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Previous research established that rhythmic sensory stimulation can affect subsequent stimulus perception, possibly through 'entrainment' of oscillations in the brain. Alpha frequency is a natural target for visual entrainment, because fluctuations in posterior alpha oscillations have been linked to visual target detection or discrimination. On the other hand, alpha oscillations also relate to attentional mechanisms, such as attentional orienting or selection. Previous visual alpha entrainment studies focused on differential processing of targets presented in-phase with the preceding rhythmic stimulation relative to out-of-phase targets (an 'SOA effect'), putatively related to the phase of entrained neuronal alpha oscillations. Fewer studies probed the consequences of rhythmic alpha stimulation for attention mechanisms related to alpha power. Here, we asked whether alpha stimulation of one hemifield has similar effects on reaction times as we see for increased alpha synchronization in magneto/electroencephalography (M/EEG) studies (i.e., more alpha means impaired processing and functional inhibition). We implemented a task inspired by attention studies, assessing reaction times to ipsilateral vs. contralateral visual targets, with and without concurrent presentation of distractors. Yet, in place of any attention cues, we presented a rhythmic, vs. arrhythmic, alpha-frequency train of visual flashes to one hemifield, in a large sample size (N = 115) in an online experiment. We found clear evidence that flash train rhythmicity did not impact task performance. We also found that the spatial congruence between the unilateral flash train and the subsequent visual target did impact response times but only in the presence of contralateral distractor stimuli. We discuss implications, limitations and future directions.

Contexte : La régulation émotionnelle est un ensemble de processus responsables du contrôle, de l’évaluation et de l’ajustement des émotions dans un objectif. Les résultats d’imagerie fonctionnelle s’accordent sur l’implication des structures frontales et limbiques tandis que les résultats en neurophysiologie, encore rares, suggèrent un rôle du rythme alpha dans l’induction émotionnelle et du rythme thêta dans la régulation. Objectifs et hypothèses : Notre objectif était d’étudier le rythme thêta et alpha pendant la réévaluation de stimuli déplaisants. Nous avons émis l’hypothèse que l’activité alpha serait modulée lors de l’induction émotionnelle seulement tandis que l’activité thêta préfrontale serait positivement corrélée à une régulation réussie. Méthode : Vingt-quatre participants sains ont été enregistrés avec 64 électrodes EEG alors qu’ils regardaient passivement ou réévaluaient des images négatives et neutres. Les rythmes thêta et alpha ont été comparés lors de l’induction émotionnelle puis dans les conditions de maintien, de diminution et d’augmentation de l’émotion, et une localisation de la source a estimé les générateurs. Résultats : Le rythme alpha était non sensible à l’induction et à la régulation. L’activité thêta était systématiquement plus élevée dans la condition de régulation à la hausse que dans la condition de maintien (p=.04) principalement au début de la régulation (1-3 sec) pour thêta bas et plus tard (5-7 sec) pour le thêta haut avec comme générateur du thêta bas le gyrus frontal moyen et le cortex cingulaire antérieur dorsal. Conclusion : Le rythme thêta était impliqué dans les processus de réévaluation à la hausse de l’émotion., Context: Emotion regulation is a set of processes responsible for controlling, evaluating and adjusting reactions to achieve a goal. Results derived from magnetic resonance imaging agreed on the involvement of frontal and limbic structures in this process. Findings using cognition and physiology interactions are still scarce but suggest a role for alpha rhythm in emotional induction and theta in regulation. Objectives and hypotheses: Our goal was to investigate theta and alpha rhythm during the reappraisal of aversive stimuli. We hypothesized that an implication of alpha rhythm in emotional induction only and an increase in prefrontal theta rhythm positively correlated with successful regulation. Method: Twenty-four healthy participants were recorded with 64 EEG electrodes while asked to passively watch or reappraise negative pictures. Theta and alpha rhythms were compared across maintain, decrease and increase regulation conditions, and a source localization estimated the generators. Results: Theta activity was consistently higher in the upregulation than in the maintenance condition (p=.04) for the entire control period, but mainly at the beginning of regulation (1-3 sec) for low-theta and later (5-7 sec) for high-theta. Moreover, our results confirm that a low-theta generator correlated with mainly the middle frontal gyrus and the dorsal anterior cingulate cortex during upregulation. Theta was sensitive to emotion upregulation, whereas the alpha oscillation was non-sensitive to emotion induction and regulation. Conclusion: The low-theta rhythm was involved explicitly in emotion upregulation processes that occur at a definite time during reappraisal, whereas the alpha rhythm was not altered by emotion induction and regulation.

Cognitive control allows to flexibly guide behaviour in a complex and ever-changing environment. It is supported by theta band (4-7 Hz) neural oscillations that coordinate distant neural populations. However, little is known about the precise neural mechanisms permitting such flexible control. Most research has focused on theta amplitude, showing that it increases when control is needed, but a second essential aspect of theta oscillations, their peak frequency, has mostly been overlooked. Here, using computational modelling and behavioural and electrophysiological recordings, in three independent datasets, we show that theta oscillations adaptively shift towards optimal frequency depending on task demands. We provide evidence that theta frequency balances reliable set-up of task representation and gating of task-relevant sensory and motor information and that this frequency shift predicts behavioural performance. Our study presents a mechanism supporting flexible control and calls for a reevaluation of the mechanistic role of theta oscillations in adaptive behaviour. Senoussi et al. present modelling, behavioural and neural evidence that frontal theta oscillations (4-7 Hz) shift their peak frequency in response to task demands to support flexible task implementation.

We studied the effect of optical stimulation (10 Hz) on the effectiveness of mnestic activity in the n-back task in healthy subjects (n=32). EEG was recorded at all stages of the examination. The absolute values of the spectral power of the 10 Hz frequency (μV2) of the alpha range were calculated. According to the results of the test without optical stimulation, the examinees were divided into groups with high (group 1) and low (group 2) task performance. In the initial state, the spectral power of 10 Hz was significantly higher in group 1 subjects. Under conditions of screen flickering, the results became poorer in group 1 and better in group 2 in comparison with the results under normal conditions. These changes were accompanied by an increase in the spectral power of 10 Hz only in group 2 subjects. These findings can provide the basis for the development of practical recommendations for improving the mnestic functions in patients with consideration for the individual characteristics of their initial EEG.

Objective Studies of the effect of valproate (VPA) on the background EEG have shown varying results. Therefore, we compared the effect of VPA and levetiracetam (LEV) on the EEG alpha peak frequency (APF). Methods We retrospectively examined the APF in resting-state EEG of patients undergoing inpatient video-EEG monitoring (VEM) during withdrawal of VPA or LEV. We assessed APF trends by computing linear fits across individual patients’ APF as a function of consecutive days, and correlated the APF and daily antiseizure medication (ASM) doses on a single-patient and group level. Results The APF in the VPA-group significantly increased over days with falling VPA doses (p = 0.005, n = 13), but did not change significantly in the LEV-group (p = 0.47, n = 18). APF correlated negatively with daily ASM doses in the VPA-group (average of r = −0.74 ± 0.12 across patients, p = 0.0039), but not in the LEV-group (average of r = −0.17 ± 0.18 across patients, p = 0.4072). Conclusions Our results suggest that VPA treatment slows the APF. This APF reduction correlates with the daily dose of VPA and is not present in LEV treatment. Significance Our study identifies a VPA-related slowing of the APF even in patients without electroencephalographic or overt clinical signs of encephalopathy.

Purpose: This study was done to analyse the influence of fixed dental prosthesis (FDP) on brain function by analysing power spectral density of partially edentulous patients Materials and Methods: The study included unilateral missing mandibular molar replacement patients. The patients were restored with three-unit metal ceramic FDP restorations. The cognitive function was analysed with a mental state questionnaire. Power spectral density (PSD) analysis of EEG alpha waves was made pre- treatment, post treatment and 3 months after FDP treatment to analyse the brain function. The data in various phases were obtained before and after chewing. The results were statistically analysed. Results: The mean pre and post treatment PSD was 0.0175 (SD ±0.0132) and 0.0178 (SD ±0.0135). The mean post treatment PSD after three months was 0.024 (SD± 0.019). The results were analysed with repeated ANOVA and were statistically significant.( P < 0.01).Conclusion: The study displayed improvement in brain function of partially edentulous patients with FDP rehabilitation

Background Cue-reactivity is the array of responses that smokers exhibit when exposed to conditioned and contextual stimuli previously associated to substance use. The difficulty to experimentally recreate the complexity of smokers’ spatial experience and context requires more ecological models. Virtual reality (VR) creates a state of immersion close to reality allowing controlled assessments of behavioral responses. To date, no studies investigated brain activation associated to smoking cue-reactivity in VR using electroencephalography (EEG). Aims To investigate whether a VR cue-reactivity paradigm (a) may increase smoking craving, (b) is feasible with EEG recording, and (c) induces craving levels associated to EEG desynchronization. Methods Smokers (N = 20) and non-smokers (N = 20) were exposed to neutral and smoking-related VR scenarios, without and with smoking conditioned stimuli, respectively. EEG was recorded from occipital and parietal leads throughout the sessions to assess alpha band desynchronization. Smoking and food craving and presence visual analogue scales (VAS) were assessed during the session. Results To be smoker, but not non-smoker, significantly influenced smoking craving VAS induced by smoking cue VR but not by neutral VR. No significant food craving changes was observed during the VR sessions. The new finding was that EEG alpha band power in posterior leads was significantly increased by the smoking context scenario only in smokers, and that the degree of smoking (i.e., heavy vs. light) was significantly associated to this neurophysiological measure. Conclusions This study demonstrated, for the first time, the feasibility of EEG recording in a VR setting, suggesting that EEG desynchronization may be a neurophysiological marker of smoking cue-reactivity.

Objective Chronic pain studies investigating the ability to detect sensory processing differences related to thalamic gating using electroencephalographic (EEG) alpha have yielded conflicting results. Alpha’s basic psychometric properties in pain populations requires further study. The present study reports on the test–retest reliability and internal consistency of EEG alpha power in older adults with chronic knee pain. Methods Repeated EEG alpha power measurements were taken of older adults (N = 31) with chronic knee pain across two sessions separated by a ten-day period associated with a pilot clinical trial study. Recordings included resting periods (eyes open and eyes closed) as well as periods involving a pain management activity. Results Most single alpha-power measures and all within-participant averages of alpha obtained within a session showed high internal consistency (Cronbach’s α > 0.7) and satisfactory-to-excellent re-test reliability (Pearson’s rs > 0.6) of both alpha power and alpha blocking (eyes closed minus eyes open) across repeated conditions. Conclusions EEG alpha power seems mostly reliable and consistent, particularly when participants’ eyes are closed, after a period of habituation, and when alpha measures are averaged as within-participant estimates. Significance This analysis suggests that within-subject averages of EEG alpha are the most reliable for developing indices of chronic knee pain.

Objective Global EEG alpha activity is negatively correlated with skin conductance level (SCL), supporting alpha as an inverse marker of arousal. Frequency Principal Components Analysis (f-PCA) of resting EEG amplitude spectra has demonstrated natural components in the alpha band of healthy persons. This is a preliminary exploration of whether such components differ with arousal, possibly underpinning the anomalous ADHD hypoarousal link to reduced alpha. Method Twenty-seven right-handed undergraduate students participated in three 2 minute blocks of resting eyes-open/closed EEG and SCL: EO1, EC, EO2. For each condition, mean EEG spectra were submitted to separate f-PCAs. Results The inverse alpha/SCL relationship was confirmed for band amplitudes. EO had two alpha components; both correlated negatively with SCL. EC alpha contained four components, but only one had a substantial negative correlation with SCL; two had no relationship, suggesting natural alpha components with different non-arousal functionality in EC. Conclusion Some alpha components in both EC and EO reflect arousal, with other non-arousal components in EC. Our f-PCA approach offers insight into previously-noted alpha anomalies in disorders such as ADHD. Significance This proof of concept demonstration in typical participants may provide the basis for a new research effort in clinical disorders involving atypical arousal patterns.

In this preregistered study (https://osf.io/s4rm9) we investigated the behavioural and neurological [electroencephalography; alpha (attention) and theta (effort)] effects of dynamic non-predictive social and non-social cues on working memory. In a virtual environment realistic human-avatars dynamically looked to the left or right side of a table. A moving stick served as a non-social control cue. Kitchen items were presented in the valid cued or invalid un-cued location for encoding. Behavioural findings showed a similar influence of the cues on working memory performance. Alpha power changes were equivalent for the cues during cueing and encoding, reflecting similar attentional processing. However, theta power changes revealed different patterns for the cues. Theta power increased more strongly for the non-social cue compared to the social cue during initial cueing. Furthermore, while for the non-social cue there was a significantly larger increase in theta power for valid compared to invalid conditions during encoding, this was reversed for the social cue, with a significantly larger increase in theta power for the invalid compared to valid conditions, indicating differences in the cues’ effects on cognitive effort. Therefore, while social and non-social attention cues impact working memory performance in a similar fashion, the underlying neural mechanisms appear to differ.

Covert spatial attention is associated with spatially specific modulation of neural activity as well as with directional biases in fixational eye-movements known as microsaccades. Recently, this link has been suggested to be obligatory, such that modulation of neural activity by covert spatial attention occurs only when paired with microsaccades toward the attended location. Here we revisited this link between microsaccades and neural modulation by covert spatial attention in humans. We investigated spatial modulation of 8-12 Hz EEG alpha activity and microsaccades in a context with no incentive for overt gaze behaviour: when attention is directed internally within the spatial layout of visual working memory. In line with a common attentional origin, we show that spatial modulations of alpha activity and microsaccades co-vary: alpha lateralisation is stronger in trials with microsaccades toward compared to away from the memorised location of the to-be-attended item and occurs earlier in trials with earlier microsaccades toward this item. Critically, however, trials without attention-driven microsaccades nevertheless showed clear spatial modulation of alpha activity – comparable to the neural modulation observed in trials with attention-driven microsaccades. Thus, directional biases in microsaccades are correlated with neural signatures of covert spatial attention, but they are not a prerequisite for neural modulation by covert spatial attention to be manifest.

BackgroundPeak individual alpha frequencies (IAF) extracted from an EEG exam can provide novel sources of information regarding brain function. This information can help measure and track changes in cognition arising from conditions such as concussion or unhealthy aging.Objective 1To validate a method for combining eyes-closed EEG with eyes-closed audio P300 ERP in order to streamline testing times involved in IAF extraction.Objective 2To validate age-stratified target ranges of IAF collected in clinic against published researchObjective 3To validate the stability of IAF for data collected in routine clinical settings.ParticipantsTwo thousand twenty-five subjects aged 13-90.MethodsEEG with audio P300 was collected as part of a health screening exam for studies through Colorado University, Children’s Hospital Colorado, Boone Heart Institute, WAVi Co., and various clinics alongside other clinical evaluations.Results(1) No differences were seen between IAF extracted during an eyes-closed resting and the P300 protocol. (2) The age-related AF trends measured in clinic match the age-related trends from previous research. (3) IAF remained stable over the course of 0-2 years in a test-retest dataset.ConclusionIn-clinic measures of peak EEG frequency corroborate the age-related trends of published research taken over the last several decades and IAF. These results also confirm that IAF is a stable trait, making it useful for within-person longitudinal tracking. By following changes in IAF over time, deviations from normal CNS functioning, such as onset or progression of disease, can be monitored.

Our recent study demonstrated that prefrontal transcranial photobiomodulation (tPBM) with 1064-nm laser enables significant changes in EEG rhythms, but these changes might result from the laser-induced heat rather than tPBM. This study hypothesized that tPBM-induced and heat-induced alterations in EEG power topography were significantly distinct. We performed two sets of measurements from two separate groups of healthy humans under tPBM (n = 46) and thermal stimulation (thermo_stim; n = 11) conditions. Each group participated in the study twice under true and respective sham stimulation with concurrent recordings of 64-channel EEG before, during, and after 8-min tPBM at 1064 nm or thermo_stim with temperature of 33–41 °C, respectively. After data preprocessing, EEG power spectral densities (PSD) per channel per subject were quantified and normalized by respective baseline PSD to remove the power-law effect. At the group level for each group, percent changes of EEG powers per channel were statistically compared between (1) tPBM vs light-stimulation sham, (2) thermo_stim vs heat-stimulation sham, and (3) tPBM vs thermo_stim after sham exclusion at five frequency bands using the non-parametric permutation tests. By performing the false discovery rate correction for multi-channel comparisons, we showed by EEG power change topographies that (1) tPBM significantly increased EEG alpha and beta powers, (2) the thermal stimulation created opposite effects on EEG power topographic patterns, and (3) tPBM and thermal stimulations induced significantly different topographies of changes in EEG alpha and beta power. Overall, this study provided evidence to support our hypothesis, showing that the laser-induced heat on the human forehead is not a mechanistic source causing increases in EEG power during and after tPBM.

The default mode network (DMN) is the most prominent intrinsic connectivity network, serving as a key architecture of the brain’s functional organization. Conversely, dysregulated DMN is characteristic of major neuropsychiatric disorders. However, the field still lacks mechanistic insights into the regulation of the DMN and effective interventions for DMN dysregulation. The current study approached this problem by manipulating neural synchrony, particularly, alpha (8-12 Hz) oscillations, a dominant intrinsic oscillatory activity that has been increasingly associated with the DMN in both function and physiology. Using high-definition (HD) alpha-frequency transcranial alternating current stimulation (α-tACS) to stimulate the cortical source of alpha oscillations, in combination with simultaneous EEG-fMRI, we demonstrated that α-tACS (vs. sham control) not only augmented EEG alpha oscillations but also strengthened fMRI and (source-level) alpha connectivity within the core of the DMN. Importantly, increase in alpha oscillations mediated the DMN connectivity enhancement. These findings thus identify a mechanistic link between alpha oscillations and DMN functioning. That transcranial alpha modulation can upregulate the DMN further highlights an effective non-invasive intervention to normalize DMN functioning in various disorders.Significance StatementIn the brain’s functional organization, the default mode network (DMN) represents a key architecture, whose dysregulation is involved in a host of major neuropsychiatric disorders. However, insights into the regulation of the DMN remain scarce. Through neural synchrony, the alpha-frequency oscillation represents another key underpinning of the brain’s organization and is thought to share an inherent interdependence with the DMN. Here, we demonstrated that transcranial alternating current stimulation of alpha oscillations (α-tACS) not only augmented alpha activity but also strengthened connectivity of the DMN, with the former serving as a mediator of the latter. These findings reveal that alpha oscillations can support DMN functioning. In addition, they identify an effective non-invasive approach to regulate the DMN via α-tACS.

We tested the role of hypnotic suggestibility, involuntariness, pain expectation, and subjective hypnotic depth in the prediction of placebo analgesia (PA) responsiveness. We also tested the link of lower and upper alpha sub-band (i.e., 'alpha1' and 'alpha2') power changes with tonic PA responding during waking and hypnosis conditions. Following an initial PA manipulation condition, we recorded EEG activity during waking and hypnosis under two treatments: (1) painful stimulation (Pain); (2) painful stimulation after application of a PA cream. Alpha1 and alpha2 power were derived using the individual alpha frequency method. We found that (1) PA in both waking and hypnosis conditions significantly reduced relative pain perception; (2) during waking, all the above mentioned contextual measures were associated with pain reduction, while involuntariness alone was associated with pain reduction within hypnosis. Enhanced alpha2 power at the left-parietal lead was solely associated with pain reduction in waking, but not in hypnosis condition. Using multiple regression and mediation analyses we found that: (i) during waking, the enhancement of relative left-parietal alpha2 power, directly influenced the enhancement in pain reduction, and, indirectly, through the mediating positive effect of involuntariness; (j) during hypnosis, the enhancement of left-temporoparietal alpha2 power, through the mediation of involuntariness, influenced pain reduction. Current findings obtained during waking suggest that enhanced alpha2 power may serve as a direct-objective measure of the subjective reduction of tonic pain in response to PA treatment. Overall, our findings suggest that placebo analgesia during waking and hypnosis involves different processes of top-down regulation.

For decades, the frontal alpha asymmetry (FAA) – a disproportion in EEG alpha oscillations power between right and left frontal channels – has been one of the most popular measures of depressive disorders (DD) in electrophysiology studies. Patients with DD often manifest a left-sided FAA: relatively higher alpha power in the left versus right frontal lobe. Recently, however, multiple studies failed to confirm this effect, questioning its reproducibility. Our purpose is to thoroughly test the validity of FAA in depression by conducting a multiverse analysis – running many related analyses and testing the sensitivity of the effect to changes in the analytical approach – on data from five independent studies. Only 13 of the 270 analyses revealed significant results. We conclude the paper by discussing theoretical assumptions underlying the FAA and suggest a list of guidelines for improving and expanding the EEG data analysis in future FAA studies.

Recent evidence suggests that relative to nonshy children, shy children exhibit a lower overall frontal EEG alpha/delta ratio (ADR) during middle childhood, possibly reflecting relatively less frontal brain maturation at this age. We examined this same ADR measure in relation to the stability of observed shyness and parent-reported child social anxiety measured across two laboratory visits separated by approximately 1 year during late childhood in 51 children (33% female, age range 10-16 years). We found that the overall frontal ADR score was significantly lower among children with high, stable observed shyness and parent-reported child social anxiety compared to children in the low, stable class. Findings provide convergent evidence suggesting that the stability of shyness in late childhood may be linked to relatively less overall frontal brain maturation at this age. We speculate on the adaptive function of delaying frontal brain maturation in the origins and maintenance of children's shyness.

What is your brain doing while your mind is wandering? This study used a within-subjects experience-sampling design to test whether episodes of mind-wandering during a demanding cognitive task are associated with increases in EEG alpha power. Alpha refers to cyclic oscillations in EEG activity at 8-12 Hz, and has been previously correlated with internally rather than externally directed cognition. Participants completed a speeded performance task with more than 800 trials while EEG was recorded. Intermittent experience-sampling probes asked participants to indicate whether their mind was wandering or on-task. Participants reported mind-wandering in response to approximately half of the probes. EEG alpha power was significantly higher preceding probes to which participants reported mind-wandering, compared with probes to which participants reported being on task. These findings imply that dynamic changes in alpha power may prove a valuable tool in studying momentary fluctuations in mind-wandering.

In this study, neural-signal electroencephalogram (EEG) methods to improve human-building interaction under different indoor air quality conditions were investigated. Experiment was conducted to study correlations between EEG frequency bands and subjective perception as well as task performance. Machine learning-based EEG pattern recognition methods as feedback mechanisms were also investigated. Results showed that EEG theta band (4–8 Hz) correlated with subjective perceptions, and EEG alpha band (8–13 Hz) correlated with task performance. These EEG indices could be utilized as more objective metrics in addition to questionnaire and task-based metrics. For the machine learning-based EEG pattern recognition methods, the linear discriminant analysis (LDA) and support vector machine (SVM) classifiers can classify mental states under different indoor air quality conditions with high accuracy. In general, the EEG theta and alpha bands as more objective indices and the machine learning-based EEG pattern recognition methods as real-time feedback mechanisms have good potential to improve the human-building interaction.

It is aimed at finding the correlation between golfer’s performance and EEG signals from the successful and unsuccessful putts. To address this issue, the inertial motion capture(mocap) system and wireless Emotiv equipment have been introduced to collect simultaneously the golfer’s performance data and EEG signals in 6 right-handed expert golfers and 6 right-handed amateur golfers. Inertial mocap modules were placed on right arm, right leg of subjects and the club-head. Subjects stood upright on a golf green simulator while playing 80 golf putts with Emotiv recording simultaneously. Then, wavelet packet decomposition(WPD) was used for extracting the alpha wave: low-frequency(8–10 Hz) and high-frequency(10–12 Hz). The correlation of alpha rhythm power spectral in two electrodes should be estimated to analyze the relationship between successful and unsuccessful putts and EEG signals. The results of the statistical variance indicated that AF3-AF4(left ahead frontal-right ahead frontal areas) and O1-O2(left occipital-right occipital areas) had a higher spectral correlation of alpha rhythm in successful putts than that in unsuccessful putts. Alpha rhythm (8–12 Hz) in the successful putts was higher than that in the unsuccessful condition and fluctuated obviously. F3-AF3(frontal-ahead frontal areas), F3-O2(left frontal-occipital areas), F4-F8, F4-O2(right frontal-occipital areas) and F4-AF3 had a higher negative correlation of successful putts from -2 s to zero time than that from the -5 s to -2 s of the putting time. P7-AF3(parietal-ahead frontal areas) had a higher negative correlation of both successful putts and unsuccessful putts from -2 s to zero time than that from the -5 s to -2 s of the putting time. P7-O2(parietal-occipital areas) had a higher negative correlation of successful putts from -2 s to zero time than that from the -5 s to -2 s of the putting time. P8-AF3 and P8-O2 had a higher negative correlation of the successful putts from -2 s to zero time than that from the -5 s to -2 s of the putting time. Experimental results of the club-head putting acceleration showed that the putting acceleration of overall high-skilled golfer was more stable than that of amateur golfers’, that had a higher successful rate of putts. Statistical results of putting acceleration of the professional players and amateur players indicated that professional players had a higher successful and stable putts than others. Experimental results demonstrated that alpha rhythm plays a major role in cognition, judgment, sensory and motor.

Working memory contents can be prioritized by retroactively deploying attention within memory. This is broadly interpreted as evidence of a concentration of memory resources to the attended, to-be-remembered stimulus. However, online attentional selection is known to additionally depend on distractor inhibition, raising the viable alternative that attentional deployment in working memory involves inhibitory control processes. Here, we demonstrate that active inhibition plays a central role in the deployment of attention in working memory. We do so using a retroactive cueing paradigm, where a briefly presented memory array is followed by a cue indicating a to-be-remembered target (Experiment 1) or a to-be-forgotten distractor (Experiment 2). We identify discrete indices of target selection and distractor inhibition in lateralized oscillatory activity over visual areas. When a retroactive cue identifies the location of a target, results show rapid decrease of lateral, target-elicited alpha band activity, representing attentional orienting toward the target. This is followed only later by emergence of an increase in distractor-elicited alpha activity, reflecting distractor inhibition. In contrast, when the retroactive cue identifies a distractor, evidence of distractor inhibition emerges first, only later followed by target selection. These results thus demonstrate that separate excitatory and inhibitory processes underlie the deployment of attention on the level of working memory representations.

The allocation of mental workload is critical to maintain cognitive-motor performance under various demands. While mental workload has been investigated during performance, limited efforts have examined it during cognitive-motor learning, while none have concurrently manipulated task difficulty. It is reasonable to surmise that the difficulty level at which a skill is practiced would impact the rate of skill acquisition and also the rate at which mental workload is reduced during learning (relatively slowed for challenging compared to easier tasks). This study aimed to monitor mental workload by assessing cortical dynamics during a task practiced under two difficulty levels over four days while perceived task demand, performance, and electroencephalography (EEG) were collected. As expected, self-reported mental workload was reduced, greater working memory engagement via EEG theta synchrony was observed, and reduced cortical activation, as indexed by progressive EEG alpha synchrony was detected during practice. Task difficulty was positively related to the magnitude of alpha desynchrony and accompanied by elevations in the theta-alpha ratio. Counter to expectation, the absence of an interaction between task difficulty and practice days for both theta and alpha power indicates that the refinement of mental processes throughout learning occurred at a comparable rate for both levels of difficulty. Thus, the assessment of brain dynamics was sensitive to the rate of change of cognitive workload with practice, but not to the degree of difficulty. Future work should consider a broader range of task demands and additional measures of brain processes to further assess this phenomenon.

EEG resting state alpha asymmetry is one of the most widely investigated forms of functional hemispheric asymmetries in both basic and clinical neuroscience. However, studies yield very inconsistent results. One crucial prerequisite to obtain reproducible results is the reliability of the index of interest. There is a body of research suggesting a moderate to good reliability of EEG resting state alpha asymmetry, but unfortunately sample sizes in these studies are typically small. This study presents the first large scale short-term reliability study of frontal and parietal EEG resting state alpha asymmetry. We used the Dortmund Vital Study data set containing 541 participants. In each participant, EEG resting state was recorded eight times, twice with their eyes opened, twice with their eyes closed, each on two different EEG systems. We found good reliability of EEG alpha power and alpha asymmetry on both systems. Interestingly, we found no reliable alpha asymmetry in frontomedial brain regions, one of the most investigate brain regions in alpha asymmetry research. Furthermore, we investigated the link between EEG alpha asymmetry and handedness, since previous studies showed that right-handedness is associated with higher rightward alpha asymmetry. Our results only partly replicate this association. In conclusion, our results suggest that while EEG alpha asymmetry is an overall reliable measure, frontal alpha asymmetry should be assessed by using multiple electrode pairs. Furthermore, the question of EEG alpha asymmetry’s association with handedness remains unsettled and needs further investigation.

Although there is consistent evidence that exposure to radiofrequency electromagnetic fields (RF-EMF) increases the spontaneous resting alpha spectral power of the electroencephalogram (EEG), the reliability of this evidence is uncertain as some studies have also failed to observe this effect. The present study aimed to determine whether the effect of RF-EMF exposure on EEG alpha power depends on whether EEG is derived from eyes open or closed conditions and assessed earlier (5-min) versus later (25-min) in the exposure interval. Thirty-six adults participated in three experimental sessions, each involving one exposure: "Sham," "Low," and "High" RF-EMF corresponding to peak spatial specific absorption rates averaged over 10 g of 0, 1, and 2 W/kg, respectively. Resting EEG was recorded at baseline (no exposure), during, and after exposure. Alpha power increase was found to be greater for the eyes open than eyes closed EEG during both the High (P = 0.04) and Low (P = 0.04) RF-EMF exposures. There was also a trend toward it being larger at the end, versus the start of the "High" 30-min exposure (P 0.01; eyes open condition). This suggests that the use of eyes closed conditions, and insufficient RF-EMF exposure durations, are likely explanations for the failure of some studies to detect an RF-EMF exposure-related increase in alpha power, as such methodological choices decrease signal-to-noise ratios and increase type II error.

ObjectiveAlpha-neurofeedback (α-NFB) is a novel therapy which trains individuals to volitionally increase their alpha power to improve pain. Learning during NFB is commonly measured using static parameters such as mean alpha power. Considering the biphasic nature of alpha rhythm (high and low alpha), dynamic parameters describing the time spent by individuals in high alpha state and the pattern of transitioning between states might be more useful. Here, we quantify the changes during α-NFB for chronic pain in terms of dynamic changes in alpha states.MethodsFour chronic pain and four healthy participants received five NFB sessions designed to increase frontal alpha power. Changes in pain resilience were measured using visual analogue scale (VAS) during repeated cold-pressor tests (CPT). Changes in alpha state static and dynamic parameters such as fractional occupancy (time in high alpha state), dwell time (length of high alpha state) and transition probability (probability of moving from low to high alpha state) were analyzed using Friedman’s Test and correlated with changes in pain scores using Pearson’s correlation.ResultsThere was no significant change in mean frontal alpha power during NFB. There was a trend of an increase in fractional occupancy, mean dwell duration and transition probability of high alpha state over the five sessions in chronic pain patients only. Significant correlations were observed between change in pain scores and fractional occupancy (r = −0.45, p = 0.03), mean dwell time (r = -0.48, p = 0.04) and transition probability from a low to high state (r = -0.47, p = 0.03) in chronic pain patients but not in healthy participants.ConclusionThere is a differential effect between patients and healthy participants in terms of correlation between change in pain scores and alpha state parameters. Parameters providing a more precise description of the alpha power dynamics than the mean may help understand the therapeutic effect of neurofeedback on chronic pain.

Background: Although cognitive decline (CD) is associated with increased post-operative morbidity and mortality, routinely screening patients remains difficult. The main objective of this prospective study is to use the EEG response to a Propofol-based general anesthesia (GA) to reveal CD.Methods: 42 patients with collected EEG and Propofol target concentration infusion (TCI) during GA had a preoperative cognitive assessment using MoCA. We evaluated the performance of three variables to detect CD (MoCA < 25 points): age, Propofol requirement to induce unconsciousness (TCI at SEF95: 8–13 Hz) and the frontal alpha band power (AP at SEF95: 8–13 Hz).Results: The 17 patients (40%) with CD were significantly older (p < 0.001), had lower TCI (p < 0.001), and AP (p < 0.001). We found using logistic models that TCI and AP were the best set of variables associated with CD (AUC: 0.89) and performed better than age (p < 0.05). Propofol TCI had a greater impact on CD probability compared to AP, although both were complementary in detecting CD.Conclusion: TCI and AP contribute additively to reveal patient with preoperative cognitive decline. Further research on post-operative cognitive trajectory are necessary to confirm the interest of intra operative variables in addition or as a substitute to cognitive evaluation.

Transcranial Direct Current Stimulation (tDCS) has been used as an alternative treatment for pain reduction in fibromyalgia. In this study, in addition to behavioral measures, we analyzed oscillations in alpha 2 frequency band in the frontal, occipital, and parietal regions, in response to the application of two neuromodulation protocols in fibromyalgia. The study was a randomized, double-blind, placebo-controlled clinical trial with 31 women diagnosed with fibromyalgia. The participants were allocated to three groups with the anodic stimulation applied on the left motor cortex: Group 1, for five consecutive days; Group 2, for 10 consecutive days; and Group 3, sham stimulation for five consecutive days. Statistical analysis showed a reduction in pain intensity after treatment for groups in general [F (1.28) = 8.02; p = 0.008; η2 = 0.223], in addition to a reduction in alpha 2 in the frontal (p = 0.039; d = 0.384) and parietal (p = 0.021; d = 0.520) regions after the treatment on five consecutive days. We conclude that neuromodulation protocols produced similar effects on pain reduction, but differed with respect to the changes in the alpha 2 frequency band in the frontal and parietal regions.

Resting frontal EEG alpha asymmetry has been extensively examined as a marker of motivational disposition. Recent research has examined how this trait-level marker of motivation influences an individual’s internal error monitoring (indexed by the error-related negativity; ERN), with mixed findings as to whether more negative ERNs are associated with greater left or right alpha power. Data from 339 children who completed an incentivized Go/No-Go task annually from Kindergarten through 2nd grade were examined for an association between ERN amplitude and EEG asymmetry, and for whether the association was developmentally stable. Results indicate an association between left-dominant activation and a more negative amplitude in Kindergarten, with an inversion of this association emerging by 2nd grade, such that a more negative ERNs were associated with right-dominant activation. We suggest that the association between EEG asymmetry and ERN amplitude is likely modulated by task condition (e.g., incentivization) and experience over time (e.g., habituation).

Objective This study aims to understand the neural and hemodynamic responses during general anesthesia in order to develop a comprehensive multimodal anesthesia depth monitor using simultaneous functional Near Infrared Spectroscopy (fNIRS) and Electroencephalogram (EEG). Methods 37 adults and 17 children were monitored with simultaneous fNIRS and EEG, during the complete general anesthesia process. The coupling of fNIRS signals with neuronal signals (EEG) was calculated. Measures of complexity (sample entropy) and phase difference were also quantified from fNIRS signals to identify unique fNIRS based biomarkers of general anesthesia. Results A significant decrease in the complexity and power of fNIRS signals characterize the anesthesia maintenance phase. Furthermore, responses to anesthesia vary between adults and children in terms of neurovascular coupling and frontal EEG alpha power. Conclusions This study shows that fNIRS signals could reliably quantify the underlying neuronal activity under general anesthesia and clearly distinguish the different phases throughout the procedure in adults and children (with less accuracy). Significance A multimodal approach incorporating the specific differences between age groups, provides a reliable measure of anesthesia depth.

Motivationally/emotionally engaging stimuli are strong competitors for the limited capacity of sensory and cognitive systems. Thus, they often act as distractors, interfering with performance in concurrent primary tasks. Keeping task-relevant information in focus while suppressing the impact of distracting stimuli is one of the functions of working memory (WM). Macroscopic brain oscillations in the alpha band (8-13 Hz) have recently been identified as a neural correlate of WM processing. Using electroencephalography, we examined the extent to which changes in alpha power and inter-site connectivity during a typical WM task are sensitive to load and emotional distraction. Participants performed a lateralized change-detection task with two levels of load (four vs. two items), which was preceded by naturalistic scenes rated either as unpleasant or neutral, acting as distractors. The results showed the expected parieto-occipital alpha reduction in the hemisphere contralateral to the WM task array, compared to the ipsilateral hemisphere, during the retention interval. Selectively heightened oscillatory coupling between frontal and occipital sensors was observed (1) during the retention interval as a function of load, and (2) upon the onset of the memory array, after viewing neutral compared to unpleasant distractors. At the end of the retention interval, we observed greater coupling during the unpleasant compared to the neutral condition. These findings are consistent with the notions that (1) representing more items in WM requires greater interconnectivity across cortical areas, and (2) unpleasant emotional distractors interfere with subsequent WM processing by disrupting processing during the encoding stage.

Prior research has shown that greater EEG alpha power (8–13 ​Hz) is characteristic of more creative individuals, and more creative task conditions. The present study investigated the potential for machine learning to classify more and less creative brain states. Participants completed an Alternate Uses Task, in which they thought of Normal or Uncommon (more creative) uses for everyday objects (e.g., brick). We hypothesized that alpha power would be greater for Uncommon (vs. Common) uses, and that a machine learning (ML) approach would enable the reliable classification data from the two conditions. Further, we expected that ML would be successful at classifying more (vs. less) creative individuals. As expected, alpha power was significantly greater for the Uncommon than for the Normal condition. Using spectrally weighted common spatial patterns to extract EEG features, and quadratic discriminant analysis, we found that classification accuracy for the two conditions varied widely among individuals, with a mean of 63.9%. For more vs. less creative individuals, 82.3% classification accuracy was attained. These findings indicate the potential for broader adoption of machine learning in creativity research.

© 2020 Elsevier B.V. This study tested the validity of EEG left-temporal alpha power and upper-alpha T7-Fz connectivity as indices of verbal activity and conscious motor control. Participants (n = 20) reached for, and transported, a jar under three conditions: a control condition and two self-talk conditions aimed at eliciting either task-unrelated verbal processing or task-related conscious control, while EEG and hand kinematics were recorded. Compared to the control condition, both self-talk conditions increased self-reported verbal processing, but only the task-related self-talk condition increased left-temporal activity (i.e., alpha power decreased). However, as cortical activity increased across the entire scalp topography, conscious control likely elicits a multitude of processes that may not be explained by left-temporal activity or verbal processing alone, but by a widespread decrease in neural efficiency. No significant effects for T7-Fz connectivity were detected. Results suggest that left-temporal EEG alpha oscillations are unlikely to uniquely reflect verbal processing during conscious motor control.

Cognitive reappraisal is an important emotion regulation skill for psychological health and well-being, however, some people cannot use this strategy effectively. We investigated EEG alpha asymmetry by calculating lateral index (LI) when twenty-six healthy participants were instructed to complete the emotion cognitive reappraisal task of viewing neutral pictures, watching negative pictures and reappraising negative pictures. According to self-reported valence and arousal, the participants were divided into effective and ineffective groups. Habitual use of rumination was also assessed using the Cognitive Emotion Regulation Questionnaire (CERQ). EEG alpha asymmetry results demonstrated that, ineffective group showed greater relative right temporal activity than effective group in the early stage of reappraisal, indicating higher subjective arousal. Both groups showed greater relative left frontal alpha activity in the late stages of reappraisal compared with watching negative images, indicating the recruitment of corresponding functions in prefrontal regulatory circuitry during the effort of reappraisal. CERQ analysis results showed that, ineffective group got significantly higher score than effective group in habitual use of rumination. Partial correlation revealed that, in male participants, temporal LI change (negative-reappraisal minus negative-watch) was negatively correlated with self-reported arousal and habitual use of rumination. In addition, by using K-means cluster analysis, temporal LI combined with CERQ-rumination score achieved a classification accuracy of 84.6 %. These findings suggested that, EEG alpha asymmetry as well as the habitual use of rumination accounted for the reappraisal effectiveness.