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1.
PLoS Biol ; 20(2): e3001541, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35167585

RESUMO

Organizing sensory information into coherent perceptual objects is fundamental to everyday perception and communication. In the visual domain, indirect evidence from cortical responses suggests that children with autism spectrum disorder (ASD) have anomalous figure-ground segregation. While auditory processing abnormalities are common in ASD, especially in environments with multiple sound sources, to date, the question of scene segregation in ASD has not been directly investigated in audition. Using magnetoencephalography, we measured cortical responses to unattended (passively experienced) auditory stimuli while parametrically manipulating the degree of temporal coherence that facilitates auditory figure-ground segregation. Results from 21 children with ASD (aged 7-17 years) and 26 age- and IQ-matched typically developing children provide evidence that children with ASD show anomalous growth of cortical neural responses with increasing temporal coherence of the auditory figure. The documented neurophysiological abnormalities did not depend on age, and were reflected both in the response evoked by changes in temporal coherence of the auditory scene and in the associated induced gamma rhythms. Furthermore, the individual neural measures were predictive of diagnosis (83% accuracy) and also correlated with behavioral measures of ASD severity and auditory processing abnormalities. These findings offer new insight into the neural mechanisms underlying auditory perceptual deficits and sensory overload in ASD, and suggest that temporal-coherence-based auditory scene analysis and suprathreshold processing of coherent auditory objects may be atypical in ASD.


Assuntos
Percepção Auditiva/fisiologia , Transtorno do Espectro Autista/fisiopatologia , Sincronização Cortical/fisiologia , Potenciais Evocados Auditivos/fisiologia , Estimulação Acústica/métodos , Adolescente , Transtorno do Espectro Autista/diagnóstico , Transtorno do Espectro Autista/psicologia , Criança , Feminino , Humanos , Magnetoencefalografia/métodos , Masculino , Tempo de Reação/fisiologia
2.
Commun Biol ; 4(1): 559, 2021 05 11.
Artigo em Inglês | MEDLINE | ID: mdl-33976360

RESUMO

The brain naturally resolves the challenge of integrating auditory and visual signals produced by the same event despite different physical propagation speeds and neural processing latencies. Temporal recalibration manifests in human perception to realign incoming signals across the senses. Recent behavioral studies show it is a fast-acting phenomenon, relying on the most recent exposure to audiovisual asynchrony. Here we show that the physiological mechanism of rapid, context-dependent recalibration builds on interdependent pre-stimulus cortical rhythms in sensory brain regions. Using magnetoencephalography, we demonstrate that individual recalibration behavior is related to subject-specific properties of fast oscillations (>35 Hz) nested within a slower alpha rhythm (8-12 Hz) in auditory cortex. We also show that the asynchrony of a previously presented audiovisual stimulus pair alters the preferred coupling phase of these fast oscillations along the alpha cycle, with a resulting phase-shift amounting to the temporal recalibration observed behaviorally. These findings suggest that cross-frequency coupled oscillations contribute to forming unified percepts across senses.


Assuntos
Percepção Auditiva/fisiologia , Sincronização Cortical/fisiologia , Percepção Visual/fisiologia , Estimulação Acústica/métodos , Adaptação Fisiológica/fisiologia , Adulto , Córtex Auditivo/fisiologia , Encéfalo/fisiologia , Ondas Encefálicas/fisiologia , Feminino , Humanos , Julgamento/fisiologia , Magnetoencefalografia/métodos , Masculino , Estimulação Luminosa/métodos , Fatores de Tempo , Córtex Visual/fisiologia
3.
Proc Natl Acad Sci U S A ; 118(6)2021 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-33526664

RESUMO

We studied correlated firing between motor thalamic and cortical cells in monkeys performing a delayed-response reaching task. Simultaneous recording of thalamocortical activity revealed that around movement onset, thalamic cells were positively correlated with cell activity in the primary motor cortex but negatively correlated with the activity of the premotor cortex. The differences in the correlation contrasted with the average neural responses, which were similar in all three areas. Neuronal correlations reveal functional cooperation and opposition between the motor thalamus and distinct motor cortical areas with specific roles in planning vs. performing movements. Thus, by enhancing and suppressing motor and premotor firing, the motor thalamus can facilitate the transition from a motor plan to execution.


Assuntos
Sincronização Cortical/fisiologia , Atividade Motora/fisiologia , Córtex Motor/fisiologia , Tálamo/fisiologia , Animais , Feminino , Macaca fascicularis , Neurônios/fisiologia , Análise e Desempenho de Tarefas
4.
Soc Cogn Affect Neurosci ; 16(1-2): 5-18, 2021 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-32128587

RESUMO

Many group-living animals, humans included, occasionally synchronize their behavior with that of conspecifics. Social psychology and neuroscience have attempted to explain this phenomenon. Here we sought to integrate results around three themes: the stimuli, the mechanisms and the benefits of interactional synchrony. As regards stimuli, we asked what characteristics, apart from temporal regularity, prompt synchronization and found that stimulus modality and complexity are important. The high temporal resolution of the auditory system and the relevance of socio-emotional information endow auditory, multimodal, emotional and somewhat variable and adaptive sequences with particular synchronizing power. Looking at the mechanisms revealed that traditional perspectives emphasizing beat-based representations of others' signals conflict with more recent work investigating the perception of temporal regularity. Timing processes supported by striato-cortical loops represent any kind of repetitive interval sequence fairly automatically. Additionally, socio-emotional processes supported by posterior superior temporal cortex help endow such sequences with value motivating the extent of synchronizing. Synchronizing benefits arise from an increased predictability of incoming signals and include many positive outcomes ranging from basic information processing at the individual level to the bonding of dyads and larger groups.


Assuntos
Encéfalo/fisiologia , Sincronização Cortical/fisiologia , Interação Social , Estimulação Acústica , Atenção , Percepção Auditiva/fisiologia , Emoções/fisiologia , Humanos , Relações Interpessoais , Lobo Temporal/fisiologia
5.
Curr Biol ; 30(24): 4944-4955.e7, 2020 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-33096037

RESUMO

In many behavioral tasks, cortex enters a desynchronized state where low-frequency fluctuations in population activity are suppressed. The precise behavioral correlates of desynchronization and its global organization are unclear. One hypothesis holds that desynchronization enhances stimulus coding in the relevant sensory cortex. Another hypothesis holds that desynchronization reflects global arousal, such as task engagement. Here, we trained mice on tasks where task engagement could be distinguished from sensory accuracy. Using widefield calcium imaging, we found that performance-related desynchronization was global and correlated better with engagement than with accuracy. Consistent with this link between desynchronization and engagement, rewards had a long-lasting desynchronizing effect. To determine whether engagement-related state changes depended on the relevant sensory modality, we trained mice on visual and auditory tasks and found that in both cases desynchronization was global, including regions such as somatomotor cortex. We conclude that variations in low-frequency fluctuations are predominately global and related to task engagement.


Assuntos
Nível de Alerta/fisiologia , Córtex Auditivo/fisiologia , Sincronização Cortical/fisiologia , Tomada de Decisões/fisiologia , Córtex Visual/fisiologia , Estimulação Acústica , Animais , Córtex Auditivo/citologia , Córtex Auditivo/diagnóstico por imagem , Eletroencefalografia , Feminino , Masculino , Camundongos , Neurônios/fisiologia , Imagem Óptica , Estimulação Luminosa , Recompensa , Técnicas Estereotáxicas , Córtex Visual/citologia , Córtex Visual/diagnóstico por imagem
6.
Cogn Affect Behav Neurosci ; 20(5): 1056-1069, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32808234

RESUMO

To investigate the effects of the Dejian mind-body intervention (DMBI), on depressive symptoms and electroencephalography (EEG) changes in relation to emotional processing in patients with depression. Seventy-five age-, gender-, and education-matched participants with depression were randomly assigned to receive either Cognitive Behavior Therapy (CBT) or DMBI or were placed in a control group. Overall depressive syndrome, specific mood-related symptoms (Hamilton Psychiatric Rating Scale for Depression, Beck Depression Inventory), and EEG data were collected individually during a resting state and during affective image viewing before and after 10 weeks of intervention. After intervention, both the DMBI and CBT groups showed significantly reduced levels of overall depressive syndrome and mood-related symptoms (Ps ≤ 0.002) than the control group. In addition, the DMBI group demonstrated a significantly greater extent of elevation in fronto-posterior EEG theta coherence on the right hemisphere when viewing different mood-induction (neutral, positive, and negative) stimuli than the CBT and control groups (Ps < 0.03). The elevated intra-right fronto-posterior coherence when viewing mood-induction stimuli correlated with improved mood levels after the intervention (Ps < 0.05). Our findings also showed that, only in the DMBI group, there was a significant suppression of theta source activity at the posterior and subcortical brain regions that are known to mediate negative emotional responses and the self-absorbed mode of thinking. The findings of reduced depressive symptoms and elevated frontoposterior coherence suggest that the DMBI can enhance emotional control in depression.


Assuntos
Terapia Cognitivo-Comportamental , Sincronização Cortical/fisiologia , Transtorno Depressivo Maior/fisiopatologia , Transtorno Depressivo Maior/terapia , Regulação Emocional/fisiologia , Terapias Mente-Corpo , Avaliação de Resultados em Cuidados de Saúde , Ritmo Teta/fisiologia , Adulto , Feminino , Humanos , Estilo de Vida , Masculino , Pessoa de Meia-Idade , Psicoterapia de Grupo
7.
Appl Psychophysiol Biofeedback ; 45(2): 49-55, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32232604

RESUMO

The aim of the study was to demonstrate the effects of the Neurofeedback-EEG training during physical exercise on the improvements in mental work performance and physiological parameters. The study examined seven swimmers based on the following anthropometric measurements: body height, body mass and body composition. The Kraepelin's work curve test, EEG and EMG during physical exercise were also performed. The athletes followed 20 Neurofeedback-EEG training sessions on the swimming ergometer for 4 months. Most mean indices of partial measures of the work curve were significantly modified (p < 0.05) following the Neurofeedback-EEG training. Mean level of maximal oxygen uptake in study participants was over 55 ml/kg/min, with statistically significant differences documented between the first and the second measurements. No significant differences were found in the fatigue rate between the measurements 1 and 2. The improved mental work performance following the Neurofeedback-EEG training facilitates optimization of psychomotor activities.


Assuntos
Atletas , Desempenho Atlético/fisiologia , Córtex Cerebral/fisiologia , Sincronização Cortical/fisiologia , Neurorretroalimentação , Desempenho Psicomotor/fisiologia , Natação/fisiologia , Pensamento/fisiologia , Adolescente , Adulto , Eletromiografia , Feminino , Humanos , Neurorretroalimentação/métodos , Adulto Jovem
8.
PLoS One ; 15(3): e0230184, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32182270

RESUMO

The left and right foot representation area is located within the interhemispheric fissure of the sensorimotor cortex and share spatial proximity. This makes it difficult to visualize the cortical lateralization of event-related (de)synchronization (ERD/ERS) during left and right foot motor imageries. The aim of this study is to investigate the possibility of using ERD/ERS in the mu, low beta, and high beta bandwidth, during left and right foot dorsiflexion kinaesthetic motor imageries (KMI), as unilateral control commands for a brain-computer interface (BCI). EEG was recorded from nine healthy participants during cue-based left-right foot dorsiflexion KMI tasks. The features were analysed for common average and bipolar references. With each reference, mu and beta band-power features were analysed using time-frequency (TF) maps, scalp topographies, and average time course for ERD/ERS. The cortical lateralization of ERD/ERS, during left and right foot KMI, was confirmed. Statistically significant features were classified using LDA, SVM, and KNN model, and evaluated using the area under ROC curves. An increase in high beta power following the end of KMI for both tasks was recorded, from right and left hemispheres, respectively, at the vertex. The single trial analysis and classification models resulted in high discrimination accuracies, i.e. maximum 83.4% for beta ERS, 79.1% for beta ERD, and 74.0% for mu ERD. With each model the features performed above the statistical chance level of 2-class discrimination for a BCI. Our findings indicate these features can evoke left-right differences in single EEG trials. This suggests that any BCI employing unilateral foot KMI can attain classification accuracy suitable for practical implementation. Given results stipulate the novel utilization of mu and beta as independent control features for discrimination of bilateral foot KMI in a BCI.


Assuntos
Sincronização Cortical/fisiologia , Pé/fisiologia , Cinestesia/fisiologia , Movimento/fisiologia , Adulto , Interfaces Cérebro-Computador , Eletroencefalografia/métodos , Feminino , Lateralidade Funcional/fisiologia , Humanos , Imagens, Psicoterapia/métodos , Imaginação/fisiologia , Masculino , Desempenho Psicomotor/fisiologia , Adulto Jovem
9.
Neuroimage Clin ; 24: 102092, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31795062

RESUMO

BACKGROUND: The outcome of stroke survivors is difficult to anticipate. While the extent of the anatomical brain lesion is only poorly correlated with the prognosis, functional measures of cortical synchrony, brain networks and cortical plasticity seem to be good predictors of clinical recovery. In this field, gamma (>30 Hz) cortical synchrony is an ideal marker of brain function, as it plays a crucial role for the integration of information, it is an indirect marker of Glutamate/GABA balance and it directly estimates the reserve of parvalbulin-positive neurons, key players in synaptic plasticity. In this study we measured gamma synchronization driven by external auditory stimulation with magnetoencephalography and tested whether it was predictive of the clinical outcome in stroke survivors undergoing intensive rehabilitation in a tertiary rehabilitation center. MATERIAL AND METHODS: Eleven stroke survivors undergoing intensive rehabilitation were prospectively recruited. Gamma synchrony was measured non-invasively within one month from stroke onset with magnetoencephalography, both at rest and during entrainment with external 40 Hz amplitude modulated binaural sounds. Lesion location and volume were quantitatively assessed through a high-resolution anatomical MRI. Barthel index (BI) and Functional Independence Measure (FIM) scales were measured at the beginning and at the end of the admission to the rehabilitation unit. RESULTS: The spatial distribution of cortical gamma synchrony was altered, and the physiological right hemispheric dominance observed in healthy controls was attenuated or lost. Entrained gamma synchronization (but not resting state gamma synchrony) showed a very high correlation with the clinical status at both admission and discharge (both BI and FIM). Neither clinical status nor gamma synchrony showed a correlation with lesion volume. CONCLUSIONS: Cortical gamma synchrony related to auditory entrainment can be reliably measured in stroke patients. Gamma synchrony is strongly associated with the clinical outcome of stroke survivors undergoing rehabilitation.


Assuntos
Sincronização Cortical/fisiologia , Ritmo Gama/fisiologia , Recuperação de Função Fisiológica , Reabilitação do Acidente Vascular Cerebral , Acidente Vascular Cerebral/fisiopatologia , Estimulação Acústica/métodos , Adulto , Idoso , Feminino , Humanos , Imageamento por Ressonância Magnética , Magnetoencefalografia , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Acidente Vascular Cerebral/diagnóstico por imagem
10.
Neurosci Lett ; 701: 142-145, 2019 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-30802464

RESUMO

Neuronal interactions coupled by phase synchronization have been studied in a wide range of frequency bands, but fluctuations below the delta frequency have often been neglected. In the present study, phase synchrony in slow cortical potentials (SCPs, 0.01-0.1 Hz) was examined during two different mental states; a resting state and a breath-focused mindfulness meditation. SCP phase synchrony in 9 long-term expert meditators (on average 22 years of experience) were compared with the data obtained from 11 novices. Additionally, after the novices attended an 8-week mindfulness-based stress reduction (MBSR) program, SCP phase synchrony was measured again. While expert meditators and novices exhibited the same amount of SCP phase synchrony in the resting state, decreased synchronization was found during meditation among expert meditators as well as novices who had participated in the MBSR program (but not prior to the program). These findings suggest that phase synchrony in slow cortical activity is context-dependent and could provide crucial information in the study of the human mind.


Assuntos
Sincronização Cortical/fisiologia , Meditação/psicologia , Adolescente , Adulto , Encéfalo/fisiologia , Eletroencefalografia , Sincronização de Fases em Eletroencefalografia/fisiologia , Feminino , Humanos , Masculino , Potenciais da Membrana/fisiologia , Atenção Plena
11.
Brain ; 141(9): 2631-2643, 2018 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-29985998

RESUMO

Epilepsy has been classically seen as a brain disorder resulting from abnormally enhanced neuronal excitability and synchronization. Although it has been described since antiquity, there are still significant challenges achieving the therapeutic goal of seizure freedom. Deep brain stimulation of the anterior nucleus of the thalamus has emerged as a promising therapy for focal drug-resistant epilepsy; the basic mechanism of action, however, remains unclear. Here, we show that desynchronization is a potential mechanism of deep brain stimulation of the anterior nucleus of the thalamus by studying local field potentials recordings from the cortex during high-frequency stimulation (130 Hz) of the anterior nucleus of the thalamus in nine patients with drug-resistant focal epilepsy. We demonstrate that high-frequency stimulation applied to the anterior nucleus of the thalamus desynchronizes ipsilateral hippocampal background electrical activity over a broad frequency range, and reduces pathological epileptic discharges including interictal spikes and high-frequency oscillations. Furthermore, high-frequency stimulation of the anterior nucleus of the thalamus is capable of decoupling large-scale neural activity involving the hippocampus and distributed cortical areas. We found that stimulation frequencies ranging from 15 to 45 Hz were associated with synchronization of hippocampal local field potentials, whereas higher frequencies (>45 Hz) promoted desynchronization of ipsilateral hippocampal activity. Moreover, reciprocal effective connectivity between the anterior nucleus of the thalamus and the hippocampus was demonstrated by hippocampal-thalamic evoked potentials and thalamic-hippocampal evoked potentials. In summary, high-frequency stimulation of the anterior nucleus of the thalamus is shown to desynchronize focal and large-scale epileptic networks, and here is proposed as the mechanism for reducing seizure generation and propagation. Our data also demonstrate position-specific correlation between deep brain stimulation applied to the anterior nucleus of the thalamus and patients with temporal lobe epilepsy and seizure onset zone within the Papaz circuit or limbic system. Our observation may prove useful for guiding electrode implantation to increase clinical efficacy.


Assuntos
Núcleos Anteriores do Tálamo/fisiopatologia , Estimulação Encefálica Profunda/métodos , Epilepsia/terapia , Adolescente , Adulto , Córtex Cerebral/fisiologia , China , Sincronização Cortical/fisiologia , Eletrodos Implantados , Eletroencefalografia/métodos , Epilepsia/fisiopatologia , Potenciais Evocados/fisiologia , Feminino , Hipocampo/fisiologia , Humanos , Masculino , Rede Nervosa/fisiopatologia , Convulsões/fisiopatologia , Tálamo/fisiologia
12.
Neuropsychologia ; 117: 102-112, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29792887

RESUMO

Neurophysiological research has shown that auditory and motor systems interact during movement to rhythmic auditory stimuli through a process called entrainment. This study explores the neural oscillations underlying auditory-motor entrainment using electroencephalography. Forty young adults were randomly assigned to one of two control conditions, an auditory-only condition or a motor-only condition, prior to a rhythmic auditory-motor synchronization condition (referred to as combined condition). Participants assigned to the auditory-only condition auditory-first group) listened to 400 trials of auditory stimuli presented every 800 ms, while those in the motor-only condition (motor-first group) were asked to tap rhythmically every 800 ms without any external stimuli. Following their control condition, all participants completed an auditory-motor combined condition that required tapping along with auditory stimuli every 800 ms. As expected, the neural processes for the combined condition for each group were different compared to their respective control condition. Time-frequency analysis of total power at an electrode site on the left central scalp (C3) indicated that the neural oscillations elicited by auditory stimuli, especially in the beta and gamma range, drove the auditory-motor entrainment. For the combined condition, the auditory-first group had significantly lower evoked power for a region of interest representing sensorimotor processing (4-20 Hz) and less total power in a region associated with anticipation and predictive timing (13-16 Hz) than the motor-first group. Thus, the auditory-only condition served as a priming facilitator of the neural processes in the combined condition, more so than the motor-only condition. Results suggest that even brief periods of rhythmic training of the auditory system leads to neural efficiency facilitating the motor system during the process of entrainment. These findings have implications for interventions using rhythmic auditory stimulation.


Assuntos
Percepção Auditiva/fisiologia , Mapeamento Encefálico , Sincronização Cortical/fisiologia , Potenciais Evocados/fisiologia , Movimento/fisiologia , Desempenho Psicomotor/fisiologia , Estimulação Acústica , Adolescente , Adulto , Estudos Transversais , Eletroencefalografia , Eletroculografia , Feminino , Humanos , Masculino , Fatores de Tempo , Adulto Jovem
13.
J Neurosci ; 37(26): 6331-6341, 2017 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-28559379

RESUMO

Most humans have a near-automatic inclination to tap, clap, or move to the beat of music. The capacity to extract a periodic beat from a complex musical segment is remarkable, as it requires abstraction from the temporal structure of the stimulus. It has been suggested that nonlinear interactions in neural networks result in cortical oscillations at the beat frequency, and that such entrained oscillations give rise to the percept of a beat or a pulse. Here we tested this neural resonance theory using MEG recordings as female and male individuals listened to 30 s sequences of complex syncopated drumbeats designed so that they contain no net energy at the pulse frequency when measured using linear analysis. We analyzed the spectrum of the neural activity while listening and compared it to the modulation spectrum of the stimuli. We found enhanced neural response in the auditory cortex at the pulse frequency. We also showed phase locking at the times of the missing pulse, even though the pulse was absent from the stimulus itself. Moreover, the strength of this pulse response correlated with individuals' speed in finding the pulse of these stimuli, as tested in a follow-up session. These findings demonstrate that neural activity at the pulse frequency in the auditory cortex is internally generated rather than stimulus-driven. The current results are both consistent with neural resonance theory and with models based on nonlinear response of the brain to rhythmic stimuli. The results thus help narrow the search for valid models of beat perception.SIGNIFICANCE STATEMENT Humans perceive music as having a regular pulse marking equally spaced points in time, within which musical notes are temporally organized. Neural resonance theory (NRT) provides a theoretical model explaining how an internal periodic representation of a pulse may emerge through nonlinear coupling between oscillating neural systems. After testing key falsifiable predictions of NRT using MEG recordings, we demonstrate the emergence of neural oscillations at the pulse frequency, which can be related to pulse perception. These findings rule out alternative explanations for neural entrainment and provide evidence linking neural synchronization to the perception of pulse, a widely debated topic in recent years.


Assuntos
Córtex Auditivo/fisiologia , Percepção Auditiva/fisiologia , Relógios Biológicos/fisiologia , Sincronização Cortical/fisiologia , Potenciais Evocados Auditivos/fisiologia , Periodicidade , Estimulação Acústica/métodos , Potenciais de Ação/fisiologia , Adulto , Sinais (Psicologia) , Retroalimentação Fisiológica , Feminino , Humanos , Masculino , Modelos Neurológicos , Música
14.
J Neurosci ; 37(19): 4903-4912, 2017 05 10.
Artigo em Inglês | MEDLINE | ID: mdl-28411273

RESUMO

Many environmental stimuli contain temporal regularities, a feature that can help predict forthcoming input. Phase locking (entrainment) of ongoing low-frequency neuronal oscillations to rhythmic stimuli is proposed as a potential mechanism for enhancing neuronal responses and perceptual sensitivity, by aligning high-excitability phases to events within a stimulus stream. Previous experiments show that rhythmic structure has a behavioral benefit even when the rhythm itself is below perceptual detection thresholds (ten Oever et al., 2014). It is not known whether this "inaudible" rhythmic sound stream also induces entrainment. Here we tested this hypothesis using magnetoencephalography and electrocorticography in humans to record changes in neuronal activity as subthreshold rhythmic stimuli gradually became audible. We found that significant phase locking to the rhythmic sounds preceded participants' detection of them. Moreover, no significant auditory-evoked responses accompanied this prethreshold entrainment. These auditory-evoked responses, distinguished by robust, broad-band increases in intertrial coherence, only appeared after sounds were reported as audible. Taken together with the reduced perceptual thresholds observed for rhythmic sequences, these findings support the proposition that entrainment of low-frequency oscillations serves a mechanistic role in enhancing perceptual sensitivity for temporally predictive sounds. This framework has broad implications for understanding the neural mechanisms involved in generating temporal predictions and their relevance for perception, attention, and awareness.SIGNIFICANCE STATEMENT The environment is full of rhythmically structured signals that the nervous system can exploit for information processing. Thus, it is important to understand how the brain processes such temporally structured, regular features of external stimuli. Here we report the alignment of slowly fluctuating oscillatory brain activity to external rhythmic structure before its behavioral detection. These results indicate that phase alignment is a general mechanism of the brain to process rhythmic structure and can occur without the perceptual detection of this temporal structure.


Assuntos
Estimulação Acústica/métodos , Percepção Auditiva/fisiologia , Limiar Auditivo/fisiologia , Relógios Biológicos/fisiologia , Ondas Encefálicas/fisiologia , Sincronização Cortical/fisiologia , Adulto , Feminino , Humanos , Masculino , Periodicidade , Gravidez
15.
J Neurosci ; 37(17): 4552-4564, 2017 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-28336572

RESUMO

The neural underpinnings of rhythmic behavior, including music and dance, have been studied using the synchronization-continuation task (SCT), where subjects initially tap in synchrony with an isochronous metronome and then keep tapping at a similar rate via an internal beat mechanism. Here, we provide behavioral and neural evidence that supports a resetting drift-diffusion model (DDM) during SCT. Behaviorally, we show the model replicates the linear relation between the mean and standard-deviation of the intervals produced by monkeys in SCT. We then show that neural populations in the medial premotor cortex (MPC) contain an accurate trial-by-trial representation of elapsed-time between taps. Interestingly, the autocorrelation structure of the elapsed-time representation is consistent with a DDM. These results indicate that MPC has an orderly representation of time with features characteristic of concatenated DDMs and that this population signal can be used to orchestrate the rhythmic structure of the internally timed elements of SCT.SIGNIFICANCE STATEMENT The present study used behavioral data, ensemble recordings from medial premotor cortex (MPC) in macaque monkeys, and computational modeling, to establish evidence in favor of a class of drift-diffusion models of rhythmic timing during a synchronization-continuation tapping task (SCT). The linear relation between the mean and standard-deviation of the intervals produced by monkeys in SCT is replicated by the model. Populations of MPC cells faithfully represent the elapsed time between taps, and there is significant trial-by-trial relation between decoded times and the timing behavior of the monkeys. Notably, the neural decoding properties, including its autocorrelation structure are consistent with a set of drift-diffusion models that are arranged sequentially and that are resetting in each SCT tap.


Assuntos
Sincronização Cortical/fisiologia , Córtex Motor/fisiologia , Periodicidade , Estimulação Acústica , Algoritmos , Animais , Comportamento Animal/fisiologia , Macaca mulatta , Masculino , Modelos Neurológicos , Córtex Motor/citologia , Neurônios/fisiologia , Desempenho Psicomotor/fisiologia , Tempo de Reação
16.
PLoS One ; 12(3): e0174906, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28358852

RESUMO

Music training can improve cognitive functions. Previous studies have shown that children and adults with music training demonstrate better verbal learning and memory performance than those without such training. Although prior studies have shown an association between music training and changes in the structural and functional organization of the brain, there is no concrete evidence of the underlying neural correlates of the verbal memory encoding phase involved in such enhanced memory performance. Therefore, we carried out an electroencephalography (EEG) study to investigate how music training was associated with brain activity during the verbal memory encoding phase. Sixty participants were recruited, 30 of whom had received music training for at least one year (the MT group) and 30 of whom had never received music training (the NMT group). The participants in the two groups were matched for age, education, gender distribution, and cognitive capability. Their verbal and visual memory functions were assessed using standardized neuropsychological tests and EEG was used to record their brain activity during the verbal memory encoding phase. Consistent with previous studies, the MT group demonstrated better verbal memory than the NMT group during both the learning and the delayed recall trials in the paper-and-pencil tests. The MT group also exhibited greater learning capacity during the learning trials. Compared with the NMT group, the MT group showed an increase in long-range left and right intrahemispheric EEG coherence in the theta frequency band during the verbal memory encoding phase. In addition, their event-related left intrahemispheric theta coherence was positively associated with subsequent verbal memory performance as measured by discrimination scores. These results suggest that music training may modulate the cortical synchronization of the neural networks involved in verbal memory formation.


Assuntos
Sincronização Cortical/fisiologia , Eletroencefalografia/métodos , Memória/fisiologia , Música , Adulto , Feminino , Humanos , Masculino , Musicoterapia , Testes Neuropsicológicos , Adulto Jovem
17.
Conscious Cogn ; 49: 157-162, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28214765

RESUMO

This study compared subjective experiences and EEG patterns in 37 subjects when listening to live Vedic recitation and when practicing Transcendental Meditation (TM). Content analysis of experiences when listening to Vedic recitation yielded three higher-order code. Experiences during Vedic recitation were: (1) deeper than during TM practice; (2) experienced as an inner process; and (3) characterized by lively silence. EEG patterns support these higher-order codes. Theta2 and alpha1 frontal, parietal, and frontal-parietal coherence were significantly higher when listening to Vedic recitation, than during TM practice. Theta2 coherence is seen when attending to internal mental processes. Higher theta2 coherence supports subjects' descriptions that the Vedic recitations were "not external sounds but internal vibrations." Alpha1 coherence is reported during pure consciousness experiences during TM practice. Higher alpha1 coherence supports subjects' descriptions that they "experienced a depth of experience, rarely experienced even during deep TM practice." These data support the utility of listening to Vedic recitation to culture deep inner experiences.


Assuntos
Ritmo alfa/fisiologia , Córtex Cerebral/fisiologia , Sincronização Cortical/fisiologia , Hinduísmo , Meditação , Percepção da Fala/fisiologia , Ritmo Teta/fisiologia , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
18.
J Neural Eng ; 14(2): 026014, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28145275

RESUMO

OBJECTIVE: Synchronization in activated regions of cortical networks affect the brain's frequency response, which has been associated with a wide range of states and abilities, including memory. A non-invasive method for manipulating cortical synchronization is binaural beats. Binaural beats take advantage of the brain's response to two pure tones, delivered independently to each ear, when those tones have a small frequency mismatch. The mismatch between the tones is interpreted as a beat frequency, which may act to synchronize cortical oscillations. Neural synchrony is particularly important for working memory processes, the system controlling online organization and retention of information for successful goal-directed behavior. Therefore, manipulation of synchrony via binaural beats provides a unique window into working memory and associated connectivity of cortical networks. APPROACH: In this study, we examined the effects of different acoustic stimulation conditions during an N-back working memory task, and we measured participant response accuracy and cortical network topology via EEG recordings. Six acoustic stimulation conditions were used: None, Pure Tone, Classical Music, 5 Hz binaural beats, 10 Hz binaural beats, and 15 Hz binaural beats. MAIN RESULTS: We determined that listening to 15 Hz binaural beats during an N-Back working memory task increased the individual participant's accuracy, modulated the cortical frequency response, and changed the cortical network connection strengths during the task. Only the 15 Hz binaural beats produced significant change in relative accuracy compared to the None condition. SIGNIFICANCE: Listening to 15 Hz binaural beats during the N-back task activated salient frequency bands and produced networks characterized by higher information transfer as compared to other auditory stimulation conditions.


Assuntos
Estimulação Acústica/métodos , Córtex Cerebral/fisiologia , Conectoma/métodos , Sincronização Cortical/fisiologia , Memória de Curto Prazo/fisiologia , Rede Nervosa/fisiologia , Percepção da Altura Sonora/fisiologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Análise e Desempenho de Tarefas , Adulto Jovem
19.
PLoS One ; 11(12): e0168304, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27977790

RESUMO

Over 5 experiments, we challenge the idea that the capacity of audio-visual integration need be fixed at 1 item. We observe that the conditions under which audio-visual integration is most likely to exceed 1 occur when stimulus change operates at a slow rather than fast rate of presentation and when the task is of intermediate difficulty such as when low levels of proactive interference (3 rather than 8 interfering visual presentations) are combined with the temporal unpredictability of the critical frame (Experiment 2), or, high levels of proactive interference are combined with the temporal predictability of the critical frame (Experiment 4). Neural data suggest that capacity might also be determined by the quality of perceptual information entering working memory. Experiment 5 supported the proposition that audio-visual integration was at play during the previous experiments. The data are consistent with the dynamic nature usually associated with cross-modal binding, and while audio-visual integration capacity likely cannot exceed uni-modal capacity estimates, performance may be better than being able to associate only one visual stimulus with one auditory stimulus.


Assuntos
Percepção Auditiva/fisiologia , Memória de Curto Prazo/fisiologia , Processos Mentais/fisiologia , Vias Neurais/fisiologia , Percepção Visual/fisiologia , Estimulação Acústica , Adolescente , Adulto , Sincronização Cortical/fisiologia , Feminino , Humanos , Masculino , Estimulação Luminosa , Inibição Proativa , Análise e Desempenho de Tarefas , Adulto Jovem
20.
Stud Health Technol Inform ; 225: 917-8, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27332408

RESUMO

Compared to rookie nurses, it is often said that a skilled nurse's injection is less degree of pain. The authors believe that the reason why the pain is reduced is because skilled nurses can make themselves relaxed and synchronize their state to the patients. So, if we can make people relaxed and synchronized intentionally by giving artificial stimulation, the technique will be so valuable not only in the inheritance of injection skills but also in various medical situations including the care of aged, nursing of infant and so on. In this paper, we focused on the synchronization of brain waves, and examined the method of inducing the relaxed state and the synchronization in brain waves of subjects by giving a vibratory stimulation.


Assuntos
Ondas Encefálicas/fisiologia , Sincronização Cortical/fisiologia , Estimulação Física/métodos , Terapia de Relaxamento/métodos , Vibração , Frequência Cardíaca/fisiologia , Humanos , Terapia de Relaxamento/psicologia , Taxa Respiratória/fisiologia
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