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Evidence accumulates to show that semantic cognition requires, in addition to semantic representations, control processes that regulate the accessibility and use of semantic knowledge in a task- and time-appropriate fashion. Semantic control has been recently proposed to rely on a distributed network that includes the posterior temporal cortex. Along these lines, recent meta-analyses of neuroimaging data and studies with patients suffering from semantic aphasia have suggested that the left posterior middle temporal gyrus (pMTG) is critically involved whenever situational context must constrain semantic retrieval. In the present experiment, we used transcranial direct current stimulation over the left posterior temporal lobe in an attempt to interfere with semantic control while participants performed a DRM task, a procedure for inducing conceptually-based false recognition that is contingent on both activation and control processes. Paralleling findings with patients suffering from brain damage restricted to the temporoparietal cortex, anodal stimulation (relative to sham stimulation) resulted in increased false recognition but intact true recognition. These findings fit well with the idea that the left pMTG is a key component of a semantic control network, the alteration of which results in memory performance that is affected by the intrusion of contextually-inappropriate semantic information.
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Memória Episódica , Estimulação Transcraniana por Corrente Contínua , Humanos , Semântica , Mapeamento Encefálico , Lobo Temporal/fisiologia , Imageamento por Ressonância MagnéticaRESUMO
If life developed in hydrothermal vents, it would have been within mineral membranes. The first proto-cells must have evolved to manipulate the mineral membranes that formed their compartments in order to control their metabolism. There must have occurred a biological takeover of the self-assembled mineral structures of the vents, with the incorporation of proto-biological molecules within the mineral membranes to alter their properties for life's purposes. Here, we study a laboratory analogue of this process: chemical-garden precipitation of the amino acids arginine and tryptophan with the metal salt iron chloride and sodium silicate. We produced these chemical gardens using different methodologies in order to determine the dependence of the morphology and chemistry on the growth conditions, as well as the effect of the amino acids on the formation of the iron-silicate chemical garden. We compared the effects of having amino acids initially within the forming chemical garden, corresponding to the internal zones of hydrothermal vents, or else outside, corresponding to the surrounding ocean. The characterization of the formed chemical gardens using X-ray diffraction, Fourier transform infrared spectroscopy, elemental analysis, and scanning electron microscopy demonstrates the presence of amino acids in these structures. The growth method in which the amino acid is initially in the tablet with the iron salt is that which generated chemical gardens with more amino acids in their structures.
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Fontes Hidrotermais , Compostos Inorgânicos , Aminoácidos , Biomineralização , Fontes Hidrotermais/química , Ferro/químicaRESUMO
Chemical gardens are self-assembled structures of mineral precipitates enabled by semi-permeable membranes. To explore the effects of gravity on the formation of chemical gardens, we have studied chemical gardens grown from cobalt chloride pellets and aqueous sodium silicate solution in a vertical Hele-Shaw cell. Through photography, we have observed and quantitatively analysed upward growing tubes and downward growing fingers. The latter were not seen in previous experimental studies involving similar physicochemical systems in 3-dimensional or horizontal confined geometry. To better understand the results, further studies of flow patterns, buoyancy forces, and growth dynamics under schlieren optics have been carried out, together with characterisation of the precipitates with scanning electron microscopy and X-ray diffractometry. In addition to an ascending flow and the resulting precipitation of tubular filaments, a previously not reported descending flow has been observed which, under some conditions, is accompanied by precipitation of solid fingering structures. We conclude that the physics of both the ascending and descending flows are shaped by buoyancy, together with osmosis and chemical reaction. The existence of the descending flow might highlight a limitation in current experimental methods for growing chemical gardens under gravity, where seeds are typically not suspended in the middle of the solution and are confined by the bottom of the vessel.
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OBJECTIVES: Normal aging involves progressive prefrontal declines and impairments in executive control. This study aimed to examine the efficacy of an executive-control training focusing on working memory and inhibition, in healthy older adults, and to explore the role of individual differences in baseline capacities and motivation in explaining training gains. METHODS: Forty-four healthy older adults were randomly assigned to an experimental (training executive control) or active control group (training processing speed). Participants completed six online training sessions distributed across two weeks. Transfer effects to working memory (Operation Span test), response inhibition (Stop-Signal test), processing speed (Pattern Comparison) and reasoning (Raven's Advanced Progressive Matrices and Cattell Culture Fair test) were evaluated. Furthermore, we explored individual differences in baseline capacities and assessed motivation during and after the intervention. RESULTS: The experimental group, but not the active control, showed significant transfer to response inhibition. Moreover, a general compensation effect was found: older adults with lower baseline capacities achieved higher levels of training improvement. Motivation was not related to training performance. CONCLUSION: Our results encourage the use of executive control training to improve cognitive functions, reveal the importance of individual differences in training-related gains, and provide further support for cognitive plasticity during healthy aging.
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Função Executiva , Motivação , Idoso , Envelhecimento/psicologia , Cognição , Função Executiva/fisiologia , Humanos , Memória de Curto Prazo/fisiologiaRESUMO
Not much research has adopted a multicomponent approach to examine the relationship between mindfulness and cognitive control. Studies addressing this issue have produced mixed results that may be due to the incorporation of different questionnaires to assess mindfulness and to the assessment of different stages and types of mindfulness itself. In the present study, we aimed to investigate to which extent dispositional mindfulness relates to a dynamic use of control modes as understood from the dual mechanisms of control theory. Further, we aimed to test this hypothesis by including two different frequently used mindfulness questionnaires in order to explore their confluence. Hundred thirty young adults completed two well-established assessment tools of mindfulness (Mindful Attention Awareness Scale and Five Facets Mindfulness Questionnaire) and two well-validated experimental tasks measuring proactive/reactive control modes (AX-Continuous Performance Task and Cued Task-Switching Paradigm). The data analyses were performed considering the continuous values in multiple regression analyses, as it is thought to better capture individual differences. The results replicate the previous findings suggesting that mindful individuals tend to use proactive and reactive control in a balanced manner in comparison to low mindfulness individuals, who tend to rely more on proactive control. Moreover, mindful individuals showed greater flexibility when the two processing modes were available. Hence, the major effects were found by using the two questionnaires. Altogether our findings indicate that mindful individuals, who have been characterized by an enhanced focus on the present moment without judgment, are less attached to the previous contextual information, which allows them to exhibit a more flexible performance.
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Atenção Plena , Atenção , Cognição , Humanos , Julgamento , Inquéritos e QuestionáriosRESUMO
Previous research has shown that variations in the accessibility of relevant information that stem from retrieval practice may impair analogical reasoning. In the present study, we sought to examine the neural signatures of inhibitory control during selective retrieval and its effects on a subsequent analogical reasoning task by employing electrophysiological measures. At a behavioral level, we found that selective retrieval of a subset of potential solutions led to impaired performance on the analogy test. ERPs analyses during selective retrieval revealed that (1) the repeated presentation of retrieval cues was associated with decreased amplitudes for the FN400 ERP effect, possibly reflecting reduced reactivation of competitor associates and interference across retrieval attempts; (2) this effect correlated positively with the retrieval-related impairment in analogical reasoning performance. During the analogy test, the production of control solutions (non-affected by prior retrieval practice) was characterized by more positive modulations of anterior frontal and parietal ERPs than the production of unstudied solutions, whereas inhibited solutions elicited similar amplitudes to unstudied solutions. This effect was restricted to the retrieval phase of the analogy where the actual solutions had to be retrieved, but it did not affect the mapping phase where the accessibility status of the possible solutions failed to reveal significant amplitude differences. These findings suggest that control during selective retrieval may lead to the downregulation of competing memory representations and advance our understanding of the neural correlates of analogical thinking.
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Encéfalo/fisiologia , Potenciais Evocados/fisiologia , Rememoração Mental/fisiologia , Resolução de Problemas/fisiologia , Adolescente , Sinais (Psicologia) , Eletroencefalografia , Feminino , Humanos , Masculino , Testes Neuropsicológicos , Adulto JovemRESUMO
BACKGROUND: Cumulative evidence suggests an analgesic effect of thiamine, pyridoxine, and cyanocobalamin (TPC) in monotherapy, and also when combined with nonsteroidal anti-inflammatory drugs (NSAIDs), particularly diclofenac, in a synergistic manner. The aim of this review was to determine the effects of diclofenac combined with TPC compared with diclofenac monotherapy for low back pain (LBP) management. METHODS: We searched for randomized clinical trials on the MEDLINE, EMBASE, LILACS, and Cochrane databases of records of clinical trials, among other sources. We evaluated the risk of bias regarding randomization, allocation concealment, blinding, incomplete outcome data, selective reporting, and other biases. A random-effects meta-analysis to examine patients with acute LBP (N = 1,108 adults) was performed, along with a subsequent sensitivity analysis. RESULTS: Five studies in patients with LBP were included in the qualitative synthesis. Four of these studies in acute LBP were included in the first meta-analysis. A sensitivity test based on risk of bias (three moderate- to high-quality studies) found that the combination therapy of diclofenac plus TPC was associated with a significant reduction in the duration of treatment (around 50%) compared with diclofenac monotherapy (odds ratio = 2.23, 95% confidence interval = 1.59 to 3.13, P < 0.00001). We found no differences in the safety profile and patient satisfaction. CONCLUSIONS: This meta-analysis demonstrated that combination therapy of diclofenac with TPC might have an analgesic superiority compared with diclofenac monotherapy in acute LBP. However, there is not enough evidence to recommend this therapy in other types of pain due to the scarcity of high-quality studies.
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Anti-Inflamatórios não Esteroides/uso terapêutico , Diclofenaco/uso terapêutico , Dor Lombar/tratamento farmacológico , Complexo Vitamínico B/uso terapêutico , Quimioterapia Combinada , Humanos , Medição da Dor , Piridoxina/uso terapêutico , Tiamina/uso terapêutico , Vitamina B 12/uso terapêuticoRESUMO
Chemical gardens and clock reactions are two of the best-known demonstration reactions in chemistry. Until now these have been separate categories. We have discovered that a chemical garden confined to two dimensions is a clock reaction involving a phase change, so that after a reproducible and controllable induction period it explodes.
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Research has shown that selective retrieval of episodic memories usually leads to forgetting of related memories that compete for retrieval [a phenomenon known as retrieval-induced forgetting (RIF)]. However, there are conflicting data regarding the duration of this incidental kind of forgetting. While some studies have found that this forgetting effect disappears within 24 h after selective retrieval, others suggest that it may last for as long as at least a week. In two experiments, we explored whether discrepancies in the durability of RIF may be due to variations in the type of relationships (preexisting vs. novel) that are present between items associated with a given cue. We explored this issue by manipulating the degree of involvement of preexisting/novel associations among competing items as well as the delay between retrieval practice and test (immediate in Experiment 1 and 24-h delay test in Experiment 2). The results suggest that forgetting lasts longer when the degree of preexisting associations among targets and competitors is low.
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Sinais (Psicologia) , Inibição Psicológica , Memória Episódica , Rememoração Mental , Reconhecimento Psicológico , Adulto , Feminino , Humanos , Masculino , Semântica , Estudantes , Fatores de Tempo , Universidades , Aprendizagem Verbal , Adulto JovemRESUMO
OBJECTIVE: To describe the prevalence of obesity and analyse possible differences in it according to sociodemographic characteristics, diet, physical activity, screen use and family perception of the weight and dietary habits of schoolchildren aged 3 to 4 years in Barcelona. METHODS: We conducted a cross-sectional study in a representative sample of schools selected based on the socioeconomic status (SES) of the corresponding neighbourhood and school ownership. We selected 101 schools in Barcelona and recruited pupils aged 3 to 4 years during the 2016-17 academic year (n = 2936 children). Anthropometric measurements were taken in each participant. Family members completed a questionnaire on eating habits, physical activity, sleeping hours, screen use and the family's perception of the child's weight and diet. The primary variable was the body mass index (BMI) for age and sex, subsequently categorised as normal weight, overweight or obese. RESULTS: Approximately 7.0% of girls and 7.1% of boys aged 3 to 4 years presented obesity. The prevalence of obesity (8.3%) was higher in neighbourhoods of lower SES compared to those of higher SES (5.2%; p = .004). Parents of children with obesity reported that the child had some excess weight or excess weight in 46.9% of cases, 3.9% indicated the child's weight was appropriate and 0.9% that the child was a little underweight or underweight (p < .001). DISCUSSION: The prevalence of obesity in children aged 3 to 4 years is high. There are social and geographical inequalities, and obesity was more prevalent in areas of lower SES. A large percentage of the families of children with obesity do not consider that the child's weight is excessive.
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Obesidade Infantil , Humanos , Masculino , Estudos Transversais , Feminino , Pré-Escolar , Prevalência , Obesidade Infantil/epidemiologia , Espanha/epidemiologia , Comportamento Alimentar , Índice de Massa Corporal , Exercício Físico , Dieta/estatística & dados numéricos , Fatores SocioeconômicosRESUMO
While growing evidence supports that dispositional mindfulness relates to psychological health and cognitive enhancement, to date there have been only a few attempts to characterize its neural underpinnings. In the present study, we aimed at exploring the electrophysiological (EEG) signature of dispositional mindfulness using quantitative and complexity measures of EEG during resting state and while performing a learning task. Hundred twenty participants were assessed with the Five Facet Mindfulness Questionnaire and underwent 5 min eyes-closed resting state and 5 min at task EEG recording. We hypothesized that high mindfulness individuals would show patterns of brain activity related to (a) lower involvement of the default mode network (DMN) at rest (reduced frontal gamma power) and (b) a state of 'task readiness' reflected in a more similar pattern from rest to task (reduced overall q-EEG power at rest but not at task), as compared to their low mindfulness counterparts. Dispositional mindfulness was significantly linked to reduced frontal gamma power at rest and lower overall power during rest but not at task. In addition, we found a trend towards higher entropy during task performance in mindful individuals, which has recently been reported during mindfulness meditation. Altogether, our results add to those from expert meditators to show that high (dispositional) mindfulness seems to have a specific electrophysiological pattern characteristic of less involvement of the DMN and mind-wandering processes.
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Mapeamento Encefálico , Atenção Plena , Humanos , Atenção Plena/métodos , Olho , Aprendizagem , Eletroencefalografia , Encéfalo/fisiologiaRESUMO
[This corrects the article DOI: 10.3389/fnins.2023.1223950.].
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The alpha rhythm is often associated with relaxed wakefulness or idling and is altered by various factors. Abnormalities in the alpha rhythm have been linked to several neurological and psychiatric disorders, including Alzheimer's disease. Transcranial alternating current stimulation (tACS) has been proposed as a potential tool to restore a disrupted alpha rhythm in the brain by stimulating at the individual alpha frequency (IAF), although some research has produced contradictory results. In this study, we applied an IAF-tACS protocol over parieto-occipital areas to a sample of healthy subjects and measured its effects over the power spectra. Additionally, we used computational models to get a deeper understanding of the results observed in the experiment. Both experimental and numerical results showed an increase in alpha power of 8.02% with respect to the sham condition in a widespread set of regions in the cortex, excluding some expected parietal regions. This result could be partially explained by taking into account the orientation of the electric field with respect to the columnar structures of the cortex, showing that the gyrification in parietal regions could generate effects in opposite directions (hyper-/depolarization) at the same time in specific brain regions. Additionally, we used a network model of spiking neuronal populations to explore the effects that these opposite polarities could have on neural activity, and we found that the best predictor of alpha power was the average of the normal components of the electric field. To sum up, our study sheds light on the mechanisms underlying tACS brain activity modulation, using both empirical and computational approaches. Non-invasive brain stimulation techniques hold promise for treating brain disorders, but further research is needed to fully understand and control their effects on brain dynamics and cognition. Our findings contribute to this growing body of research and provide a foundation for future studies aimed at optimizing the use of non-invasive brain stimulation in clinical settings.
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No cardiovascular risk score has included Latin American patients in its development. The ACC/AHA ASCVD risk score has not been validated in Latin America; consequently, its predictive capacity in the population of the region is unknown. The aim of this study is to evaluate the discrimination capacity and calibration of the ACC/AHA ASCVD score to predict the 10-year risk of a cardiovascular event in a primary prevention cohort followed in a Colombian hospital. A retrospective cohort study was conducted in primary prevention patients belonging to an intermediate/high-risk and low-risk cohort without established atherosclerotic disease. Cardiovascular risk was calculated at inclusion. The calibration was analyzed by comparing observed and expected events in the different risk categories. A discrimination analysis was made using the area under the ROC curve and C statistic. A total of 918 patients were included-202 from the intermediate/high-risk and 716 from the low-risk cohort. The median cardiovascular risk was 3.6% (IQR 1.7-8.5%). At the 10-year follow-up, 40 events (4,4%) occurred. The area under the ROC curve was 0.782 (95% CI 0.71-0.85). The Hosmer-Lemeshow test did not show differences between expected and observed events. The ACC/AHA ASCVD score is calibrated and has good discrimination capacity in predicting 10-year risk of cardiovascular events in a Colombian population.
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Aterosclerose , Doenças Cardiovasculares , Humanos , Estudos Retrospectivos , Colômbia/epidemiologia , Medição de Risco , Fatores de Risco , Aterosclerose/epidemiologia , Doenças Cardiovasculares/epidemiologia , Doenças Cardiovasculares/prevenção & controleRESUMO
Background: Lamin A/C-associated heart disease is a group of clinical entities characterized by a mutation in the LMNA gene. Multiple cardiac phenotypes have been described, including a higher risk of sudden death. Case summary: A 23-year-old asymptomatic patient with an extensive history of heart disease in the family consulted the clinic. He had a genetic test performed when he was born revealing a new frameshift mutation in the LMNA gene. Numerous cardiac function tests were ordered, which initially were normal. After a year of follow-up, Holter monitoring was positive for episodes of nonsustained ventricular tachycardia (NSVT). Because of the risk factors and higher likelihood of sudden death, a decision was made to offer an implantable cardiac defibrillator (ICD), which was performed without complications. The patient continues the follow-up with cardiology and electrophysiology consisting of yearly cardiac imaging and device recordings. Discussion: Lamins are nuclear proteins involved in various cellular processes in myocardial cells. Therefore, mutations are associated with wide phenotypic alterations. The mutation described here was not previously reported in the literature. In the face of an undescribed mutation, the decision to use an ICD for primary prevention of sudden death is challenging. Because of the episodes of NSVT and a higher likelihood of risk of sudden death due to male sex and first-degree atrioventricular block, the decision to use an ICD was made for this patient, with no complications.
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Childhood obesity is a relevant public health problem. The school food environment has been identified as an important factor for promoting healthy eating behaviors. This study assessed the availability of and proximity to unhealthy food stores around schools (n = 22) in the city of Barcelona and its association with neighborhood socioeconomic status (NSES). We conducted this cross-sectional study between 2019 and 2020. First, we identified all food retailers (n = 153) within a 400-m buffer around each school and identified those selling unhealthy food products. Then, we used Poison regression models to measure the association between NSES and the healthy food availability index (HFAI), adjusting for population density and distance. A total of 95% of the food establishments studied were classified as unhealthy (n = 146). In all, 90% of schools that had, at least, two unhealthy retailers in their proximity. There were significant differences in the mean distance to unhealthy establishments according to neighborhood SES and population density (p < 0.05). We found a positive association between schools located in higher SES neighborhoods and a higher availability and affordability of healthy food products (IIR = 1.67, 95% CI = 1.45−1.91 p = 0.000). We found strong social inequalities in the supply of healthy foods in Barcelona. Local food policy interventions addressing retail food environment around schools should consider socioeconomic inequalities.
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Obesidade Infantil , Criança , Humanos , Obesidade Infantil/epidemiologia , Estudos Transversais , Alimentos , Classe Social , Instituições Acadêmicas , Fatores Socioeconômicos , Abastecimento de Alimentos , Características de ResidênciaRESUMO
Recent research has shown that providing a cue to selectively forget one subset of previously learned facts may result in specific forgetting of this information. Behavioral evidence suggests that this selective directed forgetting effect relies on executive control and is a direct consequence of active, rather than passive, mechanisms. To date, however, no previous research has addressed the neural underpinnings of selective directed forgetting. Since the lateral prefrontal cortex is thought to mediate motivated forgetting by exerting top-down control over the brain structures that underpin memory representations, the present study aimed to test the hypothesis that selective directed forgetting is prefrontally driven. Specifically, we used transcranial direct current stimulation to disrupt activity in the dorsolateral prefrontal cortex, using a stimulation protocol that has already been shown to be effective in this regard. Our results reveal that, in contrast to sham stimulation, real stimulation abolished selective directed forgetting. Additionally, real stimulation hindered performance in an updating working memory task thought to recruit the lateral prefrontal cortex. These findings, complementing others obtained with a variety of memory control tasks, support the hypothesis that memory downregulation is achieved by control processes mediated by the right lateral prefrontal cortex.
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Estimulação Transcraniana por Corrente Contínua , Humanos , Memória de Curto Prazo/fisiologia , Córtex Pré-Frontal/fisiologiaRESUMO
Although grit is predictive of wellbeing, educational achievement, and success in life, it has been conceptualized as largely distinct from cognitive ability. The present study investigated the link between grit and executive functions since regulation abilities might underlie the expression of grit. A hundred thirty-four people were administered personality questionnaires (grit, impulsiveness, and mindfulness) and four experimental tasks tapping into Miyake's and Braver's models of executive functioning (including measures of flexibility, inhibition, working memory, and control mode dimensions). Multivariate analyses showed that two composite scores (trait and executive functioning) were reliably predictive of grit, although it was the trait composite (characterized by low impulsivity and high mindfulness) that explained more variance. Importantly, gritty participants did not demonstrate enhanced executive functioning. Instead, they exhibited a different pattern of performance that might be reflecting a cautious profile of control, characterized by paying attention to all available information, less reliance on previous contextual cues but sensitive to conflicting information of the current context. These findings converge with Duckworth's idea that high grit people do not necessarily have a greater cognitive capacity. Rather, they use it in a different way.
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Sucesso Acadêmico , Função Executiva , Logro , Cognição , Humanos , Personalidade/fisiologiaRESUMO
Prospective memory (PM) is essential in the everyday activities of children because it involves remembering intentions for the future, such as doing their homework or bringing written parental permissions to school. Developmental studies have shown increases in PM performance throughout childhood, but the specific processes underlying this development are still under debate. In the present study, event-related potentials were used to examine whether the focality of the PM task is related to the PM increments by testing two groups of children (first and last cycle of primary school) and assessing differences in N300 (cue detection), frontal positivity (switching), parietal positivity (retrieval of the intention) and frontal slow waves (monitoring of the retrieved intention). The results showed significant differences in focality in the group of older children but no differences in any of the components for their younger counterparts. In addition, the differences between prospective and ongoing trials were smaller for younger than older children. These findings suggest that the ability to adjust attentional strategies, monitor, switch and retrieve the intention develops across childhood and affects PM performance in attentionally demanding conditions.