Theta Event-related Synchronization Research Articles

Theta oscillations in observers’ temporal cortex index postural instability of point-light displays

This study investigates whether postural equilibration follows the same principles of motor resonance as goal-oriented actions, namely, whether an individual activates the same neuronal substrates when experiencing postural perturbation as when observing another individual in this condition. To address this question, we examined electroencephalographic dynamics while subjects observed point-light displays featuring an unstable human display, a stable human display, and their respective scrambled counterparts lacking shape information and biological motion. We focused on theta band (4–7 Hz), which is a fundamental frequency for modulating brain activity during challenging balance tasks and reflects postural stability monitoring. Rather than mirroring activity, our findings suggest an inhibitory response to postural instability. Theta event-related synchronization in the left temporal cortex was dampened for the unstable display as compared to its scramble counterpart and to the stable display. This low theta response coincided with an increase in left temporal-prefrontal connectivity, compatible with top-down inhibitory mechanisms. By contrast, the stronger theta response to the stable display as compared to the unstable one could be due to the difficulty of recognizing low-motion biological stimuli, or alternatively, to a facilitation of stimulus processing and strengthening of the mirroring response. The response facilitation for stable posture, coupled with a diminished response to the unstable display, could contribute to a broader mechanism mitigating postural threats and ensuring stable balance. Future investigations should leverage these findings to explore how posture-related responses correlate with perceptual and motor expertise, and to more clearly define these mechanisms during dynamic social interactions.

Age-related changes in brain oscillatory patterns during an n-back task in children and adolescents

The development of brain oscillatory responses and their possible role in the working memory (WM) performance of children, adolescents and young adults was investigated. A set of 0- and 1-back tasks with letter stimuli were administered to a final sample of 131 subjects (between 6 and 20 years of age). A decrease in response times (RTs) and an increase of the sensitivity index d-prime (d′) were seen with increased age. RTs increased and d′ decreased with load, indicating higher difficulty for higher loads. Event-related synchronization (ERS) and event-related desynchronization (ERD) were obtained by the convolution of Morlet wavelets on the recorded EEG. Statistical analyses were performed of the absolute and relative power of brain oscillations defined by topography, frequency and latency. Posterior alpha and beta ERD, and frontocentral theta ERS, were induced by the stimuli presented during the n-back task. While relative theta ERS increased with age, absolute theta ERS, absolute and relative alpha and, absolute beta ERD, decreased with age. Age-related improvement in behavioral performance was mediated by relative theta. Alpha and beta ERD were more pronounced for the most difficult task (1-back) and for the target condition. Globally, there was high consistency of the effects of target type and task load across development. Theta ERS maturation is a crucial step for improving WM performance during development, while alpha and beta ERD maturation seem to be less critical for behavioral performance improvement with age, possibly due to a sufficient level of alpha-beta ERD for good performance in young children.

Adults with cerebral palsy exhibit uncharacteristic cortical oscillations during an adaptive sensorimotor control task

Prior research has shown that the sensorimotor cortical oscillations are uncharacteristic in persons with cerebral palsy (CP); however, it is unknown if these altered cortical oscillations have an impact on adaptive sensorimotor control. This investigation evaluated the cortical dynamics when the motor action needs to be changed “on-the-fly”. Adults with CP and neurotypical controls completed a sensorimotor task that required either proactive or reactive control while undergoing magnetoencephalography (MEG). When compared with the controls, the adults with CP had a weaker beta (18–24 Hz) event-related desynchronization (ERD), post-movement beta rebound (PMBR, 16–20 Hz) and theta (4–6 Hz) event-related synchronization (ERS) in the sensorimotor cortices. In agreement with normative work, the controls exhibited differences in the strength of the sensorimotor gamma (66–84 Hz) ERS during proactive compared to reactive trials, but similar condition-wise changes were not seen in adults with CP. Lastly, the adults with CP who had a stronger theta ERS tended to have better hand dexterity, as indicated by the Box and Blocks Test and Purdue Pegboard Test. These results may suggest that alterations in the theta and gamma cortical oscillations play a role in the altered hand dexterity and uncharacteristic adaptive sensorimotor control noted in adults with CP.

Effects of Background Noise and Linguistic Violations on Frontal Theta Oscillations During Effortful Listening.

Background noise and linguistic violations have been shown to increase the listening effort. The present study aims to examine the effects of the interaction between background noise and linguistic violations on subjective listening effort and frontal theta oscillations during effortful listening. Thirty-two normal-hearing listeners participated in this study. The linguistic violation was operationalized as sentences versus random words (strings). Behavioral and electroencephalography data were collected while participants listened to sentences and strings in background noise at different signal to noise ratios (SNRs) (-9, -6, -3, 0 dB), maintained them in memory for about 3 sec in the presence of background noise, and then chose the correct sequence of words from a base matrix of words. Results showed the interaction effects of SNR and speech type on effort ratings. Although strings were inherently more effortful than sentences, decreasing SNR from 0 to -9 dB (in 3 dB steps), increased effort rating more for sentences than strings in each step, suggesting the more pronounced effect of noise on sentence processing that strings in low SNRs. Results also showed a significant interaction between SNR and speech type on frontal theta event-related synchronization during the retention interval. This interaction indicated that strings exhibited higher frontal theta event-related synchronization than sentences at SNR of 0 dB, suggesting increased verbal working memory demand for strings under challenging listening conditions. The study demonstrated that the interplay between linguistic violation and background noise shapes perceived effort and cognitive load during speech comprehension under challenging listening conditions. The differential impact of noise on processing sentences versus strings highlights the influential role of context and cognitive resource allocation in the processing of speech.

Neural correlates tracking different aspects of the emerging representation of novel visual categories.

Current studies investigating electroencephalogram correlates associated with categorization of sensory stimuli (P300 event-related potential, alpha event-related desynchronization, theta event-related synchronization) typically use an oddball paradigm with few, familiar, highly distinct stimuli providing limited insight about the aspects of categorization (e.g. difficulty, membership, uncertainty) that the correlates are linked to. Using a more complex task, we investigated whether such more specific links could be established between correlates and learning and how these links change during the emergence of new categories. In our study, participants learned to categorize novel stimuli varying continuously on multiple integral feature dimensions, while electroencephalogram was recorded from the beginning of the learning process. While there was no significant P300 event-related potential modulation, both alpha event-related desynchronization and theta event-related synchronization followed a characteristic trajectory in proportion with the gradual acquisition of the two categories. Moreover, the two correlates were modulated by different aspects of categorization, alpha event-related desynchronization by the difficulty of the task, whereas the magnitude of theta -related synchronization by the identity and possibly the strength of category membership. Thus, neural signals commonly related to categorization are appropriate for tracking both the dynamic emergence of internal representation of categories, and different meaningful aspects of the categorization process.

Acute Bouts of Aerobic Exercise Do Not Modulate Task-Evoked Midfrontal Theta Oscillations in School-Age Children

While acute aerobic exercise has been found to have a facilitative effect on task components with varied cognitive control demands in school-age children, its effects on specific neural processes evoked by a cognitive control task remain underexplored. The objective of the current study was to examine the effects of acute aerobic exercise on task-evoked midfrontal theta event-related synchronization (ERS)—which plays a crucial role in supporting cognitive control. Thirty-three preadolescent children were recruited into this within-subjects, crossover study. Participants engaged in an aerobic exercise condition and a seated rest condition in a counterbalanced order. After both conditions, participants completed a flanker task, with concurrent EEG data collection. The results revealed no differences in midfrontal theta ERS following acute aerobic exercise as compared with following the control condition. However, midfrontal theta ERS was higher during congruent trials relative to incongruent trials following control condition but not following aerobic exercise. Collectively, acute bouts of aerobic exercise do not appear to modulate the control and behavioral monitoring processes indexed by midfrontal theta ERS during cognitive control in children.

Long-term exposure to high altitude reduces alpha and beta bands event-related desynchronization in a Go/NoGo task.

More than 80 million people worldwide permanently live at high altitudes, and living in such a hypoxic environment can impair cognitive functions. However, it is largely unknown how long-term exposure to high altitude affects neural oscillations underlying these cognitive functions. The present study employed a Go/NoGo task to investigate the effects of long-term exposure to high altitude on neural oscillations during cognitive control. We compared event-related spectral perturbations between the low-altitude and high-altitude groups, and the results revealed increased theta event-related synchronization (ERS) and decreased alpha and beta event-related desynchronizations (ERDs) during the NoGo condition compared to the Go condition. Importantly, the high-altitude group showed reduced alpha and beta ERDs compared to the low-altitude group, while the theta ERS was not affected by altitude. We suggest that long-term exposure to high altitude has an impact on top-down inhibitory control and movement preparation and execution in the Go/NoGo task.

Reaction time and brain oscillations in Go/No-go tasks with different meanings of stimulus color

Color has meaning in particular contexts, and the meaning of color can impact behavioral performance. For example, the meaning of color about traffic rules (blue/green and red mean “go” and “stop” respectively) influences reaction times (RTs) to signals. Specifically, in a Go/No-go task, RTs have been reported to be longer when responding to a red signal and withholding the response to a blue signal (Red Go/Blue No-go task) than when responding to a blue signal and withholding the response to a red signal (Blue Go/Red No-go task). However, the neurophysiological background of this phenomenon has not been fully understood. The purpose of this study was to investigate the brain oscillatory activity associated with the effect of meaning of color on RTs in the Go/No-go task.Twenty participants performed a Blue simple reaction task, a Red simple reaction task, a Blue Go/Red No-go task, and a Red Go/Blue No-go task. We recorded responses to signals and electroencephalogram (EEG) during the tasks and evaluated RTs and changes in spectral power over time, referred to as event-related synchronization (ERS) and event-related desynchronization (ERD).The behavioral results were similar to previous studies. The EEG results showed that frontal beta ERD and theta ERS were greater when signals were presented in blue than red color in both simple reaction and Go/No-go tasks. In addition, the onset of theta ERS was delayed in the Red Go than Blue Go trial in the Go/No-go task.The enhanced beta ERD may indicate that blue signals facilitate motor response, and the delayed onset of theta ERS may indicate the delayed onset of cognitive process when responding to red signals as compared to blue signals in the Go/No-go task. Thus, this delay in cognitive process can be involved in the slow response in the Red Go/Blue No-go task.

Theta and alpha activity are differentially associated with physiological and rating scale measures of affective processing in adolescents with but not without ADHD.

Although atypical theta and alpha activity may be biomarkers of attention-deficit/hyperactivity disorder (ADHD) outcomes such as atypical affective processing and attention, the exact nature of the relations of these characteristics is unknown. We examined in age- and sex-matched adolescents (N = 132; Mage = 14.944, years, SD = .802) with and without ADHD, whether resting state (RS) theta and alpha power or theta and alpha event-related synchronization (ERS) during affect regulation (1) differ between adolescents with and without ADHD; (2) are differentially associated with event-related potential (ERP) and parent- and self-report measures of affective processing and inattention, given ADHD status and sex, and (3) are differentially lateralized, given ADHD status and sex. Adolescents with ADHD exhibited lower RS frontal-midline alpha power than adolescents without ADHD. In adolescents with ADHD, right parietal theta ERS was positively associated with the ERP measure of elaborate affective/motivational processing and right parietal RS alpha power was negatively associated with self-reported positive affectivity. In adolescents without ADHD, associations were nonsignificant. There was no disassociation of theta and alpha activity with affective processing and inattention. Consistent with clinical impressions, the between-group difference in frontal-midline theta ERS was more marked in boys than girls.

Cognitive control, interference inhibition and ordering of information during working memory in younger and older healthy adults

AbstractBackgroundInvestigating effects of aging on neurophysiological mechanisms underlying working memory provides a better understanding of potential targets for brain intervention to prevent cognitive decline. Theta‐gamma coupling (TGC) indexes the ability to order information processed during working memory tasks. Frontal theta event‐related synchronization (ERS) and parietal alpha event‐related desynchronization (ERD) index cognitive control and interference inhibition, respectively. Relative contributions of TGC, theta ERS and alpha ERD in relation to stimulus presentation are not characterized. Further, differential effect of normal aging on pre or post‐stimulus processes is unknown.MethodElectroencephalography was recorded in 66 younger and 41 older healthy participants while performing 3‐back working memory task. We assessed relationships between 3‐back task performance and each of post‐stimulus TGC, pre‐stimulus parietal alpha ERD, and pre‐stimulus frontal theta ERS in each age group.ResultWhile older adults performed worse on 3‐back task than younger adults. TGC, alpha ERD or theta ERS did not differ between the two groups. TGC was positively associated with 3‐back performance in both age groups; pre‐stimulus alpha ERD was associated with performance among younger adults; and pre‐stimulus theta ERS was not associated with performance in either group.ConclusionOur findings suggest that both pre‐stimulus interference inhibition and post‐stimulus ordering of information are important for working memory in younger adults. In contrast, performance in older adults appears to depend only on post‐stimulus ordering of information. These specific contributions of neurophysiological resources may explain the poorer performance of older adults and suggest different targets to enhance working memory in age groups.

Transcranial Direct Current Stimulation Modulates Working Memory Maintenance Processes in Healthy Individuals.

The effects of transcranial direct current stimulation (tDCS) at the pFC are often investigated using cognitive paradigms, particularly working memory tasks. However, the neural basis for the neuromodulatory cognitive effects of tDCS, including which subprocesses are affected by stimulation, is not completely understood. We investigated the effects of tDCS on working memory task-related spectral activity during and after tDCS to gain better insights into the neurophysiological changes associated with stimulation. We reanalyzed data from 100 healthy participants grouped by allocation to receive either sham (0 mA, 0.016 mA, and 0.034 mA) or active (1 mA or 2 mA) stimulation during a 3-back task. EEG data were used to analyze event-related spectral power in frequency bands associated with working memory performance. Frontal theta event-related synchronization (ERS) was significantly reduced post-tDCS in the active group. Participants receiving active tDCS had slower RTs following tDCS compared with sham, suggesting interference with practice effects associated with task repetition. Theta ERS was not significantly correlated with RTs or accuracy. tDCS reduced frontal theta ERS poststimulation, suggesting a selective disruption to working memory cognitive control and maintenance processes. These findings suggest that tDCS selectively affects specific subprocesses during working memory, which may explain heterogenous behavioral effects.

Time-frequency neural dynamics of ADHD children and adolescents during a Working Memory task

The present report analyzed the time-frequency changes in Event-Related Spectral perturbations (ERSP) in a sample of ADHD children and adolescents compared to a normodevelopment (ND) sample. A delayed match-to-sample (DMTS) test of working memory (WM) was presented to a group of ADHD subjects (N = 29) and compared with ND group (N = 34) with ages between 6 and 17 years old. Time-frequency decomposition was computed through wavelets. ADHD subjects presented higher Reaction Time (RT), Standard Deviation of RT (Std of RT), and a reduced percentage of correct responses. The results showed a complex pattern of oscillatory bursts during the encoding, maintenance, and recognition phases with similar dynamics in both groups. ADHD children presented a reduced Event-Related Synchronization (ERS) in the Theta range during the encoding phase, and also a reduced Alpha ERS during the late period of the maintenance phase. S1 Early theta ERS was positively correlated with Std of RT. Behavioral data, early Theta, and late Alpha ERS classified correctly above 70 % of ADHD and ND subjects when a linear discriminant analysis was applied. The reduced encoding and maintenance impaired brain dynamics of ADHD subjects would justify the poorer performance of this group of subjects.

Cognitive control, interference inhibition, and ordering of information during working memory in younger and older healthy adults.

Investigatingeffects of aging on neurophysiological mechanisms underlying working memory provides a better understanding of potential targets for brain intervention to prevent cognitive decline. Theta-gamma coupling (TGC) indexes the ability to order information processed during working memory tasks. Frontal theta event-related synchronization (ERS) and parietal alpha event-related desynchronization (ERD) index cognitive control and interference inhibition, respectively. Relative contributions of TGC, theta ERS, and alpha ERD in relation to stimulus presentation are not characterized. Further, differential effect of normal aging on pre- or post-stimulus processes is unknown. Electroencephalography was recorded in 66 younger and 41 older healthy participants while performing 3-back working memory task. We assessed relationships between 3-back task performance and each of post-stimulus TGC, pre-stimulus parietal alpha ERD, and pre-stimulus frontal theta ERS in each age group. While older adults performed worse on 3-back task than younger adults, TGC, alpha ERD, or theta ERS did not differ between the two groups. TGC was positively associated with 3-back performance in both age groups; pre-stimulus alpha ERD was associated with performance among younger adults; and pre-stimulus theta ERS was not associated with performance in either group. Our findings suggest that both pre-stimulus interference inhibition and post-stimulus ordering of information are important for working memory in younger adults. In contrast, performance in older adults appears to depend only on post-stimulus ordering of information. These specific contributions of neurophysiological resources may explain the poorer performance of older adults and suggest different targets to enhance working memory in age groups.

Abnormal Reactivity of Brain Oscillations to Visual Search Target in Children With Attention-Deficit/Hyperactivity Disorder

BackgroundPrevious studies have shown that impaired goal-directed alpha lateralization and functional disconnection within attention networks during the cue period are significant features of attention-deficit/hyperactivity disorder (ADHD). This study aimed to explore the role of brain oscillations in the visual search process, focusing on target-induced posterior alpha lateralization, midfrontal theta synchronization, and their functional connection in children with ADHD. MethodsElectroencephalograms were recorded from typically developing (TD) children (n = 72) and children with ADHD (n = 96) while they performed a visual search task. ResultsBoth the TD and ADHD groups showed significant midfrontal theta event-related synchronization (ERS) and posterior alpha lateralization. Compared with TD children, children with ADHD showed significantly lower theta ERS and higher target-induced alpha lateralization. TD children showed a positive trial-based correlation between theta ERS and alpha lateralization and a negative correlation between theta ERS and reaction time variability. However, all these correlations were absent in children with ADHD. ConclusionsAbnormal brain oscillations in children with ADHD indicate insufficient executive control function and the compensation of attention networks for attention deficits in visual selective attention. Cross-frequency disconnection reflects the common deficiency of executive control in the gating of target information. Our findings provide novel evidence for interpreting the features of brain oscillations during stimulus-driven selective attention in children with ADHD.

Oscillatory electroencephalographic patterns of arithmetic problem solving in fourth graders

Numerous studies have identified neurophysiological correlates of performing arithmetic in adults. For example, oscillatory electroencephalographic (EEG) patterns associated with retrieval and procedural strategies are well established. Whereas fact retrieval has been linked to enhanced left-hemispheric theta ERS (event-related synchronization), procedural strategies are accompanied by increased bilateral alpha ERD (event-related desynchronization). It is currently not clear if these findings generalize to children. Our study is the first to investigate oscillatory EEG activity related to strategy use and arithmetic operations in children. We assessed ERD/ERS correlates of 31 children in fourth grade (aged between nine and ten years) during arithmetic problem solving. We presented multiplication and subtraction problems, which children solved with fact retrieval or a procedure. We analyzed these four problem categories (retrieved multiplications, retrieved subtractions, procedural multiplications, and procedural subtractions) in our study. In summary, we found similar strategy-related patterns to those reported in previous studies with adults. That is, retrieval problems elicited stronger left-hemispheric theta ERS and weaker alpha ERD as compared to procedural problems. Interestingly, we observed neurophysiological differences between multiplications and subtractions within retrieval problems. Although there were no response time or accuracy differences, retrieved multiplications were accompanied by larger theta ERS than retrieved subtractions. This finding could indicate that retrieval of multiplication and subtraction facts are distinct processes, and/or that multiplications are more frequently retrieved than subtractions in this age group.

Assessing the Longitudinal Relationship between Theta-Gamma Coupling and Working Memory Performance in Older Adults.

Theta-gamma coupling (TGC) is a neurophysiologic mechanism that supports working memory (WM). TGC is associated with N-back performance, a WM task. Similar to TGC, theta and alpha event-related synchronization (ERS) and desynchronization (ERD) are also associated with WM. Few studies have examined the longitudinal relationship between WM performance and TGC, ERS, or ERD. This study aimed to determine if changes in WM performance are associated with changes in TGC (primary aim), as well as theta and alpha ERS or ERD over 6 to 12 weeks. Participants included 62 individuals aged 60 and older with no neuropsychiatric conditions or with remitted Major Depressive Disorder (MDD) and no cognitive disorders. TGC, ERS, and ERD were assessed using electroencephalography (EEG) during the N-back task (3-back condition). There was an association between changes in 3-back performance and changes in TGC, alpha ERD and ERS, and theta ERS in the control group. In contrast, there was only a significant association between changes in 3-back performance and changes in TGC in the subgroup with remitted MDD. Our results suggest that the relationship between WM performance and TGC is stable over time, while this is not the case for changes in theta and alpha ERS and ERD.

Anticipatory Parietal Alpha Desynchronization and Working Memory Performance and Capacity

Working memory deficits are common in mild cognitive impairment (MCI) and cause troubles in routine activities. Frontal theta event-related synchronization (ERS) and parietal alpha event-related desynchronization (ERD) are known to be associated with working memory capacity. However, their association with working memory performance, including at the trial-by-trial level, has yet to be determined.

The Effects of Dynamic and Static Emotional Facial Expressions of Humans and Their Avatars on the EEG: An ERP and ERD/ERS Study.

This study aimed to examine whether the cortical processing of emotional faces is modulated by the computerization of face stimuli (”avatars”) in a group of 25 healthy participants. Subjects were passively viewing 128 static and dynamic facial expressions of female and male actors and their respective avatars in neutral or fearful conditions. Event-related potentials (ERPs), as well as alpha and theta event-related synchronization and desynchronization (ERD/ERS), were derived from the EEG that was recorded during the task. All ERP features, except for the very early N100, differed in their response to avatar and actor faces. Whereas the N170 showed differences only for the neutral avatar condition, later potentials (N300 and LPP) differed in both emotional conditions (neutral and fear) and the presented agents (actor and avatar). In addition, we found that the avatar faces elicited significantly stronger reactions than the actor face for theta and alpha oscillations. Especially theta EEG frequencies responded specifically to visual emotional stimulation and were revealed to be sensitive to the emotional content of the face, whereas alpha frequency was modulated by all the stimulus types. We can conclude that the computerized avatar faces affect both, ERP components and ERD/ERS and evoke neural effects that are different from the ones elicited by real faces. This was true, although the avatars were replicas of the human faces and contained similar characteristics in their expression.

Sustained attention to response task-related beta oscillations relate to performance and provide a functional biomarker in ALS

Objective. To characterize the cortical oscillations associated with performance of the sustained attention to response task (SART) and their disruptions in the neurodegenerative condition amyotrophic lateral sclerosis (ALS). Approach. A randomised SART was undertaken by 24 ALS patients and 33 healthy controls during 128-channel electroencephalography (EEG). Complex Morlet wavelet transform was used to quantify non-phase-locked oscillatory activity in event-related spectral perturbations associated with performing the SART. We investigated the relationships between these perturbations and task performance, and associated motor and cognitive changes in ALS. Main results. SART induced theta-band event-related synchronization (ERS) and alpha- and beta-band event-related desynchronization (ERD), followed by rebound beta ERS, in both Go and NoGo trials across the frontoparietal axis, with NoGo trials eliciting greater theta ERS and lesser beta ERS. Controls with greater Go trial beta ERS performed with greater speed and less accuracy. ALS patients exhibited increased anticipation compared to controls but similar reaction times and accuracy. Prefrontal (area under the receiver operating characteristic curve (AUROC) = 0.8, Cohen’s d = 0.97) and parietal (AUROC = 0.82, Cohen’s d = 1.12) beta-band ERD was significantly reduced in ALS but did not relate to performance, while patients with higher Edinburgh Cognitive and Behavioural ALS Screen (ECAS) ALS-specific scores demonstrated greater ERS in beta (rho = 0.72) upon successful withholding. Significance. EEG measurement of task-related oscillation changes reveals variation in cortical network engagement in relation to speed versus accuracy strategies. Such measures can also capture cognitive and motor network pathophysiology in the absence of task performance decline, which may facilitate development of more sensitive early neurodegenerative disease biomarkers.

Abnormal modulation of theta oscillations in children with attention-deficit/hyperactivity disorder

Previous studies have found that theta activities exhibit posterior lateralized modulation as well as midfrontal event-related synchronization (ERS) during covert visual attention in adults. The present study investigated whether these theta modulations existed in children and whether they were associated with attentional problems in attention-deficit/hyperactivity disorder (ADHD). Electroencephalography signals were recorded from typically developing (TD) children and children with ADHD (TD: n = 24; ADHD: n = 22) while they performed a cued covert visual attention task. The participants responded to a target following a cue designed as human eyes that gazed to the left or right visual field (70% validity). Compared with the TD children, the children with ADHD showed increased midfrontal theta ERS and significant posterior theta lateralization in response to the cues. More importantly, we found that the stronger posterior theta lateralization in the right hemisphere exhibited a positive trial-based correlation with the larger midfrontal theta ERS and predicted lower RT variability at the trial level in the children with ADHD. We suggest that ADHD may be associated with some enhanced systems in the frontal and posterior areas via theta oscillations, which may be involved in the compensatory maturation for their attention deficits in childhood, thereby promoting the stability of behavioral responses.