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1.
Hum Brain Mapp ; 45(6): e26687, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38651629

RESUMO

The unprecedented increase in life expectancy presents a unique opportunity and the necessity to explore both healthy and pathological aspects of ageing. Electroencephalography (EEG) has been widely used to identify neuromarkers of cognitive ageing due to its affordability and richness in information. However, despite the growing volume of data and methodological advancements, the abundance of contradictory and non-reproducible findings has hindered clinical translation. To address these challenges, our study introduces a comprehensive workflow expanding on previous EEG studies and investigates various static and dynamic power and connectivity estimates as potential neuromarkers of cognitive ageing in a large dataset. We also assess the robustness of our findings by testing their susceptibility to band specification. Finally, we characterise our findings using functionally annotated brain networks to improve their interpretability and multi-modal integration. Our analysis demonstrates the effect of methodological choices on findings and that dynamic rather than static neuromarkers are not only more sensitive but also more robust. Consequently, they emerge as strong candidates for cognitive ageing neuromarkers. Moreover, we were able to replicate the most established EEG findings in cognitive ageing, such as alpha oscillation slowing, increased beta power, reduced reactivity across multiple bands, and decreased delta connectivity. Additionally, when considering individual variations in the alpha band, we clarified that alpha power is characteristic of memory performance rather than ageing, highlighting its potential as a neuromarker for cognitive ageing. Finally, our approach using functionally annotated source reconstruction allowed us to provide insights into domain-specific electrophysiological mechanisms underlying memory performance and ageing. HIGHLIGHTS: We provide an open and reproducible pipeline with a comprehensive workflow to investigate static and dynamic EEG neuromarkers. Neuromarkers related to neural dynamics are sensitive and robust. Individualised alpha power characterises cognitive performance rather than ageing. Functional annotation allows cross-modal interpretation of EEG findings.


Assuntos
Eletroencefalografia , Envelhecimento Saudável , Humanos , Eletroencefalografia/métodos , Envelhecimento Saudável/fisiologia , Idoso , Masculino , Adulto , Feminino , Pessoa de Meia-Idade , Adulto Jovem , Envelhecimento Cognitivo/fisiologia , Biomarcadores , Rede Nervosa/fisiologia , Ondas Encefálicas/fisiologia , Ritmo alfa/fisiologia , Memória/fisiologia , Envelhecimento/fisiologia , Idoso de 80 Anos ou mais
2.
Neuroimage ; 237: 118207, 2021 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-34048901

RESUMO

Real-time fMRI neurofeedback is an increasingly popular neuroimaging technique that allows an individual to gain control over his/her own brain signals, which can lead to improvements in behavior in healthy participants as well as to improvements of clinical symptoms in patient populations. However, a considerably large ratio of participants undergoing neurofeedback training do not learn to control their own brain signals and, consequently, do not benefit from neurofeedback interventions, which limits clinical efficacy of neurofeedback interventions. As neurofeedback success varies between studies and participants, it is important to identify factors that might influence neurofeedback success. Here, for the first time, we employed a big data machine learning approach to investigate the influence of 20 different design-specific (e.g. activity vs. connectivity feedback), region of interest-specific (e.g. cortical vs. subcortical) and subject-specific factors (e.g. age) on neurofeedback performance and improvement in 608 participants from 28 independent experiments. With a classification accuracy of 60% (considerably different from chance level), we identified two factors that significantly influenced neurofeedback performance: Both the inclusion of a pre-training no-feedback run before neurofeedback training and neurofeedback training of patients as compared to healthy participants were associated with better neurofeedback performance. The positive effect of pre-training no-feedback runs on neurofeedback performance might be due to the familiarization of participants with the neurofeedback setup and the mental imagery task before neurofeedback training runs. Better performance of patients as compared to healthy participants might be driven by higher motivation of patients, higher ranges for the regulation of dysfunctional brain signals, or a more extensive piloting of clinical experimental paradigms. Due to the large heterogeneity of our dataset, these findings likely generalize across neurofeedback studies, thus providing guidance for designing more efficient neurofeedback studies specifically for improving clinical neurofeedback-based interventions. To facilitate the development of data-driven recommendations for specific design details and subpopulations the field would benefit from stronger engagement in open science research practices and data sharing.


Assuntos
Neuroimagem Funcional , Aprendizado de Máquina , Imageamento por Ressonância Magnética , Neurorretroalimentação , Adulto , Humanos
3.
Hum Brain Mapp ; 41(14): 3839-3854, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32729652

RESUMO

Neurofeedback training has been shown to influence behavior in healthy participants as well as to alleviate clinical symptoms in neurological, psychosomatic, and psychiatric patient populations. However, many real-time fMRI neurofeedback studies report large inter-individual differences in learning success. The factors that cause this vast variability between participants remain unknown and their identification could enhance treatment success. Thus, here we employed a meta-analytic approach including data from 24 different neurofeedback studies with a total of 401 participants, including 140 patients, to determine whether levels of activity in target brain regions during pretraining functional localizer or no-feedback runs (i.e., self-regulation in the absence of neurofeedback) could predict neurofeedback learning success. We observed a slightly positive correlation between pretraining activity levels during a functional localizer run and neurofeedback learning success, but we were not able to identify common brain-based success predictors across our diverse cohort of studies. Therefore, advances need to be made in finding robust models and measures of general neurofeedback learning, and in increasing the current study database to allow for investigating further factors that might influence neurofeedback learning.


Assuntos
Mapeamento Encefálico , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Imageamento por Ressonância Magnética , Neurorretroalimentação/fisiologia , Prática Psicológica , Adulto , Humanos , Prognóstico
4.
PLoS Comput Biol ; 13(3): e1005209, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28278228

RESUMO

The rate of progress in human neurosciences is limited by the inability to easily apply a wide range of analysis methods to the plethora of different datasets acquired in labs around the world. In this work, we introduce a framework for creating, testing, versioning and archiving portable applications for analyzing neuroimaging data organized and described in compliance with the Brain Imaging Data Structure (BIDS). The portability of these applications (BIDS Apps) is achieved by using container technologies that encapsulate all binary and other dependencies in one convenient package. BIDS Apps run on all three major operating systems with no need for complex setup and configuration and thanks to the comprehensiveness of the BIDS standard they require little manual user input. Previous containerized data processing solutions were limited to single user environments and not compatible with most multi-tenant High Performance Computing systems. BIDS Apps overcome this limitation by taking advantage of the Singularity container technology. As a proof of concept, this work is accompanied by 22 ready to use BIDS Apps, packaging a diverse set of commonly used neuroimaging algorithms.


Assuntos
Encéfalo/anatomia & histologia , Interpretação de Imagem Assistida por Computador/métodos , Neuroimagem/métodos , Sistemas de Informação em Radiologia/organização & administração , Software , Interface Usuário-Computador , Algoritmos , Humanos , Imageamento por Ressonância Magnética/métodos
5.
Neuroimage ; 144(Pt B): 262-269, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-26375206

RESUMO

This paper describes the data repository for the Cambridge Centre for Ageing and Neuroscience (Cam-CAN) initial study cohort. The Cam-CAN Stage 2 repository contains multi-modal (MRI, MEG, and cognitive-behavioural) data from a large (approximately N=700), cross-sectional adult lifespan (18-87years old) population-based sample. The study is designed to characterise age-related changes in cognition and brain structure and function, and to uncover the neurocognitive mechanisms that support healthy cognitive ageing. The database contains raw and preprocessed structural MRI, functional MRI (active tasks and resting state), and MEG data (active tasks and resting state), as well as derived scores from cognitive behavioural experiments spanning five broad domains (attention, emotion, action, language, and memory), and demographic and neuropsychological data. The dataset thus provides a depth of neurocognitive phenotyping that is currently unparalleled, enabling integrative analyses of age-related changes in brain structure, brain function, and cognition, and providing a testbed for novel analyses of multi-modal neuroimaging data.


Assuntos
Envelhecimento/fisiologia , Encéfalo , Cognição/fisiologia , Bases de Dados Factuais , Neuroimagem Funcional/estatística & dados numéricos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Magnetoencefalografia/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Encéfalo/anatomia & histologia , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neurociências/estatística & dados numéricos , Adulto Jovem
6.
Hum Brain Mapp ; 37(1): 230-53, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26493275

RESUMO

In humans, both language and fine motor skills are associated with left-hemisphere specialization, whereas visuospatial skills are associated with right-hemisphere specialization. Individuals with autism spectrum conditions (ASC) show a profile of deficits and strengths that involves these lateralized cognitive functions. Here we test the hypothesis that regions implicated in these functions are atypically rightward lateralized in individuals with ASC and, that such atypicality is associated with functional performance. Participants included 67 male, right-handed adults with ASC and 69 age- and IQ-matched neurotypical males. We assessed group differences in structural asymmetries in cortical regions of interest with voxel-based analysis of grey matter volumes, followed by correlational analyses with measures of language, motor and visuospatial skills. We found stronger rightward lateralization within the inferior parietal lobule and reduced leftward lateralization extending along the auditory cortex comprising the planum temporale, Heschl's gyrus, posterior supramarginal gyrus, and parietal operculum, which was more pronounced in ASC individuals with delayed language onset compared to those without. Planned correlational analyses showed that for individuals with ASC, reduced leftward asymmetry in the auditory region was associated with more childhood social reciprocity difficulties. We conclude that atypical cerebral structural asymmetry is a potential candidate neurophenotype of ASC.


Assuntos
Transtorno Autístico/complicações , Transtorno Autístico/patologia , Córtex Cerebral/patologia , Lateralidade Funcional/fisiologia , Transtornos do Desenvolvimento da Linguagem/etiologia , Estimulação Acústica , Adolescente , Adulto , Mapeamento Encefálico , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/etiologia , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Estimulação Luminosa , Escalas de Graduação Psiquiátrica , Percepção Espacial , Estatística como Assunto , Adulto Jovem
7.
J Opt Soc Am A Opt Image Sci Vis ; 33(3): A53-64, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26974942

RESUMO

Psychophysical sensitivity to red-green chromatic modulation decreases with visual eccentricity, compared to sensitivity to luminance modulation, even after appropriate stimulus scaling. This is likely to occur at a central, rather than a retinal, site. Blood-oxygenation-level-dependent (BOLD) functional magnetic resonance imaging (fMRI) responses to stimuli designed to separately stimulate different afferent channels' [red-green, luminance, and short-wavelength (S)-cone] circular gratings were recorded as a function of visual eccentricity (±10 deg) and spatial frequency (SF) in human primary visual cortex (V1) and further visual areas (V2v, V3v). In V1, the SF tuning of BOLD fMRI responses became coarser with eccentricity. For red-green and luminance gratings, similar SF tuning curves were found at all eccentricities. The pattern for S-cone modulation differed, with SF tuning changing more slowly with eccentricity than for the other two modalities. This may be due to the different retinal distribution with eccentricity of this receptor type. A similar pattern held in V2v and V3v. This would suggest that transformation or spatial filtering of the chromatic (red-green) signal occurs beyond these areas.


Assuntos
Percepção de Cores/fisiologia , Imageamento por Ressonância Magnética , Percepção Espacial/fisiologia , Campos Visuais/fisiologia , Adulto , Sensibilidades de Contraste , Feminino , Humanos , Masculino , Estimulação Luminosa , Psicofísica
8.
Hum Brain Mapp ; 36(2): 577-90, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25324040

RESUMO

Resting-state studies conducted with stroke patients are scarce. The study of brain activity and connectivity at rest provides a unique opportunity for the investigation of brain rewiring after stroke and plasticity changes. This study sought to identify dynamic changes in the functional organization of the default mode network (DMN) of stroke patients at three months after stroke. Eleven patients (eight male and three female; age range: 48-72) with right cortical and subcortical ischemic infarctions and 17 controls (eleven males and six females; age range: 57-69) were assessed by neurological and neuropsychological examinations and scanned with resting-state functional magnetic ressonance imaging. First, we explored group differences in functional activity within the DMN by means of probabilistic independent component analysis followed by a dual regression approach. Second, we estimated functional connectivity between 11 DMN nodes both locally by means of seed-based connectivity analysis, as well as globally by means of graph-computation analysis. We found that patients had greater DMN activity in the left precuneus and the left anterior cingulate gyrus when compared with healthy controls (P < 0.05 family-wise error corrected). Seed-based connectivity analysis showed that stroke patients had significant impairment (P = 0.014; threshold = 2.00) in the connectivity between the following five DMN nodes: left superior frontal gyrus (lSFG) and posterior cingulate cortex (t = 2.01); left parahippocampal gyrus and right superior frontal gyrus (t = 2.11); left parahippocampal gyrus and lSFG (t = 2.39); right parietal and lSFG (t = 2.29). Finally, mean path length obtained from graph-computation analysis showed positive correlations with semantic fluency test (r(s) = 0.454; P = 0.023), phonetic fluency test (r(s) = 0.523; P = 0.007) and the mini mental state examination (r(s) = 0.528; P = 0.007). In conclusion, the ability to regulate activity of the DMN appears to be a central part of normal brain function in stroke patients. Our study expands the understanding of the changes occurring in the brain after stroke providing a new avenue for investigating lesion-induced network plasticity.


Assuntos
Isquemia Encefálica/fisiopatologia , Isquemia Encefálica/psicologia , Encéfalo/fisiopatologia , Acidente Vascular Cerebral/fisiopatologia , Acidente Vascular Cerebral/psicologia , Adulto , Idoso , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Vias Neurais/fisiopatologia , Testes Neuropsicológicos , Descanso , Processamento de Sinais Assistido por Computador
9.
ArXiv ; 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-37744469

RESUMO

The Brain Imaging Data Structure (BIDS) is a community-driven standard for the organization of data and metadata from a growing range of neuroscience modalities. This paper is meant as a history of how the standard has developed and grown over time. We outline the principles behind the project, the mechanisms by which it has been extended, and some of the challenges being addressed as it evolves. We also discuss the lessons learned through the project, with the aim of enabling researchers in other domains to learn from the success of BIDS.

10.
Brain Cogn ; 82(3): 319-28, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23792788

RESUMO

Most people are left-hemisphere dominant for language. However the neuroanatomy of language lateralization is not fully understood. By combining functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), we studied whether language lateralization is associated with cerebral white-matter (WM) microstructure. Sixteen healthy, left-handed women aged 20-25 were included in the study. Left-handers were targeted in order to increase the chances of involving subjects with atypical language lateralization. Language lateralization was determined by fMRI using a verbal fluency paradigm. Tract-based spatial statistics analysis of DTI data was applied to test for WM microstructural correlates of language lateralization across the whole brain. Fractional anisotropy and mean diffusivity were used as indicators of WM microstructural organization. Right-hemispheric language dominance was associated with reduced microstructural integrity of the left superior longitudinal fasciculus and left-sided parietal lobe WM. In left-handed women, reduced integrity of the left-sided language related tracts may be closely linked to the development of right hemispheric language dominance. Our results may offer new insights into language lateralization and structure-function relationships in human language system.


Assuntos
Encéfalo/citologia , Encéfalo/fisiologia , Lateralidade Funcional/fisiologia , Idioma , Adulto , Imagem de Tensor de Difusão , Feminino , Humanos , Imageamento por Ressonância Magnética , Adulto Jovem
11.
Malays J Med Sci ; 20(5): 5-15, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24643368

RESUMO

Neurofeedback (NFB) allows subjects to learn how to volitionally influence the neuronal activation in the brain by employing real-time neural activity as feedback. NFB has already been performed with electroencephalography (EEG) since the 1970s. Functional MRI (fMRI), offering a higher spatial resolution, has further increased the spatial specificity. In this paper, we briefly outline the general principles behind NFB, the implementation of fMRI-NFB studies, the feasibility of fMRI-NFB, and the application of NFB as a supplementary therapy tool.

12.
J Affect Disord ; 313: 167-176, 2022 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-35792299

RESUMO

Depression is the leading cause of disability worldwide, with prevalence rates rising. Despite the scale of the problem, available pharmacological and psychological interventions only have limited efficacy. The National Institute of Health's Science of Behaviour Change framework proposes to address this issue by capitalising on insights from basic science to identify mechanisms that can be targeted by novel interventions. The current study evaluated the potential of a computerized programme aimed at improving affective control, a mechanistic target involved in both risk and maintenance of depression. In a first phase the cognitive profiles of 48 depressed individuals (mean age: 39 years, 75 % female) were compared to cognitive functioning in 16 never-depressed individuals (mean age: 31 years, 56 % female). The sole index of functioning that differed between diagnostic groups was reaction time across negative and positively valanced trials on an affective Stroop task (d = 0.58). This index was then used to evaluate an affective control training (AffeCT) against a placebo training. Results showed no significant changes on tasks that showed no differences with never-depressed individuals in Phase I. However, compared to placebo training, AffeCT led to significantly greater improvement in the target index, affective Stroop performance (d = 1.17). Importantly, AffeCT led to greater reductions in negative affect as measured by the Positive Affect and Negative Affect Schedule compared to the placebo training (d = 0.98). This proof-of-concept study shows promising benefits of AffeCT on depressed individuals' affect, but not depressive symptoms. It further supports the utility of the Science of Behaviour Change framework, highlighting the need for determining meaningful assays of target mechanisms when evaluating novel interventions.


Assuntos
Afeto , Cognição , Depressão , Adulto , Feminino , Humanos , Masculino , Tempo de Reação , Teste de Stroop
13.
Neuroinformatics ; 20(4): 897-917, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35297018

RESUMO

Real-time quality assessment (rtQA) of functional magnetic resonance imaging (fMRI) based on blood oxygen level-dependent (BOLD) signal changes is critical for neuroimaging research and clinical applications. The losses of BOLD sensitivity because of different types of technical and physiological noise remain major sources of fMRI artifacts. Due to difficulty of subjective visual perception of image distortions during data acquisitions, a comprehensive automatic rtQA is needed. To facilitate rapid rtQA of fMRI data, we applied real-time and recursive quality assessment methods to whole-brain fMRI volumes, as well as time-series of target brain areas and resting-state networks. We estimated recursive temporal signal-to-noise ratio (rtSNR) and contrast-to-noise ratio (rtCNR), and real-time head motion parameters by a framewise rigid-body transformation (translations and rotations) using the conventional current to template volume registration. In addition, we derived real-time framewise (FD) and micro (MD) displacements based on head motion parameters and evaluated the temporal derivative of root mean squared variance over voxels (DVARS). For monitoring time-series of target regions and networks, we estimated the number of spikes and amount of filtered noise by means of a modified Kalman filter. Finally, we applied the incremental general linear modeling (GLM) to evaluate real-time contributions of nuisance regressors (linear trend and head motion). Proposed rtQA was demonstrated in real-time fMRI neurofeedback runs without and with excessive head motion and real-time simulations of neurofeedback and resting-state fMRI data. The rtQA was implemented as an extension of the open-source OpenNFT software written in Python, MATLAB and C++ for neurofeedback, task-based, and resting-state paradigms. We also developed a general Python library to unify real-time fMRI data processing and neurofeedback applications. Flexible estimation and visualization of rtQA facilitates efficient rtQA of fMRI data and helps the robustness of fMRI acquisitions by means of substantiating decisions about the necessity of the interruption and re-start of the experiment and increasing the confidence in neural estimates.


Assuntos
Mapeamento Encefálico , Neurorretroalimentação , Mapeamento Encefálico/métodos , Imageamento por Ressonância Magnética/métodos , Artefatos , Neurorretroalimentação/métodos , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Processamento de Imagem Assistida por Computador/métodos
14.
Sci Data ; 9(1): 630, 2022 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-36253426

RESUMO

Magnetic Resonance Imaging (MRI) provides a unique opportunity to investigate neural changes in healthy and clinical conditions. Its large inherent susceptibility to motion, however, often confounds the measurement. Approaches assessing, correcting, or preventing motion corruption of MRI measurements are under active development, and such efforts can greatly benefit from carefully controlled datasets. We present a unique dataset of structural brain MRI images collected from 148 healthy adults which includes both motion-free and motion-affected data acquired from the same participants. This matched dataset allows direct evaluation of motion artefacts, their impact on derived data, and testing approaches to correct for them. Our dataset further stands out by containing images with different levels of motion artefacts from the same participants, is enriched with expert scoring characterizing the image quality from a clinical point of view and is also complemented with standard image quality metrics obtained from MRIQC. The goal of the dataset is to raise awareness of the issue and provide a useful resource to assess and improve current motion correction approaches.


Assuntos
Artefatos , Imageamento por Ressonância Magnética , Adulto , Humanos , Encéfalo/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Movimento (Física) , Neuroimagem
15.
Sci Data ; 9(1): 517, 2022 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-36002444

RESUMO

The Brain Imaging Data Structure (BIDS) established community consensus on the organization of data and metadata for several neuroimaging modalities. Traditionally, BIDS had a strong focus on functional magnetic resonance imaging (MRI) datasets and lacked guidance on how to store multimodal structural MRI datasets. Here, we present and describe the BIDS Extension Proposal 001 (BEP001), which adds a range of quantitative MRI (qMRI) applications to the BIDS. In general, the aim of qMRI is to characterize brain microstructure by quantifying the physical MR parameters of the tissue via computational, biophysical models. By proposing this new standard, we envision standardization of qMRI through multicenter dissemination of interoperable datasets. This way, BIDS can act as a catalyst of convergence between qMRI methods development and application-driven neuroimaging studies that can help develop quantitative biomarkers for neural tissue characterization. In conclusion, this BIDS extension offers a common ground for developers to exchange novel imaging data and tools, reducing the entrance barrier for qMRI in the field of neuroimaging.


Assuntos
Encéfalo , Imageamento por Ressonância Magnética , Biomarcadores , Encéfalo/diagnóstico por imagem , Neuroimagem/métodos
16.
Nat Protoc ; 17(3): 596-617, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35121855

RESUMO

Low-intensity transcranial electrical stimulation (tES), including alternating or direct current stimulation, applies weak electrical stimulation to modulate the activity of brain circuits. Integration of tES with concurrent functional MRI (fMRI) allows for the mapping of neural activity during neuromodulation, supporting causal studies of both brain function and tES effects. Methodological aspects of tES-fMRI studies underpin the results, and reporting them in appropriate detail is required for reproducibility and interpretability. Despite the growing number of published reports, there are no consensus-based checklists for disclosing methodological details of concurrent tES-fMRI studies. The objective of this work was to develop a consensus-based checklist of reporting standards for concurrent tES-fMRI studies to support methodological rigor, transparency and reproducibility (ContES checklist). A two-phase Delphi consensus process was conducted by a steering committee (SC) of 13 members and 49 expert panelists through the International Network of the tES-fMRI Consortium. The process began with a circulation of a preliminary checklist of essential items and additional recommendations, developed by the SC on the basis of a systematic review of 57 concurrent tES-fMRI studies. Contributors were then invited to suggest revisions or additions to the initial checklist. After the revision phase, contributors rated the importance of the 17 essential items and 42 additional recommendations in the final checklist. The state of methodological transparency within the 57 reviewed concurrent tES-fMRI studies was then assessed by using the checklist. Experts refined the checklist through the revision and rating phases, leading to a checklist with three categories of essential items and additional recommendations: (i) technological factors, (ii) safety and noise tests and (iii) methodological factors. The level of reporting of checklist items varied among the 57 concurrent tES-fMRI papers, ranging from 24% to 76%. On average, 53% of checklist items were reported in a given article. In conclusion, use of the ContES checklist is expected to enhance the methodological reporting quality of future concurrent tES-fMRI studies and increase methodological transparency and reproducibility.


Assuntos
Lista de Checagem , Estimulação Transcraniana por Corrente Contínua , Consenso , Imageamento por Ressonância Magnética , Reprodutibilidade dos Testes
17.
Eur Radiol ; 21(11): 2369-87, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21710268

RESUMO

OBJECTIVES: Current thresholding strategies for the analysis of functional MRI (fMRI) datasets may suffer from specific limitations (e.g. with respect to the required smoothness) or lead to reduced performance for a low signal-to-noise ratio (SNR). Although a previously proposed two-threshold (TT) method offers a promising solution to these problems, the use of preset settings limits its performance. This work presents an optimised TT approach that estimates the required parameters in an iterative manner. METHODS: The iterative TT (iTT) method is compared with the original TT method, as well as other established voxel-based and cluster-based thresholding approaches and spatial mixture modelling (SMM) for both simulated data and fMRI of a hometown walking task at different experimental settings (spatial resolution, filtering and SNR). RESULTS: In general, the iTT method presents with remarkable sensitivity and good specificity that outperforms all conventional approaches tested except for SMM in a few cases. This also holds true for challenging conditions such as high spatial resolution, the absence of filtering, high noise level, or a low number of task repetitions. CONCLUSION: Thus, iTT emerges as a good candidate for both scientific fMRI studies at high spatial resolution and more routine applications for clinical purposes.


Assuntos
Mapeamento Encefálico/métodos , Encéfalo/patologia , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Adulto , Algoritmos , Simulação por Computador , Epilepsia do Lobo Temporal/diagnóstico , Epilepsia do Lobo Temporal/patologia , Humanos , Masculino , Modelos Estatísticos , Curva ROC , Caminhada
18.
J Vis ; 11(8)2011 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-21752924

RESUMO

Psychophysical sensitivity to isoluminant chromatic modulation declines at temporal frequencies beyond 4 Hz, whereas chromatically opponent cells of the afferent visual pathway (long- to middle-wavelength (L-M) cone-opponent or short-wavelength (S) cone cells) show responses at much higher temporal frequencies, indicating a central limitation in temporal processing capacity. Here, we sought to localize this limit in cortical retinotopic visual areas. We used fMRI to investigate responses of lateral geniculate nucleus and cortical visual areas in humans to isoluminant chromatic modulation as a function of temporal frequency (2-12 Hz). Our results suggest that L-M cone-opponent and S-cone signals are processed in LGN up to 12 Hz. In all visual areas except MT (middle temporal) and V3a, S-cone responses declined steeply with temporal frequency, implying that psychophysical sensitivity loss to blue-yellow modulation might occur early within these areas. While V1 showed robust L-M responses up to 12 Hz, there was a progressive falloff of responses with temporal frequency as information is transferred from V1 to higher areas (V2, V3, and V4), suggesting that, in humans, temporal limitation in perception of red-green chromatic modulation likely results from limited processing capacity of higher ventral extrastriate areas.


Assuntos
Percepção de Cores/fisiologia , Visão de Cores/fisiologia , Imageamento por Ressonância Magnética , Córtex Visual/fisiologia , Adulto , Mapeamento Encefálico/métodos , Análise por Conglomerados , Cor , Feminino , Corpos Geniculados/fisiologia , Humanos , Masculino , Estimulação Luminosa/métodos , Psicofísica/métodos , Células Fotorreceptoras Retinianas Cones/fisiologia , Adulto Jovem
19.
Front Hum Neurosci ; 15: 645048, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34113243

RESUMO

Neurofeedback (NF) is a complex learning scenario, as the task consists of trying out mental strategies while processing a feedback signal that signifies activation in the brain area to be self-regulated and acts as a potential reward signal. In an attempt to dissect these subcomponents, we obtained whole-brain networks associated with efficient self-regulation in two paradigms: parallel, where the task was performed concurrently, combining feedback with strategy execution; and serial, where the task was performed consecutively, separating feedback processing from strategy execution. Twenty participants attempted to control their anterior midcingulate cortex (aMCC) using functional magnetic resonance imaging (fMRI) NF in 18 sessions over 2 weeks, using cognitive and emotional mental strategies. We analyzed whole-brain fMRI activations in the NF training runs with the largest aMCC activation for the serial and parallel paradigms. The equal length of the strategy execution and the feedback processing periods in the serial paradigm allows a description of the two task subcomponents with equal power. The resulting activation maps were spatially correlated with functionally annotated intrinsic connectivity brain maps (BMs). Brain activation in the parallel condition correlates with the basal ganglia (BG) network, the cingulo-opercular network (CON), and the frontoparietal control network (FPCN); brain activation in the serial strategy execution condition with the default mode network (DMN), the FPCN, and the visual processing network; while brain activation in the serial feedback processing condition predominantly with the CON, the DMN, and the FPCN. Additional comparisons indicate that BG activation is characteristic to the parallel paradigm, while supramarginal gyrus (SMG) and superior temporal gyrus (STG) activations are characteristic to the serial paradigm. The multifaceted view of the subcomponents allows describing the cognitive processes associated with strategy execution and feedback processing independently in the serial feedback task and as combined processes in the multitasking scenario of the conventional parallel feedback task.

20.
Gigascience ; 10(8)2021 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-34414422

RESUMO

As the global health crisis unfolded, many academic conferences moved online in 2020. This move has been hailed as a positive step towards inclusivity in its attenuation of economic, physical, and legal barriers and effectively enabled many individuals from groups that have traditionally been underrepresented to join and participate. A number of studies have outlined how moving online made it possible to gather a more global community and has increased opportunities for individuals with various constraints, e.g., caregiving responsibilities. Yet, the mere existence of online conferences is no guarantee that everyone can attend and participate meaningfully. In fact, many elements of an online conference are still significant barriers to truly diverse participation: the tools used can be inaccessible for some individuals; the scheduling choices can favour some geographical locations; the set-up of the conference can provide more visibility to well-established researchers and reduce opportunities for early-career researchers. While acknowledging the benefits of an online setting, especially for individuals who have traditionally been underrepresented or excluded, we recognize that fostering social justice requires inclusivity to actively be centered in every aspect of online conference design. Here, we draw from the literature and from our own experiences to identify practices that purposefully encourage a diverse community to attend, participate in, and lead online conferences. Reflecting on how to design more inclusive online events is especially important as multiple scientific organizations have announced that they will continue offering an online version of their event when in-person conferences can resume.

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