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1.
Nat Commun ; 11(1): 925, 2020 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-32066740

RESUMO

Recent studies suggest that attention samples space rhythmically through oscillatory interactions in the frontoparietal network. How these attentional fluctuations coincide with spatial exploration/displacement and exploitation/selection by a dynamic attentional spotlight under top-down control is unclear. Here, we show a direct contribution of prefrontal attention selection mechanisms to a continuous space exploration. Specifically, we provide a direct high spatio-temporal resolution prefrontal population decoding of the covert attentional spotlight. We show that it continuously explores space at a 7-12 Hz rhythm. Sensory encoding and behavioral reports are increased at a specific optimal phase w/ to this rhythm. We propose that this prefrontal neuronal rhythm reflects an alpha-clocked sampling of the visual environment in the absence of eye movements. These attentional explorations are highly flexible, how they spatially unfold depending both on within-trial and across-task contingencies. These results are discussed in the context of exploration-exploitation strategies and prefrontal top-down attentional control.


Assuntos
Atenção/fisiologia , Modelos Neurológicos , Córtex Pré-Frontal/fisiologia , Movimentos Sacádicos/fisiologia , Percepção Espacial/fisiologia , Ritmo alfa/fisiologia , Animais , Técnicas de Observação do Comportamento , Comportamento Animal/fisiologia , Sinais (Psicologia) , Haplorrinos , Cadeias de Markov , Estimulação Luminosa , Análise Espaço-Temporal
2.
PLoS Biol ; 17(10): e3000511, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31603894

RESUMO

Cognitive processes are almost exclusively investigated under highly controlled settings during which voluntary body movements are suppressed. However, recent animal work suggests differences in sensory processing between movement states by showing drastically changed neural responses in early visual areas between locomotion and stillness. Does locomotion also modulate visual cortical activity in humans, and what are the perceptual consequences? Our study shows that walking increased the contrast-dependent influence of peripheral visual input on central visual input. This increase is prevalent in stimulus-locked electroencephalogram (EEG) responses (steady-state visual evoked potential [SSVEP]) alongside perceptual performance. Ongoing alpha oscillations (approximately 10 Hz) further positively correlated with the walking-induced changes of SSVEP amplitude, indicating the involvement of an altered inhibitory process during walking. The results predicted that walking leads to an increased processing of peripheral visual input. A second study indeed showed an increased contrast sensitivity for peripheral compared to central stimuli when subjects were walking. Our work shows complementary neurophysiological and behavioural evidence corroborating animal findings that walking leads to a change in early visual neuronal activity in humans. That neuronal modulation due to walking is indeed linked to specific perceptual changes extends the existing animal work.


Assuntos
Potenciais Evocados Visuais/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Desempenho Psicomotor/fisiologia , Visão Ocular/fisiologia , Caminhada/fisiologia , Adulto , Ritmo alfa/fisiologia , Feminino , Humanos , Locomoção/fisiologia , Masculino , Estimulação Luminosa , Córtex Visual/fisiologia
3.
Behav Neurol ; 2019: 1410425, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31565094

RESUMO

Previous studies have shown that the neural mechanisms underlying visual spatial attention rely on top-down control information from the frontal and parietal cortexes, which ultimately amplifies sensory processing of stimulus occurred at the attended location relative to those at unattended location. However, the modulations of effective brain networks in response to stimulus at attended and unattended location are not yet clear. In present study, we collected event-related potentials (ERPs) from 15 subjects during a visual spatial attention task, and a partial directed coherence (PDC) method was used to construct alpha-band effective brain networks of two conditions (targets at attended and nontargets at unattended location). Flow gain mapping, effective connectivity pattern, and graph measures including clustering coefficient (C), characteristic path length (L), global efficiency (E global), and local efficiency (E local) were compared between two conditions. Flow gain mapping showed that the frontal region seemed to serve as the main source of information transmission in response to targets at attended location while the parietal region served as the main source in nontarget condition. Effective connectivity pattern indicated that in response to targets, there existed obvious top-down connections from the frontal, temporal, and parietal cortexes to the visual cortex compared with in response to nontargets. Graph theory analysis was used to quantify the topographical properties of the brain networks, and results revealed that in response to targets, the brain networks were characterized by significantly smaller characteristic path length and larger global efficiency than in response to nontargets. Our findings suggested that smaller characteristic path length and larger global efficiency could facilitate global integration of information and provide a substrate for more efficient perceptual processing of targets at attended location compared with processing of nontargets at ignored location, which revealed the neural mechanisms underlying visual spatial attention from the perspective of effective brain networks and graph theory for the first time and opened new vistas to interpret a cognitive process.


Assuntos
Ritmo alfa/fisiologia , Processamento Espacial/fisiologia , Percepção Visual/fisiologia , Atenção/fisiologia , Encéfalo/fisiologia , Mapeamento Encefálico/métodos , Eletroencefalografia/métodos , Potenciais Evocados/fisiologia , Feminino , Lobo Frontal/fisiologia , Humanos , Masculino , Rede Nervosa/fisiologia , Lobo Parietal/fisiologia , Estimulação Luminosa , Adulto Jovem
4.
PLoS Biol ; 17(10): e3000487, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31581198

RESUMO

Predictive coding is a key mechanism to understand the computational processes underlying brain functioning: in a hierarchical network, higher levels predict the activity of lower levels, and the unexplained residuals (i.e., prediction errors) are passed back to higher layers. Because of its recursive nature, we wondered whether predictive coding could be related to brain oscillatory dynamics. First, we show that a simple 2-level predictive coding model of visual cortex, with physiological communication delays between levels, naturally gives rise to alpha-band rhythms, similar to experimental observations. Then, we demonstrate that a multilevel version of the same model can explain the occurrence of oscillatory traveling waves across levels, both forward (during visual stimulation) and backward (during rest). Remarkably, the predictions of our model are matched by the analysis of 2 independent electroencephalography (EEG) datasets, in which we observed oscillatory traveling waves in both directions.


Assuntos
Ritmo alfa/fisiologia , Modelos Neurológicos , Rede Nervosa/fisiologia , Córtex Visual/fisiologia , Adulto , Conjuntos de Dados como Assunto , Eletroencefalografia , Feminino , Humanos , Masculino , Estimulação Luminosa , Descanso/fisiologia
5.
Brain Stimul ; 12(6): 1572-1578, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31378603

RESUMO

BACKGROUND: The individual α frequency (IAF) has been associated with the outcome of repetitive Transcranial Magnetic Stimulation (rTMS) treatment of Major Depressive Disorder (MDD), but the association has been inconsistent. HYPOTHESIS: Proximity of IAF to the stimulation frequency, rather than the value of IAF per se, is associated with outcome for patients receiving 10 Hz rTMS. METHODS: We examined the relationships between IAF, rTMS stimulation frequency, and treatment outcome in 147 patients. All patients initially received 10 Hz rTMS unilateral treatment delivered to left dorsolateral prefrontal cortex (DLPFC) (10UL), with subsets of patients changed to unilateral 5 Hz to left DLPFC (5UL) or sequential bilateral (SB) stimulation (10 Hz/1Hz) to left and right DLPFC based upon worsening symptoms with or intolerance of 10UL. Outcome was percent change in total score on the Inventory of Depressive Symptomatology - Self Report (IDS-SR) scale from pre-treatment baseline to the 30th treatment. IAF values and absolute difference between IAF and 10 Hz (|IAF-10Hz|) were examined in relation to outcome for the overall sample and for each stimulation group separately. RESULTS: There was no correlation between IAF value, or |IAF-10Hz| and outcome in the overall sample. ANCOVA showed a significant interaction between IAF measures and treatment type. Post-hoc analyses revealed that IAF and |IAF-10Hz| were both significantly associated with degree of improvement (IDS-SR % change) for patients who received 10UL (P < 0.01) but not 5UL or SB stimulation. There was a trend-level difference in IAF between responders and non-responders only within the 10 Hz group, but not within the other treatment groups (n.s.). For the 10UL group, membership in the highest IAF quartile was associated with significantly greater clinical improvement than membership in the lowest IAF quartile (p = 0.0034). CONCLUSIONS: IAF measures were associated with clinical outcome of patients treated with 10UL but not 5UL or SB rTMS treatment. This suggests that interactions between endogenous frequencies and treatment outcome may be related to the selected stimulation parameters and/or physiologic and clinical characteristics of patients who benefit from those parameters.


Assuntos
Ritmo alfa/fisiologia , Transtorno Depressivo Maior/psicologia , Transtorno Depressivo Maior/terapia , Estimulação Magnética Transcraniana/métodos , Adulto , Idoso , Transtorno Depressivo Maior/fisiopatologia , Eletroencefalografia/métodos , Eletroencefalografia/tendências , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Córtex Pré-Frontal/fisiologia , Autorrelato , Estimulação Magnética Transcraniana/tendências , Resultado do Tratamento
6.
Biol Psychol ; 146: 107726, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31276755

RESUMO

Mental workload has been shown to correlate with alpha and theta band power but only few EEG studies focused on the relation between these bands and Event Related Potentials (ERPs), more specifically the P300 component. We report on an EEG study on mental workload where not only young but also older adults performed an N-Back task. Participants watched a sequence of visual pictures and indicated whether the current picture was the same as the one shown N pictures before. We considered N = 4 difficulty levels and analyzed the relation between these and P300 amplitude and theta and alpha band power, and also examined the effect of age, level of education, work activities, and task accuracy. Our results revealed a decrease in P300 amplitude and alpha band activity for higher difficulty levels for young adults in the parietal region. However, for older adults, fatigue played a more important role than we could anticipate as the alpha band power increased for the highest task difficulty level, and since performance accuracy also decreased, it could even be a sign of task disengagement. Beside alpha band, theta band activity showed a positive correlation with task difficulty level for both young and older adults. Additionally, we found higher P300 amplitudes for young adults compared to older adults, in line with their higher performance accuracies and lower reaction times. In conclusion, we showed that P300 amplitude and alpha and theta bands power provide complementary information for judging mental workload during N-Back performance for young and older subjects and for detecting mental fatigue and task disengagement.


Assuntos
Envelhecimento/psicologia , Potenciais Evocados/fisiologia , Carga de Trabalho , Adulto , Ritmo alfa/fisiologia , Escolaridade , Eletroencefalografia , Potencial Evocado P300/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Lobo Parietal/fisiologia , Estimulação Luminosa , Desempenho Psicomotor/fisiologia , Ritmo Teta/fisiologia , Adulto Jovem
7.
Elife ; 82019 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-31188126

RESUMO

Spontaneous fluctuations of neural activity may explain why sensory responses vary across repeated presentations of the same physical stimulus. To test this hypothesis, we recorded electroencephalography in humans during stimulation with identical visual stimuli and analyzed how prestimulus neural oscillations modulate different stages of sensory processing reflected by distinct components of the event-related potential (ERP). We found that strong prestimulus alpha- and beta-band power resulted in a suppression of early ERP components (C1 and N150) and in an amplification of late components (after 0.4 s), even after controlling for fluctuations in 1/f aperiodic signal and sleepiness. Whereas functional inhibition of sensory processing underlies the reduction of early ERP responses, we found that the modulation of non-zero-mean oscillations (baseline shift) accounted for the amplification of late responses. Distinguishing between these two mechanisms is crucial for understanding how internal brain states modulate the processing of incoming sensory information.


Assuntos
Ritmo alfa/fisiologia , Encéfalo/fisiologia , Eletroencefalografia , Potenciais Evocados/fisiologia , Adulto , Feminino , Humanos , Masculino , Estimulação Luminosa
8.
Neuroimage ; 199: 635-650, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31189075

RESUMO

Previous work has investigated the electrophysiological origins of the intra-modal (within the stimulated sensory cortex) negative BOLD fMRI response (NBR, decrease from baseline) but little attention has been paid to the origin of cross-modal NBRs, those in a different sensory cortex. In the current study we use simultaneous EEG-fMRI recordings to assess the neural correlates of both intra- and cross-modal responses to left-hemifield visual stimuli and right-hand motor tasks, and evaluate the balance of activation and deactivation between the visual and motor systems. Within- and between-subject covariations of EEG and fMRI responses to both tasks are assessed to determine how patterns of event-related desynchronization/synchronisation (ERD/ERS) of alpha/beta frequency oscillations relate to the NBR in the two sensory cortices. We show that both visual and motor tasks induce intra-modal NBR and cross-modal NBR (e.g. visual stimuli evoked NBRs in both visual and motor cortices). In the EEG data, bilateral intra-modal alpha/beta ERD were consistently observed to both tasks, whilst the cross-modal EEG response varied across subjects between alpha/beta ERD and ERS. Both the mean cross-modal EEG and fMRI response amplitudes showed a small increase in magnitude with increasing task intensity. In response to the visual stimuli, subjects displaying cross-modal ERS of motor beta power displayed a significantly larger magnitude of cross-modal NBR in motor cortex. However, in contrast to the motor stimuli, larger cross-modal ERD of visual alpha power was associated with larger cross-modal visual NBR. Single-trial correlation analysis provided further evidence of relationship between EEG signals and the NBR, motor cortex beta responses to motor tasks were significantly negatively correlated with cross-modal visual cortex NBR amplitude, and positively correlated with intra-modal motor cortex PBR. This study provides a new body of evidence that the coupling between BOLD and low-frequency (alpha/beta) sensory cortex EEG responses extends to cross-modal NBR.


Assuntos
Ritmo alfa/fisiologia , Ritmo beta/fisiologia , Sincronização Cortical/fisiologia , Neuroimagem Funcional/métodos , Atividade Motora/fisiologia , Córtex Motor/fisiologia , Reconhecimento Visual de Modelos/fisiologia , Córtex Visual/fisiologia , Adulto , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Córtex Motor/diagnóstico por imagem , Córtex Visual/diagnóstico por imagem
9.
Exp Brain Res ; 237(8): 2061-2073, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31172241

RESUMO

Frequency-dependent brightness enhancement, a perceptual illusion in which a flickering light can appear twice as bright as a constant light, has historically been reported to produce maximum effects at a flicker rate within the alpha (8-12 Hz) band (Bartley in J Exp Psychol 23(3):313-319, 1938). Our recent examinations of this phenomenon using brightness discrimination between two flickering stimuli, however, have instead revealed the brightest percepts from theta-band (4-7 Hz) flicker (Bertrand et al. in Sci Rep 8(1):6152, 2018). Two primary questions arise from these seemingly contradictory findings: first, could task differences between these studies have caused recruitment of discrete oscillatory processes? Second, could the reported theta-band flicker enhancement be the result of an aliased alpha rhythm, sequentially sampling two stimulus locations, resulting in an ~ 5 Hz half-alpha rhythm? Here, we investigated these questions with two experiments: one replicating Bartley's (1938) adjustment paradigm, and one containing both Bartley's adjustment task and Bertrand's (2018) discrimination task, but presenting stimuli only sequentially (rather than concurrently). Examination of a range of frequencies (2-12 Hz) revealed the greatest brightness enhancement arising from flicker in the delta- and theta-band across all conditions, regardless of the spatial or temporal configuration of the stimuli. We speculate that these slower rhythms play an integral role in complex visual operations (e.g., a discrimination decision) where the entrainment of the endogenous neural rhythm to matched exogenous rhythmic stimulation promotes more efficient processing of visual information and thus produces perceptual biases as seen in frequency-dependent brightness enhancement.


Assuntos
Ritmo alfa/fisiologia , Ritmo Delta/fisiologia , Aprendizagem por Discriminação/fisiologia , Ilusões/fisiologia , Estimulação Luminosa/métodos , Ritmo Teta/fisiologia , Adolescente , Feminino , Humanos , Ilusões/psicologia , Luminescência , Masculino , Distribuição Aleatória , Percepção Visual , Adulto Jovem
10.
Neuroimage ; 199: 408-417, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31173906

RESUMO

Virtual reality (VR) provides an immersive environment in which a participant can experience a feeling of presence in a virtual world. Such environments generate strong emotional and physical responses and have been used for wide-ranging applications. The ability to collect functional neuroimaging data whilst a participant is immersed in VR would represent a step change for experimental paradigms; unfortunately, traditional brain imaging requires participants to remain still, limiting the scope of naturalistic interaction within VR. Recently however, a new type of magnetoencephalography (MEG) device has been developed, that employs scalp-mounted optically-pumped magnetometers (OPMs) to measure brain electrophysiology. Lightweight OPMs, coupled with precise control of the background magnetic field, enables participant movement during data acquisition. Here, we exploit this technology to acquire MEG data whilst a participant uses a virtual reality head-mounted display (VRHMD). We show that, despite increased magnetic interference from the VRHMD, we were able to measure modulation of alpha-band oscillations, and the visual evoked field. Moreover, in a VR experiment in which a participant had to move their head to look around a virtual wall and view a visual stimulus, we showed that the measured MEG signals map spatially in accordance with the known organisation of primary visual cortex. This technique could transform the type of neuroscientific experiment that can be undertaken using functional neuroimaging.


Assuntos
Ritmo alfa/fisiologia , Córtex Cerebral/fisiologia , Potenciais Evocados Visuais/fisiologia , Magnetoencefalografia/métodos , Realidade Virtual , Adulto , Humanos , Magnetoencefalografia/instrumentação , Córtex Visual/fisiologia
11.
Neuroimage ; 199: 228-236, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31154048

RESUMO

Attention is crucial for efficiently coordinating resources over multiple objects in a visual scene. Recently, a growing number of studies suggest that attention is implemented through a temporal organization process during which resources are dynamically allocated over a multitude of objects, yet the associated neural evidence, particularly in low-level sensory areas, is still limited. Here we used EEG recordings in combination with a temporal response function (TRF) approach to examine the spatiotemporal characteristics of neuronal impulse response in covert selective attention. We demonstrate two distinct alpha-band components - one in post-central parietal area and one in contralateral occipital area - that are involved in coordinating neural representations of attended and unattended stimuli. Specifically, consistent with previous findings, the central alpha-band component showed enhanced activities for unattended versus attended stimuli within the first 200 ms temporal lag of TRF response, suggesting its inhibitory function in attention. In contrast, the contralateral occipital component displayed relatively earlier activation for the attended than unattended one in the TRF response. Furthermore, the central component but not the occipital component was correlated with attentional behavioral performance. Finally, the parietal area exerted directional influences on the occipital activity through alpha-band rhythm. Taken together, spatial attention involves two hierarchically organized alpha-band components that are associated with distinct spatiotemporal characteristics and presumably play different functions.


Assuntos
Ritmo alfa/fisiologia , Atenção/fisiologia , Lobo Occipital/fisiologia , Lobo Parietal/fisiologia , Percepção Espacial/fisiologia , Adolescente , Adulto , Humanos , Adulto Jovem
12.
Dev Cogn Neurosci ; 38: 100671, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31229834

RESUMO

Attention-deficit/hyperactivity disorder (ADHD) is characterized by problems in directing and sustaining attention. Recent behavioral studies indicated that children with ADHD are more likely to fail to show the orienting effect in response to human eye gaze. The present study aimed to identify the neurophysiological bases of attention deficits directed by social human eye gaze in children with ADHD, focusing on the relationship between alpha modulations and ADHD symptoms. The electroencephalography data were recorded from 8-13-year-old children (typically developing (TD): n = 24; ADHD: n = 21) while they performed a cued visuospatial covert attention task. The cues were designed as human eyes that might gaze to the left or right visual field. The results revealed that TD children showed a significant alpha lateralization in response to the gaze of human eyes, whereas children with ADHD showed an inverse pattern of alpha modulation in the left parieto-occipital area. Importantly, the abnormal alpha modulation in the left hemisphere predicted inattentive symptom severity and behavioral accuracy in children with ADHD. These results suggest that the dysfunction of alpha modulation in the left hemisphere in response to social cues might be a potential neurophysiologic marker of attention deficit in children with ADHD.


Assuntos
Ritmo alfa/fisiologia , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Atenção/fisiologia , Fixação Ocular/fisiologia , Índice de Gravidade de Doença , Adolescente , Criança , Sinais (Psicologia) , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Valor Preditivo dos Testes , Tempo de Reação/fisiologia
13.
Brain Stimul ; 12(6): 1508-1516, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31235367

RESUMO

BACKGROUND: The motor evoked potentials (MEPs) elicited by single-pulse transcranial magnetic stimulation (TMS) vary considerably at rest, but the mechanism underlying this amplitude variation is largely unknown. We hypothesized that prestimulus EEG oscillations modulate the subsequent MEPs in a state-dependent manner. OBJECTIVE: We studied the relationship between prestimulus alpha/beta oscillations and MEPs during eyes open (EO)/closed (EC) conditions, and then modulated TMS intensity in the EO condition. Furthermore, we developed an EEG-triggered TMS system ("informed open-loop") to verify our hypothesis. METHODS: TMS was applied to the left motor cortex. We first compared EEG power differences between high- and low-amplitude MEP epochs in the EO and EC conditions when using a high TMS intensity. Next, we evaluated the effects of varying TMS intensities (high vs. low) on the EEG-MEP relationship. Finally, we used EEG-triggered TMS to determine whether prestimulus EEG oscillations predicted MEP amplitudes. RESULTS: Prestimulus higher-power alpha/low-beta bands produced larger MEPs only in the high-intensity EO condition. A positive relationship between EEG power and MEP amplitude was observed at C3 and left frontal electrodes. This relationship was obscured when using the lower TMS intensity but was observed in the high-intensity condition at the C3 electrode. EEG-triggered TMS demonstrated that higher alpha power predicted higher MEP amplitudes, but beta power at around 20 Hz did not. CONCLUSIONS: A causal relationship between alpha/low-beta oscillations and MEP amplitudes at rest requires high TMS intensity delivered when eyes are open. This association may allow us to develop a new informed open-loop TMS protocol.


Assuntos
Ritmo alfa/fisiologia , Ritmo beta/fisiologia , Potencial Evocado Motor/fisiologia , Córtex Motor/fisiologia , Estimulação Magnética Transcraniana/métodos , Adulto , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Distribuição Aleatória
14.
Neurosci Lett ; 705: 131-137, 2019 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-31042570

RESUMO

An event-related decrease in alpha power contralateral to the presentation of a stimulus is now a well-established phenomenon. Two distinct accounts of the functional role of alpha changes are present in the literature that either focus on alpha changes observed during attentional or simple perceptual tasks. This study directly compares tasks that invoke alpha decreases during exogenous, endogenous and perceptual processing. Using a data driven approach to compare alpha changes we show that alpha decreases differ only between exogenous and endogenous attention tasks for only a short time window, 500-600 ms after cue onset. We suggest this indicates a role for alpha in voluntary orientating and stimulus predictability.


Assuntos
Ritmo alfa/fisiologia , Atenção/fisiologia , Percepção do Tato/fisiologia , Adulto , Sinais (Psicologia) , Potenciais Somatossensoriais Evocados/fisiologia , Feminino , Humanos , Masculino , Adulto Jovem
15.
Biomed Res Int ; 2019: 7851047, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31058192

RESUMO

Objective: The objective of this prospective cross-sectional study was to analyze the differences between patients with fibromyalgia and non-pain controls in terms of EEG power in the eyes-closed resting state. This study also aims to evaluate potential correlations between EEG power and subjective pain. Methods: The fibromyalgia patients were recruited by the Extremadura Association of Fibromyalgia (AFIBROEX) in Cáceres, Spain. Age- and sex-matched healthy controls (1:1 ratio) were recruited from university facilities and people close to the AFIBROEX by public calls. All underwent EEG during a 1-minute resting period with their eyes closed. The theta, alpha-1, alpha-2, beta-1, beta-2, and beta-3 frequency bands were analyzed by using EEGLAB. Self-reported visual analog scale pain scores were determined just prior to EEG. Results: A total of 62 women participated in the study, 31 of them diagnosed with fibromyalgia and 31 healthy controls. Fibromyalgia group exhibited a significantly lower alpha-2 in C4, T3, P4, Pz, and O2 compared to the healthy controls. Interestingly, pain correlated negatively with alpha-2 in Cz, P4, and Pz only in the fibromyalgia group. Conclusion: The fibromyalgia group exhibited decrease alpha-2 power in central, temporoparietal, and occipital brain areas. Furthermore, higher values of pain correlated with lower level of alpha-2 power in Cz, P4, and Pz. These findings may point the importance of alpha-2 power in pain in women with fibromyalgia.


Assuntos
Ritmo alfa/fisiologia , Eletroencefalografia , Fibromialgia/fisiopatologia , Dor/fisiopatologia , Adulto , Ritmo beta , Encéfalo/fisiopatologia , Mapeamento Encefálico , Feminino , Fibromialgia/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Dor/diagnóstico , Medição da Dor/métodos , Descanso/fisiologia , Ritmo Teta
16.
Biol Psychol ; 145: 167-173, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31102670

RESUMO

Working memory can be enhanced by directing attention to task-relevant representations. Alpha oscillations are a neural correlate of spatial attention either to the perceptual or the mnemonic domain. Specifically, an enhancement of alpha power is observed in the ipsilateral posterior cortex to the locus of attention, along with a suppression in the contralateral hemisphere. In this study we aim to unravel the contribution of bottom-up processes in the top-down guidance of attention inside WM. In this way, emotionality of the memoranda was manipulated in a retro-cue task. Behaviorally, we found a recognition advantage for emotional cued items, and significantly, that the emotionality of the non-cued items did not influence accuracy. We found that bilateral alpha power was greater for the emotional irrelevant condition, which could be reflecting the greater demands to suppress an emotional item from the focus of attention. Critically, we found that alpha power lateralization was not modulated by neither the emotionality of the cued or the non-cued items. However, we found that the latency at which alpha lateralization emerged was modulated by the emotionality of the memory representations. In conclusion, we propose that while alpha power lateralization might be reflecting a general spatial orienting mechanism, in our experiment it is influenced by the selection of relevant information within WM.


Assuntos
Ritmo alfa/fisiologia , Atenção/fisiologia , Emoções , Memória de Curto Prazo/fisiologia , Percepção Espacial/fisiologia , Adulto , Córtex Cerebral/fisiologia , Sinais (Psicologia) , Feminino , Humanos , Masculino
17.
Neuroscience ; 410: 16-28, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31078688

RESUMO

The present study investigated how pain appraisals from other individuals modulated self-pain anticipation and perception. Appraisals of pain intensity from 10 other individuals were presented before the participants received identical electrical pain stimulation themselves. In reality, the presented other's pain appraisals, with either low or high in mean and variance, were generated by the experimenter, and were randomly paired with the subsequent electrical stimulation at either low or high intensity. Specifically, the mean and variance of others' pain appraisals were manipulated to induce participants' expectation and certainty to the upcoming pain. Subjective ratings of pain intensity and electroencephalographic (EEG) responses to the electrical stimulation, as well as anticipatory EEG activities measured prior to the onset of electrical stimulation, were compared. Results showed that the mean and variance of others' pain appraisal modulated the subjective pain ratings and the affective-motivational P2 responses elicited by the electrical stimulation, as well as anticipatory sensorimotor α-oscillation measured before the onset of pain stimulation. When the mean of others' pain appraisal was low, higher variance suppressed the sensorimotor α-oscillations and enhanced subsequent pain perception. In contrast, when the mean was high, the higher variance enhanced sensorimotor α-oscillations and suppressed subsequent pain perception. These results demonstrated that others' pain appraisals can modulate both of the anticipation and perception of first-hand pain. It also suggested that the top-down modulation of others' pain appraisals on pain perception could be partially driven by the different brain states during the anticipation stage, as captured by the prestimulus sensorimotor α-oscillations.


Assuntos
Ritmo alfa/fisiologia , Antecipação Psicológica/fisiologia , Medição da Dor/psicologia , Percepção da Dor/fisiologia , Dor/psicologia , Adolescente , Estimulação Elétrica/efeitos adversos , Eletroencefalografia/métodos , Eletroencefalografia/psicologia , Feminino , Humanos , Masculino , Dor/diagnóstico , Medição da Dor/métodos , Adulto Jovem
18.
Biol Psychol ; 145: 84-95, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30999009

RESUMO

Prior work has demonstrated that the serial order effect is commonly observed during the Alternative Uses Task, where generated uses become more creative over time while fluency decreases. Yet the neural correlates of the serial order effect are still relatively unexplored. The present study aimed to investigate the electrophysiological correlates underlying this effect. EEG alpha activity was measured using a task-related power paradigm while participants completed both the Alternative Uses Task as well as a Category Fluency Task. The results indicated that left hemisphere alpha power increased relative to right alpha power as a function of the serial order effect in the Alternative Uses Task, but not in the Category Fluency Task. This finding provides evidence that the pattern of observed EEG alpha activity changes over the course of the serial order effect.


Assuntos
Ritmo alfa/fisiologia , Pensamento/fisiologia , Adulto , Encéfalo/fisiologia , Criatividade , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Teste de Sequência Alfanumérica
19.
Sensors (Basel) ; 19(7)2019 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-30965606

RESUMO

Concentration and immersion belong to a similar mental state in which a person is preoccupied with a particular task. In this study, we investigated a possibility of diagnosing two mental states with a subtle difference. Concentration and immersion states were induced to analyze the electroencephalography (EEG) changes during these states. Thirty-two college students in their 20s participated in the study. For concentration, subjects were asked to focus on a red dot at the center of a white screen, and for immersion they were asked to focus on playing a computer game. Relative to rest, Alpha waves decreased during concentration and immersion. Relative to rest, Theta waves decreased at almost all channels during concentration and, on the other hand, increased at all channels during immersion. Beta waves increased during concentration and immersion in the frontal and occipital lobes, with a higher increase in immersion. In the temporal lobe, Beta waves decreased during concentration and increased during immersion. In the central region, Beta waves decreased during concentration and immersion, and the decrease during immersion was larger. Such evident differences between the EEG results for concentration and immersion can imply diagnostic capabilities of various other mental states.


Assuntos
Atenção/fisiologia , Encéfalo/fisiologia , Eletroencefalografia/métodos , Testes de Estado Mental e Demência , Adulto , Ritmo alfa/fisiologia , Ritmo beta/fisiologia , Feminino , Humanos , Masculino , Ritmo Teta/fisiologia , Jogos de Vídeo , Adulto Jovem
20.
PLoS Comput Biol ; 15(4): e1006924, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30951525

RESUMO

We revisit the CROS ("CRitical OScillations") model which was recently proposed as an attempt to reproduce both scale-invariant neuronal avalanches and long-range temporal correlations. With excitatory and inhibitory stochastic neurons locally connected in a two-dimensional disordered network, the model exhibits a transition where alpha-band oscillations emerge. Precisely at the transition, the fluctuations of the network activity have nontrivial detrended fluctuation analysis (DFA) exponents, and avalanches (defined as supra-threshold activity) have power law distributions of size and duration. We show that, differently from previous results, the exponents governing the distributions of avalanche size and duration are not necessarily those of the mean-field directed percolation universality class (3/2 and 2, respectively). Instead, in a narrow region of parameter space, avalanche exponents obtained via a maximum-likelihood estimator vary continuously and follow a linear relation, in good agreement with results obtained from M/EEG data. In that region, moreover, the values of avalanche and DFA exponents display a spread with positive correlations, reproducing human MEG results.


Assuntos
Modelos Neurológicos , Neurônios/fisiologia , Potenciais de Ação/fisiologia , Ritmo alfa/fisiologia , Encéfalo/fisiologia , Biologia Computacional , Eletroencefalografia/estatística & dados numéricos , Humanos , Funções Verossimilhança , Magnetoencefalografia/estatística & dados numéricos , Rede Nervosa/fisiologia , Processos Estocásticos , Biologia de Sistemas
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