Humans Integrate Monetary and Liquid Incentives to Motivate Cognitive Task Performance

It is unequivocal that a wide variety of incentives can motivate behavior. However, few studies have explicitly examined whether and how different incentives are integrated in terms of their motivational influence. The current study examines the combined effects of monetary and liquid incentives on cognitive processing, and whether appetitive and aversive incentives have distinct influences. We introduce a novel task paradigm, in which participants perform cued task-switching for monetary rewards that vary parametrically across trials, with liquid incentives serving as post-trial performance feedback. Critically, the symbolic meaning of the liquid was held constant (indicating successful reward attainment), while liquid valence was blocked. In the first experiment, monetary rewards combined additively with appetitive liquid feedback to improve subject task performance. Aversive liquid feedback counteracted monetary reward effects in low monetary reward trials, particularly in a subset of participants who tended to avoid responding under these conditions. Self-report motivation ratings predicted behavioral performance above and beyond experimental effects. A follow-up experiment replicated the predictive power of motivation ratings even when only appetitive liquids were use, suggesting that ratings reflect idiosyncratic subjective values of, rather than categorical differences between, the liquid incentives. Together, the findings indicate an integrative relationship between primary and secondary incentives and potentially dissociable influences in modulating motivational value, while informing hypotheses regarding candidate neural mechanisms

The applicability of the alternative workplace strategies in the real estate operations in Hong Kong

Thesis (B.Sc)--University of Hong Kong, 2004.published_or_final_versio

An fMRI protocol for administering liquid incentives to human participants

This protocol describes the materials and approaches for administering liquid incentives to human participants during fMRI scanning. We first describe preparation of the liquid solutions (e.g., neutral solution and saltwater) and liquid delivery setups. We then detail steps to connect the setups to the computer-controlled syringe pump in the MRI control room, followed by procedures for testing the syringe pump dispensing a liquid bolus during the task. Description of custom software and required adapters for implementing the liquid setup are included. For complete details on the use and execution of this protocol, please refer to Yee et al. (2021)

Dorsal anterior cingulate cortex encodes the integrated incentive motivational value of cognitive task performance

Humans can seamlessly combine value signals from diverse motivational incentives, yet it is not well understood how these signals are bundled in the brain to modulate cognitive control. The dorsal ACC (dACC) is theorized to integrate motivational value dimensions in the service of goal-directed action, although this hypothesis has yet to receive rigorous confirmation. In the present study, we examined the role of human dACC in motivational incentive integration. Healthy young adult men and women were scanned with fMRI while engaged in an experimental paradigm that quantifies the combined effects of liquid (e.g., juice, neutral, saltwater) and monetary incentives on cognitive task performance. Monetary incentives modulated trial-by-trial dACC activation, whereas block-related effects of liquid incentives on dACC activity were observed. When bundled together, incentive-related dACC modulation predicted fluctuations in both cognitive performance and self-report motivation ratings. Statistical mediation analyses suggest that dACC encoded the incentives in terms of their integrated subjective motivational value, and that this value signal was most proximally associated with task performance. Finally, we confirmed that these incentive integration effects were selectively present in dACC. Together, the results support an account in which dACC integrates motivational signals to compute the expected value of goal-directed cognitive control

Neural Correlates of Letter Reversal in Children and Adults

Children often make letter reversal errors when first learning to read and write, even for letters whose reversed forms do not appear in normal print. However, the brain basis of such letter reversal in children learning to read is unknown. The present study compared the neuroanatomical correlates (via functional magnetic resonance imaging) and the electrophysiological correlates (via event-related potentials or ERPs) of this phenomenon in children, ages 5–12, relative to young adults. When viewing reversed letters relative to typically oriented letters, adults exhibited widespread occipital, parietal, and temporal lobe activations, including activation in the functionally localized visual word form area (VWFA) in left occipito-temporal cortex. Adults exhibited significantly greater activation than children in all of these regions; children only exhibited such activation in a limited frontal region. Similarly, on the P1 and N170 ERP components, adults exhibited significantly greater differences between typical and reversed letters than children, who failed to exhibit significant differences between typical and reversed letters. These findings indicate that adults distinguish typical and reversed letters in the early stages of specialized brain processing of print, but that children do not recognize this distinction during the early stages of processing. Specialized brain processes responsible for early stages of letter perception that distinguish between typical and reversed letters may develop slowly and remain immature even in older children who no longer produce letter reversals in their writing

Population genetic analysis of Plasmodium knowlesi reveals differential selection and exchange events between Borneo and Peninsular sub-populations

Funding: A.T. was funded by a Newton Institutional Links Grant (British Council, no. 261868591). S.C. was funded by BloomsburySET and Medical Research Council UK grants (MR/M01360X/1, MR/R025576/1, MR/R020973/1, and MR/X005895/1). T.G.C. was funded by the Medical Research Council UK (Grant nos. MR/M01360X/1, MR/N010469/1, MR/R025576/1, MR/R020973/1, and MR/X005895/1).The zoonotic Plasmodium knowlesi parasite is a growing public health concern in Southeast Asia, especially in Malaysia, where elimination of P. falciparum and P. vivax malaria has been the focus of control efforts. Understanding of the genetic diversity of P. knowlesi parasites can provide insights into its evolution, population structure, diagnostics, transmission dynamics, and the emergence of drug resistance. Previous work has revealed that P. knowlesi fall into three main sub-populations distinguished by a combination of geographical location and macaque host (Macaca fascicularis and M. nemestrina). It has been shown that Malaysian Borneo groups display profound heterogeneity with long regions of high or low divergence resulting in mosaic patterns between sub-populations, with some evidence of chromosomal-segment exchanges. However, the genetic structure of non-Borneo sub-populations is less clear. By gathering one of the largest collections of P. knowlesi whole-genome sequencing data, we studied structural genomic changes across sub-populations, with the analysis revealing differences in Borneo clusters linked to mosquito-related stages of the parasite cycle, in contrast to differences in host-related stages for the Peninsular group. Our work identifies new genetic exchange events, including introgressions between Malaysian Peninsular and M. nemestrina-associated clusters on various chromosomes, including in parasite invasion genes (DBPβ, NBPXα and NBPXβ), and important proteins expressed in the vertebrate parasite stages. Recombination events appear to have occurred between the Peninsular and M. fascicularis-associated groups, including in the DBPβ and DBPγ invasion associated genes. Overall, our work finds that genetic exchange events have occurred among the recognised contemporary groups of P. knowlesi parasites during their evolutionary history, leading to apparent mosaicism between these sub-populations. These findings generate new hypotheses relevant to parasite evolutionary biology and P. knowlesi epidemiology, which can inform malaria control approaches to containing the impact of zoonotic malaria on human communities.Publisher PDFPeer reviewe

Promising insights into the health related quality of life for children with severe obesity

Background Childhood obesity is a growing health concern known to adversely affect quality of life in children and adolescents. The Patient Reported Outcomes Measurement Information System (PROMIS) pediatric measures were developed to capture child self-reports across a variety of health conditions experienced by children and adolescents. The purpose of this study is to begin the process of validation of the PROMIS pediatric measures in children and adolescents affected by obesity. Methods The pediatric PROMIS instruments were administered to 138 children and adolescents in a cross-sectional study of patient reported outcomes in children aged 8–17 years with age-adjusted body mass index (BMI) greater than the 85th percentile in a design to establish known-group validity. The children completed the depressive symptoms, anxiety, anger, peer relationships, pain interference, fatigue, upper extremity, and mobility PROMIS domains utilizing a computer interface. PROMIS domains and individual items were administered in random order and included a total of 95 items. Patient responses were compared between patients with BMI 85 to < 99th percentile versus ≥ 99th percentile. Results 136 participants were recruited and had all necessary clinical data for analysis. Of the 136 participants, 5% ended the survey early resulting in missing domain scores at the end of survey administration. In multivariate analysis, patients with BMI ≥ 99th percentile had worse scores for depressive symptoms, anger, fatigue, and mobility (p < 0.05). Parent-reported exercise was associated with better scores for depressive symptoms, anxiety, and fatigue (p < 0.05). Conclusions Children and adolescents ranging from overweight to severely obese can complete multiple PROMIS pediatric measures using a computer interface in the outpatient setting. In the 5% with missing domain scores, the missing scores were consistently found in the domains administered last, suggesting the length of the assessment is important. The differences in domain scores found in this study are consistent with previous reports investigating the quality of life in children and adolescents with obesity. We show that the PROMIS instrument represents a feasible and potentially valuable instrument for the future study of the effect of pediatric obesity on quality of life

Population genetic analysis of Plasmodium knowlesi reveals differential selection and exchange events between Borneo and Peninsular sub-populations.

The zoonotic Plasmodium knowlesi parasite is a growing public health concern in Southeast Asia, especially in Malaysia, where elimination of P. falciparum and P. vivax malaria has been the focus of control efforts. Understanding of the genetic diversity of P. knowlesi parasites can provide insights into its evolution, population structure, diagnostics, transmission dynamics, and the emergence of drug resistance. Previous work has revealed that P. knowlesi fall into three main sub-populations distinguished by a combination of geographical location and macaque host (Macaca fascicularis and M. nemestrina). It has been shown that Malaysian Borneo groups display profound heterogeneity with long regions of high or low divergence resulting in mosaic patterns between sub-populations, with some evidence of chromosomal-segment exchanges. However, the genetic structure of non-Borneo sub-populations is less clear. By gathering one of the largest collections of P. knowlesi whole-genome sequencing data, we studied structural genomic changes across sub-populations, with the analysis revealing differences in Borneo clusters linked to mosquito-related stages of the parasite cycle, in contrast to differences in host-related stages for the Peninsular group. Our work identifies new genetic exchange events, including introgressions between Malaysian Peninsular and M. nemestrina-associated clusters on various chromosomes, including in parasite invasion genes (DBP[Formula: see text], NBPX[Formula: see text] and NBPX[Formula: see text]), and important proteins expressed in the vertebrate parasite stages. Recombination events appear to have occurred between the Peninsular and M. fascicularis-associated groups, including in the DBP[Formula: see text] and DBP[Formula: see text] invasion associated genes. Overall, our work finds that genetic exchange events have occurred among the recognised contemporary groups of P. knowlesi parasites during their evolutionary history, leading to apparent mosaicism between these sub-populations. These findings generate new hypotheses relevant to parasite evolutionary biology and P. knowlesi epidemiology, which can inform malaria control approaches to containing the impact of zoonotic malaria on human communities