relatively small but growing as its significance becomes increasingly implicated in the obesity epidemic. The greater prevalence of obesity, especially severe obesity, among females than males suggests that there may be sex differences in hormones driving eating behaviors and in food reward processing. There is an important gap in the literature – a paucity of studies employing robust psychosocial stressors in combination with a food-related reward neuroimaging task to examine sex differences in the effect of psychosocial stress on hormones and food reward processing in humans. We hypothesized that male and female healthy subjects exposed to stressful situations during the Maastricht Acute Stress Test (MAST) will show sex differences in physiological, subjective self-report, and neural measures. The physiological variables measured ghrelin and cortisol reactivity. Subjective self-report variables measured perceived threat (pre-/post-task appraisals), state anxiety (pre-/post-scan state anxiety), and visual analogue scale ratings of appetite and mood (hunger/sadness/tension). The neural variables utilized a food incentive delay (FID) task that measured hedonic value (valence ratings of reward vs. neutral cue, success, or fail), incentive motivation (reaction time to reward vs. neutral success), and reward sensitivity (blood-oxygen-level-dependent activation during functional magnetic resonance imaging in response to food reward vs. neutral anticipation and receipt) in predefined brain regions of interest (ROIs): the caudate, nucleus accumbens, putamen, amygdala, and hypothalamus. METHODS: A total of 42 healthy subjects between the ages of 21 and 45 with body mass index between 18 and 35 were enrolled. Each participant completed a stress visit, during which the stress version of the MAST was administered, and a no-stress visit, during which the no-stress version of the MAST was administered. The order of visits for each subject was randomly assigned. Demographic data as well as physiological, subjective self-report, and neural measures were obtained at each visit. RESULTS: Subjects experienced greater percent increase in cortisol from pre-MAST to post-MAST at the stress visit than the no-stress visit. At the stress visit, post-MAST raw cortisol levels were significantly higher in males than in females and pre-FID raw ghrelin levels were significantly higher in females than males. Subjects endorsed higher perceived threat, lower pre-scan state anxiety, and more negative post-MAST mood at the stress visit compared to the no-stress visit. During the stress visit, no significant sex differences were found in perceived threat, state anxiety, or mood. Lastly, there were no main effects of visit or sex on appetite, valence ratings, and functional response in the ROIs. Across visits, females reacted significantly slower than males to food reward and neutral cues. There was a significant effect of phase on functional response in the amygdala, but not in any other ROIs, with subjects across visits showing significantly greater amygdala activation in response to food reward (vs. neutral) receipt than anticipation. DISCUSSION: Our study revealed, as predicted, that there was a significant effect of stress on cortisol and ghrelin, and on subjective self-reported perceived threat, pre-scan state anxiety, and post-MAST mood. At the stress visit, compared to the no-stress visit, subjects showed greater increase in cortisol and reported higher perceived threat, lower pre-scan state anxiety, and more negative post-MAST mood, indicating that the stressful impact of the MAST induced the intended physiological consequences. Sex differences were observed in the effect of stress on cortisol at post-MAST time point (T20) and on ghrelin at pre-FID time point (T80). Our findings support sex differences in ghrelin and cortisol response to stress in agreement with previous studies’ findings. We failed to reject the null hypothesis that there is no effect of stress on appetite, valence ratings, reaction times, and functional response in the ROIs in response to food reward (vs. neutral) anticipation and receipt. We also did not find significant sex differences, or interactions involving sex, in perceived threat, state anxiety, appetite, mood, or valence ratings. Notably, we did not detect statistically significant sex differences in blood-oxygen-level-dependent signal activation in the caudate, nucleus accumbens, putamen, amygdala, or hypothalamus in response to reward (vs. neutral) anticipation and receipt. Future research can extend our findings by examining individual and potential sex differences in pervasive trait-level qualities to better understand the role of emotional eating tendencies on ghrelin, and reward anticipation and receipt.

Given the current economic climate, organisations and their management teams are faced with many decisions. Cost cutting policies, restructuring decisions and downsizing decisions are under consideration before implementation. Furthermore, these decisions and policies may have a negative effect on employees and could sway motivation, loyalty, morale, attitudes and views of employees.This research considers the impact of the reward systems and programmes, monetary and non-monetary rewards, as a means of motivating employees to achieve organisations identified strategic objectives. Many organisations face the dilemma around what the ideal reward programme should be in order to increase employee motivation and at the same time achieve the organisational objectives. The purpose of this research was to discover whether a well-designed reward programme would result in the motivation of employees.A questionnaire was developed using reward categories from the WorldatWork Total Reward Model and the Towers Perrin Total Rewards Effectiveness Blueprint. This was administered to a sample of past and present MBA students from a Johannesburg based business school in order to elicit responses around the aspects of their individual reward preferences and their organisations reward preferences. Data was gathered to understand the preferences between the various monetary and non-monetary reward categories and elements. The sample group of 180 respondents participated through a self-administered on-line survey. Statistical analysis was conducted on the data which involved both descriptive and inferential statistics.The results of the survey indicated that both organisations and employees recommend financial benefits as being the most important reward category. However, there was more of a preference from employees for career development, coaching/mentoring and work life balance than there was from the organisations. Furthermore it is evident from the results that organisations are utilising a combination of both monetary and non-monetary rewards, as a share of the reward package in relation to the varying needs of the labour force. Given the current economic climate, there is a major case for providing more value on non-monetary rewards to motivate employees, given the cost pressures faced by organisations. Although monetary rewards were rated as being the most important, there is an opportunity to combine them with non-monetary rewards and presented to an individual as a reward package.The reward approach can only be maximised by organisations if they understand the needs of employees based on the understanding of employee preferences; the dynamic nature of the work force and the potential impact on external factors. It is recommended that a new reward framework be designed to incorporate the reward preferences and expectations of both the employee and the organisation whilst taking into account the effect of the external environment, the job design and the link between the expectations from the organisation and the individual. / Dissertation (MBA)--University of Pretoria, 2012. / Gordon Institute of Business Science (GIBS) / unrestricted

The presence of different generations in a workforce can cause several complications in terms of employee performance and rewarding a workforce effectively. The preferences that each generation has towards a certain reward differs and therefore nullify a homogeneous total reward strategy. The study is aimed at uncovering if there are any generational specific preferences for certain rewards; and if they exist, can a company use them to attract, motivate and engage their workforce better than with a standardised total reward package as currently exists in the work environment. A quantitative study using a questionnaire as the data collection method was performed on a company in the South African financial industry, to determine if there is any evidence of a disparity in the preferences the identified generations have to the same package of rewards. The sample size collected was 6 316 respondents and the analysis of their responses were statistically completed. It was found that the different generation cohorts have different preferences to components of the total reward package. As each of them value a reward diffently, a more strategic approach in using the total reward package should be considered by the employer. / Dissertation (MBA)--University of Pretoria, 2010. / Gordon Institute of Business Science (GIBS) / unrestricted

The current study examined 236 undergraduate students in a week long twice-per-day ecological momentary assessment exploring the influence of baseline reward sensitivity and interactions between circadian variables (i.e., total sleep time, sleep quality) and daily measures of reward. Though primary study findings did not support reward sensitivity related moderation of sleep-reward pathways, a number of notable findings emerged. We found evidence of specific domains of reward sensitivity (anticipatory reward and reward responsiveness) which are uniquely related to daily experiences of reward. In addition, bidirectional circadian-reward pathways were found between sleep quality and daily rewards which suggests pathways towards reward-related engagement. Evidence also supported interactions between sleep quality and total sleep time on experience of daily reward, further highlighting the complexity of sleep-reward pathways and their relevance to mood symptoms.