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1.
Neuroimage ; 292: 120615, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38631617

RESUMO

Functional near-infrared spectroscopy (fNIRS) studies often aim to measure changes in the brain's hemodynamic response in relation to a specific intervention. We recently showed how a fNIRS device could induce photobiomodulatory effects on cognition by using its near-infrared (NIR) light. However, so far, fNIRS research has overlooked the stimulatory potential intrinsic to this technique. The work by Kuwamizu et al. (2023) on pupil dynamics during exercise is no exception. Here, we suggest a fix to their experimental design, which could be taken into account in other fNIRS studies, to guarantee an adequate level of control for possible unconsidered photobiomodulatory effects.


Assuntos
Cognição , Exercício Físico , Espectroscopia de Luz Próxima ao Infravermelho , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Humanos , Exercício Físico/fisiologia , Cognição/fisiologia , Raios Infravermelhos , Encéfalo/fisiologia , Encéfalo/diagnóstico por imagem , Neuroimagem Funcional/métodos
2.
Ann Clin Transl Neurol ; 11(5): 1135-1147, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38532258

RESUMO

OBJECTIVE: In parallel to standard vagus nerve stimulation (VNS), microburst stimulation delivery has been developed. We evaluated the fMRI-related signal changes associated with standard and optimized microburst stimulation in a proof-of-concept study (NCT03446664). METHODS: Twenty-nine drug-resistant epilepsy patients were prospectively implanted with VNS. Three 3T fMRI scans were collected 2 weeks postimplantation. The maximum tolerated VNS intensity was determined prior to each scan starting at 0.125 mA with 0.125 mA increments. FMRI scans were block-design with alternating 30 sec stimulation [ON] and 30 sec no stimulation [OFF]: Scan 1 utilized standard VNS and Scan 3 optimized microburst parameters to determine target settings. Semi-automated on-site fMRI data processing utilized ON-OFF block modeling to determine VNS-related fMRI activation per stimulation setting. Anatomical thalamic mask was used to derive highest mean thalamic t-value for determination of microburst stimulation parameters. Paired t-tests corrected at P < 0.05 examined differences in fMRI responses to each stimulation type. RESULTS: Standard and microburst stimulation intensities at Scans 1 and 3 were similar (P = 0.16). Thalamic fMRI responses were obtained in 28 participants (19 with focal; 9 with generalized seizures). Group activation maps showed standard VNS elicited thalamic activation while optimized microburst VNS showed widespread activation patterns including thalamus. Comparison of stimulation types revealed significantly greater cerebellar, midbrain, and parietal fMRI signal changes in microburst compared to standard VNS. These differences were not associated with seizure responses. INTERPRETATION: While standard and optimized microburst VNS elicited thalamic activation, microburst also engaged other brain regions. Relationship between these fMRI activation patterns and clinical response warrants further investigation. CLINICAL TRIAL REGISTRATION: The study was registered with clinicaltrials.gov (NCT03446664).


Assuntos
Epilepsia Resistente a Medicamentos , Imageamento por Ressonância Magnética , Tálamo , Estimulação do Nervo Vago , Humanos , Adulto , Epilepsia Resistente a Medicamentos/terapia , Epilepsia Resistente a Medicamentos/diagnóstico por imagem , Epilepsia Resistente a Medicamentos/fisiopatologia , Feminino , Tálamo/diagnóstico por imagem , Masculino , Estimulação do Nervo Vago/métodos , Adulto Jovem , Adolescente , Pessoa de Meia-Idade , Estudo de Prova de Conceito , Neuroimagem Funcional/normas , Neuroimagem Funcional/métodos
3.
Hum Brain Mapp ; 44(15): 5167-5179, 2023 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-37605825

RESUMO

In this article, we focus on estimating the joint relationship between structural magnetic resonance imaging (sMRI) gray matter (GM), and multiple functional MRI (fMRI) intrinsic connectivity networks (ICNs). To achieve this, we propose a multilink joint independent component analysis (ml-jICA) method using the same core algorithm as jICA. To relax the jICA assumption, we propose another extension called parallel multilink jICA (pml-jICA) that allows for a more balanced weight distribution over ml-jICA/jICA. We assume a shared mixing matrix for both the sMRI and fMRI modalities, while allowing for different mixing matrices linking the sMRI data to the different ICNs. We introduce the model and then apply this approach to study the differences in resting fMRI and sMRI data from patients with Alzheimer's disease (AD) versus controls. The results of the pml-jICA yield significant differences with large effect sizes that include regions in overlapping portions of default mode network, and also hippocampus and thalamus. Importantly, we identify two joint components with partially overlapping regions which show opposite effects for AD versus controls, but were able to be separated due to being linked to distinct functional and structural patterns. This highlights the unique strength of our approach and multimodal fusion approaches generally in revealing potentially biomarkers of brain disorders that would likely be missed by a unimodal approach. These results represent the first work linking multiple fMRI ICNs to GM components within a multimodal data fusion model and challenges the typical view that brain structure is more sensitive to AD than fMRI.


Assuntos
Neuroimagem Funcional , Substância Cinzenta , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/fisiopatologia , Descanso , Imageamento por Ressonância Magnética/métodos , Humanos , Substância Cinzenta/diagnóstico por imagem , Masculino , Feminino , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Hipocampo/diagnóstico por imagem , Tálamo/diagnóstico por imagem , Neuroimagem Funcional/métodos
4.
Neurosci Lett ; 812: 137381, 2023 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-37419305

RESUMO

The cerebellum plays a vital role in cognition, communication with the cerebral cortex, and fine motor coordination. Near-infrared spectroscopy (NIRS) is a portable, less restrictive, and noninvasive functional brain imaging method that can capture brain activity during movements by measuring the relative oxyhemoglobin (oxy-Hb) concentrations in the blood. However, the feasibility of using NIRS to measure cerebellar activity requires discussion. We compared NIRS responses between areas assumed to be the cerebellum and the occipital lobe during a fine motor task (tying a bow knot) and a visual task. Our results showed that the oxy-Hb concentration increased more in the occipital lobe than in the cerebellum during the visual task (p =.034). In contrast, during the fine motor task, the oxy-Hb concentration decreased in the occipital lobe but increased significantly in the cerebellum, indicating a notable difference (p =.015). These findings suggest that we successfully captured cerebellar activity associated with processing, particularly fine motor coordination. Moreover, the observed responses did not differ between individuals with autism spectrum disorder and those with typical development. Our study demonstrates the meaningful utility of NIRS as a method for measuring cerebellar activity during movements.


Assuntos
Transtorno do Espectro Autista , Espectroscopia de Luz Próxima ao Infravermelho , Humanos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Transtorno do Espectro Autista/diagnóstico por imagem , Oxiemoglobinas/metabolismo , Neuroimagem Funcional/métodos , Cerebelo/metabolismo
5.
Cereb Cortex ; 33(12): 7642-7658, 2023 06 08.
Artigo em Inglês | MEDLINE | ID: mdl-36929009

RESUMO

Schizophrenia is a debilitating neuropsychiatric disorder whose underlying correlates remain unclear despite decades of neuroimaging investigation. One contentious topic concerns the role of global signal (GS) fluctuations and how they affect more focal functional changes. Moreover, it has been difficult to pinpoint causal mechanisms of circuit disruption. Here, we analyzed resting-state fMRI data from 47 schizophrenia patients and 118 age-matched healthy controls and used dynamical analyses to investigate how global fluctuations and other functional metastable states are affected by this disorder. We found that brain dynamics in the schizophrenia group were characterized by an increased probability of globally coherent states and reduced recurrence of a substate dominated by coupled activity in the default mode and limbic networks. We then used the in silico perturbation of a whole-brain model to identify critical areas involved in the disease. Perturbing a set of temporo-parietal sensory and associative areas in a model of the healthy brain reproduced global pathological dynamics. Healthy brain dynamics were instead restored by perturbing a set of medial fronto-temporal and cingulate regions in the model of pathology. These results highlight the relevance of GS alterations in schizophrenia and identify a set of vulnerable areas involved in determining a shift in brain state.


Assuntos
Esquizofrenia , Humanos , Encéfalo , Mapeamento Encefálico , Giro do Cíngulo , Neuroimagem Funcional/métodos , Imageamento por Ressonância Magnética/métodos
6.
Neuroimage ; 270: 119949, 2023 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-36804422

RESUMO

As the neuroimaging field moves towards detecting smaller effects at higher spatial resolutions, and faster sampling rates, there is increased attention given to the deleterious contribution of unstructured, thermal noise. Here, we critically evaluate the performance of a recently developed reconstruction method, termed NORDIC, for suppressing thermal noise using datasets acquired with various field strengths, voxel sizes, sampling rates, and task designs. Following minimal preprocessing, statistical activation (t-values) of NORDIC processed data was compared to the results obtained with alternative denoising methods. Additionally, we examined the consistency of the estimates of task responses at the single-voxel, single run level, using a finite impulse response (FIR) model. To examine the potential impact on effective image resolution, the overall smoothness of the data processed with different methods was estimated. Finally, to determine if NORDIC alters or removes temporal information important for modeling responses, we employed an exhaustive leave-p-out cross validation approach, using FIR task responses to predict held out timeseries, quantified using R2. After NORDIC, the t-values are increased, an improvement comparable to what could be achieved by 1.5 voxels smoothing, and task events are clearly visible and have less cross-run error. These advantages are achieved with smoothness estimates increasing by less than 4%, while 1.5 voxel smoothing is associated with increases of over 140%. Cross-validated R2s based on the FIR models show that NORDIC is not measurably distorting the temporal structure of the data under this approach and is the best predictor of non-denoised time courses. The results demonstrate that analyzing 1 run of data after NORDIC produces results equivalent to using 2 to 3 original runs and that NORDIC performs equally well across a diverse array of functional imaging protocols. Significance Statement: For functional neuroimaging, the increasing availability of higher field strengths and ever higher spatiotemporal resolutions has led to concomitant increase in concerns about the deleterious effects of thermal noise. Historically this noise source was suppressed using methods that reduce spatial precision such as image blurring or averaging over a large number of trials or sessions, which necessitates large data collection efforts. Here, we critically evaluate the performance of a recently developed reconstruction method, termed NORDIC, which suppresses thermal noise. Across datasets varying in field strength, voxel sizes, sampling rates, and task designs, NORDIC produces substantial gains in data quality. Both conventional t-statistics derived from general linear models and coefficients of determination for predicting unseen data are improved. These gains match or even exceed those associated with 1 voxel Full Width Half Max image smoothing, however, even such small amounts of smoothing are associated with a 52% reduction in estimates of spatial precision, whereas the measurable difference in spatial precision is less than 4% following NORDIC.


Assuntos
Neuroimagem Funcional , Imageamento por Ressonância Magnética , Humanos , Imageamento por Ressonância Magnética/métodos , Neuroimagem Funcional/métodos , Projetos de Pesquisa , Processamento de Imagem Assistida por Computador/métodos
7.
Neuron ; 111(8): 1316-1330.e5, 2023 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-36803653

RESUMO

Hierarchical processing requires activity propagating between higher- and lower-order cortical areas. However, functional neuroimaging studies have chiefly quantified fluctuations within regions over time rather than propagations occurring over space. Here, we leverage advances in neuroimaging and computer vision to track cortical activity propagations in a large sample of youth (n = 388). We delineate cortical propagations that systematically ascend and descend a cortical hierarchy in all individuals in our developmental cohort, as well as in an independent dataset of densely sampled adults. Further, we demonstrate that top-down, descending hierarchical propagations become more prevalent with greater demands for cognitive control as well as with development in youth. These findings emphasize that hierarchical processing is reflected in the directionality of propagating cortical activity and suggest top-down propagations as a potential mechanism of neurocognitive maturation in youth.


Assuntos
Desenvolvimento do Adolescente , Córtex Cerebral , Desenvolvimento Infantil , Neuroimagem Funcional , Adolescente , Adulto , Criança , Feminino , Humanos , Masculino , Adulto Jovem , Córtex Cerebral/diagnóstico por imagem , Córtex Cerebral/fisiologia , Cognição/fisiologia , Estudos de Coortes , Conjuntos de Dados como Assunto , Neuroimagem Funcional/métodos , Fluxo Óptico
8.
Genes (Basel) ; 13(10)2022 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-36292574

RESUMO

Studying rare diseases, particularly those with neurological dysfunction, is a challenge to researchers and healthcare professionals due to their complexity and small population with geographical dispersion. Universal and standardized biomarkers generated by tools such as functional neuroimaging have been forged to collect baseline data as well as treatment effects. However, the cost and heavily infrastructural requirement of those technologies have substantially limited their availability. Thus, developing non-invasive, portable, and inexpensive modalities has become a major focus for both researchers and clinicians. When considering neurological disorders and diseases with executive dysfunction, EEG is the most convenient tool to obtain biomarkers which can correlate the objective severity and clinical observation of these conditions. However, studies have also shown that EEG biomarkers and clinical observations alone are not sensitive enough since not all the patients present classical phenotypical features or EEG evidence of dysfunction. This article reviews disorders, including two rare disorders with neurological dysfunction and the usefulness of functional near-infrared spectroscopy (fNIRS) as a non-invasive optical modality to obtain hemodynamic biomarkers of diseases and for screening and monitoring the disease.


Assuntos
Doenças Raras , Espectroscopia de Luz Próxima ao Infravermelho , Humanos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Doenças Raras/diagnóstico , Neuroimagem Funcional/métodos
9.
J Biomed Opt ; 27(2)2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35212200

RESUMO

SIGNIFICANCE: Functional near-infrared spectroscopy (fNIRS) is a promising optical neuroimaging technique, measuring the hemodynamic signals from the cortex. However, improving signal quality and reducing artifacts arising from oscillation and baseline shift (BS) are still challenging up to now for fNIRS applications. AIM: Considering the advantages and weaknesses of the different algorithms to reduce the artifact effect in fNIRS signals, we propose a hybrid artifact detection and correction approach. APPROACH: First, distinct artifact detection was realized through an fNIRS detection strategy. Then the artifacts were divided into three categories: BS, slight oscillation, and severe oscillation. A comprehensive correction was applied through three main steps: severe artifact correction by cubic spline interpolation, BS removal by spline interpolation, and slight oscillation reduction by dual-threshold wavelet-based method. RESULTS: Using fNIRS data acquired during whole night sleep monitoring, we compared the performance of our approach with existing algorithms in signal-to-noise ratio (SNR) and Pearson's correlation coefficient (R). We found that the proposed method showed improvements in performance in SNR and R with strong stability. CONCLUSIONS: These results suggest that the new hybrid artifact detection and correction method enhances the viability of fNIRS as a functional neuroimaging modality.


Assuntos
Artefatos , Espectroscopia de Luz Próxima ao Infravermelho , Algoritmos , Neuroimagem Funcional/métodos , Movimento (Física) , Espectroscopia de Luz Próxima ao Infravermelho/métodos
10.
Comput Math Methods Med ; 2022: 4295985, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35096130

RESUMO

OBJECTIVE: Based on resting-state functional magnetic resonance imaging (rs-fMRI), to observe the changes of brain function of bilateral uterine points stimulated by electroacupuncture, so as to provide imaging basis for acupuncture in the treatment of gynecological and reproductive diseases. METHODS: 20 healthy female subjects were selected to stimulate bilateral uterine points (EX-CA1) by electroacupuncture. FMRI data before and after acupuncture were collected. The ReHo values before and after acupuncture were compared by using the analysis method of regional homogeneity (ReHo) of the whole brain, so as to explore the regulatory effect of acupuncture intervention on brain functional activities of healthy subjects. RESULTS: Compared with before acupuncture, the ReHo values of the left precuneus lobe, left central posterior gyrus, calcarine, left lingual gyrus, and cerebellum decreased significantly after acupuncture. CONCLUSION: Electroacupuncture at bilateral uterine points can induce functional activities in brain areas such as the precuneus, cerebellum, posterior central gyrus, talform sulcus, and lingual gyrus. The neural activities in these brain areas may be related to reproductive hormone level, emotional changes, somatic sensation, and visual information. It can clarify the neural mechanism of acupuncture at uterine points in the treatment of reproductive and gynecological diseases to a certain extent.


Assuntos
Pontos de Acupuntura , Eletroacupuntura/métodos , Imageamento por Ressonância Magnética/métodos , Útero/diagnóstico por imagem , Adulto , Encéfalo/fisiologia , Mapeamento Encefálico , Biologia Computacional , Feminino , Neuroimagem Funcional/métodos , Neuroimagem Funcional/estatística & dados numéricos , Doenças dos Genitais Femininos/diagnóstico por imagem , Doenças dos Genitais Femininos/fisiopatologia , Voluntários Saudáveis , Humanos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Útero/fisiologia , Adulto Jovem
11.
Nat Commun ; 13(1): 4, 2022 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-35013147

RESUMO

The emergence of distributed patterns of neural activity supporting brain functions and behavior can be understood by study of the brain's low-dimensional topology. Functional neuroimaging demonstrates that brain activity linked to adaptive behavior is constrained to low-dimensional manifolds. In human participants, we tested whether these low-dimensional constraints preserve working memory performance following local neuronal perturbations. We combined multi-session functional magnetic resonance imaging, non-invasive transcranial magnetic stimulation (TMS), and methods translated from the fields of complex systems and computational biology to assess the functional link between changes in local neural activity and the reshaping of task-related low dimensional trajectories of brain activity. We show that specific reconfigurations of low-dimensional trajectories of brain activity sustain effective working memory performance following TMS manipulation of local activity on, but not off, the space traversed by these trajectories. We highlight an association between the multi-scale changes in brain activity underpinning cognitive function.


Assuntos
Mapeamento Encefálico , Encéfalo/fisiologia , Cognição/fisiologia , Adolescente , Adulto , Mapeamento Encefálico/métodos , Feminino , Neuroimagem Funcional/métodos , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Memória de Curto Prazo/fisiologia , Estimulação Magnética Transcraniana/métodos
12.
Neuroimage ; 249: 118873, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-34998969

RESUMO

This study applies adaptive mixture independent component analysis (AMICA) to learn a set of ICA models, each optimized by fitting a distributional model for each identified component process while maximizing component process independence within some subsets of time points of a multi-channel EEG dataset. Here, we applied 20-model AMICA decomposition to long-duration (1-2 h), high-density (128-channel) EEG data recorded while participants used guided imagination to imagine situations stimulating the experience of 15 specified emotions. These decompositions tended to return models identifying spatiotemporal EEG patterns or states within single emotion imagination periods. Model probability transitions reflected time-courses of EEG dynamics during emotion imagination, which varied across emotions. Transitions between models accounting for imagined "grief" and "happiness" were more abrupt and better aligned with participant reports, while transitions for imagined "contentment" extended into adjoining "relaxation" periods. The spatial distributions of brain-localizable independent component processes (ICs) were more similar within participants (across emotions) than emotions (across participants). Across participants, brain regions with differences in IC spatial distributions (i.e., dipole density) between emotion imagination versus relaxation were identified in or near the left rostrolateral prefrontal, posterior cingulate cortex, right insula, bilateral sensorimotor, premotor, and associative visual cortex. No difference in dipole density was found between positive versus negative emotions. AMICA models of changes in high-density EEG dynamics may allow data-driven insights into brain dynamics during emotional experience, possibly enabling the improved performance of EEG-based emotion decoding and advancing our understanding of emotion.


Assuntos
Córtex Cerebral/fisiologia , Eletroencefalografia/métodos , Emoções/fisiologia , Neuroimagem Funcional/métodos , Imaginação/fisiologia , Aprendizado de Máquina não Supervisionado , Adulto , Humanos
13.
Hum Brain Mapp ; 43(4): 1214-1230, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34786780

RESUMO

Evoked response potentials are often divided up into numerous components, each with their own body of literature. But is there less variety than we might suppose? In this study, we nudge one component into looking like another. Both the N170 and recognition potential (RP) are N1 components in response to familiar objects. However, the RP is often measured with a forward mask that ends at stimulus onset whereas the N170 is often measured with no masking at all. This study investigates how inter-stimulus interval (ISI) may delay and distort the N170 into an RP by manipulating the temporal gap (ISI) between forward mask and target. The results revealed reverse relationships between the ISI on the one hand, and the N170 latency, single-trial N1 jitter (an approximation of N1 width) and reaction time on the other hand. Importantly, we find that scalp topographies have a unique signature at the N1 peak across all conditions, from the longest gap (N170) to the shortest (RP). These findings prove that the mask-delayed N1 is still the same N170, even under conditions that are normally associated with a different component like the RP. In general, our results suggest greater synthesis in the study of event related potential components.


Assuntos
Córtex Cerebral/fisiologia , Eletroencefalografia/métodos , Potenciais Evocados/fisiologia , Neuroimagem Funcional/métodos , Adulto , Feminino , Humanos , Masculino , Reconhecimento Visual de Modelos/fisiologia , Mascaramento Perceptivo/fisiologia , Leitura , Adulto Jovem
14.
Neuropharmacology ; 203: 108815, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34695441

RESUMO

Individuals with a diagnosis of co-morbid HIV infection and cocaine use disorder are at higher risk of poor health outcomes. Active cocaine users, both with and without HIV infection, show clear deficits in response inhibition and other measures of executive function that are instrumental in maintaining drug abstinence, factors that may complicate treatment. Neuroimaging and behavioral evidence indicate normalization of executive control processes in former cocaine users as a function of the duration of drug abstinence, but it is unknown to what extent co-morbid diagnosis of HIV affects this process. To this end, we investigate the combinatorial effects of HIV and cocaine dependence on the neural substrates of cognitive control in cocaine-abstinent individuals with a history of cocaine dependence. Blood-oxygen level dependent signal changes were measured as 86 participants performed a Go/NoGo response inhibition task while undergoing functional magnetic resonance imaging (fMRI). Four groups of participants were selected based on HIV and cocaine-dependence status. Participants affected by both conditions demonstrated the lowest response accuracy of all participant groups. In a region of interest analysis, hyperactivation in the left putamen and midline-cingulate hyperactivation was observed in individuals with both HIV and cocaine dependence relative to individuals with only one condition. Results of a whole-brain analysis indicate response inhibition-related hyperactivation in the bilateral supplementary motor area, bilateral hippocampi, bilateral primary somatosensory areas, right dorsal anterior cingulate, and left insula in the CD+/HIV+ group relative to all other groups. These results indicate complex and interactive alterations in neural activation during response inhibition and highlight the importance of examining the neurocognitive effects of co-morbid conditions.


Assuntos
Transtornos Relacionados ao Uso de Cocaína/diagnóstico por imagem , Cognição/fisiologia , Neuroimagem Funcional/métodos , Infecções por HIV/diagnóstico por imagem , Inibição Psicológica , Tempo de Reação/fisiologia , Adulto , Transtornos Relacionados ao Uso de Cocaína/epidemiologia , Transtornos Relacionados ao Uso de Cocaína/psicologia , Feminino , Infecções por HIV/epidemiologia , Infecções por HIV/psicologia , Humanos , Masculino , Testes de Estado Mental e Demência , Pessoa de Meia-Idade , Desempenho Psicomotor/fisiologia
15.
Hum Brain Mapp ; 43(4): 1231-1255, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34806255

RESUMO

Data fusion refers to the joint analysis of multiple datasets that provide different (e.g., complementary) views of the same task. In general, it can extract more information than separate analyses can. Jointly analyzing electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) measurements has been proved to be highly beneficial to the study of the brain function, mainly because these neuroimaging modalities have complementary spatiotemporal resolution: EEG offers good temporal resolution while fMRI is better in its spatial resolution. The EEG-fMRI fusion methods that have been reported so far ignore the underlying multiway nature of the data in at least one of the modalities and/or rely on very strong assumptions concerning the relation of the respective datasets. For example, in multisubject analysis, it is commonly assumed that the hemodynamic response function is a priori known for all subjects and/or the coupling across corresponding modes is assumed to be exact (hard). In this article, these two limitations are overcome by adopting tensor models for both modalities and by following soft and flexible coupling approaches to implement the multimodal fusion. The obtained results are compared against those of parallel independent component analysis and hard coupling alternatives, with both synthetic and real data (epilepsy and visual oddball paradigm). Our results demonstrate the clear advantage of using soft and flexible coupled tensor decompositions in scenarios that do not conform with the hard coupling assumption.


Assuntos
Encéfalo , Eletroencefalografia/métodos , Neuroimagem Funcional/métodos , Imageamento por Ressonância Magnética/métodos , Rede Nervosa , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Epilepsia/diagnóstico por imagem , Feminino , Humanos , Masculino , Modelos Teóricos , Imagem Multimodal , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia , Adulto Jovem
16.
Neuroimage ; 246: 118780, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34875383

RESUMO

Learning how to reach a reward over long series of actions is a remarkable capability of humans, and potentially guided by multiple parallel learning modules. Current brain imaging of learning modules is limited by (i) simple experimental paradigms, (ii) entanglement of brain signals of different learning modules, and (iii) a limited number of computational models considered as candidates for explaining behavior. Here, we address these three limitations and (i) introduce a complex sequential decision making task with surprising events that allows us to (ii) dissociate correlates of reward prediction errors from those of surprise in functional magnetic resonance imaging (fMRI); and (iii) we test behavior against a large repertoire of model-free, model-based, and hybrid reinforcement learning algorithms, including a novel surprise-modulated actor-critic algorithm. Surprise, derived from an approximate Bayesian approach for learning the world-model, is extracted in our algorithm from a state prediction error. Surprise is then used to modulate the learning rate of a model-free actor, which itself learns via the reward prediction error from model-free value estimation by the critic. We find that action choices are well explained by pure model-free policy gradient, but reaction times and neural data are not. We identify signatures of both model-free and surprise-based learning signals in blood oxygen level dependent (BOLD) responses, supporting the existence of multiple parallel learning modules in the brain. Our results extend previous fMRI findings to a multi-step setting and emphasize the role of policy gradient and surprise signalling in human learning.


Assuntos
Encéfalo/fisiologia , Tomada de Decisões/fisiologia , Neuroimagem Funcional/métodos , Aprendizagem/fisiologia , Imageamento por Ressonância Magnética/métodos , Adulto , Encéfalo/diagnóstico por imagem , Feminino , Humanos , Masculino , Modelos Biológicos , Reforço Psicológico , Adulto Jovem
17.
Hum Brain Mapp ; 43(4): 1280-1294, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34811846

RESUMO

Advances in imaging acquisition techniques allow multiple imaging modalities to be collected from the same subject. Each individual modality offers limited yet unique views of the functional, structural, or dynamic temporal features of the brain. Multimodal fusion provides effective ways to leverage these complementary perspectives from multiple modalities. However, the majority of current multimodal fusion approaches involving functional magnetic resonance imaging (fMRI) are limited to 3D feature summaries that do not incorporate its rich temporal information. Thus, we propose a novel three-way parallel group independent component analysis (pGICA) fusion method that incorporates the first-level 4D fMRI data (temporal information included) by parallelizing group ICA into parallel ICA via a unified optimization framework. A new variability matrix was defined to capture subject-wise functional variability and then link it to the mixing matrices of the other two modalities. Simulation results show that the three-way pGICA provides highly accurate cross-modality linkage estimation under both weakly and strongly correlated conditions, as well as comparable source estimation under different noise levels. Results using real brain imaging data identified one linked functional-structural-diffusion component associated to differences between schizophrenia and controls. This was replicated in an independent cohort, and the identified components were also correlated with major cognitive domains. Functional network connectivity revealed visual-subcortical and default mode-cerebellum pairs that discriminate between schizophrenia and controls. Overall, both simulation and real data results support the use of three-way pGICA to identify multimodal spatiotemporal links and to pursue the study of brain disorders under a single unifying multimodal framework.


Assuntos
Encéfalo , Neuroimagem Funcional/métodos , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Rede Nervosa , Análise Espacial , Adulto , Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Rede Nervosa/diagnóstico por imagem , Rede Nervosa/fisiologia , Esquizofrenia/diagnóstico por imagem , Esquizofrenia/fisiopatologia , Análise Espaço-Temporal
18.
Neuroimage ; 246: 118777, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34864151

RESUMO

Trust can be a dynamic social process, during which the social identity of the interacting agents (e.g., an investor and a trustee) can bias trust outcomes. Here, we investigated how social status modulates trust and the neural mechanisms underlying this process. An investor and a trustee performed a 10-round repeated trust game while their brain activity was being simultaneously recorded using functional near-infrared spectroscopy. The social status (either high or low) of both investors and trustees was manipulated via a math competition task. The behavioral results showed that in the initial round, individuals invested more in low-status partners. However, the investment ratio increased faster as the number of rounds increased during trust interaction when individuals were paired with a high-status partner. This increasing trend was particularly prominent in the low (investor)-high (trustee) status group. Moreover, the low-high group showed increased investor-trustee brain synchronization in the right temporoparietal junction as the number of rounds increased, while brain activation in the right dorsolateral prefrontal cortex of the investor decreased as the number of rounds increased. Both interpersonal brain synchronization and brain activation predicted investment performance at the early stage; furthermore, two-brain data provided earlier predictions than did single-brain data. These effects were detectable in the investment phase in the low-high group only; no comparable effects were observed in the repayment phase or other groups. Overall, this study demonstrated a multi-brain mechanism for the integration of social status and trust.


Assuntos
Córtex Cerebral/fisiologia , Neuroimagem Funcional/métodos , Interação Social , Status Social , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Confiança , Adulto , Córtex Cerebral/diagnóstico por imagem , Feminino , Jogos Experimentais , Humanos , Fatores de Tempo , Adulto Jovem
19.
Neuroimage ; 246: 118738, 2022 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-34800666

RESUMO

Spiral fMRI has been put forward as a viable alternative to rectilinear echo-planar imaging, in particular due to its enhanced average k-space speed and thus high acquisition efficiency. This renders spirals attractive for contemporary fMRI applications that require high spatiotemporal resolution, such as laminar or columnar fMRI. However, in practice, spiral fMRI is typically hampered by its reduced robustness and ensuing blurring artifacts, which arise from imperfections in both static and dynamic magnetic fields. Recently, these limitations have been overcome by the concerted application of an expanded signal model that accounts for such field imperfections, and its inversion by iterative image reconstruction. In the challenging ultra-high field environment of 7 Tesla, where field inhomogeneity effects are aggravated, both multi-shot and single-shot 2D spiral imaging at sub-millimeter resolution was demonstrated with high depiction quality and anatomical congruency. In this work, we further these advances towards a time series application of spiral readouts, namely, single-shot spiral BOLD fMRI at 0.8 mm in-plane resolution. We demonstrate that high-resolution spiral fMRI at 7 T is not only feasible, but delivers both excellent image quality, BOLD sensitivity, and spatial specificity of the activation maps, with little artifactual blurring. Furthermore, we show the versatility of the approach with a combined in/out spiral readout at a more typical resolution (1.5 mm), where the high acquisition efficiency allows to acquire two images per shot for improved sensitivity by echo combination.


Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/fisiologia , Neuroimagem Funcional/métodos , Processamento de Imagem Assistida por Computador/métodos , Imageamento por Ressonância Magnética/métodos , Adulto , Estudos de Viabilidade , Feminino , Humanos , Masculino , Adulto Jovem
20.
Comput Math Methods Med ; 2021: 7749540, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34899970

RESUMO

Concussion syndrome is a common disease in neurosurgery, and its incidence ranks first among all traumatic brain injuries. Cognitive dysfunction is one of the most common functional impairments in concussion syndrome. Neuroimaging and content assessments on concussion patients and healthy control subjects are used in this study, which uses MRI technology to evaluate brain pictures of concussion patients. Moreover, this paper separately evaluates the scores of the concussion syndrome group and the healthy control group in multiple functional aspects and performs independent sample t-test after statistics of the two scores. In addition, this paper uses resting-state fMRI to study the changes in the functional connectivity of the medial prefrontal lobe in patients with PCS, which has certain significance in revealing cognitive dysfunction after concussion and has a certain effect on improving the clinical emergency diagnosis and treatment of concussion.


Assuntos
Concussão Encefálica/diagnóstico por imagem , Neuroimagem Funcional/métodos , Imageamento por Ressonância Magnética/métodos , Encéfalo/diagnóstico por imagem , Concussão Encefálica/etiologia , Concussão Encefálica/psicologia , Estudos de Casos e Controles , Cognição , Biologia Computacional , Conectoma , Manual Diagnóstico e Estatístico de Transtornos Mentais , Serviços Médicos de Emergência , Feminino , Neuroimagem Funcional/estatística & dados numéricos , Escala de Coma de Glasgow , Humanos , Imageamento por Ressonância Magnética/estatística & dados numéricos , Masculino , Córtex Pré-Frontal/diagnóstico por imagem
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