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1.
Nat Commun ; 14(1): 5473, 2023 09 06.
Artigo em Inglês | MEDLINE | ID: mdl-37673881

RESUMO

According to Bayesian models, both decisions and confidence are based on the same precision-weighted integration of prior expectations ("priors") and incoming information ("likelihoods"). This assumes that priors are integrated optimally and equally in decisions and confidence, which has not been tested. In three experiments, we quantify how priors inform decisions and confidence. With a dual-decision task we create pairs of conditions that are matched in posterior information, but differ on whether the prior or likelihood is more informative. We find that priors are underweighted in discrimination decisions, but are less underweighted in confidence about those decisions, and this is not due to differences in processing time. The same patterns remain with exogenous probabilistic cues as priors. With a Bayesian model we quantify the weighting parameters for the prior at both levels, and find converging evidence that priors are more optimally used in explicit confidence, even when underused in decisions.


Assuntos
Sinais (Psicologia) , Processos Mentais , Teorema de Bayes , Probabilidade
2.
Cognition ; 235: 105388, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36753807

RESUMO

We can monitor our intentional movements and form explicit representations about our movements, allowing us to describe how we move our bodies. But it is unclear which information this metacognitive monitoring relies on. For example, when throwing a ball to hit a target, we might use the visual information about how the ball flew to metacognitively assess our performance. Alternatively, we might disregard the ball trajectory - given that it is not directly relevant to our goal - and metacognitively assess our performance based solely on whether we reached the goal of hitting the target. In two experiments we aimed to distinguish between these two alternatives and asked whether the distal outcome of a goal-directed action (hitting or missing a target) informs the metacognitive representations of our own movements. Participants performed a semi-virtual task where they moved their arm to throw a virtual ball at a target. After each throw, participants discriminated which of two ball trajectories displayed on the screen corresponded to the flight path of their throw and then rated their confidence in this decision. The task included two conditions that differed on whether the distal outcome of the two trajectories shown matched (congruent) or differed (incongruent). Participants were significantly more accurate in discriminating between the two trajectories, and responded faster in the incongruent condition and, accordingly, were significantly more confident on these trials. Crucially, we found significant differences in metacognitive performance (measured as meta-d'/d') between the two conditions only on successful trials, where the virtual ball had hit the target. These results indicate that participants successfully incorporated information about the outcome of the movement into both their discrimination and confidence responses. However, information about the outcome selectively sharpened the precision of confidence ratings only when the outcome of their throw matched their intention. We argue that these findings underline the separation between the different levels of information that may contribute to body monitoring, and we provide evidence that intentions might play a central role in metacognitive motor representations.


Assuntos
Intenção , Metacognição , Humanos , Metacognição/fisiologia , Movimento/fisiologia
3.
Mov Disord ; 38(3): 435-443, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36606550

RESUMO

BACKGROUND: Motor symptoms in functional movement disorders (FMDs) are experienced as involuntary but share characteristics of voluntary action. Clinical and experimental evidence indicate alterations in monitoring, control, and subjective experience of self-performed movements. OBJECTIVE: The objective of this study was to test the prediction that FMDs are associated with a reduced ability to make accurate (metacognitive) judgments about self-performed movements. METHODS: We compared 24 patients with FMD (including functional gait disturbance, functional tremor, and functional tics) with 24 age- and sex-matched healthy control subjects in a novel visuomotor-metacognitive paradigm. Participants performed target-directed movements on a graphics tablet with restricted visual feedback, decided which of two visually presented trajectories was closer to their preceding movement, and reported their confidence in the visuomotor decision. We quantified individual metacognitive performance as participants' ability to assign high confidence preferentially to correct visuomotor decisions. RESULTS: Patients and control subjects showed comparable motor performance, response accuracy, and use of the confidence scale. However, visuomotor sensitivity in the trajectory judgment was reduced in patients with FMD compared with healthy control subjects. Moreover, metacognitive performance was impaired in patients, that is, their confidence ratings were less predictive of the correctness of visuomotor decisions. Exploratory subgroup analyses suggest metacognitive deficits to be most pronounced in patients with a functional gait disturbance or functional tremor. CONCLUSIONS: Patients with FMD exhibited deficits both when making visuomotor decisions about their own movements and in the metacognitive evaluation of these decisions. Reduced metacognitive insight into voluntary motor control may play a role in FMD pathophysiology and could lay the groundwork for new treatment strategies. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.


Assuntos
Transtorno Conversivo , Metacognição , Transtornos dos Movimentos , Humanos , Metacognição/fisiologia , Tremor , Julgamento/fisiologia , Movimento/fisiologia
4.
Psychon Bull Rev ; 30(3): 1125-1135, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-36333519

RESUMO

It is still debated whether metacognition, or the ability to monitor our own mental states, relies on processes that are "domain-general" (a single set of processes can account for the monitoring of any mental process) or "domain-specific" (metacognition is accomplished by a collection of multiple monitoring modules, one for each cognitive domain). It has been speculated that two broad categories of metacognitive processes may exist: those that monitor primarily externally generated versus those that monitor primarily internally generated information. To test this proposed division, we measured metacognitive performance (using m-ratio, a signal detection theoretical measure) in four tasks that could be ranked along an internal-external axis of the source of information, namely memory, motor, visuomotor, and visual tasks. We found correlations between m-ratios in visuomotor and motor tasks, but no correlations between m-ratios in visual and visuomotor tasks, or between motor and memory tasks. While we found no correlation in metacognitive ability between visual and memory tasks, and a positive correlation between visuomotor and motor tasks, we found no evidence for a correlation between motor and memory tasks. This pattern of correlations does not support the grouping of domains based on whether the source of information is primarily internal or external. We suggest that other groupings could be more reflective of the nature of metacognition and discuss the need to consider other non-domain task-features when using correlations as a way to test the underlying shared processes between domains.


Assuntos
Metacognição , Humanos , Fonte de Informação
5.
Perspect Psychol Sci ; 17(6): 1746-1765, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35839099

RESUMO

Despite the tangible progress in psychological and cognitive sciences over the last several years, these disciplines still trail other more mature sciences in identifying the most important questions that need to be solved. Reaching such consensus could lead to greater synergy across different laboratories, faster progress, and increased focus on solving important problems rather than pursuing isolated, niche efforts. Here, 26 researchers from the field of visual metacognition reached consensus on four long-term and two medium-term common goals. We describe the process that we followed, the goals themselves, and our plans for accomplishing these goals. If this effort proves successful within the next few years, such consensus building around common goals could be adopted more widely in psychological science.


Assuntos
Metacognição , Humanos , Consenso , Objetivos , Logro
6.
Cognition ; 225: 105155, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35537345

RESUMO

As humans we communicate important information through fine nuances in our facial expressions, but because conscious motor representations are noisy, we might not be able to report these fine movements. Here we measured the precision of the explicit metacognitive information that young adults have about their own facial expressions. Participants imitated pictures of themselves making facial expressions and triggered a camera to take a picture of them while doing so. They then rated how well they thought they imitated each expression. We defined metacognitive access to facial expressions as the relationship between objective performance (how well the two pictures matched) and subjective performance ratings. As a group, participants' metacognitive confidence ratings were only about four times less precise than their own similarity ratings. In turn, machine learning analyses revealed that participants' performance ratings were based on idiosyncratic subsets of features. We conclude that metacognitive access to one's own facial expressions is only partial.


Assuntos
Expressão Facial , Metacognição , Humanos , Adulto Jovem
7.
Parkinsonism Relat Disord ; 97: 29-33, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35294915

RESUMO

INTRODUCTION: Premonitory urges in Tourette disorder are often linked to altered somatosensory processing, which might include deficits in metacognition. We explored tactile and visual metacognitive ability in people with Tourette disorder and healthy control participants. METHODS: Patients with Tourrete disorder and healthy control participants completed a tactile and a visual metacognitive task. On each trial, participants did a forced choice discrimination and then rated their confidence in their decision. To quantify metacognitive ability, we used m-ratio - a bias-free measure that allows for comparisons across modalities. Correlations between severity of tics and premonitory urges with tactile metacognitive sensitivity were also performed. RESULTS: Metacognitive ability in both tactile and visual domains was comparable between adults with Tourette disorder and healthy controls. We also found no evidence for correlations between tactile metacognitive ability and severity of premonitory urges or tic severity. CONCLUSIONS: Tactile and visual metacognition is not impaired in adults with Tourette disorder. These results question the role of altered tactile metacognition in pathophysiology of tic disorders.


Assuntos
Metacognição , Transtornos de Tique , Tiques , Síndrome de Tourette , Adulto , Estudos de Casos e Controles , Humanos , Índice de Gravidade de Doença , Síndrome de Tourette/complicações
8.
J Exp Psychol Gen ; 151(9): 2083-2091, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35157481

RESUMO

Metacognition is defined as the capacity to monitor and control one's own cognitive processes. Recently, Carpenter and colleagues (2019) reported that metacognitive performance can be improved through adaptive training: healthy participants performed a perceptual discrimination task, and subsequently indicated confidence in their response. Metacognitive performance, defined as how much information these confidence judgments contain about the accuracy of perceptual decisions, was found to increase in a group of participants receiving monetary reward based on their confidence judgments over hundreds of trials and multiple sessions. By contrast, in a control group where only perceptual performance was incentivized, metacognitive performance remained constant across experimental sessions. We identified two possible confounds that may have led to an artificial increase in metacognitive performance, namely the absence of reward in the initial session and an inconsistency between the reward scheme and the instructions about the confidence scale. We thus conducted a preregistered conceptual replication where all sessions were rewarded and where instructions were consistent with the reward scheme. Critically, once these two confounds were corrected we found moderate evidence for an absence of metacognitive training. Our data thus suggest that previous claims about metacognitive training are premature, and calls for more research on how to train individuals to monitor their own performance. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Assuntos
Metacognição , Humanos , Julgamento/fisiologia , Metacognição/fisiologia
9.
Elife ; 112022 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-35049503

RESUMO

Acting in the world is accompanied by a sense of agency, or experience of control over our actions and their outcomes. As humans, we can report on this experience through judgments of agency. These judgments often occur under noisy conditions. We examined the computations underlying judgments of agency, in particular under the influence of sensory noise. Building on previous literature, we studied whether judgments of agency incorporate uncertainty in the same way that confidence judgments do, which would imply that the former share computational mechanisms with metacognitive judgments. In two tasks, participants rated agency, or confidence in a decision about their agency, over a virtual hand that tracked their movements, either synchronously or with a delay and either under high or low noise. We compared the predictions of two computational models to participants' ratings and found that agency ratings, unlike confidence, were best explained by a model involving no estimates of sensory noise. We propose that agency judgments reflect first-order measures of the internal signal, without involving metacognitive computations, challenging the assumed link between the two cognitive processes.


Assuntos
Tomada de Decisões/fisiologia , Julgamento , Metacognição , Percepção/fisiologia , Adolescente , Adulto , Simulação por Computador , Humanos , Adulto Jovem
10.
World J Biol Psychiatry ; 23(3): 201-207, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34231438

RESUMO

OBJECTIVES: The effects of nature on physical and mental health are an emerging topic in empirical research with increasing influence on practical health recommendations. Here we set out to investigate the association between spending time outdoors and brain structural plasticity in conjunctions with self-reported affect. METHODS: We established the Day2day study, which includes an unprecedented in-depth assessment of variability of brain structure in a serial sequence of 40-50 structural magnetic resonance imaging (MRI) acquisitions of each of six young healthy participants for 6-8 months (n = 281 MRI scans in total). RESULTS: A whole-brain analysis revealed that time spent outdoors was positively associated with grey matter volume in the right dorsolateral prefrontal cortex and positive affect, also after controlling for physical activity, fluid intake, free time, and hours of sunshine. CONCLUSIONS: Results indicate remarkable and potentially behaviorally relevant plasticity of cerebral structure within a short time frame driven by the daily time spent outdoors. This is compatible with anecdotal evidence of the health and mood-promoting effects of going for a walk. The study may provide the first evidence for underlying cerebral mechanisms of so-called green prescriptions with possible consequences for future interventions in mental disorders.


Assuntos
Encéfalo , Imageamento por Ressonância Magnética , Humanos , Encéfalo/diagnóstico por imagem , Substância Cinzenta/patologia , Córtex Cerebral/patologia , Estudos Longitudinais
11.
J Exp Psychol Gen ; 150(11): 2208-2229, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-33900097

RESUMO

We can make exquisitely precise movements without the apparent need for conscious monitoring. But can we monitor the low-level movement parameters when prompted? And what are the mechanisms that allow us to monitor our movements? To answer these questions, we designed a semivirtual ball throwing task. On each trial, participants first threw a virtual ball by moving their arm (with or without visual feedback, or replayed from a previous trial) and then made a two-alternative forced choice on the resulting ball trajectory. They then rated their confidence in their decision. We measured metacognitive efficiency using meta-d'/d' and compared it between different informational domains of the first-order task (motor, visuomotor or visual information alone), as well as between two different versions of the task based on different parameters of the movement: proximal (position of the arm) or distal (resulting trajectory of the ball thrown). We found that participants were able to monitor their performance based on distal motor information as well as when proximal information was available. Their metacognitive efficiency was also equally high in conditions with different sources of information available. The analysis of correlations across participants revealed an unexpected result: While metacognitive efficiency correlated between informational domains (which would indicate domain-generality of metacognition), it did not correlate across the different parameters of movement. We discuss possible sources of this discrepancy and argue that specific first-order task demands may play a crucial role in our metacognitive ability and should be considered when making inferences about domain-generality based on correlations. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Assuntos
Metacognição , Humanos , Julgamento , Movimento
12.
eNeuro ; 7(3)2020.
Artigo em Inglês | MEDLINE | ID: mdl-32327471

RESUMO

Confidence judgments are a central tool in metacognition research. In a typical task, participants first perform perceptual (first-order) decisions and then rate their confidence in these decisions. The relationship between confidence and first-order accuracy is taken as a measure of metacognitive performance. Confidence is often assumed to stem from decision-monitoring processes alone, but processes that co-occur with the first-order decision may also play a role in confidence formation. In fact, some recent studies have revealed that directly manipulating motor regions in the brain, or the time of first-order decisions relative to second-order decisions, affects confidence judgments. This finding suggests that confidence could be informed by a readout of reaction times in addition to decision-monitoring processes. To test this possibility, we assessed the contribution of response-related signals to confidence and, in particular, to metacognitive performance (i.e., a measure of the adequacy of these confidence judgments). In human volunteers, we measured the effect of making an overt (vs covert) decision, as well as the effect of pairing an action to the stimulus about which the first-order decision is made. Against our expectations, we found no differences in overall confidence or metacognitive performance when first-order responses were covert as opposed to overt. Further, actions paired to visual stimuli presented led to higher confidence ratings, but did not affect metacognitive performance. These results suggest that confidence ratings do not always incorporate motor information.


Assuntos
Metacognição , Encéfalo , Tomada de Decisões , Humanos , Julgamento , Tempo de Reação
13.
Nat Hum Behav ; 4(3): 317-325, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32015487

RESUMO

Understanding how people rate their confidence is critical for the characterization of a wide range of perceptual, memory, motor and cognitive processes. To enable the continued exploration of these processes, we created a large database of confidence studies spanning a broad set of paradigms, participant populations and fields of study. The data from each study are structured in a common, easy-to-use format that can be easily imported and analysed using multiple software packages. Each dataset is accompanied by an explanation regarding the nature of the collected data. At the time of publication, the Confidence Database (which is available at https://osf.io/s46pr/) contained 145 datasets with data from more than 8,700 participants and almost 4 million trials. The database will remain open for new submissions indefinitely and is expected to continue to grow. Here we show the usefulness of this large collection of datasets in four different analyses that provide precise estimations of several foundational confidence-related effects.


Assuntos
Bases de Dados Factuais/estatística & dados numéricos , Processos Mentais/fisiologia , Metacognição/fisiologia , Psicometria , Análise e Desempenho de Tarefas , Adulto , Comportamento de Escolha/fisiologia , Conjuntos de Dados como Assunto/estatística & dados numéricos , Humanos , Psicometria/instrumentação , Psicometria/estatística & dados numéricos , Tempo de Reação/fisiologia
14.
Dev Cogn Neurosci ; 41: 100738, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31790955

RESUMO

Metacognition plays a pivotal role in human development. The ability to realize that we do not know something, or meta-ignorance, emerges after approximately five years of age. We sought for the brain systems that underlie the developmental emergence of this ability in a preschool sample. Twenty-four children aged between five and six years answered questions under three conditions. In the critical partial knowledge condition, an experimenter first showed two toys to a child, then announced that she would place one of them in a box, out of sight from the child. The experimenter then asked the child whether she knew which toy was in the box. Children who gave consistently correct answers to this question (n = 9) showed greater cortical thickness in a cluster within left medial orbitofrontal cortex than children who did not (n = 15). Further, seed-based functional connectivity analyses of the brain during resting state revealed that this region is functionally connected to the medial orbitofrontal gyrus, posterior cingulate gyrus and precuneus, and mid- and inferior temporal gyri. This finding suggests that the default mode network, critically through its prefrontal regions, supports introspective processing. It leads to the emergence of metacognitive monitoring allowing children to explicitly report their own ignorance.


Assuntos
Cognição/fisiologia , Imageamento por Ressonância Magnética/métodos , Encéfalo/fisiopatologia , Mapeamento Encefálico , Criança , Pré-Escolar , Feminino , Humanos , Masculino
15.
Neuroimage ; 200: 575-589, 2019 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-31108215

RESUMO

Adequate reliability of measurement is a precondition for investigating individual differences and age-related changes in brain structure. One approach to improve reliability is to identify and control for variables that are predictive of within-person variance. To this end, we applied both classical statistical methods and machine-learning-inspired approaches to structural magnetic resonance imaging (sMRI) data of six participants aged 24-31 years gathered at 40-50 occasions distributed over 6-8 months from the Day2day study. We explored the within-person associations between 21 variables covering physiological, affective, social, and environmental factors and global measures of brain volume estimated by VBM8 and FreeSurfer. Time since the first scan was reliably associated with Freesurfer estimates of grey matter volume and total cortex volume, in line with a rate of annual brain volume shrinkage of about 1 percent. For the same two structural measures, time of day also emerged as a reliable predictor with an estimated diurnal volume decrease of, again, about 1 percent. Furthermore, we found weak predictive evidence for the number of steps taken on the previous day and testosterone levels. The results suggest a need to control for time-of-day effects in sMRI research. In particular, we recommend that researchers interested in assessing longitudinal change in the context of intervention studies or longitudinal panels make sure that, at each measurement occasion, (a) a given participant is measured at the same time of day; (b) all participants are measured at about the same time of day. Furthermore, the potential effects of physical activity, including moderate amounts of aerobic exercise, and testosterone levels on MRI-based measures of brain structure deserve further investigation.


Assuntos
Envelhecimento , Variação Biológica Individual , Encéfalo/anatomia & histologia , Aprendizado de Máquina , Imageamento por Ressonância Magnética , Neuroimagem , Adulto , Encéfalo/diagnóstico por imagem , Feminino , Humanos , Individualidade , Estudos Longitudinais , Imageamento por Ressonância Magnética/normas , Masculino , Neuroimagem/normas , Reprodutibilidade dos Testes , Fatores de Tempo , Adulto Jovem
16.
Psychol Res ; 83(3): 613-630, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29273969

RESUMO

Humans can exploit recognition memory as a simple cue for judgment. The utility of recognition depends on the interplay with the environment, particularly on its predictive power (validity) in a domain. It is, therefore, an important question whether people are sensitive to differences in recognition validity between domains. Strategic, intra-individual changes in the reliance on recognition have not been investigated so far. The present study fills this gap by scrutinizing within-person changes in using a frugal strategy, the recognition heuristic (RH), across two task domains that differed in recognition validity. The results showed adaptive changes in the reliance on recognition between domains. However, these changes were neither associated with the individual recognition validities nor with corresponding changes in these validities. These findings support a domain-adaptivity explanation, suggesting that people have broader intuitions about the usefulness of recognition across different domains that are nonetheless sufficiently robust for adaptive decision making. The analysis of metacognitive confidence reports mirrored and extended these results. Like RH use, confidence ratings covaried with task domain, but not with individual recognition validities. The changes in confidence suggest that people may have metacognitive access to information about global differences between task domains, but not to individual cue validities.


Assuntos
Adaptação Psicológica/fisiologia , Tomada de Decisões/fisiologia , Heurística , Julgamento/fisiologia , Memória/fisiologia , Reconhecimento Psicológico/fisiologia , Adulto , Idoso , Feminino , Humanos , Individualidade , Masculino , Pessoa de Meia-Idade , Adulto Jovem
17.
J Neurosci ; 38(2): 263-277, 2018 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-28916521

RESUMO

Human metacognition, or the capacity to introspect on one's own mental states, has been mostly characterized through confidence reports in visual tasks. A pressing question is to what extent results from visual studies generalize to other domains. Answering this question allows determining whether metacognition operates through shared, supramodal mechanisms or through idiosyncratic, modality-specific mechanisms. Here, we report three new lines of evidence for decisional and postdecisional mechanisms arguing for the supramodality of metacognition. First, metacognitive efficiency correlated among auditory, tactile, visual, and audiovisual tasks. Second, confidence in an audiovisual task was best modeled using supramodal formats based on integrated representations of auditory and visual signals. Third, confidence in correct responses involved similar electrophysiological markers for visual and audiovisual tasks that are associated with motor preparation preceding the perceptual judgment. We conclude that the supramodality of metacognition relies on supramodal confidence estimates and decisional signals that are shared across sensory modalities.SIGNIFICANCE STATEMENT Metacognitive monitoring is the capacity to access, report, and regulate one's own mental states. In perception, this allows rating our confidence in what we have seen, heard, or touched. Although metacognitive monitoring can operate on different cognitive domains, we ignore whether it involves a single supramodal mechanism common to multiple cognitive domains or modality-specific mechanisms idiosyncratic to each domain. Here, we bring evidence in favor of the supramodality hypothesis by showing that participants with high metacognitive performance in one modality are likely to perform well in other modalities. Based on computational modeling and electrophysiology, we propose that supramodality can be explained by the existence of supramodal confidence estimates and by the influence of decisional cues on confidence estimates.


Assuntos
Encéfalo/fisiologia , Metacognição/fisiologia , Modelos Neurológicos , Eletroencefalografia , Feminino , Humanos , Masculino , Percepção/fisiologia , Adulto Jovem
18.
BMC Neurosci ; 18(1): 65, 2017 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-28836958

RESUMO

BACKGROUND: Most studies of brain structure and function, and their relationships to cognitive ability, have relied on inter-individual variability in magnetic resonance (MR) images. Intra-individual variability is often ignored or implicitly assumed to be equivalent to the former. Testing this assumption empirically by collecting enough data on single individuals is cumbersome and costly. We collected a dataset of multiple MR sequences and behavioural covariates to quantify and characterize intra-individual variability in MR images for multiple individuals. METHODS AND DESIGN: Eight participants volunteered to undergo brain scanning 40-50 times over the course of 6 months. Six participants completed the full set of sessions. T1-weighted, T2*-weighted during rest, T2-weighted high-resolution hippocampus, diffusion-tensor imaging (DTI), and proton magnetic resonance spectroscopy sequences were collected, along with a rich set of stable and time-varying physical, behavioural and physiological variables. Participants did not change their lifestyle or participated in any training programs during the period of data collection. CONCLUSION: This imaging dataset provides a large number of MRI scans in different modalities for six participants. It enables the analysis of the time course and correlates of intra-individual variability in structural, chemical, and functional aspects of the human brain.


Assuntos
Encéfalo/patologia , Encéfalo/fisiologia , Imagem de Tensor de Difusão , Imageamento por Ressonância Magnética , Adulto , Feminino , Humanos , Individualidade , Imageamento por Ressonância Magnética/métodos , Masculino , Descanso/fisiologia , Fatores de Tempo , Adulto Jovem
19.
Neuroimage ; 157: 250-262, 2017 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-28599964

RESUMO

The functional architecture of spontaneous BOLD fluctuations has been characterized in detail by numerous studies, demonstrating its potential relevance as a biomarker. However, the systematic investigation of its consistency is still in its infancy. Here, we analyze within- and between-subject variability and test-retest reliability of resting-state functional connectivity (FC) in a unique data set comprising multiple fMRI scans (42) from 5 subjects, and 50 single scans from 50 subjects. We adopt a statistical framework that enables us to identify different sources of variability in FC. We show that the low reliability of single links can be significantly improved by using multiple scans per subject. Moreover, in contrast to earlier studies, we show that spatial heterogeneity in FC reliability is not significant. Finally, we demonstrate that despite the low reliability of individual links, the information carried by the whole-brain FC matrix is robust and can be used as a functional fingerprint to identify individual subjects from the population.


Assuntos
Encéfalo/diagnóstico por imagem , Conectoma/normas , Imageamento por Ressonância Magnética/normas , Adolescente , Adulto , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Adulto Jovem
20.
Front Hum Neurosci ; 11: 301, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28649194

RESUMO

Ambiguous images such as Rubin's vase-face can be interpreted in at least two different ways. These interpretations are typically taken to be mutually exclusive, and ambiguous images have thus served as models of perceptual competition. Here, we present data that challenges this view. In an online survey, we found that a large proportion of people within the general population reported that the two percepts were not competing but could be perceived simultaneously. Of those who reported that they could see both percepts simultaneously, we invited 17 participants to take part in a functional magnetic resonance imaging (fMRI) experiment. In the scanner, participants saw images that could be interpreted as either a landscape or a face and reported at every point in time whether they perceived predominantly the face, the landscape, or both simultaneously. We explored behavioral and neurophysiological (with fMRI) correlates of the reported subjective experience of entertaining two percepts simultaneously by comparing them to those of the simple percepts (i.e., face or landscape). First, by comparing percept durations, we found that the simultaneous state was as stable as the two other percepts. Second, by measuring blood-oxygen-level-dependent (BOLD) signal levels within the fusiform face area (FFA), occipital face area (OFA) and parahippocampal place area (PPA), we found evidence from objective data that confirmed the subjective reports. While the results in FFA and OFA were not conclusive, in PPA, BOLD signal levels during subjective reports of perceiving both a landscape and a face were lower than the BOLD signal levels associated with reports of perceiving a landscape (and, in turn, reports of seeing a landscape were associated with greater BOLD signal levels than reports of seeing a face, thus suggesting that BOLD signal levels in PPA are a valid correlate of subjective experience in this task). In sum, the objective measures suggest that entertaining two percepts simultaneously in mind can be regarded as a distinct (mixed) perceptual state. We argue with these results that a more central role of subjective report in cognitive neuroscience is sometimes warranted.

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