Neurocomputational Accounts of Choice Variability and Affect during Decision-making

Humans exhibit surprising variability in behaviour, often making different choices under identical conditions. While the outcomes of these choices typically lead to explicit rewards that have been shown to influence subsequent affective states, less well understood is how the brain represents rewards that are intrinsically meaningful to an individual. The first part of this thesis examines the contributions of endogenous fluctuations in brain activity to behaviour. Resting-state studies suggest that ongoing endogenous fluctuations in brain activity can influence low-level perceptual and motor processes but it remains unknown whether such fluctuations also influence high-level cognitive processes including decision making. Using a novel application of real-time functional magnetic resonance imaging, I find that low pre-stimulus brain activity lead to increased occurrences of risky choice. Using computational modeling, I show that greater risk taking is explained by enhanced phasic responses to offers in a decision network. These findings demonstrate that endogenous brain activity provides a physiological basis for variability in complex behaviour. I then examine how the neuroanatomy of the brain in the form of tissue microstructure relates to risk preferences by leveraging on in vivo histology using magnetic resonance imaging. The second part of this thesis investigates how experienced events, such as rewards received following choice, are aggregated into affective states. Despite their relevance to ideas like goal-setting and well-being, little is known about the impact of intrinsic rewards on affective states and their representation in the brain. A reinforcement learning task incorporating a skilled performance component that did not influence payment was developed to examine this. Computational modeling revealed that momentary happiness depended on past extrinsic rewards and also intrinsic rewards related to the experience of successful skilled performance. Individuals for whom intrinsic rewards more strongly influence momentary happiness exhibit stronger ventromedial prefrontal cortex responses for successful skilled performance. These findings show that the ventromedial prefrontal cortex represents the subjective value of intrinsic rewards, and that computational models of mood dynamics provide a tool that can be used to measure implicit values of abstract goods and experiences

The Single Item Literacy Screener: Evaluation of a brief instrument to identify limited reading ability

BACKGROUND: Reading skills are important for accessing health information, using health care services, managing one's health and achieving desirable health outcomes. Our objective was to assess the diagnostic accuracy of the Single Item Literacy Screener (SILS) to identify limited reading ability, one component of health literacy, as measured by the S-TOFHLA. METHODS: Cross-sectional interview with 999 adults with diabetes residing in Vermont and bordering states. Participants were randomly recruited from Primary Care practices in the Vermont Diabetes Information System June 2003 – December 2004. The main outcome was limited reading ability. The primary predictor was the SILS. RESULTS: Of the 999 persons screened, 169 (17%) had limited reading ability. The sensitivity of the SILS in detecting limited reading ability was 54% [95% CI: 47%, 61%] and the specificity was 83% [95% CI: 81%, 86%] with an area under the Receiver Operating Characteristics Curve (ROC) of 0.73 [95% CI: 0.69, 0.78]. Seven hundred seventy (77%) screened negative on the SILS and 692 of these subjects had adequate reading skills (negative predictive value = 0.90 [95% CI: 0.88, 0.92]). Of the 229 who scored positive on the SILS, 92 had limited reading ability (positive predictive value = 0.4 [95% CI: 0.34, 0.47]). CONCLUSION: The SILS is a simple instrument designed to identify patients with limited reading ability who need help reading health-related materials. The SILS performs moderately well at ruling out limited reading ability in adults and allows providers to target additional assessment of health literacy skills to those most in need. Further study of the use of the SILS in clinical settings and with more diverse populations is warranted

The functions of self‐harm in young people and their perspectives about future general practitioner‐led care: A qualitative study

Background Self-harm in young people is a serious concern but a deeper understanding of the functions of self-harm in young people can tailor care and inform new clinical interventions to reduce repeat self-harm and suicide risk. General practitioners (GPs), as frontline healthcare professionals, have an important role in managing self-harm in young people. This study aimed to explore the functions of self-harm in young people and their perspectives on future GP-led care. Methods A qualitative study using interviews with young people aged between 16 and 25 years with a personal history of self-harm was conducted. Interviews were transcribed and analysed using reflexive thematic analysis. Findings Four distinct functions were identified: (1) handling emotional states; (2) self-punishment; (3) coping with mental illness and trauma; and (4) positive thoughts and protection. Young people valued GP-led support and felt future GP interventions should include self-help and be personalised. Conclusions These findings support clinicians, including GPs, to explore the functions of self-harm in young people aged 16–25 in a personalised approach to self-harm care. It should be noted that self-harm may serve more than one function for a young person and thus interventions should recognise this. Patient and Public Contribution A group consisting of young people with lived experience of self-harm, carers, the public, and those who work with young people who harm themselves conceived this study idea, informed recruitment methods and the interview topic guide, and supported the interpretation of findings

Australian ethnomedicinal plant extracts promote apoptosis-mediated cell death In human hepatocellular carcinoma in vitro

Introduction: Hepatocellular carcinoma (HCC) Is the leading cause of primary liver cancer with Its prevalence continuing to rise. Although the number of cases continues to rise In both developing and developed countries, prognosis remains poor due to a lack of successful treatments. Inspired by the prospect of developing complementary medicines for this condition, we explore several native Australian plants for anti-carcinogenic activity, especially against HCC. Methods: Cytotoxicity assays against HCC cell lines were conducted using various plant extracts. Biochemical profiling of the plant species was conducted for total phenolics and antioxidant capacity, while reverse transcription-polymerase chain reaction (RT-PCR) was used to determine the active apoptotic pathways. Results: Westringia fruticosa and Prostanthera ovalifolia (small-leaved variety) had high antioxidant (410 and 227 mg/g, respectively) and phenolic contents (72.7 and 42.7 mg/g, respectively). P ovalifolia (small-leaved variety) demonstrated the greatest cytotoxic activity against HepG2 cells (IC50 4.61 ± 0.98 pg/mL) followed by Solanum laciniatum leaves (11.79 ± 0.43 pg/mL) and fruit extracts (ripe, unripe) (14.85 ± 1.80 and 19 ± 1.32 pg/mL, respectively). RT-PCR results confirmed apoptotic events in HepG2 cells, exposed to ripe and unripe S. laciniatum fruit extracts, via caspase-3 pathway. The highest apoptotic induction occurred after 8 hr. Compared to unripe fruits, ripe fruits induced a greater level of apoptosis, as evidenced by a 73 % higher level of caspase-3 mRNA expression and 22 % lower IC50 value. Conclusion: With further investigation, these fruits may provide a valuable source of anticarcinogenic compounds for use as chemotherapeutic or complementary therapies

Voltage Balancing for Bipolar DC Distribution Grids: A Power Flow based Binary Integer Multi-Objective Optimization Approach

The re-emergence of two-phase bipolar dc distribution network, which utilizes the neutral wire for efficient distribution, has spurred research interest in recent years. In practice, system efficiency (power loss) and voltage unbalance are major concerns for the planning and design of the two-phase dc bipolar network. While most of the existing methodologies are power electronics solutions, there are very few works on resolving the problem from the power system perspective. This paper proposes a model-based optimization method by first formulating the power flow model for two-phase dc bipolar network using the single line modeling technique and nodal analysis. Second, a binary integer load distribution model is proposed to consider the re-distribution of unipolar loads across the two unipolar distribution poles. Together with the power flow model, the system power loss and system voltage unbalance indices are formulated as a binary integer quadratic model. Third, a multi-objective optimization model is formulated and solved using the weighted sum approach. The proposed method is applied to a dc LED lighting system design, which considers both voltage unbalance and power loss. Using a 15 bus single source and a 33 bus multi-source network as case studies, the developed power flow model is validated with very high accuracy. Compared to existing iterative methods, the proposed model-based approach is able to significantly improve the voltage balancing across the distribution system.NRF (Natl Research Foundation, S’pore)MOE (Min. of Education, S’pore

Self-directed self-management interventions to prevent or address distress in young people with long-term physical conditions: a rapid review.

Background: Comorbid distress in adolescents and young adults with physical long‐ term conditions (LTCs) is common but can be difficult to identify and manage. Self‐ directed self‐management interventions to reduce distress and improve wellbeing may be beneficial. It is unknown, however, which intervention characteristics are successful in supporting young people. This rapid review aimed to identify characteristics of self‐directed self‐management interventions that aimed, in whole or part, to address distress, wellbeing or self‐efficacy in this population. Methods: A systematic search was conducted for relevant controlled studies in six databases. Data on study settings, population, intervention characteristics, outcome measures, process measures and summary effects were extracted. The risk of bias was assessed using the Cochrane Risk of Bias tool v1, and the strength of evidence was rated (informed by Grading of Recommendations, Assessment, Development and Evaluations). Patient and public involvement members supported the review process, including interpretation of results. The rapid review was registered with PROSPERO (ID: CRD42021285867). Results: Fourteen studies were included, all of which were randomised trials. Heterogeneity was identified in the health conditions targeted; type of intervention; outcome measures; duration of intervention and follow‐up. Three had distress, wellbeing or self‐efficacy as their primary outcome. Four modes of delivery were identified across interventions—websites, smartphone applications, text messages and workbooks; and within these, 38 individual components. Six interventions had a significant benefit in mental health, wellbeing or self‐efficacy; however, intervention characteristics were similar for beneficial and non‐beneficial interventions. Conclusions: There is a paucity of interventions directly targeting distress and wellbeing in young people with physical LTCs. In those identified, the heterogeneity of interventions and study design makes it difficult to identify which characteristics result in positive outcomes. We propose the need for high‐quality, evidence‐based self‐management interventions for this population; including (1) more detailed reporting of intervention design, content and delivery; (2) robust process evaluation; (3) a core outcome set for measuring mental health and wellbeing for self‐ management interventions and (4) consistency in follow up periods. Public Contribution: Seven young people with an LTC were involved throughout the rapid review, from the development of the review protocol where they informed the focus and aims, with a central role in the interpretation of findings.peer-reviewe

Healthcare professionals’ priorities for training to identify and manage distress experienced by young people with a stoma due to inflammatory bowel disease: a consensus study using online nominal group technique

Young people with a stoma due to inflammatory bowel disease (IBD) commonly experience distress; however, this is not always well managed in clinical settings. More effective support may/is likely to reduce the possibility of individuals experiencing sustained distress, which may engender depression or anxiety. This study aimed to gain consensus among a multidisciplinary group of healthcare professionals (HCPs) on priorities for training in the identification and management of distress in this population. One of the authors is a young person with a stoma. Design Participants were recruited through Twitter (X) and the researchers’ clinical/research contacts. Two consensus group meetings were conducted using Nominal Group Technique, involving participants generating, discussing and rating on a Likert scale, topics for inclusion in an HCP training package. Setting Online video conferencing. Participants were located across England, with one based in the USA. Participants Nineteen HCPs participated: three general practitioners, three stoma nurses, two IBD nurses, nine clinical psychologists and two gastroenterologists. Results Twenty-five topics were generated by participants; 19 reached consensus of ≥80%, that is, a mean of ≥5.6 on a 7-point Likert scale. These included: recognising and validating different levels of, and variation in, distress; tackling stigma and normalising having a stoma; everyday practicalities of stoma management, including food and sleep; opening and holding conversations about stoma-related distress; considering the impact of different cultural beliefs on adaptation after stoma surgery; training in simple techniques for gauging the patient’s distress during clinical encounters; having conversations about body image; and myth-busting common fears, such as odour. Conclusions This study is the first to identify HCP training priorities for managing stoma-related distress in young people. Consensus was reached for 19 topics, reflecting the varied needs of young people with a stoma. Findings will inform development of a training package for HCPs treating young people with IBD and a stoma.peer-reviewe

COVID-19-related knowledge, attitudes, and practices among decisionmakers of indigenous municipalities in Guatemala: Study description

Indigenous communities are often socially and economically marginalized which makes them particularly vulnerable to the impact of COVID-19. The Population Council has a longstanding partnership with indigenous communities in Guatemala through the Abriendo Oportunidades program. To understand the knowledge, perspectives, and needs related to the COVID-19 pandemic, we will conduct key informant interviews with indigenous community leaders and frontline workers. Phone-based surveys will be carried out with approximately 130 key informants in the municipalities of Chisec, Patzún, San Andrés Semetabaj, San Juan Ostuncalco, San Juan Sacatepéquez, San Pedro Carchá, Santa María Chiquimula, Totonicapán, Uspantán and Sololá in April 2020. These individual profiles will include heads of household, former girl-program mentors, community health workers and providers, education officers, traditional birth attendants, and municipal officers. We anticipate this effort will provide initial baseline information and subsequent interviews may be conducted throughout 2020. Results from this study will help inform national and municipal prevention and mitigation strategies for indigenous communities and identify government resources that may be prioritized to meet the needs of these communities. Findings will also help decisionmakers understand the effects that COVID-19 is having on girls, girls’ education, and sexual and reproductive health under these rapidly changing conditions