Glutamine-to-glutamate ratio in the nucleus accumbens predicts effort-based motivated performance in humans

Substantial evidence implicates the nucleus accumbens in motivated performance, but very little is known about the neurochemical underpinnings of individual differences in motivation. Here, we applied 1H magnetic resonance spectroscopy (1H-MRS) at ultra-high-field in the nucleus accumbens and inquired whether levels of glutamate (Glu), glutamine (Gln), GABA or their ratios predict interindividual differences in effort-based motivated task performance. Given the incentive value of social competition, we also examined differences in performance under self-motivated or competition settings. Our results indicate that higher accumbal Gln-to-Glu ratio predicts better overall performance and reduced effort perception. As performance is the outcome of multiple cognitive, motor and physiological processes, we applied computational modeling to estimate best-fitting individual parameters related to specific processes modeled with utility, effort and performance functions. This model-based analysis revealed that accumbal Gln-to-Glu ratio specifically relates to stamina; i.e., the capacity to maintain performance over long periods. It also indicated that competition boosts performance from task onset, particularly for low Gln-to-Glu individuals. In conclusion, our findings provide novel insights implicating accumbal Gln and Glu balance on the prediction of specific computational components of motivated performance. This approach and findings can help developing therapeutic strategies based on targeting metabolism to ameliorate deficits in effort engagement

Place Matters: Rivalry, Rival Perceptions, and the Influence of Exposure and Proximity

This chapter uses two studies to illustrate the use of the Sport Rivalry Fan Perception Scale (SRFPS) by investigating differences in rival perceptions based on exposure and relative proximity to the out-group. Specifically, Study 1 examined how having visited the city where the rival team plays outside of sport consumption influenced perceptions of the rival team, and Study 2 compared how college students at the University of Colorado, Colorado State University, and the University of Wyoming viewed their rival schools. Results showed that both out-group exposure and relative proximity influenced participant rival perceptions. Taken together, the studies added further support for using the SRFPS and added to the literature on rivalry and group behavior. Implications and avenues for future research are discussed

Consumer Reactions to Rival Failure: Examining Glory Out of Reflected Failure

This chapter focuses on the Glory Out of Reflected Failure (GORFing) phenomenon and its relationships regarding team identification, rival perceptions, and favorite team behavior intentions. A sample of 555 sport fans provides responses regarding their team identification, the perceptions of rival teams, their likelihood to experience GORFing, and behavioral intentions toward the favorite team when their rival loses to a third, neutral team. Structural model results showed that rival perceptions are associated with the likelihood of experiencing GORFing, which in turn was associated with behavioral intentions following a rival team’s loss to a comparable team, and mediated the relationship between rival perceptions and behavioral intentions. Contributions and implications for researchers and practitioners are discussed, and avenues for future study are introduced