Synchronization Of Alpha Rhythm Research Articles

Changes in alpha rhythm parameters when using the wrist tapping method in patients with generalized genetic epilepsy

Target. To investigate the effect of the EpiTapp® application on alpha rhythm synchronization in patients with genetic generalized epilepsy.Materials and methods. The total sample size was 81 people, including: patients suffering from juvenile myoclonic epilepsy (main group, mean age — 2 7 [23; 38] years) — 30 people; healthy volunteers (control group, mean age — 39 [21; 56] years) — 51 people.Results. The present study showed that wrist tapping using the EpiTapp® application statistically significantly reduced the degree of alpha synchronization in juvenile myoclonic epilepsy. At the same time, a decrease in the synchronization of the alpha rhythm is achieved in 66.7 % of cases.Conclusion. Our results of changes in the bioelectrical activity of the brain after a session of wrist tapping indicate the possibility of using the EpiTapp® application as a non-drug rehabilitation method related to seizure relief programs in patients with juvenile myoclonic epilepsy.

Beyond alpha-band: The neural correlate of creative thinking

The compound nature of creativity entails the interplay of multiple cognitive processes, making it difficult to attribute creativity to a single neural signature. Divergent thinking paradigms, widely adopted to investigate creative production, have highlighted the key role of specific mental operations subserving creativity, such as inhibition of external stimuli, loose semantic associations, and mental imagery. Neurophysiological studies have typically shown a high alpha rhythm synchronization when individuals are engaged in creative ideation. Also, oculomotor activity and pupil diameter have been proposed as useful indicators of mental operations involved in such a thinking process. The goal of this study was to investigate whether beyond alpha-band activity other higher frequency bands, such as beta and gamma, may subserve divergent and convergent thinking and whether those could be associated with a different gaze bias and pupil response during ideas generation. Implementing a within-subjects design we collected behavioral measures, neural activity, gaze patterns, and pupil dilation while participants performed a revised version of the Alternative Uses Task, in which divergent thinking is contrasted to convergent thinking. As expected, participants took longer to generate creative ideas as compared to common ones. Interestingly, during divergent thinking participants displayed alpha synchronization along with beta and gamma desynchronization, more pronounced leftward gaze shift, and greater pupil dilation. During convergent thinking, an opposite pattern was observed: desynchronization in alpha and an increase in beta and gamma rhythm, along with a reduction of leftward gaze shift and greater pupil constriction. The present study uncovered specific neural dynamics and physiological patterns during idea generation, providing novel insight into the complex physiological signature of creative production.

Influence of wrist tapping on alpha rhythm synchronization in healthy adults and adults with juvenile myoclonic epilepsy

Background: The aim of this study was to assess the effect of wrist tapping (WT), according to the author's method, on the synchronization of alpha activity in healthy adults and patients with juvenile myoclonic epilepsy (JME).

Influence of Wrist Tapping on Alpha Rhythm Synchronization in Patients with Juvenile Myoclonic Epilepsy

Background: The aim of this study was to assess the effect of wrist tapping (WT), according to the author's method, on the synchronization of alpha activity in healthy adults and patients with juvenile myoclonic epilepsy (JME). Methods and Results: The study included 71 people of working age, including 51 clinically healthy volunteers (median age - 39[21;56] years) and 20 patients with JME (median age 27[23;35] years). Under the influence of WT in a state of sensory deprivation, statistically significant changes in the alpha peak frequency (APF) (P<0.001) and alpha power (AP) (P<0.05) were found in healthy adults. In JME patients, there were statistically significant changes in the APF (P<0.05) and AP (P<0.05), as well as a statistically significant increase in the ARW (P<0.05) after WT. WT, according to the author's technique, allows reducing the severity of alpha rhythm synchronization and leads to a shift in the peak frequency of the alpha rhythm in the occipital leads towards the alpha-2 sub-frequency range and a decrease in AP in both healthy volunteers and JME patients. At the same time, the alpha range width in the occipital leads is statistically significantly increased in JME patients. Conclusion: The nature of the change in the alpha rhythm, in comparison with the control, indicates the phenomenon of resonance with the frequency of the WT rhythm. The WT effect testifies to the prospects of the clinical application of WT in JME, since it was previously shown that if the selected external frequencies enter into resonance with the neurons of the antiepileptic system, then an antiepileptic effect could be obtained.

Dynamics of the EEG sensorimotor and alpha rhythm amplitude patterns in a training series of controlling the power platform with visual feedback

The study of the EEG alpha reactivity patterns in the prefrontal, central, parietal and occipital regions involved 25 healthy male subjects who participated in four training sessions of controlling the power platform with visual feedback. A significant prefrontal alpha rhythm synchronization was found which was not essentially modulated in a series of subsequent trainings. A significant desynchronization of the occipital alpha was registered for the second session which gradually increased up to the fourth session. The sensorimotor alpha rhythm didn’t show regular patterns. The use of the dominant (right) hand resulted in a significant desynchronization of the parietal alpha in the right hemisphere in the third and the fourth training sessions.

Resting state cortical oscillations of patients with Parkinson disease and with and without subthalamic deep brain stimulation: a magnetoencephalography study.

In this study, we investigate the modification to cortical oscillations of patients with Parkinson disease (PD) by subthalamic deep brain stimulation (STN-DBS). Spontaneous cortical oscillations of patients with PD were recorded with magnetoencephalography during on and off subthalamic nucleus deep brain stimulation states. Several features such as average frequency, average power, and relative subband power in regions of interest were extracted in the frequency domain, and these features were correlated with Unified Parkinson Disease Rating Scale III evaluation. The same features were also investigated in patients with PD without surgery and healthy controls. Patients with Parkinson disease without surgery compared with healthy controls had a significantly lower average frequency and an increased average power in 1 to 48 Hz range in whole cortex. Higher relative power in theta and simultaneous decrease in beta and gamma over temporal and occipital were also observed in patients with PD. The Unified Parkinson Disease Rating Scale III rigidity score correlated with the average frequency and with the relative power of beta and gamma in frontal areas. During subthalamic nucleus deep brain stimulation, the average frequency increased significantly when stimulation was on compared with off state. In addition, the relative power dropped in delta, whereas it rose in beta over the whole cortex. Through the course of stimulation, the Unified Parkinson Disease Rating Scale III rigidity and tremor scores correlated with the relative power of alpha over left parietal. Subthalamic nucleus deep brain stimulation improves the symptoms of PD by suppressing the synchronization of alpha rhythm in somatomotor region.

Dynamics of Induced Cortical Electrical Activity during the Pauses between Target and Trigger Stimuli on Formation of a Set to an Emotionally Negative Facial Expression

Studies in healthy adults (n = 70) using a cognitive set model addressed the effects of increased loading on working memory, imposed by lengthening the pause between the target (facial image) and trigger stimuli, on recognition of a facial emotional expression. Increases in the interstimulus interval from 1 to 8 sec led to increases in set plasticity and decreases in the number of contrast illusions on recognition of facial expressions, along with reductions in trigger stimulus reaction times. Analysis of EEG dynamics in the alpha and theta ranges during individual segments of the interstimulus pause led to a hypothesis for the neural mechanisms of these changes in cognitive activity. The initial hypothesis was: repetition of stimuli with a particular pause leads to learning, which forms an internal representation of the time interval, this serving as a source for modulation of visual attention, decreasing it when no relevant event was expected and increasing it before onset of an event. Induced alpha rhythm synchronization at the middle of the interstimulus pause, which was clearly more marked in plastic forms of the set and in trials in which the facial expression was correctly recognized, was a measure of top-down inhibitory control, suppressing the influences of irrelevant stimuli on the cortex. The dynamics of the theta rhythm during the interstimulus pause evidently result from the emotional memory factor due to recognition of the negative facial expression.

Induced synchronization of alpha rhythm in the time intervals between the visual stimuli at different degrees of set flexibility

In healthy adults (n = 35) was used the model the set study of recognition angry facial expression. The load on working memory by extending the interstimuli time up to 16 sec between the target (facial image) and starting (spot light) stimuli does not lead to a significant slowdown of switching of the set. Differences in the magnitude of the induced synchronization of the alpha rhythm in interstimulus period obtained in the subjects with the change in recognition of emotional facial expressions and the subjects "without errors". At the last group synchronization is clearly more pronounced. The implementation of successive cognitive acts is modulated by selective attention, whichis evident in the level of changes the induced synchronization/desynchronization of alpha range potential. The proposed mechanism "inhibitory control" provides the flexibility of cognitive processes by suppressing effect on cortical processes irrelevant factors during interstimulation pauses. This "protective" mechanism, we believe due to little effect of the loading on working memory.

Психофизиологические признаки высокопластичных форм установки на эмоционально-негативное выражение лица

In a series of studies of influence of past experience on an recognition of emotionally negative facial expression where obtained experimental facts which we consider as the formation signs of under certain conditions high-plastic cognitive (flexible) sets ("not fixed sets", according to D.N. Uznadze) when there switching or updating was not accompanied by illusory distortion of recognition. The studies of this form of set revealed: 1--the induced reaction of synchronization of a teta-rhythm to target stimulus was larger, than in cases with rigid set; 2--the induced reaction of an alpha rhythm to target stimulus is expressed in its synchronization, at the others cases--in a desynchronization; 3--at increase in a time interval between target and trigger stimuli observe alpha rhythm synchronization in the prestimulus period and in time intervals between them, at other cases it wasn't observed; 4--at children this form of set observed at the age of 10-11 years when "mature" set on an facial expression is formed.

Mind over chatter: Plastic up-regulation of the fMRI salience network directly after EEG neurofeedback

Neurofeedback (NFB) involves a brain-computer interface that allows users to learn to voluntarily control their cortical oscillations, reflected in the electroencephalogram (EEG). Although NFB is being pioneered as a noninvasive tool for treating brain disorders, there is insufficient evidence on the mechanism of its impact on brain function. Furthermore, the dominant rhythm of the human brain is the alpha oscillation (8-12 Hz), yet its behavioral significance remains multifaceted and largely correlative. In this study with 34 healthy participants, we examined whether during the performance of an attentional task, the functional connectivity of distinct fMRI networks would be plastically altered after a 30-min session of voluntary reduction of alpha rhythm (n=17) versus a sham-feedback condition (n=17). We reveal that compared to sham-feedback, NFB induced an increase of connectivity within regions of the salience network involved in intrinsic alertness (dorsal anterior cingulate), which was detectable 30 min after termination of training. The increase in salience network (default-mode network) connectivity was negatively (positively) correlated with changes in 'on task' mind-wandering as well as resting state alpha rhythm. Crucially, we observed a causal dependence between alpha rhythm synchronization during NFB and its subsequent change at resting state, not exhibited by the SHAM group. Our findings provide neurobehavioral evidence for the brain's exquisite functional plasticity, and for a temporally direct impact of NFB on a key cognitive control network, suggesting a promising basis for its use to treat cognitive disorders under physiological conditions.

Differential Contribution of Right and Left Parietal Cortex to the Control of Spatial Attention: A Simultaneous EEG-rTMS Study

We have recently shown that interference with repetitive transcranial magnetic stimulation (rTMS) of right posterior intraparietal sulcus (IPS) cortex during the allocation of spatial attention leads to abnormal desynchronization of anticipatory (pretarget) electroencephalographic alpha rhythms (8-12 Hz) in occipital-parietal cortex and the detection of subsequently presented visual targets (Capotosto et al. 2009). Since lesion data suggest that lesions of the right frontoparietal cortices produce more severe and long-lasting deficits of visual spatial attention than lesions of the left hemisphere, here, we used the mentioned rTMS-electroencephalographic procedure to test if the control of anticipatory alpha rhythms by IPS is asymmetrically organized in the 2 hemispheres. Results showed that interference with either left or right IPS during covert spatial attention equally disrupted the normally lateralized anticipatory modulation of occipital visual cortex, with stronger alpha desynchronization contralaterally to the attended visual field. In contrast, only interference with right IPS induced a paradoxical pretarget synchronization of alpha rhythms and bilateral deficits of target identification. These results suggest that the control of spatial topography of anticipatory alpha rhythms in occipital-parietal cortex is shared between left and right IPS cortex, but that right IPS uniquely contributes to a bilateral prestimulus activation of occipital visual cortex.

Low frequency oscillations in rat posterior parietal cortex are differentially activated by cues and distractors

The posterior parietal cortex (PPC) is hypothesized to detect visual cues among competing distractors. Anatomical and neurophysiologic evidence indicates that the rat PPC is part of a network of brain areas involved in directed attention, specifically when new task parameters or conditions are introduced. Here, we test the hypothesis that changes in the local field potential (LFP) of the PPC of rats performing a sustained attention task reflect aspects of detection. Two event-related potentials were observed during detection: the P300 response and the contingent negative variation (CNV). Spectrogram analysis also indicated a detection-specific increase in alpha power in the retention interval of this task. This is consistent with observations from human studies, which indicate that tasks requiring a subject to withhold a response produced a pronounced synchronization of alpha rhythms during the delay, and desynchronization during retrieval. We also found cycles of alpha synchrony and desynchrony in response to a periodic distractor. These cycles were most pronounced in the initial trial block of the distractor when the false alarm rate was highest, and as task performance improved these cycles significantly diminished. This result suggests that alpha cycling in the PPC represent neural activity critical for learning to inhibit distractors. The occurrence of alpha synchronization and desynchronization to attention-demanding stimuli, in addition to the P300 and CNV responses observed during detection, is evidence that rat PPC is involved in sustained attention, particularly in the presence of distractors.

Double frequency synchronization for working memory operation in the brain - a computational study for bridging human scalp EEG data and neural dynamics

Event Abstract Back to Event Double frequency synchronization for working memory operation in the brain - a computational study for bridging human scalp EEG data and neural dynamics Yoko Yamaguchi1*, David Chik1, Masahiro Kawasaki2 and Hideki Oka3 1 RIKEN BSI, Lab for Dynamics of Emergent Intelligence, Japan 2 RIKEN BTCC, Rhythm-based Brain Computation Unit, Japan 3 Osaka University, The Center for Adv Med Eng and Informatics, Japan Current studies on brain dynamics in various levels more and more reveal the dynamical brain coordinated by synchronization of oscillations. In the decade, the synchronization hypothesis for dynamical linking was extensively studied in animals and humans. Most of neural systems are known to show various oscillation frequencies in cellular levels and also during cognitive tasks in human scalp EEG. Among them, complexity of synchfonization dynamics provides fascinating problems for understanding neural mechanisms of intellectual properties. According to the dynamical system theory (e.g. the slaving principle by H Haken), slow oscillations of human EEG, such as the delta, theta and alpha can concern with higher cognitive functions to regulate local processes with fast oscillations. We hypothesize that synchronization network in each frequency band has each role in cognitive functions and that their dynamical linking among modules within the same frequency band or through cross-frequency coupling could execute the real-time computation by implementing multiple constraints for cognitive control. Recently we have reported that EEG theta rhythm related network (4~8 Hz) distributing over frontal midline regions and posterior regions is related with central executive functions (Mizuhara et al. 2007) and furthermore that the theta rhythm network emerges restrictively in manipulation period of working memory(Kawasaki et al. 2010). In the working memory task, alpha rhythm (~10 Hz) around relevant sensory regions is observed in both of storage period and operation period. interestingly, theta and alpha rhythms exhibit one to two phase-locking in the manipulation period. The network mechanism of this double frequency synchronization and its possible functional mechanism are unsolved. In this paper, we propose a alpha-theta cross frequency coupling network model for the working memory task. In the model, alpha oscillation networks are described by flip-flop oscillation networks (Colliaux et al,. 2009). A limit cycle attractor in the up state of the associative memory network represents the working memory storage. Theta network is assumed to consist of frontal midline module and sensory modality specific modules with mutual coupling. By introducing a coupling between theta and alpha rhythm units, we show theta network can regulate alpha rhythm synchronization so that dynamically linking among alpha oscillations can retrieve or manipulate memory. This is in agreement with the results suggested by Kawasaki et al. (2010). We conclude that double frequency phase locking between theta and alpha oscillations can work for cognitive control through hierarchical dynamical linking. Then, for the sake of direct comparison with our oscillation network model and human EEG scalp data, we developed a simulation system of scalp EEG by assuming electronic charge in a given location of the brain. Our programming Using InsilicoML and InsilicoDE, showed usefulness of this system on basic simulation and also suggested possible computational neuroscience approach from complex neural dynamics for understanding cognitive functions. This study was partially supported by Grant-in-Aid for Scientific Research on Innovative Areas No. 4103. The simulation study is supported by physiome.jp and dynamic brain platform (DBPF).

Diagnosis of epilepsy with the level of spatial alpha rhythm synchronization

Diagnosis of epilepsy with the level of spatial alpha rhythm synchronization

Control of emotional behavior based on biological feedback

With the use of an original technique, we studied the mechanisms of a self-photostimulation-induced effect on the emotional behavior of intact and stressed rats. The technique is based on free selection of the parameters of photostimulation by the animals; the frequency range (4, 6 and 9 sec−1) was close to that of EEG potentials. After a series of self-photostimulation sessions, the arterial pressure, heart rate, and tension of the heart rhythm in rats with experimental emotional stress-related hypertonia decreased. The EEGs of these animals demonstrated suppression of the seizure activity, formation of the slow-wave activity in the neocortex, and synchronization of alpha rhythm in the limbic structures. Possibilities for balancing the emotional homeostasis with the use of self-photostimulation, which promotes normalization of the heart electrogenesis and vascular responsiveness, are discussed.