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1.
PLoS Comput Biol ; 15(11): e1007268, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31725712

RESUMO

Origin and functions of intermittent transitions among sleep stages, including short awakenings and arousals, constitute a challenge to the current homeostatic framework for sleep regulation, focusing on factors modulating sleep over large time scales. Here we propose that the complex micro-architecture characterizing the sleep-wake cycle results from an underlying non-equilibrium critical dynamics, bridging collective behaviors across spatio-temporal scales. We investigate θ and δ wave dynamics in control rats and in rats with lesions of sleep-promoting neurons in the parafacial zone. We demonstrate that intermittent bursts in θ and δ rhythms exhibit a complex temporal organization, with long-range power-law correlations and a robust duality of power law (θ-bursts, active phase) and exponential-like (δ-bursts, quiescent phase) duration distributions, typical features of non-equilibrium systems self-organizing at criticality. Crucially, such temporal organization relates to anti-correlated coupling between θ- and δ-bursts, and is independent of the dominant physiologic state and lesions, a solid indication of a basic principle in sleep dynamics.


Assuntos
Fases do Sono/fisiologia , Vigília/fisiologia , Animais , Nível de Alerta/fisiologia , Ritmo Delta/fisiologia , Eletroencefalografia , Homeostase , Masculino , Neurônios , Ratos , Ratos Sprague-Dawley , Sono/fisiologia , Ritmo Teta/fisiologia
2.
Nat Hum Behav ; 3(12): 1263-1270, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31477910

RESUMO

Attending to our inner world is a fundamental cognitive phenomenon1-3, yet its neural underpinnings remain largely unknown. Neuroimaging evidence implicates the default network (DN) and frontoparietal control network (FPCN)4; however, the electrophysiological basis for the interaction between these networks is unclear. Here we recorded intracranial electroencephalogram from DN and FPCN electrodes implanted in individuals undergoing presurgical monitoring for refractory epilepsy. Subjects performed an attention task during which they attended to tones (that is, externally directed attention) or ignored the tones and thought about whatever came to mind (that is, internally directed attention). Given the emerging role of theta band connectivity in attentional processes5,6, we examined the theta power correlation between DN and two subsystems of the FPCN as a function of attention states. We found increased connectivity between DN and FPCNA during internally directed attention compared to externally directed attention, which positively correlated with attention ratings. There was no statistically significant difference between attention states in the connectivity between DN and FPCNB. Our results indicate that enhanced theta band connectivity between the DN and FPCNA is a core electrophysiological mechanism that underlies internally directed attention.


Assuntos
Atenção/fisiologia , Encéfalo/fisiologia , Lobo Frontal/fisiologia , Rede Nervosa/fisiologia , Lobo Parietal/fisiologia , Ritmo Teta , Adolescente , Adulto , Idoso , Encéfalo/diagnóstico por imagem , Eletroencefalografia , Feminino , Humanos , Imagem por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neuroimagem , Ritmo Teta/fisiologia , Adulto Jovem
3.
J Clin Neurophysiol ; 36(5): 389-391, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31490453

RESUMO

Smartphones and other personal electronic devices present novel cortical processing tasks with potential for identification of novel EEG waveforms. A 17-year-old patient with epilepsy manifested as recurrent myoclonic seizures, absence seizures, and a single generalized tonic-clonic seizure was hospitalized to undergo video-EEG monitoring for seizure quantification and classification of the epilepsy syndrome. During the monitoring session, a frontocentral predominant 5 to 6 Hz theta rhythm was identified only when the patient was actively texting or playing a video game on his smartphone. Previously, patients with focal epilepsy have been found to have a frontocentral theta rhythm on EEG while texting on mobile devices. We report similar EEG findings in a patient with genetic generalized epilepsy during smartphone gaming to expand the population and triggers for this theta waveform. Given the young age and type of epilepsy, we suggest that the waveform represents the EEG manifestation of the attention-visuomotor pathway that is stimulus independent.


Assuntos
Epilepsias Mioclônicas/fisiopatologia , Smartphone/tendências , Ritmo Teta/fisiologia , Jogos de Vídeo/tendências , Adolescente , Eletroencefalografia/métodos , Eletroencefalografia/tendências , Epilepsias Mioclônicas/diagnóstico , Humanos , Masculino , Mensagem de Texto/tendências , Jogos de Vídeo/efeitos adversos
4.
Brain Stimul ; 12(6): 1565-1571, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31383594

RESUMO

BACKGROUND: Obsessive-compulsive disorder (OCD) is a complex disorder with 40 to 60 % of patients resistant to treatment. Theta burst transcranial magnetic stimulation (TBS) is a promising new technique that has been shown to induce potent and long lasting effects on cortical excitability. The present study evaluated for the first time therapeutic efficacy and tolerability of continuous TBS (cTBS) over the supplementary motor area (SMA) in treatment resistant OCD patients using a double blind, sham-controlled design. METHODS: Thirty treatment resistant OCD outpatients were randomized to receive either active cTBS or sham cTBS for 6 weeks (5 sessions per week). Each treatment session consisted of 600 stimuli at an intensity of 70% of resting motor threshold. Patients were evaluated at baseline, at the end of treatment (week 6), and follow-up (week 12). Response to treatment was defined as at least 25% decrease on the Yale-Brown Obsessive Compulsive Scale. RESULTS: There was no significant difference between active and sham cTBS groups in treatment efficacy. Responder rates were not different between the two groups at week 6 (cTBS 28% versus sham 36%; p = 0.686) and week 12 (cTBS 28% versus sham 36%; p = 0.686). Depressive and anxious symptoms improvements were similar in the two groups. CONCLUSION: This study is the first controlled trial using cTBS in treatment resistant OCD patients. The use of cTBS over the SMA is safe but not sufficient to improve OCD symptoms. Further studies are needed to identify the optimal parameters to be used in OCD patients.


Assuntos
Córtex Motor/fisiologia , Transtorno Obsessivo-Compulsivo/psicologia , Transtorno Obsessivo-Compulsivo/terapia , Ritmo Teta/fisiologia , Estimulação Magnética Transcraniana/métodos , Adulto , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transtorno Obsessivo-Compulsivo/fisiopatologia , Resultado do Tratamento , Adulto Jovem
5.
Exp Brain Res ; 237(9): 2279-2295, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31267218

RESUMO

While several studies have examined attentional reserve (via event-related potentials) and mental effort (via EEG spectral content) from various cortical regions during dual-task walking, none have assessed changes in the magnitude of interregional (cortico-cortical) communication as a measure of mental workload. Therefore, by deploying a traditional montage of electrode sites centered over the motor planning region as well as a more comprehensive graph theory-based approach encompassing the entire scalp, this study aimed to systematically examine changes in the magnitude of functional connectivity underlying cortico-cortical communication to assess changes in mental workload under various levels of challenge. Specifically, the Weighted Phase Lag Index (WPLI) was computed to assess the changes in magnitude of functional connectivity as participants performed a cognitive task under two demands (low and high) and two conditions (seated and walking). The results revealed enhanced fronto-centro-temporo-parietal theta connectivity during dual-task walking relative to being seated as well as a reduced inhibition of fronto-centro-temporo-parieto-occipital alpha networking as the demand on the secondary cognitive task increased. Collectively, these findings may reflect greater recruitment of task relevant processes to respond to increased cognitive-motor demands and thus an elevation of mental workload in an effort to maintain performance under varying levels of challenge. This work has the potential to inform future mental workload assessment applications in patient populations, including those who employ prostheses during cognitive-motor performance under various task demands.


Assuntos
Córtex Cerebral/fisiologia , Conectoma , Função Executiva/fisiologia , Rede Nervosa/fisiologia , Desempenho Psicomotor/fisiologia , Ritmo Teta/fisiologia , Caminhada/fisiologia , Adulto , Ritmo alfa , Percepção de Cores/fisiologia , Feminino , Humanos , Masculino , Reconhecimento Visual de Modelos/fisiologia , Adulto Jovem
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.
Clin EEG Neurosci ; 50(5): 339-347, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31321994

RESUMO

Attention-deficit hyperactivity disorder (ADHD) is one of the most common neuropsychiatric disorders of childhood. Diagnosis of ADHD is based on core symptoms and checklists. However, these are both subjective, which can lead to the problems of overdiagnosis and underdiagnosis. Elevated theta/beta ratio (TBR) of EEG band has been approved by the US Food and Drug Administration as a tool to assist in the diagnosis of ADHD. However, several recent studies have demonstrated that there are no significant differences in TBR between people with and without ADHD. In this study, we attempted to develop a new method for differentiating between male with and without ADHD by analyzing EEG features. Thirty boys with ADHD combined type (aged 8 years 5 months ± 1 year 11 months) and 30 age-matched controls (aged 8 years 5 months ± 1 year 8 months) were enrolled in this study. A classification analysis-based approach comprising training and classification phases was developed for classifying each subject's EEG features as ADHD or non-ADHD. Eight crucial feature descriptors were selected and ranked based on the t test. Compared with TBR in our study, the developed method had a higher area under the curve (87.78%), sensitivity (80.0%), and specificity (80.0%). Our method is more precise than using TBR in the diagnosis of ADHD. This newly developed method is a useful tool in identifying patients with ADHD and might reduce the possibility of overdiagnosis and underdiagnosis.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Ritmo beta/fisiologia , Eletroencefalografia , Adolescente , Mapeamento Encefálico/métodos , Criança , Eletroencefalografia/métodos , Humanos , Masculino , Projetos de Pesquisa , Ritmo Teta/fisiologia
9.
Clin EEG Neurosci ; 50(5): 332-338, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31304784

RESUMO

Attention-deficit/hyperactivity disorder (ADHD) is the most common neurodevelopmental disorder and is characterized by symptoms of inattention and/or hyperactivity and impulsivity. In the current study, we obtained quantitative EEG (QEEG) recordings of 51 children aged between 6 and 12 years before the initiation of methylphenidate treatment. The relationship between changes in the scores of ADHD symptoms and initial QEEG features (power/power ratios values) were assessed. In addition, the children were classified as responder and nonresponder according to the ratio of their response to the medication (>25% improvement after medication). Logistic regression analyses were performed to analyze the accuracy of QEEG features for predicting responders. The findings indicate that patients with increased delta power at F8, theta power at Fz, F4, C3, Cz, T5, and gamma power at T6 and decreased beta powers at F8 and P3 showed more improvement in ADHD hyperactivity symptoms. In addition, increased delta/beta power ratio at F8 and theta/beta power ratio at F8, F3, Fz, F4, C3, Cz, P3, and T5 showed negative correlations with Conners' score difference of hyperactivity as well. This means, those with greater theta/beta and delta/beta powers showed more improvement in hyperactivity following medication. Theta power at Cz and T5 and theta/beta power ratios at C3, Cz, and T5 have significantly classified responders and nonresponders according to the logistic binary regression analysis. The results show that slow and fast oscillations may have predictive value for treatment response in ADHD. Future studies should seek for more sensitive biomarkers.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/tratamento farmacológico , Encéfalo/efeitos dos fármacos , Eletroencefalografia/efeitos dos fármacos , Metilfenidato/uso terapêutico , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Transtorno do Deficit de Atenção com Hiperatividade/fisiopatologia , Ritmo beta/efeitos dos fármacos , Ritmo beta/fisiologia , Encéfalo/fisiopatologia , Criança , Cognição/efeitos dos fármacos , Cognição/fisiologia , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Ritmo Teta/efeitos dos fármacos , Ritmo Teta/fisiologia
10.
Neuron ; 103(3): 489-505.e7, 2019 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-31204082

RESUMO

Despite a wealth of clinical and preclinical data implicating the serotonin (5-HT) system in fear-related affective disorders, a precise definition of this neuromodulator's role in fear remains elusive. Using convergent anatomical and functional approaches, we interrogate the contribution to fear of basal amygdala (BA) 5-HT inputs from the dorsal raphe nucleus (DRN). We show the DRN→BA 5-HT pathway is engaged during fear memory formation and retrieval, and activity of these projections facilitates fear and impairs extinction. The DRN→BA 5-HT pathway amplifies fear-associated BA neuronal firing and theta power and phase-locking. Although fear recruits 5-HT and VGluT3 co-expressing DRN neurons, the fear-potentiating influence of the DRN→BA 5-HT pathway requires signaling at BA 5-HT1A/2A receptors. Input-output mapping illustrates how the DRN→BA 5-HT pathway is anatomically distinct and connected with other brain regions that mediate fear. These findings reveal how a discrete 5-HT circuit orchestrates a broader neural network to calibrate aversive memory.


Assuntos
Tonsila do Cerebelo/fisiologia , Aprendizagem da Esquiva/fisiologia , Núcleo Dorsal da Rafe/fisiologia , Vias Neurais/fisiologia , Serotonina/fisiologia , Animais , Condicionamento Clássico/fisiologia , Extinção Psicológica , Medo/fisiologia , Feminino , Genes Reporter , Resposta de Imobilidade Tônica/fisiologia , Masculino , Rememoração Mental/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Optogenética , Sinaptofisina/administração & dosagem , Sinaptofisina/análise , Ritmo Teta/fisiologia
11.
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
12.
Brain Stimul ; 12(5): 1253-1260, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31088732

RESUMO

BACKGROUND: Prior studies have found that continuous theta burst stimulation (cTBS) targeting the left dlPFC results in reliable increases in consumption of calorie-dense food items. However, it is not known to what extent such effects are modified by cues in the immediate eating environment. Tempting environments (i.e., those saturated with appetitive eating cues) may lead to more reliance on cognitive control networks involving the dlPFC, thereby enhancing cTBS effects on indulgent eating. OBJECTIVE/HYPOTHESIS: The objective was to examine the extent to which cTBS effects on indulgent eating would be modified by contextual cues. It was hypothesized that cTBS effects would be stronger in the presence of facilitating cues. METHODS: Using a single-blinded between-subjects factorial design, 107 TMS-naïve adults were randomly assigned to one of four conditions: 1) active cTBS + facilitating cues, 2) sham cTBS + facilitating cues, 3) active cTBS + inhibiting cues, 4) sham cTBS + inhibiting cues. Following stimulation participants completed a flanker paradigm and a taste test during which quantity consumed was assessed surreptitiously. RESULTS: Findings revealed a significant interaction between stimulation and cue type (F(1,102) = 6.235, p = .014), such that cTBS resulted in increased food consumption (compared to sham) in the presence of the facilitating cue but not in the presence of the inhibiting cue. Moderated mediational analyses showed selective mediation of cTBS effects on consumption through cTBS attenuation of flanker interference scores. CONCLUSIONS: The effects of cTBS on indulgent eating are strengthened in the presence of facilitating cues. Methodologically speaking, facilitating cues may be a functional prerequisite for exploring cTBS effects on eating in the laboratory. Substantively, the findings also suggest that facilitating cues in the eating environment may amplify counter-intentional food indulgence in everyday life via cognitive control failure.


Assuntos
Fissura/fisiologia , Sinais (Psicologia) , Comportamento Alimentar/fisiologia , Comportamento Alimentar/psicologia , Estimulação Luminosa/métodos , Ritmo Teta/fisiologia , Adolescente , Adulto , Feminino , Humanos , Estudos Longitudinais , Masculino , Córtex Pré-Frontal/fisiologia , Método Simples-Cego , Estimulação Magnética Transcraniana/métodos , Adulto Jovem
13.
J Integr Neurosci ; 18(1): 33-41, 2019 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31091846

RESUMO

Deep brain stimulation is an emerging treatment for brain disorders. However, the mechanisms of high-frequency brain stimulation are unclear. Recent studies have suggested that high-frequency stimulation might produce therapeutic effects by eliminating pathological rhythms in neuronal firing. To test the hypothesis, the present study investigated whether stimulation of axonal afferent fibers might alter firing rhythms of downstream neurons in in-vivo experiments with Sprague-Dawley rats. Stimulation trains of 100 Hz with one minute duration were applied to the Schaffer collaterals of hippocampus Area CA1 in anaesthetized rats. Spikes of single interneurons and pyramidal neurons in the downstream region were analyzed. The spike rhythms before, during, and after the stimulations were evaluated by analyzing the power spectrum density of autocorrelograms of the spiking sequences. The rhythms of local field potentials were also evaluated by power spectrum density. During baseline recordings, theta rhythms were obvious in the spiking sequences of both types of neuron and in the local field potentials of the stratum radiatum. However, these theta rhythms were all suppressed significantly during the stimulations. Additionally, the results of Pearson's correlation analysis showed that 20-30% variation in the theta rhythms of neuronal firing could be explained by changes of the theta rhythms in local field potentials. High-frequency axonal stimulation might prevent the original rhythmic excitation in afferent fibers and generate new excitation by stimulation pulses per se, thereby suppressing the theta rhythms of individual neuron firing and of local field potentials in the region downstream from stimulation. The results provide new evidence to support the hypothesis that high-frequency stimulation can alter the firing rhythms of neurons, which may underlie the therapeutic effects of deep brain stimulation.


Assuntos
Potenciais de Ação/fisiologia , Axônios/fisiologia , Estimulação Elétrica , Interneurônios/fisiologia , Neurônios Aferentes/fisiologia , Células Piramidais/fisiologia , Animais , Região CA1 Hipocampal/fisiologia , Estimulação Elétrica/métodos , Masculino , Ratos Sprague-Dawley , Ritmo Teta/fisiologia
14.
Neurobiol Aging ; 79: 1-10, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31026617

RESUMO

Age-related impairments in episodic memory have been linked to alterations in encoding-induced neural activity. In young individuals, even prestimulus activity has been shown to influence the encoding of an upcoming stimulus, with ongoing theta and beta oscillations being predictive of subsequent recognition. The present study investigated if these memory-related ongoing oscillations are also affected by aging. In an EEG experiment, healthy older and young individuals performed an encoding task with a subsequent recognition test on picture and word stimuli. The group of younger participants showed an increased oscillatory activity in the lower frequency range (ranging from 3 to 17 Hz) in the pre- and post-stimulus period compared with the older adults. Only in young participants, ongoing beta power during encoding was related to later memory in both stimulus categories, whereas in older participants, this effect was diminished. Interestingly, there was no general age-related decrease in recognition performance. These results indicate that ongoing low beta oscillations might constitute a functional indicator of cognitive aging that reveals itself even before a strong decline in behavioral performance is noticeable, and that could be a potential target for neuromodulatory interventions.


Assuntos
Envelhecimento Cognitivo/fisiologia , Envelhecimento Cognitivo/psicologia , Eletroencefalografia , Envelhecimento Saudável/fisiologia , Envelhecimento Saudável/psicologia , Memória Episódica , Idoso , Ritmo beta/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ritmo Teta/fisiologia
15.
Neural Netw ; 116: 119-138, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31029053

RESUMO

The hippocampal theta rhythm (4-12 Hz) is one of the most important electrophysiological processes in the hippocampus, it participates in cognitive hippocampal functions, such as navigation in space, novelty detection, and declarative memory. We use neural network modeling to study the mechanism of theta rhythm emergence in the CA1 microcircuitry. Our model of the CA1 field includes biophysical representation of major cell types related to the theta rhythm emergence: excitatory pyramidal cells and two types of inhibitory interneurons, PV+ basket cells and oriens lacunosum-moleculare (OLM) cells. The main inputs to the CA1 cells come from the entorhinal cortex via perforant pathway, the CA3 field via Schaffer collaterals, and the medial septum via fimbria-fornix. By computer simulations we investigated the influence of each input, intrinsic parameters of neurons, and connections between neurons on phase coupling between the theta rhythm and the firing of pyramidal, PV+ basket and OLM cells in the CA1. We found that the input from the CA3 field via Schaffercollaterals plays a major role in the formation of phase relations that have been observed in experiments in vivo. The direct input from the medial septum participates in the formation of proper phase relations, but it is not crucial for the production of the theta rhythm in CA1 neural populations.


Assuntos
Região CA1 Hipocampal/fisiologia , Células Piramidais/fisiologia , Ritmo Teta/fisiologia , Animais , Região CA1 Hipocampal/citologia , Córtex Entorrinal/fisiologia , Hipocampo/citologia , Hipocampo/fisiologia , Interneurônios/fisiologia , Neurônios/fisiologia
16.
Mol Brain ; 12(1): 30, 2019 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-30943994

RESUMO

Theta-burst stimulation (TBS) induces short-term potentiation (STP) plus two types of transcriptionally-independent forms of long-term potentiation (LTP), termed LTP1 and LTP2. We have compared the susceptibility of these three types of synaptic plasticity to depotentiation, induced by low frequency stimulation (LFS; 2 Hz for 10 min) at the Schaffer collateral-commissural pathway in area CA1 of adult rat hippocampal slices. In interleaved experiments, STP and LTP were induced by three episodes of either compressed or spaced TBS (cTBS or sTBS). LFS had a more pronounced effect on the LTP induced by the cTBS. One traditional interpretation of these results is a difference in the time-dependent immunity against depotentiation. We suggest an alternative explanation: LFS rapidly reverses STP to reveal a slowly developing LTP. The cTBS protocol induces LTP1 that is moderately sensitive to depotentiation. The sTBS induces an additional component of LTP (LTP2) that is resistant to depotentiation.


Assuntos
Hipocampo/fisiologia , Potenciação de Longa Duração/fisiologia , Sinapses/fisiologia , Animais , Estimulação Elétrica , Depressão Sináptica de Longo Prazo/fisiologia , Masculino , Ratos Sprague-Dawley , Ritmo Teta/fisiologia
17.
Brain Struct Funct ; 224(5): 1697-1709, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30945000

RESUMO

Goal-directed behavior has been shown to be affected by consciously and subliminally induced conflicts. Both types of conflict conjointly modulate behavioral performance, but the underlying neuronal mechanisms have remained unclear. While cognitive control is linked to oscillations in the theta frequency band, there are several mechanisms via which theta oscillations may enable cognitive control: via the coordination and synchronization of a large and complex neuronal network and/or via local processes within the medial frontal cortex. We, therefore, investigated this issue with a focus on theta oscillations and the underlying neuronal networks. For this purpose, n = 40 healthy young participants performed a conflict paradigm that combines conscious and subliminal distractors while an EEG was recorded. The data show that separate processes modulate the theta-based activation and organization of cognitive control networks: EEG beamforming analyses showed that variations in theta band power generated in the supplementary motor area reflected the need for control and task-relevant goal shielding, as both conflicts as well as their conjoint effect on behavior increased theta power. Yet, large networks were not modulated by this and graph theoretical analyses of the efficiency (i.e. small worldness) of theta-driven networks did not reflect the need for control. Instead, theta network efficiency was decreased by subliminal conflicts only. This dissociation suggests that while both kinds of conflict require control and goal shielding, which are induced by an increase in theta band power and modulate processes in the medial frontal cortex, only non-conscious conflicts diminish the efficiency of theta-driven large-scale networks.


Assuntos
Comportamento/fisiologia , Cognição/fisiologia , Estado de Consciência/fisiologia , Rede Nervosa/fisiologia , Adolescente , Adulto , Eletroencefalografia/métodos , Função Executiva/fisiologia , Feminino , Lobo Frontal/fisiologia , Humanos , Masculino , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Ritmo Teta/fisiologia , Adulto Jovem
18.
Biol Psychol ; 145: 62-75, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31004720

RESUMO

The present study investigated the locus of the effect of alerting on response conflict, and examined whether this effect may be interpreted as an alerting-triggered imbalance of speed-accuracy tradeoff (SAT). Participants performed the flanker task with an alerting tone in half of the trials and SAT manipulation. Behavioral results showed the usual increase of the conflict effect (incongruent-congruent flankers) in the alerting trials. This interaction was not affected by SAT manipulation in response times, although accuracy emphasis abolished alerting effects in error rates. Event-related potential (ERP) results showed that alerting increased the conflict by facilitating the selection and activation of stimulus-response links, reflected in modulations of the P3b component, and by enhancing the activation of incorrect response evoked by incongruent flankers, reflected in an increased initial incorrect activation in the lateralized readiness potential (LRP). Time-frequency analysis showed that the alerting-triggered increase of conflict entailed stronger response of executive mechanisms, reflected in a larger conflict-related midfrontal theta-band power. These EEG effects were not affected by SAT manipulation. In conclusion, alerting affects both the emergence of conflict and conflict control, and this alerting-conflict interaction could not be explained in terms of SAT.


Assuntos
Variação Contingente Negativa/fisiologia , Potenciais Evocados/fisiologia , Tempo de Reação/fisiologia , Adulto , Eletroencefalografia , Feminino , Humanos , Masculino , Ritmo Teta/fisiologia , Adulto Jovem
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.
Behav Neurosci ; 133(4): 341-349, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30869951

RESUMO

The primary motor area (M1) has been implicated in visuomotor sequence learning. However, it has been suggested there are multiple neural networks that undertake visuomotor sequence learning. The role of M1 in sequence learning may be specific to learning simple sequences comprising predictable associations between adjacent movements. This study aimed to investigate the role of M1 in learning simple ("first-order conditional") and more complex ("second-order conditional") sequences. It was hypothesized that continuous theta burst stimulation (cTBS) over M1 would result in poorer learning of the simple sequence only. Forty-eight healthy adults received cTBS to either M1 or the parietal lobe or received sham cTBS before immediately completing 2 visuomotor sequence learning tasks. The tasks only differed in relation to the structure (i.e., simple vs. complex) of the sequence. The group who received cTBS over M1 demonstrated significantly poorer learning of the simple sequence in comparison to the more complex sequence. The parietal lobe stimulation and sham stimulation did not affect learning of either sequence. This is the first study to show differential involvement of M1 in visuomotor sequence learning, dependent on sequence structure. The study provides new evidence that sequence learning might be supported by different networks in the brain. Specifically, M1 sequence learning appears to be important for learning simple item-to-item associations but not for more complex sequences. (PsycINFO Database Record (c) 2019 APA, all rights reserved).


Assuntos
Córtex Motor/fisiologia , Aprendizagem Seriada/fisiologia , Adulto , Atenção , Encéfalo , Feminino , Humanos , Aprendizagem/fisiologia , Masculino , Destreza Motora/fisiologia , Rede Nervosa/fisiologia , Lobo Parietal , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Ritmo Teta/fisiologia , Estimulação Magnética Transcraniana/métodos
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