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1.
BMJ Open ; 13(5): e068810, 2023 05 02.
Artigo em Inglês | MEDLINE | ID: mdl-37130681

RESUMO

OBJECTIVES: Postoperative outcomes vary considerably across bariatric patients and may be related to psychosocial factors. In this study, we examined whether a patient's family support predicts postsurgical weight loss and the remission of type 2 diabetes mellitus (T2DM). DESIGN: Retrospective cohort study in Singapore. SETTING: Participants were recruited from a public hospital in Singapore. PARTICIPANTS: Between 2008 and 2018, 359 patients completed a presurgical questionnaire before undergoing gastric bypass or sleeve gastrectomy. OUTCOME MEASURES: As part of the questionnaire, patients described their family support in terms of structure (marital status, number of family members in the household) and function (marriage satisfaction, family emotional support, family practical support). Linear mixed-effects and Cox proportional-hazard models were used to examine whether these family support variables predicted percent total weight loss or T2DM remission up to 5 years postsurgery. T2DM remission was defined as glycated haemoglobin (HbA1c) <6.0% without medications. RESULTS: Participants had a mean preoperative body mass index of 42.6±7.7 kg/m2 and HbA1c (%) of 6.82±1.67. Marital satisfaction was found to be a significant predictor of postsurgical weight trajectories. Namely, patients who reported higher marital satisfaction were more likely to sustain weight loss than patients who reported lower marital satisfaction (ß=0.92, SE=0.37, p=0.02). Family support did not significantly predict T2DM remission. CONCLUSIONS: Given the link between marital support and long-term weight outcomes, providers could consider asking patients about their spousal relationships during presurgical counselling. TRIAL REGISTRATION NUMBER: NCT04303611.


Assuntos
Cirurgia Bariátrica , Diabetes Mellitus Tipo 2 , Derivação Gástrica , Obesidade Mórbida , Humanos , Diabetes Mellitus Tipo 2/cirurgia , Obesidade Mórbida/cirurgia , Hemoglobinas Glicadas , Estudos Retrospectivos , Singapura , Apoio Familiar , Resultado do Tratamento , Glicemia , Redução de Peso , Indução de Remissão
3.
BMJ Open ; 11(11): e051273, 2021 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-34785552

RESUMO

OBJECTIVES: Intensive care audits point to family refusal as a major barrier to organ donation. In this study, we sought to understand refusal by accounting for the decision-maker's mindset. This focused on: (1) how decisions compare when made on behalf of a relative (vs the self); and (2) confidence in decisions made for family members. DESIGN: Cross-sectional survey in Singapore. SETTING: Participants were recruited from community settings via door-to-door sampling and community eateries. PARTICIPANTS: 973 adults who qualified as organ donors in Singapore. RESULTS: Although 68.1% of participants were willing to donate their own organs, only 51.8% were willing to donate a relative's organs. Using machine learning, we found that consistency was predicted by: (1) religion, and (2) fears about organ donation. Conversely, participants who were willing to donate their own organs but not their relative's were less driven by these factors, and may instead have resorted to heuristics in decision-making. Finally, we observed how individuals were overconfident in their decision-making abilities: although 78% had never discussed organ donation with their relatives, the large majority expressed high confidence that they would respect their relatives' wishes on death. CONCLUSIONS: These findings underscore the distinct psychological processes involved when donation decisions are made for family members. Amidst a global shortage of organ donors, addressing the decision-maker's mindset (eg, overconfidence, the use of heuristics) may be key to actualizing potential donors identified in intensive care units.


Assuntos
Transplante de Órgãos , Obtenção de Tecidos e Órgãos , Adulto , Estudos Transversais , Tomada de Decisões , Família , Humanos , Doadores de Tecidos
4.
JMIR Mhealth Uhealth ; 9(5): e22929, 2021 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-33955842

RESUMO

BACKGROUND: Despite a large volume of research on the impact of other digital screens (eg, televisions) on eating behavior, little is known about the nature and impact of mealtime smartphone use. OBJECTIVE: We investigated how smartphones are used in everyday meals, whether phone users differ according to mealtime phone use patterns, and whether specific phone functions (particularly food photography) would affect the amount and enjoyment of food eaten. METHODS: Across 2 studies, we used the experience sampling method to track 1780 meals in situ. In study 1, a total 137 young adults reported on their mealtime smartphone use 3 times per day over 7 consecutive days. This corresponded to each main meal, with participants recording whether they used their phones and what phone functions they engaged in while eating. In study 2, a total of 71 young adults were similarly tracked for 3 meals per day over 7 days. Across the week, participants' meals were randomized to 1 of 3 smartphone conditions: food photography while eating, nonfood photography while eating, or no phone use. As the outcome measures, participants reported on the amount and enjoyment of food they ate. RESULTS: During the week-long tracking, most participants (110/129, 85.3%) recorded at least one instance of mealtime smartphone use, with an average frequency of 1 in 3 meals where phones were used (27.1%; 95% CI 23.6-30.6). Unlike traditional digital screens, mealtime phone use encompassed a wide range of social and nonsocial activities. Further, specific forms of phone use behaviors influenced food intake in different ways. Specifically, in study 2, participants showed the typical pattern of increased food intake across the day when they engaged in nonfood photography during a meal (P<.001); however, this pattern was disrupted when they engaged in food photography (P=.73). CONCLUSIONS: Our findings underscore the prevalence and multifaceted nature of mealtime phone use, distinguishing mobile phones from traditional forms of digital screens. TRIAL REGISTRATION: ClinicalTrials.gov NCT03299075; https://www.clinicaltrials.gov/ct2/show/NCT03299075 and ClinicalTrials.gov NCT03346785; https://clinicaltrials.gov/ct2/show/NCT03346785.


Assuntos
Telefone Celular , Smartphone , Emoções , Comportamento Alimentar , Humanos , Refeições , Adulto Jovem
5.
Ann Acad Med Singap ; 50(3): 222-231, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33855318

RESUMO

INTRODUCTION: As part of infection control measures for COVID-19, individuals have been encouraged to adopt both preventive (such as handwashing) and avoidant behavioural changes (e.g. avoiding crowds). In this study, we examined whether demographics predicted the likelihood that a person would adopt these behaviours in Singapore. METHODS: A total of 1,145 participants responded to an online survey conducted between 7 March and 21 April 2020. We collected demographic information and asked participants to report which of 17 behaviour changes they had undertaken because of the COVID-19 outbreak. Regression analyses were performed to predict the number of behavioural changes (preventive, avoidant, and total) as a function of demographics. Finally, we sought to identify predictors of persons who declared that they had not undertaken any of these measures following the outbreak. RESULTS: Most participants (97%) reported at least one behavioural change on account of the pandemic, with changes increasing with the number of local COVID-19 cases (P<0.001). Additionally, women and those who were younger adopted more preventive behaviours (gender: P<0.001; age: P=0.001). Women were more likely to increase handwashing frequency, and younger individuals were more likely to wear face masks prior to legislation. Finally, women and those who were married adopted more avoidant behaviours (gender: P<0.001; marital status: P<0.001), with both groups avoiding crowded areas and staying home more than usual. Women also voluntarily reduced physical contact, whereas those who were married preferentially chose outdoor venues and relied on online shopping. CONCLUSION: Our characterisation of behavioural changes provides a baseline for public health advisories. Moving forward, health authorities can focus their efforts on encouraging segments of the population who do not readily adopt infection control measures against COVID-19.


Assuntos
COVID-19/prevenção & controle , COVID-19/psicologia , Desinfecção das Mãos/tendências , Comportamentos Relacionados com a Saúde , Distanciamento Físico , Assunção de Riscos , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , COVID-19/epidemiologia , Feminino , Seguimentos , Política de Saúde , Inquéritos Epidemiológicos , Humanos , Masculino , Pessoa de Meia-Idade , Pandemias , Autorrelato , Fatores Sexuais , Singapura/epidemiologia , Fatores Socioeconômicos
6.
J Med Internet Res ; 22(9): e22142, 2020 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-32877349

RESUMO

BACKGROUND: In a global pandemic, digital technology offers innovative methods to disseminate public health messages. As an example, the messenger app WhatsApp was adopted by both the World Health Organization and government agencies to provide updates on the coronavirus disease (COVID-19). During a time when rumors and excessive news threaten psychological well-being, these services allow for rapid transmission of information and may boost resilience. OBJECTIVE: In this study, we sought to accomplish the following: (1) assess well-being during the pandemic; (2) replicate prior findings linking exposure to COVID-19 news with psychological distress; and (3) examine whether subscription to an official WhatsApp channel can mitigate this risk. METHODS: Across 8 weeks of the COVID-19 outbreak (March 7 to April 21, 2020), we conducted a survey of 1145 adults in Singapore. As the primary outcome measure, participants completed the Depression, Anxiety, and Stress Scale (DASS-21). As predictor variables, participants also answered questions pertaining to the following: (1) their exposure to COVID-19 news; (2) their use of the Singapore government's WhatsApp channel; and (3) their demographics. RESULTS: Within the sample, 7.9% of participants had severe or extremely severe symptoms on at least one DASS-21 subscale. Depression scores were associated with increased time spent receiving COVID-19 updates, whereas use of the official WhatsApp channel emerged as a protective factor (b=-0.07, t[863]=-2.04, P=.04). Similarly, increased anxiety scores were associated with increased exposure to both updates and rumors, but this risk was mitigated by trust in the government's WhatsApp messages (b=-0.05, t[863]=-2.13, P=.03). Finally, although stress symptoms increased with the amount of time spent receiving updates, these symptoms were not significantly related to WhatsApp use. CONCLUSIONS: Our findings suggest that messenger apps may be an effective medium for disseminating pandemic-related information, allowing official agencies to reach a broad sector of the population rapidly. In turn, this use may promote public well-being amid an "infodemic." TRIAL REGISTRATION: ClinicalTrials.gov NCT04305574; https://clinicaltrials.gov/ct2/show/NCT04305574.


Assuntos
Ansiedade/epidemiologia , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/psicologia , Depressão/epidemiologia , Inquéritos Epidemiológicos , Saúde Mental/estatística & dados numéricos , Aplicativos Móveis , Pneumonia Viral/epidemiologia , Pneumonia Viral/psicologia , Saúde Pública/métodos , Saúde Pública/estatística & dados numéricos , Adulto , COVID-19 , Estudos Transversais , Surtos de Doenças , Feminino , Humanos , Masculino , Pandemias
7.
Appetite ; 154: 104787, 2020 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-32579971

RESUMO

Advances in cell phone technology have the potential to disrupt eating patterns. In this research, we focused on the camera function of a cell phone, characterizing: (i) the extent to which this function is used during meals; (ii) whether meal-time photographers show signs of pathological eating; and (iii) whether the act of taking food photographs alters the amount and enjoyment of food eaten. In the first study, we used the experience sampling method to track one week of meals from 137 young adults. Although we observed a low base rate of meal-time photography (5.44% of the 1140 meals captured), phone users who engaged in this practice had higher external eating scores than those who did not. That is, these meal-time photographers were more likely to eat in response to external cues (e.g. the sight of palatable food) than to internal cues of hunger. However, when participants were randomly assigned to take either food or non-food photographs within a lab setting (Study 2), we found no evidence that the type of photography influenced either the amount or enjoyment of food eaten. Taken together, our findings suggest a limited role for cell phone photography in an obesogenic environment.


Assuntos
Telefone Celular , Ingestão de Alimentos , Comportamento Alimentar , Humanos , Refeições , Fotografação , Adulto Jovem
8.
J Med Internet Res ; 21(9): e12500, 2019 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-31573913

RESUMO

BACKGROUND: Receiving insufficient sleep has wide-ranging consequences for health and well-being. Although educational programs have been developed to promote sleep, these have had limited success in extending sleep duration. To address this gap, we developed a Web-based program emphasizing how physical appearances change with varying amounts of sleep. OBJECTIVE: The aims of this study were to evaluate (1) whether participants can detect changes in appearances as a function of sleep and (2) whether this intervention can alter habitual sleep patterns. METHODS: We conducted a 5-week, parallel-group, randomized controlled trial among 70 habitual short sleepers (healthy adults who reported having <7 hours of sleep routinely). Upon study enrollment, participants were randomly assigned (1:1) to receive either standard information or an appearance-based intervention. Both groups received educational materials about sleep, but those in the appearance group also viewed a website containing digitally edited photographs that showed how they would look with varying amounts of sleep. As the outcome variables, sleep duration was monitored objectively via actigraphy (at baseline and at postintervention weeks 1 and 4), and participants completed a measure of sleep hygiene (at baseline and at postintervention weeks 2, 4, and 5). For each outcome, we ran intention-to-treat analyses using linear mixed-effects models. RESULTS: In total, 35 participants were assigned to each group. Validating the intervention, participants in the appearance group (1) were able to identify what they looked like at baseline and (2) judged that they would look more attractive with a longer sleep duration (t26=10.35, P<.001). In turn, this translated to changes in sleep hygiene. Whereas participants in the appearance group showed improvements following the intervention (F1,107.99=9.05, P=.003), those in the information group did not (F1,84.7=0.19, P=.66). Finally, there was no significant effect of group nor interaction of group and time on actigraphy-measured sleep duration (smallest P=.26). CONCLUSIONS: Our findings suggest that an appearance-based intervention, while not sufficient as a stand-alone, could have an adjunctive role in sleep promotion. TRIAL REGISTRATION: ClinicalTrials.gov NCT02491138; https://clinicaltrials.gov/ct2/show/study/NCT02491138.


Assuntos
Actigrafia/métodos , Internet , Transtornos do Sono-Vigília/terapia , Sono , Adulto , Imagem Corporal , Face , Feminino , Promoção da Saúde , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Percepção , Inquéritos e Questionários , Adulto Jovem
9.
Transplantation ; 103(4): 755-763, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30747852

RESUMO

BACKGROUND: Historically, brain death legislation was adopted in Asia at a much later stage than it was in the West, with heated public debates surrounding these laws. In this study, we investigated whether the poor acceptance of brain death continues to the present day, focusing on the following: (1) what the Asian public understands brain death to be; (2) how views toward brain death are compared with those of cardiac death; and (3) the extent to which brain death perception contributes to the low rate of deceased organ donation that has been observed amongst Asians. METHODS: Using a door-to-door sampling strategy, we recruited 622 residents in Singapore between September 2016 and July 2017. RESULTS: Our results suggest that resistance toward brain death persists, with the majority of respondents equating this as a bleak outcome but not as death. Correspondingly, they considered cardiac death a better indicator of death and were more fearful of being alive during organ donation. In turn, these views predicted a decreased willingness to donate either their own or their family members' organs. CONCLUSIONS: Taken together, our results suggest that views of brain death continue to hamper organ donation, and are seemingly resistant to both time and legislation.


Assuntos
Morte Encefálica , Obtenção de Tecidos e Órgãos , Ásia , Estudos Transversais , Parada Cardíaca , Humanos , Inquéritos e Questionários
10.
Psychol Med ; 49(2): 335-344, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-29743128

RESUMO

BACKGROUND: While studies suggest that nutritional supplementation may reduce aggressive behavior in children, few have examined their effects on specific forms of aggression. This study tests the primary hypothesis that omega-3 (ω-3), both alone and in conjunction with social skills training, will have particular post-treatment efficacy for reducing childhood reactive aggression relative to baseline. METHODS: In this randomized, double-blind, stratified, placebo-controlled, factorial trial, a clinical sample of 282 children with externalizing behavior aged 7-16 years was randomized into ω-3 only, social skills only, ω-3 + social skills, and placebo control groups. Treatment duration was 6 months. The primary outcome measure was reactive aggression collected at 0, 3, 6, 9, and 12 months, with antisocial behavior as a secondary outcome. RESULTS: Children in the ω-3-only group showed a short-term reduction (at 3 and 6 months) in self-report reactive aggression, and also a short-term reduction in overall antisocial behavior. Sensitivity analyses and a robustness check replicated significant interaction effects. Effect sizes (d) were small, ranging from 0.17 to 0.31. CONCLUSIONS: Findings provide some initial support for the efficacy of ω-3 in reducing reactive aggression over and above standard care (medication and parent training), but yield only preliminary and limited support for the efficacy of ω-3 in reducing overall externalizing behavior in children. Future studies could test further whether ω-3 shows promise in reducing more reactive, impulsive forms of aggression.


Assuntos
Comportamento do Adolescente , Agressão , Sintomas Comportamentais/terapia , Comportamento Infantil , Ácidos Graxos Ômega-3/farmacologia , Psicoterapia , Comportamento Social , Habilidades Sociais , Adolescente , Sintomas Comportamentais/dietoterapia , Criança , Terapia Combinada , Método Duplo-Cego , Ácidos Graxos Ômega-3/administração & dosagem , Feminino , Seguimentos , Humanos , Masculino , Avaliação de Resultados em Cuidados de Saúde , Comportamento Problema
11.
Psychoneuroendocrinology ; 81: 151-156, 2017 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28482312

RESUMO

Inadequate sleep and psychological stress can both elevate physiological stress markers, such as cortisol. Prior studies that have applied induced psychosocial stress after a night of experimental sleep deprivation have found these effects to be compounded. We examined whether the relationship between stress reactivity and poor sleep also extends to habitual sleep patterns. Fifty-nine adult male participants were recruited. Habitual sleep patterns were monitored with actigraphy for a week. Participants subsequently underwent the Trier Social Stress Test. Cardiovascular responses and salivary cortisol were measured at baseline, during stress, and during recovery. Subjects who showed poor habitual sleep efficiency during the week before stress induction responded with higher stress-related elevations of blood pressure and cortisol levels as compared to subjects with high sleep efficiency. This relationship between poor sleep efficiency and elevated blood pressure persisted during the post-stress recovery period. Similar associations between total sleep time in the week prior to the stress induction and physiological reactivity did not reach significance. Our findings indicate that habitual low sleep efficiency exaggerates cardiovascular and neuroendocrine effects of psychosocial stress, in a male population.


Assuntos
Pressão Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Hidrocortisona/metabolismo , Privação do Sono/metabolismo , Privação do Sono/fisiopatologia , Estresse Psicológico/metabolismo , Estresse Psicológico/fisiopatologia , Humanos , Masculino , Saliva/metabolismo , Adulto Jovem
12.
Front Psychol ; 8: 2298, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29358925

RESUMO

Surveys of mobile phone usage suggest that adolescents habitually use their phones while eating. In this study, we explored whether the manner in which one uses a mobile phone - to engage in a social or non-social activity - can affect appetite regulation. Participants were fifty male adolescents randomly assigned to engage in one of the following phone-based activities: (1) sending and receiving messages (social activity), or (2) reading a neutral article (non-social activity). When given the opportunity to snack, participants in the messaging group consumed more snacks that those who read the article. Our findings correspond to a large literature emphasizing social influences on food intake, and suggest that phone use patterns may predispose an individual to overeating.

13.
Front Neurosci ; 9: 352, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26500479

RESUMO

Sleep deprivation alters decision making; however, it is unclear what specific cognitive processes are modified to drive altered choices. In this manuscript, we examined how one night of total sleep deprivation (TSD) alters economic decision making. We specifically examined changes in uncertainty preferences dissociably from changes in the strategy with which participants engage with presented choice information. With high test-retest reliability, we show that TSD does not alter uncertainty preferences or loss aversion. Rather, TSD alters the information the participants rely upon to make their choices. Utilizing a choice strategy metric which contrasts the influence of maximizing and satisficing information on choice behavior, we find that TSD alters the relative reliance on maximizing information and satisficing information, in the gains domain. This alteration is the result of participants both decreasing their reliance on cognitively-complex maximizing information and a concomitant increase in the use of readily-available satisficing information. TSD did not result in a decrease in overall information use in either domain. These results show that sleep deprivation alters decision making by altering the informational strategies that participants employ, without altering their preferences.

14.
Ann Acad Med Singap ; 44(3): 85-91, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25882235

RESUMO

INTRODUCTION: Incidental reports collected in clinical trials suggest that amongst participants, omega-3 fatty acids derived from fish oil ('omega-3') may be difficult to blind. MATERIALS AND METHODS: We conducted a systematic evaluation of blinding success in a 24-week trial of omega-3 versus an oil-based placebo. Within 1 week of supplement commencement (Week 1), a blinding questionnaire was completed by 131 children enrolled in a trial of omega-3 for the treatment of disruptive behaviour disorders. A version of the questionnaire was also completed by their parents at Week 1, and by the children at the end of supplement administration (Week 24). RESULTS: Participants were unable to differentiate omega-3 from placebo, and accuracy did not improve as a function of: the confidence of guesses, reason for guesses, notice of any change, beliefs about what should change, or time. Child and parent guesses also showed high concordance. CONCLUSION: Taken together, these data provide strong evidence that the identity of omega-3 can be blinded to participants.


Assuntos
Transtornos de Deficit da Atenção e do Comportamento Disruptivo/dietoterapia , Suplementos Nutricionais , Ácidos Graxos Ômega-3/uso terapêutico , Método Simples-Cego , Adolescente , Criança , Feminino , Humanos , Masculino , Pais , Inquéritos e Questionários
15.
Sleep ; 38(1): 155-9, 2015 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-25325448

RESUMO

STUDY OBJECTIVES: We examined how sleep deprivation alters physiological responses to psychosocial stress by evaluating changes in skin conductance. DESIGN: Between-subjects design with one group allocated to 24 h of total sleep deprivation and the other to rested wakefulness. SETTING: The study took place in a research laboratory. PARTICIPANTS: Participants were 40 healthy young adults recruited from a university. INTERVENTIONS: Sleep deprivation and feedback. MEASUREMENTS AND RESULTS: Electrodermal activity was monitored while participants completed a difficult perceptual task with false feedback. All participants showed increased skin conductance levels following stress. However, compared to well-rested participants, sleep deprived participants showed higher skin conductance reactivity with increasing stress levels. CONCLUSIONS: Our results suggest that sleep deprivation augments allostatic responses to increasing psychosocial stress. Consequentially, we propose sleep loss as a risk factor that can influence the pathogenic effects of stress.


Assuntos
Resposta Galvânica da Pele/fisiologia , Privação do Sono/fisiopatologia , Privação do Sono/psicologia , Estresse Psicológico/fisiopatologia , Sudorese/fisiologia , Adolescente , Adulto , Retroalimentação , Feminino , Humanos , Masculino , Descanso/fisiologia , Descanso/psicologia , Fatores de Risco , Sono/fisiologia , Estresse Psicológico/psicologia , Vigília/fisiologia , Adulto Jovem
16.
J Sleep Res ; 23(4): 448-57, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24605921

RESUMO

Previous research suggests that sleep deprivation may heighten normal reactions to an aversive social encounter. In this study, we explored how 24 h of sleep deprivation may influence responses to ostracism. Ninety-six healthy young adults were randomly allocated to either the sleep-deprivation or well-rested condition, wherein they engaged in two rounds of a ball-tossing game (Cyberball) programmed so that they would be included or ostracized. As compared with being included, being ostracized reduced participants' fulfillment of four essential needs (to belong; to have control; to have self-esteem; and to have a meaningful existence); participants also showed poorer mood and had poorer perceptions of their co-players. These effects were not influenced by sleep deprivation. Taken together, our findings suggest that sleep deprivation does not influence immediate distress responses to ostracism.


Assuntos
Descanso/psicologia , Autorrelato , Privação do Sono/psicologia , Isolamento Social/psicologia , Emoções , Feminino , Jogos Experimentais , Humanos , Masculino , Autoimagem , Sono/fisiologia , Confiança , Adulto Jovem
17.
Am J Clin Nutr ; 97(5): 919-25, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23553164

RESUMO

BACKGROUND: Dietary disinhibition is a behavioral trait associated with weight gain and obesity. Because food choices are made according to the relative value assigned to each option, examination of valuation signals through functional magnetic resonance imaging (fMRI) may elucidate the neural basis for the association between dietary disinhibition and weight gain. OBJECTIVE: We examined how food valuation signals differ in the fed and fasted states between persons with high dietary disinhibition (HD) and low dietary disinhibition (LD). DESIGN: Sixteen men with HD and 14 with LD underwent fMRI once while fasted and once after being fed in a counterbalanced order. In-scanner preference to consume a test food relative to a neutral-tasting, neutral-health reference food was examined. The slope of magnetic resonance signal change corresponding to these food preferences constituted the food valuation signal that was compared across disinhibition group and satiety state. RESULTS: Both the HD and LD participants reported being less hungry (F(1,28) = 113.11, P < 0.001) after being fed than when fasted. However, food valuation signals in the ventromedial prefrontal cortex (vmPFC) differed between the groups (F(1,28) = 21.34, P < 0.001). Although LD participants showed attenuated vmPFC activity after being fed (t(13) = 4.11, P < 0.001), HD participants showed greater vmPFC activity in the fed than in the fasted state (t(15) = -2.56, P < 0.05). CONCLUSIONS: Despite reporting normal decreases in hunger ratings after being fed, persons with HD have an altered neural valuation of food. This may be a mechanism underlying their propensity to overeat and gain weight. This trial was registered at clinicaltrials.gov as NCT00988819.


Assuntos
Dieta , Jejum/fisiologia , Córtex Pré-Frontal/fisiologia , Saciação/fisiologia , Adulto , Índice de Massa Corporal , Estudos de Casos e Controles , Comportamento de Escolha , Preferências Alimentares , Humanos , Hiperfagia , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Inquéritos e Questionários , Paladar/fisiologia , Aumento de Peso , Adulto Jovem
18.
Psychoneuroendocrinology ; 38(4): 587-91, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22920910

RESUMO

Previous studies with prairie voles suggest that the hormone oxytocin is crucial for bond formation - indicated when a partner preference is formed towards the target vole. In this study, we conduct the first empirical test of whether oxytocin likewise promotes partner preferences in humans. Seventy-six undergraduate students received either oxytocin or placebo before being introduced to a male and female persona (via pre-recorded videoclips). One day later, participants were assessed for a partner preference towards the personae: across three situations, participants were asked to choose as company one of the personae they had been introduced to, or an opposite- or same-gendered person they had not been introduced to before; participants were additionally offered a choice to have no company. We found evidence suggesting oxytocin increases preference for persons introduced under the influence of oxytocin; however, this was not targeted at persons of the opposite-gender, and was found in only one aspect of social interaction (finding out more information about the person, but not in choice of company to work with or for a date). Taken together, our findings suggest that oxytocin might not promote human bond formation in ways analogous to prairie voles - that is, by inducing a partner preference effect.


Assuntos
Comportamento de Escolha/efeitos dos fármacos , Apego ao Objeto , Ocitocina/farmacologia , Administração Intranasal , Adulto , Método Duplo-Cego , Feminino , Humanos , Relações Interpessoais , Masculino , Ocitocina/administração & dosagem
19.
Horm Behav ; 62(5): 585-91, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22999976

RESUMO

Research in animals and humans suggests a role of oxytocin in social approach to strangers. We tested this by introducing undergraduate students to opposite-gendered strangers, with each member of the pair having taken either oxytocin or placebo. One hundred and four undergraduate students were paired up and engaged in a face-to-face conversation structured with a series of intimate topics for discussion. We found that oxytocin increased conversational intimacy in female but not male participants, but that this was matched with compensatory decreases in eye-contact (relative to placebo). Argyle and Dean (1965) conceptualise intimacy as a function of physical distance, eye-contact, and conversational intimacy, such that equilibrium is maintained when increases in one domain are matched by compensatory decreases in another domain. Based on this notion, our results suggest that oxytocin does not facilitate social approach by increasing the intimacy equilibrium between two strangers.


Assuntos
Relações Interpessoais , Ocitocina/farmacologia , Comportamento Social , Adolescente , Adulto , Comunicação , Comportamento Cooperativo , Movimentos Oculares/efeitos dos fármacos , Movimentos Oculares/fisiologia , Feminino , Humanos , Cinésica , Masculino , Placebos , Distância Psicológica , Adulto Jovem
20.
Biol Psychol ; 87(3): 393-400, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21586313

RESUMO

Squire et al. have proposed that trace and delay eyeblink conditioning procedures engage separate learning systems: a declarative hippocampal/cortical system associated with conscious contingency awareness, and a reflexive sub-cortical system independent of awareness, respectively (Clark and Squire, 1998; Smith et al., 2005). The only difference between these two procedures is that the conditioned stimulus (CS) and the unconditioned stimulus (US) overlap in delay conditioning, whereas there is a brief interval (e.g., 1s) between them in trace conditioning. In two experiments using the same procedure as Clark and Squire's group, we observed differential conditioning only in participants who showed contingency awareness in a post-experimental questionnaire, with both trace and delay procedures. We interpret these results to suggest that, although there may be multiple brain regions involved in learning, these regions are organized as a coordinated system rather than as separate, independent systems.


Assuntos
Conscientização/fisiologia , Condicionamento Clássico/fisiologia , Condicionamento Palpebral/fisiologia , Feminino , Humanos , Masculino , Inquéritos e Questionários , Adulto Jovem
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