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1.
Child Dev ; 94(6): 1672-1696, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37307398

RESUMO

This study compared the acoustic properties of 26 (100% female, 100% monolingual) Danish caregivers' spontaneous speech addressed to their 11- to 24-month-old infants (infant-directed speech, IDS) and an adult experimenter (adult-directed speech, ADS). The data were collected between 2016 and 2018 in Aarhus, Denmark. Prosodic properties of Danish IDS conformed to cross-linguistic patterns, with a higher pitch, greater pitch variability, and slower articulation rate than ADS. However, an acoustic analysis of vocalic properties revealed that Danish IDS had a reduced or similar vowel space, higher within-vowel variability, raised formants, and lower degree of vowel discriminability compared to ADS. None of the measures, except articulation rate, showed age-related differences. These results push for future research to conduct theory-driven comparisons across languages with distinct phonological systems.


Assuntos
Percepção da Fala , Fala , Adulto , Lactente , Humanos , Feminino , Pré-Escolar , Masculino , Criança , Idioma , Desenvolvimento da Linguagem , Linguagem Infantil , Dinamarca , Fonética , Acústica da Fala
2.
Brain ; 144(5): 1603-1614, 2021 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-33829262

RESUMO

An abnormality in inference, resulting in distorted internal models of the world, has been argued to be a common mechanism underlying the heterogeneous psychopathology in schizophrenia. However, findings have been mixed as to wherein the abnormality lies and have typically failed to find convincing relations to symptoms. The limited and inconsistent findings may have been due to methodological limitations of the experimental design, such as conflating other factors (e.g. comprehension) with the inferential process of interest, and a failure to adequately assess and model the key aspects of the inferential process. Here, we investigated probabilistic inference based on multiple sources of information using a new digital version of the beads task, framed in a social context. Thirty-five patients with schizophrenia or schizoaffective disorder with a wide range of symptoms and 40 matched healthy control subjects performed the task, where they guessed the colour of the next marble drawn from a jar based on a sample from the jar as well as the choices and the expressed confidence of four people, each with their own independent sample (which was hidden from participant view). We relied on theoretically motivated computational models to assess which model best captured the inferential process and investigated whether it could serve as a mechanistic model for both psychotic and negative symptoms. We found that 'circular inference' best described the inference process, where patients over-weighed and overcounted direct experience and under-weighed information from others. Crucially, overcounting of direct experience was uniquely associated with most psychotic and negative symptoms. In addition, patients with worse social cognitive function had more difficulties using others' confidence to inform their choices. This difficulty was related to worse real-world functioning. The findings could not be easily ascribed to differences in working memory, executive function, intelligence or antipsychotic medication. These results suggest hallucinations, delusions and negative symptoms could stem from a common underlying abnormality in inference, where directly experienced information is assigned an unreasonable weight and taken into account multiple times. By this, even unreliable first-hand experiences may gain disproportionate significance. The effect could lead to false perceptions (hallucinations), false beliefs (delusions) and deviant social behaviour (e.g. loss of interest in others, bizarre and inappropriate behaviour). This may be particularly problematic for patients with social cognitive deficits, as they may fail to make use of corrective information from others, ultimately leading to worse social functioning.


Assuntos
Psicologia do Esquizofrênico , Comportamento Social , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Esquizofrenia
3.
Infancy ; 27(1): 67-96, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34542230

RESUMO

This paper quantifies the extent to which infants can perceive audio-visual congruence for speech information and assesses whether this ability changes with native language exposure over time. A hierarchical Bayesian robust regression model of 92 separate effect sizes extracted from 24 studies indicates a moderate effect size in a positive direction (0.35, CI [0.21: 0.50]). This result suggests that infants possess a robust ability to detect audio-visual congruence for speech. Moderator analyses, moreover, suggest that infants' audio-visual matching ability for speech emerges at an early point in the process of language acquisition and remains stable for both native and non-native speech throughout early development. A sensitivity analysis of the meta-analytic data, however, indicates that a moderate publication bias for significant results could shift the lower credible interval to include null effects. Based on these findings, we outline recommendations for new lines of enquiry and suggest ways to improve the replicability of results in future investigations.


Assuntos
Percepção da Fala , Fala , Teorema de Bayes , Humanos , Lactente , Idioma , Desenvolvimento da Linguagem
4.
Proc Natl Acad Sci U S A ; 112(12): 3835-40, 2015 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-25775532

RESUMO

We tend to think that everyone deserves an equal say in a debate. This seemingly innocuous assumption can be damaging when we make decisions together as part of a group. To make optimal decisions, group members should weight their differing opinions according to how competent they are relative to one another; whenever they differ in competence, an equal weighting is suboptimal. Here, we asked how people deal with individual differences in competence in the context of a collective perceptual decision-making task. We developed a metric for estimating how participants weight their partner's opinion relative to their own and compared this weighting to an optimal benchmark. Replicated across three countries (Denmark, Iran, and China), we show that participants assigned nearly equal weights to each other's opinions regardless of true differences in their competence-even when informed by explicit feedback about their competence gap or under monetary incentives to maximize collective accuracy. This equality bias, whereby people behave as if they are as good or as bad as their partner, is particularly costly for a group when a competence gap separates its members.


Assuntos
Tomada de Decisões , Preconceito , Adulto , China , Cognição , Comunicação , Simulação por Computador , Comportamento Cooperativo , Características Culturais , Dinamarca , Humanos , Relações Interpessoais , Irã (Geográfico) , Masculino , Reprodutibilidade dos Testes , Comportamento Social
5.
Neuroimage ; 153: 109-121, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28341164

RESUMO

The neural processing and experience of pain are influenced by both expectations and attention. For example, the amplitude of event-related pain responses is enhanced by both novel and unexpected pain, and by moving the focus of attention towards a painful stimulus. Under predictive coding, this congruence can be explained by appeal to a precision-weighting mechanism, which mediates bottom-up and top-down attentional processes by modulating the influence of feedforward and feedback signals throughout the cortical hierarchy. The influence of expectation and attention on pain processing can be mapped onto changes in effective connectivity between or within specific neuronal populations, using a canonical microcircuit (CMC) model of hierarchical processing. We thus implemented a CMC within dynamic causal modelling for magnetoencephalography in human subjects, to investigate how expectation violation and attention to pain modulate intrinsic (within-source) and extrinsic (between-source) connectivity in the somatosensory hierarchy. This enabled us to establish whether both expectancy and attentional processes are mediated by a similar precision-encoding mechanism within a network of somatosensory, frontal and parietal sources. We found that both unexpected and attended pain modulated the gain of superficial pyramidal cells in primary and secondary somatosensory cortex. This modulation occurred in the context of increased lateralized recurrent connectivity between somatosensory and fronto-parietal sources, driven by unexpected painful occurrences. Finally, the strength of effective connectivity parameters in S1, S2 and IFG predicted individual differences in subjective pain modulation ratings. Our findings suggest that neuromodulatory gain control in the somatosensory hierarchy underlies the influence of both expectation violation and attention on cortical processing and pain perception.


Assuntos
Atenção/fisiologia , Modelos Neurológicos , Percepção da Dor/fisiologia , Córtex Somatossensorial/fisiologia , Adulto , Mapeamento Encefálico , Eletrochoque , Feminino , Lobo Frontal/fisiologia , Humanos , Magnetoencefalografia , Masculino , Vias Neurais/fisiologia , Lobo Parietal/fisiologia , Adulto Jovem
6.
Neuroimage ; 134: 105-112, 2016 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-27039141

RESUMO

Symbolic artifacts present a challenge to theories of neurocognitive processing due to their hybrid nature: they are at the same time physical objects and vehicles of intangible social meanings. While their physical properties can be read of their perceptual appearance, the meaning of symbolic artifacts depends on the perceiver's interpretative attitude and embeddedness in cultural practices. In this study, participants built models of LEGO bricks to illustrate their understanding of abstract concepts. They were then scanned with fMRI while presented to photographs of their own and others' models. When participants attended to the meaning of the models in contrast to their bare physical properties, we observed activations in mPFC and TPJ, areas often associated with social cognition, and IFG, possibly related to semantics. When contrasting own and others' models, we also found activations in precuneus, an area associated with autobiographical memory and agency, while looking at one's own collective models yielded interaction effects in rostral ACC, right IFG and left Insula. Interestingly, variability in the insula was predicted by individual differences in participants' feeling of relatedness to their fellow group members during LEGO construction activity. Our findings support a view of symbolic artifacts as neuro-cognitive trails of human social interactions.


Assuntos
Córtex Cerebral/fisiologia , Compreensão/fisiologia , Formação de Conceito/fisiologia , Individualidade , Rede Nervosa/fisiologia , Comportamento Social , Simbolismo , Feminino , Processos Grupais , Humanos , Masculino , Percepção Visual/fisiologia , Adulto Jovem
7.
Neuroimage ; 127: 34-43, 2016 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-26584870

RESUMO

The body underlies our sense of self, emotion, and agency. Signals arising from the skin convey warmth, social touch, and the physical characteristics of external stimuli. Surprising or unexpected tactile sensations can herald events of motivational salience, including imminent threats (e.g., an insect bite) and hedonic rewards (e.g., a caressing touch). Awareness of such events is thought to depend upon the hierarchical integration of body-related mismatch responses by the anterior insula. To investigate this possibility, we measured brain activity using functional magnetic resonance imaging, while healthy participants performed a roving tactile oddball task. Mass-univariate analysis demonstrated robust activations in limbic, somatosensory, and prefrontal cortical areas previously implicated in tactile deviancy, body awareness, and cognitive control. Dynamic Causal Modelling revealed that unexpected stimuli increased the strength of forward connections along a caudal to rostral hierarchy-projecting from thalamic and somatosensory regions towards insula, cingulate and prefrontal cortices. Within this ascending flow of sensory information, the AIC was the only region to show increased backwards connectivity to the somatosensory cortex, augmenting a reciprocal exchange of neuronal signals. Further, participants who rated stimulus changes as easier to detect showed stronger modulation of descending PFC to AIC connections by deviance. These results suggest that the AIC coordinates hierarchical processing of tactile prediction error. They are interpreted in support of an embodied predictive coding model where AIC mediated body awareness is involved in anchoring a global neuronal workspace.


Assuntos
Córtex Cerebral/fisiologia , Vias Neurais/fisiologia , Percepção do Tato/fisiologia , Adulto , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Modelos Neurológicos , Adulto Jovem
8.
J Neurosci ; 34(14): 5003-11, 2014 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-24695717

RESUMO

Detecting the location of salient sounds in the environment rests on the brain's ability to use differences in sounds arriving at both ears. Functional neuroimaging studies in humans indicate that the left and right auditory hemispaces are coded asymmetrically, with a rightward attentional bias that reflects spatial attention in vision. Neuropsychological observations in patients with spatial neglect have led to the formulation of two competing models: the orientation bias and right-hemisphere dominance models. The orientation bias model posits a symmetrical mapping between one side of the sensorium and the contralateral hemisphere, with mutual inhibition of the ipsilateral hemisphere. The right-hemisphere dominance model introduces a functional asymmetry in the brain's coding of space: the left hemisphere represents the right side, whereas the right hemisphere represents both sides of the sensorium. We used Dynamic Causal Modeling of effective connectivity and Bayesian model comparison to adjudicate between these alternative network architectures, based on human electroencephalographic data acquired during an auditory location oddball paradigm. Our results support a hemispheric asymmetry in a frontoparietal network that conforms to the right-hemisphere dominance model. We show that, within this frontoparietal network, forward connectivity increases selectively in the hemisphere contralateral to the side of sensory stimulation. We interpret this finding in light of hierarchical predictive coding as a selective increase in attentional gain, which is mediated by feedforward connections that carry precision-weighted prediction errors during perceptual inference. This finding supports the disconnection hypothesis of unilateral neglect and has implications for theories of its etiology.


Assuntos
Vias Auditivas/fisiologia , Percepção Auditiva/fisiologia , Mapeamento Encefálico , Dominância Cerebral/fisiologia , Percepção Espacial/fisiologia , Estimulação Acústica , Adulto , Teorema de Bayes , Eletroencefalografia , Potenciais Evocados Auditivos , Feminino , Voluntários Saudáveis , Humanos , Magnetoencefalografia , Masculino , Modelos Neurológicos , Dinâmica não Linear , Orientação , Adulto Jovem
9.
Neuroimage ; 120: 350-61, 2015 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-26162551

RESUMO

Mental imagery has the potential to influence perception by directly altering sensory, cognitive, and affective brain activity associated with imagined content. While it is well established that mental imagery can both exacerbate and alleviate acute and chronic pain, it is currently unknown how imagery mechanisms regulate pain perception. For example, studies to date have been unable to determine whether imagery effects depend upon a general redirection of attention away from pain or focused attentional mechanisms. To address these issues, we recorded subjective, behavioral and ERP responses using 64-channel EEG while healthy human participants applied a mental imagery strategy to decrease or increase pain sensations. When imagining a glove covering the forearm, participants reported decreased perceived intensity and unpleasantness, classified fewer high-intensity stimuli as painful, and showed a more conservative response bias. In contrast, when imagining a lesion on the forearm, participants reported increased pain intensity and unpleasantness, classified more low-intensity stimuli as painful, and displayed a more liberal response bias. Using a mass-univariate approach, we further showed differential modulation of the N2 potentials across conditions, with inhibition and facilitation respectively increasing and decreasing N2 amplitudes between 122 and 180 ms. Within this time window, source localization associated inhibiting vs. facilitating pain with neural activity in cortical regions involved in cognitive inhibitory control and in the retrieval of semantic information (i.e., right inferior frontal and temporal regions). In contrast, the main sources of neural activity associated with facilitating vs. inhibiting pain were identified in cortical regions typically implicated in salience processing and emotion regulation (i.e., left insular, inferior-middle frontal, supplementary motor and precentral regions). Overall, these findings suggest that the content of a mental image directly alters pain-related decision and evaluative processing to flexibly produce hypoalgesic and hyperalgesic outcomes.


Assuntos
Córtex Cerebral/fisiologia , Eletroencefalografia/métodos , Potenciais Evocados/fisiologia , Função Executiva/fisiologia , Hiperalgesia/fisiopatologia , Imaginação/fisiologia , Inibição Psicológica , Percepção da Dor/fisiologia , Adulto , Feminino , Humanos , Masculino , Adulto Jovem
11.
Neuroimage ; 94: 79-88, 2014 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-24631790

RESUMO

Successful social interactions rely upon the abilities of two or more people to mutually exchange information in real-time, while simultaneously adapting to one another. The neural basis of social cognition has mostly been investigated in isolated individuals, and more recently using two-person paradigms to quantify the neuronal dynamics underlying social interaction. While several studies have shown the relevance of understanding complementary and mutually adaptive processes, the neural mechanisms underlying such coordinative behavioral patterns during joint action remain largely unknown. Here, we employed a synchronized finger-tapping task while measuring dual-EEG from pairs of human participants who either mutually adjusted to each other in an interactive task or followed a computer metronome. Neurophysiologically, the interactive condition was characterized by a stronger suppression of alpha and low-beta oscillations over motor and frontal areas in contrast to the non-interactive computer condition. A multivariate analysis of two-brain activity to classify interactive versus non-interactive trials revealed asymmetric patterns of the frontal alpha-suppression in each pair, during both task anticipation and execution, such that only one member showed the frontal component. Analysis of the behavioral data showed that this distinction coincided with the leader-follower relationship in 8/9 pairs, with the leaders characterized by the stronger frontal alpha-suppression. This suggests that leaders invest more resources in prospective planning and control. Hence our results show that the spontaneous emergence of leader-follower relationships in dyadic interactions can be predicted from EEG recordings of brain activity prior to and during interaction. Furthermore, this emphasizes the importance of investigating complementarity in joint action.


Assuntos
Ritmo alfa/fisiologia , Encéfalo/fisiologia , Lobo Frontal/fisiologia , Relações Interpessoais , Liderança , Modelos Estatísticos , Adulto , Relógios Biológicos/fisiologia , Mapeamento Encefálico/métodos , Simulação por Computador , Interpretação Estatística de Dados , Feminino , Humanos , Masculino , Modelos Neurológicos , Análise Multivariada , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Predomínio Social , Adulto Jovem
12.
Conscious Cogn ; 26: 13-23, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24650632

RESUMO

In a range of contexts, individuals arrive at collective decisions by sharing confidence in their judgements. This tendency to evaluate the reliability of information by the confidence with which it is expressed has been termed the 'confidence heuristic'. We tested two ways of implementing the confidence heuristic in the context of a collective perceptual decision-making task: either directly, by opting for the judgement made with higher confidence, or indirectly, by opting for the faster judgement, exploiting an inverse correlation between confidence and reaction time. We found that the success of these heuristics depends on how similar individuals are in terms of the reliability of their judgements and, more importantly, that for dissimilar individuals such heuristics are dramatically inferior to interaction. Interaction allows individuals to alleviate, but not fully resolve, differences in the reliability of their judgements. We discuss the implications of these findings for models of confidence and collective decision-making.


Assuntos
Tomada de Decisões/fisiologia , Relações Interpessoais , Julgamento/fisiologia , Negociação , Adulto , Humanos , Masculino , Negociação/psicologia , Adulto Jovem
13.
Proc Natl Acad Sci U S A ; 108(20): 8514-9, 2011 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-21536887

RESUMO

Collective rituals are present in all known societies, but their function is a matter of long-standing debates. Field observations suggest that they may enhance social cohesion and that their effects are not limited to those actively performing but affect the audience as well. Here we show physiological effects of synchronized arousal in a Spanish fire-walking ritual, between active participants and related spectators, but not participants and other members of the audience. We assessed arousal by heart rate dynamics and applied nonlinear mathematical analysis to heart rate data obtained from 38 participants. We compared synchronized arousal between fire-walkers and spectators. For this comparison, we used recurrence quantification analysis on individual data and cross-recurrence quantification analysis on pairs of participants' data. These methods identified fine-grained commonalities of arousal during the 30-min ritual between fire-walkers and related spectators but not unrelated spectators. This indicates that the mediating mechanism may be informational, because participants and related observers had very different bodily behavior. This study demonstrates that a collective ritual may evoke synchronized arousal over time between active participants and bystanders. It links field observations to a physiological basis and offers a unique approach for the quantification of social effects on human physiology during real-world interactions.


Assuntos
Nível de Alerta/fisiologia , Comportamento Ritualístico , Frequência Cardíaca , Comportamento Social , Incêndios , Humanos , Espanha , Caminhada
14.
Med Anthropol ; 43(2): 146-160, 2024 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-38451485

RESUMO

COVID-testing was central to control the spread of infection in Denmark. Drawing on ethnographic fieldwork, we show that testing was not just a diagnostic sign; it was also a biosocial practice that enacted a public health morality, centered on responsibility, care, and belonging. We argue that testing led to a public healthicization of everyday life, as it moralized individual and collective behavior and created a moral divide between the tested and the untested. By attending to COVID-19 testing as a material-semiotic sign, we show how testing is embedded within a particular cultural and moral framework of the Danish welfare state.


Assuntos
Teste para COVID-19 , COVID-19 , Humanos , Antropologia Médica , Princípios Morais , Dinamarca
15.
J Neurosci ; 32(38): 13032-8, 2012 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-22993421

RESUMO

Methylphenidate (MPH) is a stimulant that increases extracellular levels of dopamine and noradrenaline. It can diminish risky decision-making tendencies in certain clinical populations. MPH is also used, without license, by healthy adults, but the impact on their decision-making is not well established. Previous work has found that dopamine receptor activity of healthy adults can modulate the influence of stake magnitude on decisions to persistently gamble after incurring a loss. In this study, we tested for modulation of this effect by MPH in 40 healthy human adults. In a double-blind experiment, 20 subjects received 20 mg of MPH, while 20 matched controls received a placebo. All were provided with 30 rounds of opportunities to accept an incurred loss from their assets or opt for a "double-or-nothing" gamble that would either avoid or double it. Rounds began with a variable loss that would double with every failed gamble until it was accepted, recovered, or reached a specified maximum. Probability of recovery on any gamble was low and ambiguous. Subjects receiving placebo gambled less as the magnitude of the stake was raised and as the magnitude of accumulated loss escalated over the course of the task. In contrast, subjects treated with MPH gambled at a consistent rate, well above chance, across all stakes and trials. Trait reward responsiveness also reduced the impact of high stakes. The findings suggest that elevated catecholamine activity by MPH can disrupt inhibitory influences on persistent risky choice in healthy adults.


Assuntos
Estimulantes do Sistema Nervoso Central/farmacologia , Tomada de Decisões/efeitos dos fármacos , Inibição Psicológica , Metilfenidato/farmacologia , Assunção de Riscos , Adulto , Estudos de Casos e Controles , Método Duplo-Cego , Feminino , Jogos Experimentais , Humanos , Masculino , Motivação/efeitos dos fármacos , Personalidade/efeitos dos fármacos , Probabilidade , Tempo de Reação/efeitos dos fármacos , Recompensa , Análise e Desempenho de Tarefas , Adulto Jovem
16.
J Neurosci ; 32(44): 15601-10, 2012 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-23115195

RESUMO

Mindfulness meditation is a set of attention-based, regulatory, and self-inquiry training regimes. Although the impact of mindfulness training (MT) on self-regulation is well established, the neural mechanisms supporting such plasticity are poorly understood. MT is thought to act through interoceptive salience and attentional control mechanisms, but until now conflicting evidence from behavioral and neural measures renders difficult distinguishing their respective roles. To resolve this question we conducted a fully randomized 6 week longitudinal trial of MT, explicitly controlling for cognitive and treatment effects with an active-control group. We measured behavioral metacognition and whole-brain blood oxygenation level-dependent (BOLD) signals using functional MRI during an affective Stroop task before and after intervention in healthy human subjects. Although both groups improved significantly on a response-inhibition task, only the MT group showed reduced affective Stroop conflict. Moreover, the MT group displayed greater dorsolateral prefrontal cortex responses during executive processing, consistent with increased recruitment of top-down mechanisms to resolve conflict. In contrast, we did not observe overall group-by-time interactions on negative affect-related reaction times or BOLD responses. However, only participants with the greatest amount of MT practice showed improvements in response inhibition and increased recruitment of dorsal anterior cingulate cortex, medial prefrontal cortex, and right anterior insula during negative valence processing. Our findings highlight the importance of active control in MT research, indicate unique neural mechanisms for progressive stages of mindfulness training, and suggest that optimal application of MT may differ depending on context, contrary to a one-size-fits-all approach.


Assuntos
Afeto/fisiologia , Cognição/fisiologia , Meditação/psicologia , Plasticidade Neuronal/fisiologia , Adolescente , Adulto , Atenção/fisiologia , Conscientização/fisiologia , Emoções/fisiologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Estudos Longitudinais , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Oxigênio/sangue , Cooperação do Paciente , Estimulação Luminosa , Desempenho Psicomotor/fisiologia , Terapia de Relaxamento , Teste de Stroop , Adulto Jovem
17.
Neuroimage ; 83: 397-407, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23827330

RESUMO

Neurovascular coupling links neuronal activity to vasodilation. Nitric oxide (NO) is a potent vasodilator, and in neurovascular coupling NO production from NO synthases plays an important role. However, another pathway for NO production also exists, namely the nitrate-nitrite-NO pathway. On this basis, we hypothesized that dietary nitrate (NO3-) could influence the brain's hemodynamic response to neuronal stimulation. In the present study, 20 healthy male participants were given either sodium nitrate (NaNO3) or sodium chloride (NaCl) (saline placebo) in a crossover study and were shown visual stimuli based on the retinotopic characteristics of the visual cortex. Our primary measure of the hemodynamic response was the blood oxygenation level dependent (BOLD) response measured with high-resolution functional magnetic resonance imaging (0.64×0.64×1.8 mm) in the visual cortex. From this response, we made a direct estimate of key parameters characterizing the shape of the BOLD response (i.e. lag and amplitude). During elevated nitrate intake, corresponding to the nitrate content of a large plate of salad, both the hemodynamic lag and the BOLD amplitude decreased significantly (7.0±2% and 7.9±4%, respectively), and the variation across activated voxels of both measures decreased (12.3±4% and 15.3±7%, respectively). The baseline cerebral blood flow was not affected by nitrate. Our experiments demonstrate, for the first time, that dietary nitrate may modulate the local cerebral hemodynamic response to stimuli. A faster and smaller BOLD response, with less variation across local cortex, is consistent with an enhanced hemodynamic coupling during elevated nitrate intake. These findings suggest that dietary patterns, via the nitrate-nitrite-NO pathway, may be a potential way to affect key properties of neurovascular coupling. This could have major clinical implications, which remain to be explored.


Assuntos
Mapeamento Encefálico/métodos , Circulação Cerebrovascular/fisiologia , Nitratos/administração & dosagem , Óxido Nítrico/metabolismo , Nitritos/metabolismo , Estimulação Luminosa/métodos , Percepção Visual/fisiologia , Administração Oral , Adulto , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Velocidade do Fluxo Sanguíneo/fisiologia , Circulação Cerebrovascular/efeitos dos fármacos , Estudos Cross-Over , Método Duplo-Cego , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Efeito Placebo , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
18.
J Behav Med ; 36(4): 413-26, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22772583

RESUMO

Although the use of prayer as a religious coping strategy is widespread and often claimed to have positive effects on physical disorders including pain, it has never been tested in a controlled experimental setting whether prayer has a pain relieving effect. Religious beliefs and practices are complex phenomena and the use of prayer may be mediated by general psychological factors known to be related to the pain experience, such as expectations, desire for pain relief, and anxiety. Twenty religious and twenty non-religious healthy volunteers were exposed to painful electrical stimulation during internal prayer to God, a secular contrast condition, and a pain-only control condition. Subjects rated expected pain intensity levels, desire for pain relief, and anxiety before each trial and pain intensity and pain unpleasantness immediately after on mechanical visual analogue scales. Autonomic and cardiovascular measures provided continuous non-invasive objective means for assessing the potential analgesic effects of prayer. Prayer reduced pain intensity by 34 % and pain unpleasantness by 38 % for religious participants, but not for non-religious participants. For religious participants, expectancy and desire predicted 56-64 % of the variance in pain intensity scores, but for non-religious participants, only expectancy was significantly predictive of pain intensity (65-73 %). Conversely, prayer-induced reduction in pain intensity and pain unpleasantness were not followed by autonomic and cardiovascular changes.


Assuntos
Adaptação Psicológica/fisiologia , Dor/psicologia , Religião e Psicologia , Religião , Adulto , Estimulação Elétrica/instrumentação , Estimulação Elétrica/métodos , Feminino , Humanos , Masculino , Dor/etiologia , Dor/fisiopatologia , Medição da Dor , Adulto Jovem
19.
Behav Brain Sci ; 36(3): 224-5, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23663865

RESUMO

Predictive processing models of cognition are promising an elegant way to unite action, perception, and learning. However, in the current formulations, they are species-unspecific and have very little particularly human about them. I propose to examine how, in this framework, humans can be able to massively interact and to build shared worlds that are both material and symbolic.


Assuntos
Atenção/fisiologia , Encéfalo/fisiologia , Cognição/fisiologia , Ciência Cognitiva/tendências , Percepção/fisiologia , Humanos
20.
Psychol Rev ; 130(2): 462-479, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-35708932

RESUMO

In this article, we argue that a predictive processing framework (PP) may provide elements for a proximate model of play in children and adults. We propose that play is a behavior in which the agent, in contexts of freedom from the demands of certain competing cognitive systems, deliberately seeks out or creates surprising situations that gravitate toward sweet-spots of relative complexity with the goal of resolving surprise. We further propose that play is experientially associated with a feel-good quality because the agent is reducing significant levels of prediction error (i.e., surprise) faster than expected. We argue that this framework can unify a range of well-established findings in play and developmental research that highlights the role of play in learning, and that casts children as Bayesian learners. The theory integrates the role of positive valence in play (i.e., explaining why play is fun); and what it is to be in a playful mood. Central to the account is the idea that playful agents may create and establish an environment tailored to the generation and further resolution of surprise and uncertainty. Play emerges here as a variety of niche construction where the organism modulates its physical and social environment in order to maximize the productive potential of surprise. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Assuntos
Emoções , Aprendizagem , Adulto , Criança , Humanos , Teorema de Bayes , Incerteza , Cognição
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