On the relevance of EEG resting theta activity for the neurophysiological dynamics underlying motor inhibitory control

Individual peak alpha frequency does not index individual differences in inhibitory cognitive control

Previous work has indicated that individual differences in cognitive performance can be predicted by characteristics of resting state oscillations, such as individual peak alpha frequency (IAF). Although IAF has previously been correlated with cognitive functions, such as memory, attention, or mental speed, its link to cognitive conflict processing remains unexplored. The current work investigated the relationship between IAF and inhibitory cognitive control in two well-established conflict tasks, Stroop and Navon task, while also controlling for alpha power, theta power, and the 1/f offset of aperiodic broadband activity. In Bayesian analyses on a large sample of 127 healthy participants, we found substantial evidence against the assumption that IAF predicts individual abilities to spontaneously exert cognitive control. Similarly, our findings yielded substantial evidence against links between cognitive control and resting state power in the alpha and theta bands or between cognitive control and aperiodic 1/f offset. In sum, our results challenge frameworks suggesting that an individual's ability to spontaneously engage attentional control networks may be mirrored in resting state EEG characteristics.

Interindividual aperiodic resting-state EEG activity predicts cognitive-control styles

The ability to find the right balance between more persistent and more flexible cognitive-control styles is known as "metacontrol." Recent findings suggest a relevance of aperiodic EEG activity and task conditions that are likely to elicit a specific metacontrol style. Here we investigated whether individual differences in aperiodic EEG activity obtained off-task (during resting state) predict individual cognitive-control styles under task conditions that pose different demands on metacontrol. We analyzed EEG resting-state data, task-EEG, and behavioral outcomes from a sample of N = 65 healthy participants performing a Go/Nogo task. We examined aperiodic activity as indicator of "neural noise" in the EEG power spectrum, and participants were assigned to a high-noise or low-noise group according to a median split of the exponents obtained for resting state. We found that off-task aperiodic exponents predicted different cognitive-control styles in Go and Nogo conditions: Overall, aperiodic exponents were higher (i.e., noise was lower) in the low-noise group, who however showed no difference between Go and Nogo trials, whereas the high-noise group exhibited significant noise reduction in the more persistence-heavy Nogo condition. This suggests that trait-like biases determine the default cognitive-control style, which however can be overwritten or compensated for under challenging task demands. We suggest that aperiodic activity in EEG signals represents valid indicators of highly dynamic arbitration between metacontrol styles, representing the brain's capability to reorganize itself and adapt its neural activity patterns to changing environmental conditions.

Aperiodic and periodic components of oscillatory brain activity in relation to cognition and symptoms in pediatric ADHD

Children with attention-deficit/hyperactivity disorder show deficits in processing speed, as well as aberrant neural oscillations, including both periodic (oscillatory) and aperiodic (1/f-like) activity, reflecting the pattern of power across frequencies. Both components were suggested as underlying neural mechanisms of cognitive dysfunctions in attention-deficit/hyperactivity disorder. Here, we examined differences in processing speed and resting-state-Electroencephalogram neural oscillations and their associations between 6- and 12-year-old children with (n = 33) and without (n = 33) attention-deficit/hyperactivity disorder. Spectral analyses of the resting-state EEG signal using fast Fourier transform revealed increased power in fronto-central theta and beta oscillations for the attention-deficit/hyperactivity disorder group, but no differences in the theta/beta ratio. Using the parameterization method, we found a higher aperiodic exponent, which has been suggested to reflect lower neuronal excitation-inhibition, in the attention-deficit/hyperactivity disorder group. While fast Fourier transform-based theta power correlated with clinical symptoms for the attention-deficit/hyperactivity disorder group only, the aperiodic exponent was negatively correlated with processing speed across the entire sample. Finally, the aperiodic exponent was correlated with fast Fourier transform-based beta power. These results highlight the different and complementary contribution of periodic and aperiodic components of the neural spectrum as metrics for evaluation of processing speed in attention-deficit/hyperactivity disorder. Future studies should further clarify the roles of periodic and aperiodic components in additional cognitive functions and in relation to clinical status.

Theta activity and cognitive functioning: Integrating evidence from resting-state and task-related developmental electroencephalography (EEG) research

The theta band is one of the most prominent frequency bands in the electroencephalography (EEG) power spectrum and presents an interesting paradox: while elevated theta power during resting state is linked to lower cognitive abilities in children and adolescents, increased theta power during cognitive tasks is associated with higher cognitive performance. Why does theta power, measured during resting state versus cognitive tasks, show differential correlations with cognitive functioning? This review provides an integrated account of the functional correlates of theta across different contexts. We first present evidence that higher theta power during resting state is correlated with lower executive functioning, attentional abilities, language skills, and IQ. Next, we review research showing that theta power increases during memory, attention, and cognitive control, and that higher theta power during these processes is correlated with better performance. Finally, we discuss potential explanations for the differential correlations between resting/task-related theta and cognitive functioning, and offer suggestions for future research in this area.

Extracting Stress-Related EEG Patterns From Pre-Sleep EEG for Forecasting Slow-Wave Sleep Deficiency

Sleep is vital to our daily activity. Lack of proper sleep can impair functionality and overall health. While stress is known for its detrimental impact on sleep quality, the precise effect of pre-sleep stress on subsequent sleep structure remains unknown. This study introduced a novel approach to study the pre-sleep stress effect on sleep structure, specifically slow-wave sleep (SWS) deficiency. To achieve this, we selected forehead resting EEG immediately before and upon sleep onset to extract stress-related neurological markers through power spectra and entropy analysis. These markers include beta/delta correlation, alpha asymmetry, fuzzy entropy (FuzzEn) and spectral entropy (SpEn). Fifteen subjects were included in this study. Our results showed that subjects lacking SWS often exhibited signs of stress in EEG, such as an increased beta/delta correlation, higher alpha asymmetry, and increased FuzzEn in frontal EEG. Conversely, individuals with ample SWS displayed a weak beta/delta correlation and reduced FuzzEn. Finally, we employed several supervised learning models and found that the selected neurological markers can predict subsequent SWS deficiency. Our investigation demonstrated that the classifiers could effectively predict varying levels of slow-wave sleep (SWS) from pre-sleep EEG segments, achieving a mean balanced accuracy surpassing 0.75. The SMOTE-Tomek resampling method could improve the performance to 0.77. This study suggests that stress-related neurological markers derived from pre-sleep EEG can effectively predict SWS deficiency. Such information can be integrated with existing sleep-improving techniques to provide a personalized sleep forecasting and improvement solution.

Adolescents rats engage the orbitofrontal-striatal pathway differently than adults during impulsive actions

Adolescence is characterized by increased impulsive and risk-taking behaviors. To better understand the neural networks that subserves impulsivity in adolescents, we used a reward-guided behavioral model that quantifies age differences in impulsive actions in adult and adolescent rats of both sexes. Using chemogenetics, we identified orbitofrontal cortex (OFC) projections to the dorsomedial striatum (DMS) as a critical pathway for age-related execution of impulsive actions. Simultaneous recording of single units and local field potentials in the OFC and DMS during task performance revealed an overall muted response in adolescents during impulsive actions as well as age-specific differences in theta power and OFC-DMS functional connectivity. Collectively, these data reveal that the OFC-DMS pathway is critical for age-differences in reward-guided impulsive actions and provide a network mechanism to enhance our understanding of how adolescent and adult brains coordinate behavioral inhibition.

Real-time cortical dynamics during motor inhibition

The inhibition of action is a fundamental executive mechanism of human behaviour that involve a complex neural network. In spite of the progresses made so far, many questions regarding the brain dynamics occurring during action inhibition are still unsolved. Here, we used a novel approach optimized to investigate real-time effective brain dynamics, which combines transcranial magnetic stimulation (TMS) with simultaneous electroencephalographic (EEG) recordings. 22 healthy volunteers performed a motor Go/NoGo task during TMS of the hand-hotspot of the primary motor cortex (M1) and whole-scalp EEG recordings. We reconstructed source-based real-time spatiotemporal dynamics of cortical activity and cortico-cortical connectivity throughout the task. Our results showed a task-dependent bi-directional change in theta/gamma supplementary motor cortex (SMA) and M1 connectivity that, when participants were instructed to inhibit their response, resulted in an increase of a specific TMS-evoked EEG potential (N100), likely due to a GABA-mediated inhibition. Interestingly, these changes were linearly related to reaction times, when participants were asked to produce a motor response. In addition, TMS perturbation revealed a task-dependent long-lasting modulation of SMA-M1 natural frequencies, i.e. alpha/beta activity. Some of these results are shared by animal models and shed new light on the physiological mechanisms of motor inhibition in humans.

Contamination-Focussed Vignettes as an Analogue of Infectious Pandemics: An Experimental Validation using the State Disgust and Anxiety Responses in OCD

Despite infectious pandemics proving particularly detrimental to those with Obsessive-Compulsive Disorder (OCD), the investigation of analogous experimental paradigms is lacking. To address this gap, we conducted two studies employing vignettes that depicted contamination-related situations commonly experienced during a pandemic (e.g., Coughing into hands and failing to use hand sanitizer). We manipulated the salience of these vignettes across three levels: high contamination, low contamination, and a neutral control condition. Our examination of state anxiety and disgust responses in all participants revealed the successful manipulation of the vignettes' impact. Specifically, individuals with more severe OCD symptoms reported significantly higher levels of state disgust and anxiety for both high and low contamination vignettes, in contrast to the group with lower symptom severity. No significant differences were observed in the neutral vignette condition between the high- and low-scoring groups. Interestingly, for those with higher OCD symptoms, high salience contamination-focused vignettes resulted in similarly elevated state disgust and anxiety, regardless of whether the vignettes were situated in public (Study 1) or domestic (Study 2) settings. This suggests that the heightened sensitivity to contamination-related scenarios observed in individuals with OCD symptoms in the present study is not confined to a specific context. These findings support the use of contamination-focused vignettes as analogues for studying infectious pandemics and provide valuable insights into OCD models, interventions, and future research.

Theta oscillations within right dorsolateral prefrontal cortex contribute differently to speech versus limb inhibition

Evidence suggests that speech and limb movement inhibition are subserved by common neural mechanisms, particularly within the right prefrontal cortex. In a recent study, we found that cathodal stimulation of right dorsolateral prefrontal cortex (rDLPFC) differentially modulated P3 event-related potentials for speech versus limb inhibition. In the present study, we further analyzed these data to examine the effects of cathodal high-definition transcranial direct current stimulation (HD-tDCS) over rDLPFC on frontal theta - an oscillatory marker of cognitive control - in response to speech and limb inhibition, during a Go/No-Go task in 21 neurotypical adults. Electroencephalography data demonstrated that both speech and limb No-Go elicited prominent theta activity over right prefrontal electrodes, with stronger activity for speech compared to limb. Moreover, we found that cathodal stimulation significantly increased theta power over right prefrontal electrodes for speech versus limb No-Go. Source analysis revealed that cathodal, but not sham, stimulation increased theta activity within rDLPFC and bilateral premotor cortex for speech No-Go compared to limb movement inhibition. These findings complement our previous report and suggest (1) right prefrontal theta activity is an amodal oscillatory mechanism supporting speech and limb inhibition, (2) larger theta activity in prefrontal electrodes for speech versus limb following cathodal stimulation may reflect allocation of additional neural resources for a more complex motor task, such as speech compared to limb movement. These findings have translational implications for conditions such as Parkinson's disease, wherein both speech and limb movement are impaired.

Aging alters functional connectivity of motor theta networks during sensorimotor reactions

OBJECTIVE

Both cognitive and primary motor networks alter with advancing age in humans. The networks activated in response to external environmental stimuli supported by theta oscillations remain less well explored. The present study aimed to characterize the effects of aging on the functional connectivity of response-related theta networks during sensorimotor tasks.

METHODS

Electroencephalographic signals were recorded in young and middle-to-older age adults during three tasks performed in two modalities, auditory and visual: a simple reaction task, a Go-NoGo task, and a choice-reaction task. Response-related theta oscillations were computed. The phase-locking value (PLV) was used to analyze the spatial synchronization of primary motor and motor control theta networks.

RESULTS

Performance was overall preserved in older adults. Independently of the task, aging was associated with reorganized connectivity of the contra-lateral primary motor cortex. In younger adults, it was synchronized with motor control regions (intra-hemispheric premotor/frontal and medial frontal). In older adults, it was only synchronized with intra-hemispheric sensorimotor regions.

CONCLUSIONS

Motor theta networks of older adults manifest a functional decoupling between the response-generating motor cortex and motor control regions, which was not modulated by task variables. The overall preserved performance in older adults suggests that the increased connectivity within the sensorimotor network is associated with an excessive reliance on sensorimotor feedback during movement execution compensating for a deficient cognitive regulation of motor regions during sensorimotor reactions.

SIGNIFICANCE

New evidence is provided for the reorganization of motor networks during sensorimotor reactions already at the transition from middle to old age.

The Ability to Voluntarily Regulate Theta Band Activity Affects How Pharmacological Manipulation of the Catecholaminergic System Impacts Cognitive Control

BACKGROUND

The catecholaminergic system influences response inhibition, but the magnitude of the impact of catecholaminergic manipulation is heterogeneous. Theoretical considerations suggest that the voluntary modulability of theta band activity can explain this variance. The study aimed to investigate to what extent interindividual differences in catecholaminergic effects on response inhibition depend on voluntary theta band activity modulation.

METHODS

A total of 67 healthy adults were tested in a randomized, double-blind, cross-over study design. At each appointment, they received a single dose of methylphenidate or placebo and performed a Go/Nogo task with stimuli of varying complexity. Before the first appointment, the individual's ability to modulate theta band activity was measured. Recorded EEG data were analyzed using temporal decomposition and multivariate pattern analysis.

RESULTS

Methylphenidate effects and voluntary modulability of theta band activity showed an interactive effect on the false alarm rates of the different Nogo conditions. The multivariate pattern analysis revealed that methylphenidate effects interacted with voluntary modulability of theta band activity at a stimulus processing level, whereas during response selection methylphenidate effects interacted with the complexity of the Nogo condition.

CONCLUSIONS

The findings reveal that the individual's theta band modulability affects the responsiveness of an individual's catecholaminergic system to pharmacological modulation. Thus, the impact of pharmacological manipulation of the catecholaminergic system on cognitive control most likely depends on the existing ability to self-modulate relevant brain oscillatory patterns underlying the cognitive processes being targeted by pharmacological modulations.

Alpha and theta band activity share information relevant to proactive and reactive control during conflict-modulated response inhibition

Response inhibition is an important instance of cognitive control and can be complicated by perceptual conflict. The neurophysiological mechanisms underlying these processes are still not understood. Especially the relationship between neural processes directly preceding cognitive control (proactive control) and processes underlying cognitive control (reactive control) has not been examined although there should be close links. In the current study, we investigate these aspects in a sample of N = 50 healthy adults. Time-frequency and beamforming approaches were applied to analyze the interrelation of brain states before (pre-trial) and during (within-trial) cognitive control. The behavioral data replicate a perceptual conflict-dependent modulation of response inhibition. During the pre-trial period, insular, inferior frontal, superior temporal, and precentral alpha activity was positively correlated with theta activity in the same regions and the superior frontal gyrus. Additionally, participants with a stronger pre-trial alpha activity in the primary motor cortex showed a stronger (within-trial) conflict effect in the theta band in the primary motor cortex. This theta conflict effect was further related to a stronger theta conflict effect in the midcingulate cortex until the end of the trial. The temporal cascade of these processes suggests that successful proactive preparation (anticipatory information gating) entails a stronger reactive processing of the conflicting stimulus information likely resulting in a realization of the need to adapt the current action plan. The results indicate that theta and alpha band activity share and transfer aspects of information when it comes to the interrelationship between proactive and reactive control during conflict-modulated motor inhibition.

Subregional prefrontal cortex recruitment as a function of inhibitory demand: an fMRI metanalysis

Convergent studies corroborated the idea that the right prefrontal cortex is the crucial brain region responsible for inhibiting our actions. However, which sub-regions of the right prefrontal cortex are involved is still a matter of debate. To map the inhibitory function of the sub-regions of the right prefrontal cortex, we performed Activation Likelihood Estimation (ALE) meta-analyses and meta-regressions (ES-SDM) of fMRI studies exploring inhibitory control. Sixty-eight studies (1684 subjects, 912 foci) were identified and divided in three groups depending on the incremental demand. Overall, our results showed that higher was the inhibitory demand based on the individual differences in performances, more the upper portion of the right prefrontal cortex was activated to achieve a successful inhibition. Conversely, a lower demand of the inhibitory function, was associated with the inferior portions of the right prefrontal cortex recruitment. Notably, in the latter case, we also observed activation of areas associated with working memory and responsible for cognitive strategies.

The neurophysiology of continuous action monitoring

Monitoring actions is essential for goal-directed behavior. However, as opposed to short-lasting, and regularly reinstating monitoring functions, the neural processes underlying continuous action monitoring are poorly understood. We investigate this using a pursuit-tracking paradigm. We show that beta band activity likely maintains the sensorimotor program, while theta and alpha bands probably support attentional sampling and information gating, respectively. Alpha and beta band activity are most relevant during the initial tracking period, when sensorimotor calibrations are most intense. Theta band shifts from parietal to frontal cortices throughout tracking, likely reflecting a shift in the functional relevance from attentional sampling to action monitoring. This study shows that resource allocation mechanisms in prefrontal areas and stimulus-response mapping processes in the parietal cortex are crucial for adapting sensorimotor processes. It fills a knowledge gap in understanding the neural processes underlying action monitoring and suggests new directions for examining sensorimotor integration in more naturalistic experiments.

Impeded frontal-occipital communications during Go/Nogo tasks in humans owing to mental workload

Human brains rely on oscillatory coupling mechanisms for regulating access to prefrontal cognitive resources, dynamically communicating between the frontal and remote cortex. We worry that communications across cortical regions will be impeded when humans in extreme space environments travel with mental load work, affecting the successful completion of missions. Here, we monitored crews of workers performing a Go/Nogo task in space travel, accompanied by acquisitions of electroencephalography (EEG) signals. These data demonstrated that when the target stimulus suddenly changed to the non-target stimulus, an instantaneous communication mechanism between the frontal and occipital cortex was established by theta-gamma phase-amplitude coupling (PAC). However, this frontal-occipital communication was impeded because of the mental workload of space travel. 86 healthy volunteers who participated in the ground imitation further indicated that mental workload caused decoupled theta-gamma PAC during the Go/Nogo task, impeding frontal-occipital communications and behavioral performance. We also found that the degree of theta-gamma PAC coupling in space was significantly lower than on the ground, indicating that mental workload and other hazards worsen the impeded frontal-occipital communications of humans. These results could guide countermeasures for the inadaptability of humans working in spaceflight.

The Effects of Different Theta and Beta Neurofeedback Training Protocols on Cognitive Control in ADHD

Neurofeedback (NF) is an important treatment for attention deficit/hyperactivity disorder (ADHD). In ADHD, cognitive control deficits pose considerable problems to patients. However, NF protocols are not yet optimized to enhance cognitive control alongside with clinical symptoms, partly because they are not driven by basic cognitive neuroscience. In this study, we evaluated different EEG theta and/or beta frequency band NF protocols designed to enhance cognitive control. Participants were n = 157 children and adolescents, n = 129 of them were patients with ADHD (n = 28 typically developing (TD) controls). Patients with ADHD were divided into five groups in the order of referral, with four of them taking part in different NF protocols systematically varying theta and beta power. The fifth ADHD group and the TD group did not undergo NF. All NF protocols resulted in reductions of ADHD symptoms. Importantly, only when beta frequencies were enhanced during NF (without any theta regulation or in combination with theta upregulation), consistent enhancing effects in both response inhibition and conflict control were achieved. The theta/beta NF protocol most widely used in clinical settings revealed comparatively limited effects. Enhancements in beta band activity are key when aiming to improve cognitive control functions in ADHD. This calls for a change in the use of theta/beta NF protocols and shows that protocols differing from the current clinical standard are effective in enhancing important facets of cognitive control in ADHD. Further studies need to examine regulation data within the neurofeedback sessions to provide more information about the mechanisms underlying the observed effects.

Inhibitory Control and Brain–Heart Interaction: An HRV-EEG Study

Background: Motor inhibition is a complex cognitive function regulated by specific brain regions and influenced by the activity of the Central Autonomic Network. We investigate the two-way Brain–Heart interaction during a Go/NoGo task. Spectral EEG ϑ, α powerbands, and HRV parameters (Complexity Index (CI), Low Frequency (LF) and High Frequency (HF) powers) were recorded. Methods: Fourteen healthy volunteers were enrolled. We used a modified version of the classical Go/NoGo task, based on Rule Shift Cards, characterized by a baseline and two different tasks of different complexity. The participants were divided into subjects with Good (GP) and Poor (PP) performances. Results: In the baseline, CI was negatively correlated with α/ϑ. In task 1, the CI was negatively correlated with the errors and α/ϑ, while the errors were positively correlated with α/ϑ. In task 2, CI was negatively correlated with the Reaction Time and positively with α, and the errors were negatively correlated with the Reaction Time and positively correlated with α/ϑ. The GP group showed, at baseline, a negative correlation between CI and α/ϑ. Conclusions: We provide a new combined Brain–Heart model underlying inhibitory control abilities. The results are consistent with the complementary role of α and ϑ oscillations in cognitive control.

An Action-Independent Role for Midfrontal Theta Activity Prior to Error Commission

Error-related electroencephalographic (EEG) signals have been widely studied concerning the human cognitive capability of differentiating between erroneous and correct actions. Midfrontal error-related negativity (ERN) and theta band oscillations are believed to underlie post-action error monitoring. However, it remains elusive how early monitoring activity is trackable and what are the pre-response brain mechanisms related to performance monitoring. Moreover, it is still unclear how task-specific parameters, such as cognitive demand or motor control, influence these processes. Here, we aimed to test pre- and post-error EEG patterns for different types of motor responses and investigate the neuronal mechanisms leading to erroneous actions. We implemented a go/no-go paradigm based on keypresses and saccades. Participants received an initial instruction about the direction of response to be given based on a facial cue and a subsequent one about the type of action to be performed based on an object cue. The paradigm was tested in 20 healthy volunteers combining EEG and eye tracking. We found significant differences in reaction time, number, and type of errors between the two actions. Saccadic responses reflected a higher number of premature responses and errors compared to the keypress ones. Nevertheless, both led to similar EEG patterns, supporting previous evidence for increased ERN amplitude and midfrontal theta power during error commission. Moreover, we found pre-error decreased theta activity independent of the type of action. Source analysis suggested different origin for such pre- and post-error neuronal patterns, matching the anterior insular cortex and the anterior cingulate cortex, respectively. This opposite pattern supports previous evidence of midfrontal theta not only as a neuronal marker of error commission but also as a predictor of action performance. Midfrontal theta, mostly associated with alert mechanisms triggering behavioral adjustments, also seems to reflect pre-response attentional mechanisms independently of the action to be performed. Our findings also add to the discussion regarding how salience network nodes interact during performance monitoring by suggesting that pre- and post-error patterns have different neuronal sources within this network.

Electrocorticography to Investigate Age-Related Brain Lateralization on Pediatric Motor Inhibition

Response inhibition refers to the ability to suppress inappropriate actions that interfere with goal-driven behavior. The inferior frontal gyrus (IFG) is known to be associated with inhibition of a motor response by assuming executive control over motor cortex outputs. This study aimed to evaluate the pediatric development of response inhibition through subdural electrocorticography (ECoG) recording. Subdural ECoG recorded neural activities simultaneously during a Go/No-Go task, which was optimized for children. Different frequency power [theta: 4–8 Hz; beta: 12–40 Hz; high-gamma (HG): 70–200 Hz] was estimated within the IFG and motor cortex. Age-related analysis was computed by each bandpass power ratio between Go and No-Go conditions, and phase-amplitude coupling (PAC) over IFG by using the modulating index metric in two conditions. For all the eight pediatric patients, HG power was more activated in No-Go trials than in Go trials, in either right- or left-side IFG when available. In the IFG region, the power over theta and HG in No-Go conditions was higher than those in Go conditions, with significance over the right side (p < 0.05). The age-related lateralization from both sides to the right side was observed from the ratio of HG power and PAC value between the No-Go and Go trials. In the pediatric population, the role of motor inhibition was observed in both IFG, with age-related lateralization to the right side, which was proved in the previous functional magnetic resonance imaging studies. In this study, the evidence correlation of age and response inhibition was observed directly by the evidence of cortical recordings.

Resting-state theta activity is linked to information content-specific coding levels during response inhibition

The neurophysiological processes underlying the inhibition of impulsive responses have been studied extensively. While also the role of theta oscillations during response inhibition is well examined, the relevance of resting-state theta activity for inhibitory control processes is largely unknown. We test the hypothesis that there are specific relationships between resting-state theta activity and sensory/motor coding levels during response inhibition using EEG methods. We show that resting theta activity is specifically linked to the stimulus-related fraction of neurophysiological activity in specific time windows during motor inhibition. In contrast, concomitantly coded processes related to decision-making or response selection as well as the behavioral inhibition performance were not associated with resting theta activity. Even at the peak of task-related theta power, where task-related theta activity and resting theta activity differed the most, there was still predominantly a significant correlation between both types of theta activity. This suggests that aspects similar to resting dynamics are evident in the proportion of inhibition-related neurophysiological activity that reflects an “alarm” signal, whose function is to process and indicate the need for cognitive control. Thus, specific aspects of task-related theta power may build upon resting theta activity when cognitive control is necessary.

Alpha and Theta Bands Dynamics Serve Distinct Functions during Perception-Action Integration in Response Inhibition

The ability to inhibit responses is central for situational behavior. However, the mechanisms how sensory information is used to inform inhibitory control processes are incompletely understood. In the current study, we examined neurophysiological processes of perception-action integration in response inhibition using the theory of event coding as a conceptual framework. Based on theoretical considerations, we focused on theta and alpha band activity in close connection to the functional neuroanatomical level using EEG beamforming. Moreover, we performed a network-based analysis of theta and alpha band activity. We show a seesaw-like relationship between medial and superior frontal cortex theta band activity and frontoparietal cortex alpha band activity during perception-action integration in response inhibition, depending on the necessity to reconfigure perception-action associations. When perception-action integration was more demanding, because perception-action associations (bindings) have to be reconfigured, there was an increase of theta and a decrease of alpha band activity. Vice versa, when there was no need to reconfigure perception-action bindings, theta band activity was low and alpha band activity was high. However, theta band processes seem to be most important for perception-action integration in response inhibition, because only the sensor-level network organization of theta band activity showed variations depending on the necessity to reconfigure perception-action associations. When no reconfiguration was necessary, the network architecture was more small-world-like, likely enabling efficient processing. When reconfigurations were necessary, the network organization becomes more random. These differences were particularly strong for fractions of the neurophysiological signal supposed to reflect response selection processes.

Electroencephalography complexity in resting and task states in adults with attention-deficit/hyperactivity disorder

Analysing EEG complexity could provide insight into neural connectivity underlying attention-deficit/hyperactivity disorder symptoms. EEG complexity was calculated through multiscale entropy and compared between adults with attention-deficit/hyperactivity disorder and their peers during resting and go/nogo task states. Multiscale entropy change from the resting state to the task state was also examined as an index of the brain’s ability to change from a resting to an active state. Thirty unmedicated adults with attention-deficit/hyperactivity disorder were compared with 30 match-paired healthy peers on the multiscale entropy in the resting and task states as well as their multiscale entropy change. Results showed differences in multiscale entropy between individuals with attention-deficit/hyperactivity disorder and their peers during the resting state as well as the task state. The multiscale entropy measured from the comparison group was larger than that from the attention-deficit/hyperactivity disorder group in the resting state, whereas the reverse pattern was found during the task state. Our most robust finding showed that the multiscale entropy change from individuals with attention-deficit/hyperactivity disorder was smaller than that from their peers, specifically at frontal sites. Interestingly, individuals without attention-deficit/hyperactivity disorder performed better with decreasing multiscale entropy changes, demonstrating higher accuracy, faster reaction time and less variability in their reaction times. These data suggest that multiscale entropy could not only provide insight into neural connectivity differences between adults with attention-deficit/hyperactivity disorder and their peers but also into their behavioural performance.

Pretrial Theta Band Activity Affects Context-dependent Modulation of Response Inhibition

The ability to inhibit a prepotent response is a crucial prerequisite of goal-directed behavior. So far, research on response inhibition has mainly examined these processes when there is little to no cognitive control during the decision to respond. We manipulated the "context" in which response inhibition has to be exerted (i.e., a controlled or an automated context) by combining a Simon task with a go/no-go task and focused on theta band activity. To investigate the role of "context" in response inhibition, we also examined how far theta band activity in the pretrial period modulates context-dependent variations of theta band activity during response inhibition. This was done in an EEG study applying beamforming methods. Here, we examined n = 43 individuals. We show that an automated context, as opposed to a controlled context, compromises response inhibition performance and increases the need for cognitive control. This was also related to context-dependent modulations of theta band activity in superior frontal and middle frontal regions. Of note, results showed that theta band activity in the pretrial period, associated with the right inferior frontal cortex, was substantially correlated with context-dependent modulations of theta band activity during response inhibition. The direction of the obtained correlation provides insights into the functional relevance of a pretrial theta band activity. The data suggest that pretrial theta band activity reflects some form of attentional sampling to inform possible upcoming processes signaling the need for cognitive control.

Superior frontal regions reflect the dynamics of task engagement and theta band-related control processes in time-on task effects

Impairment of cognitive performance is often observed in time-on tasks. Theoretical considerations suggest that especially prefrontal cortex cognitive control functions is affected by time-on-task effects, but the role of effort/task engagement is not understood. We examine time-on-task effects in cognitive control on a neurophysiological level using a working-memory modulated response inhibition task and inter-relate prefrontal neuroanatomical region-specific theta-band activity with pupil diameter data using EEG-beamforming approaches. We show that task performance declines with time-on tasks, which was paralleled by a concomitant decreases of task-evoked superior frontal gyrus theta-band activity and a reduction in phasic pupil diameter modulations. A strong relation between cognitive control-related superior frontal theta-band activity and effort/task engagement indexed by phasic pupil diameter modulations was observed in the beginning of the experiment, especially for tasks requiring inhibitory controls and demanding high working memory. This strong relation vanished at the end of the experiment, suggesting a decoupling of cognitive control resources useable for a task and effort invested that characterizes time-on-task effects in prefrontal cortical structures.

Event-related synchronization/desynchronization and functional neuroanatomical regions associated with fatigue effects on cognitive flexibility

Cognitive flexibility is an essential prerequisite for goal-directed behavior, and daily observations already show that it deteriorates when one is engaged in a task for a (too) long time. Yet, the neural mechanisms underlying such fatigability effect in cognitive flexibility are poorly understood. We examined how theta, alpha, and beta frequency event-related synchronization and desynchronization processes during cued memory-based task switching are modulated by time-on-task effects. We put special emphasis on the examination of functional neuroanatomical regions being associated with these modulations, using EEG beamforming. We show clear declines in task switching performance (increased switch costs) with time on task. For processes occurring before rule switching or repetition processes, we show that anticipatory attentional sampling and selection mechanisms associated with fronto-parietal structures are modulated by time-on-task effects but sensory areas (occipital cortex) also show fatigability-dependent modulations. After target stimulus presentation, the allocation of processing resources for response selection as reflected by theta-related activity in parietal cortices is compromised with time on task and similarly a concomitant increase in alpha and beta band-related attentional processing or gating mechanisms in frontal and occipital regions. Yet, considering the behavioral data showing an apparent decline in performance, this probably compensatory increase is still insufficient to allow reasonable performance. The same is likely the case for processes occurring before rule switching or repetition processes. Comparative analyses show that modulations of alpha band activity are as strongly modulated by fatigability as theta band activity. Implications of these findings for theoretical concepts on fatigability are discussed.NEW & NOTEWORTHY We examine the neurophysiological and functional neuroanatomical basis of fatigability in cognitive flexibility. We show that alpha and theta modulations in fronto-parietal and primary sensory areas are central for the understanding of fatigability effects in cognitive flexibility.

The interplay of resting and inhibitory control-related theta-band activity depends on age

Resting‐state neural activity plays an important role for cognitive control processes. Regarding response inhibition processes, an important facet of cognitive control, especially theta‐band activity has been the focus of research. Theoretical considerations suggest that the interrelation of resting and task‐related theta activity is subject to maturational effects. To investigate whether the relationship between resting theta activity and task‐related theta activity during a response inhibition task changes even in young age, we tested N = 166 healthy participants between 8 and 30 years of age. We found significant correlations between resting and inhibitory control‐related theta activity as well as behavioral inhibition performance. Importantly, these correlations were moderated by age. The moderation analysis revealed that higher resting theta activity was associated with stronger inhibition‐related theta activity in individuals above the age of ~10.7 years. The EEG beamforming analysis showed that this activity is associated with superior frontal region function (BA6). The correlation between resting and superior frontal response inhibition‐related theta activity became stronger with increasing age. A similar pattern was found for response inhibition performance, albeit only evident from the age of ~19.5 years. The results suggest that with increasing age, resting theta activity becomes increasingly important for processing the alarm/surprise signals in superior frontal brain regions during inhibitory control. Possible causes for these developmental changes are discussed.

Shared and unique neural mechanisms underlying pediatric trichotillomania and obsessive compulsive disorder

BACKGROUND

Little is known about the neural underpinnings of pediatric trichotillomania (TTM). We examined error-related negativity (ERN)-amplitude and theta-EEG power differences among youth with TTM, OCD, and healthy controls (HC).

METHODS

Forty channel EEG was recorded from 63 pediatric participants (22 with TTM, 22 with OCD, and 19 HC) during the Eriksen Flanker Task. EEG data from inhibitory control were used to derive estimates of ERN amplitude and event-related spectral power associated with motor inhibition.

RESULTS

TTM and HC were similar in brain activity patterns in frontal and central regions and TTM and OCD were similar in the parietal region. Frontal ERN-amplitude was significantly larger in OCD relative to TTM and HC, who did not differ from each other. The TTM group had higher theta power compared to OCD in frontal and central regions, and higher theta than both comparison groups in right motor cortex and superior parietal regions. Within TTM, flanker task performance was correlated with EEG activity in frontal, central, and motor cortices whereas global functioning and impairment were associated with EEG power in bilateral motor and parietal cortices.

CONCLUSIONS

Findings are discussed in terms of shared and unique neural mechanisms in TTM and OCD and treatment implications.

Spontaneous Alpha and Theta Oscillations Are Related to Complementary Aspects of Cognitive Control in Younger and Older Adults

The resting-state human electroencephalogram (EEG) power spectrum is dominated by alpha (8-12 Hz) and theta (4-8 Hz) oscillations, and also includes non-oscillatory broadband activity inversely related to frequency (1/f activity). Gratton proposed that alpha and theta oscillations are both related to cognitive control function, though in a complementary manner. Alpha activity is hypothesized to facilitate the maintenance of representations, such as task sets in preparation for expected task conditions. In contrast, theta activity would facilitate changes in representations, such as the updating of task sets in response to unpredicted task demands. Therefore, theta should be related to reactive control (which may prompt changes in task representations), while alpha may be more relevant to proactive control (which implies the maintenance of current task representations). Less is known about the possible relationship between 1/f activity and cognitive control, which was analyzed here in an exploratory fashion. To investigate these hypothesized relationships, we recorded eyes-open and eyes-closed resting-state EEG from younger and older adults and subsequently tested their performance on a cued flanker task, expected to elicit both proactive and reactive control processes. Results showed that alpha power and 1/f offset were smaller in older than younger adults, whereas theta power did not show age-related reductions. Resting alpha power and 1/f offset were associated with proactive control processes, whereas theta power was related to reactive control as measured by the cued flanker task. All associations were present over and above the effect of age, suggesting that these resting-state EEG correlates could be indicative of trait-like individual differences in cognitive control performance, which may be already evident in younger adults, and are still similarly present in healthy older adults.

The dynamics of theta-related pro-active control and response inhibition processes in AD(H)D

Impulsivity and deficits in response inhibition are hallmarks of attention-deficit(-hyperactivity) disorder (AD(H)D), can cause severe problems in daily functioning, and are thus of high clinical relevance. Traditionally, research to elucidate associated neural correlates has intensively, but also quite selectively examined mechanisms during response inhibition in various tasks. Doing so, in-between trial periods or periods prior to the response inhibition process, where no information relevant to inhibitory control is presented, have been neglected. Yet, these periods may nevertheless reveal relevant information. In the present study, using a case-control cross-sectional design, we take a more holistic approach, examining the inter-relation of pre-trial and within-trial periods in a Go/Nogo task with a focus on EEG theta band activity. Applying EEG beamforming methods, we show that the dynamics between pre-trial (pro-active) and within-trial (inhibition-related) control processes significantly differ between AD(H)D subtypes. We show that response inhibition, and differences between AD(H)D subtypes, exhibit distinct patterns of (at least) three factors: (i) strength of pre-trial (pro-active control) theta-band activity, (ii) the inter-relation of pro-active control and inhibition-relation theta band activity and (iii) the functional neuroanatomical region active during theta-related pro-active control processes. This multi-factorial pattern is captured by AD(H)D subtype clinical symptom clusters. The study provides a first hint that novel cognitive-neurophysiological facets of AD(H)D may be relevant to distinguish AD(H)D subtypes.

Resting theta activity is associated with specific coding levels in event-related theta activity during conflict monitoring

Brain electrical activity in the theta frequency band is essential for cognitive control (e.g., during conflict monitoring), but is also evident in the resting state. The link between resting state theta activity and its relevance for theta-related neural mechanisms during cognitive control is still undetermined. Yet, theoretical considerations suggest that there may be a connection. To examine the link between resting state theta activity and conflict-related theta activity, we combined temporal EEG signal decomposition methods with time-frequency decomposition and beamforming methods in N = 86 healthy participants. Results indicate that resting state theta activity is closely associated with the strength of conflict-related neural activity at the level of ERPs and total theta power (consisting of phase-locked and nonphase-locked aspects of theta activity). The data reveal that resting state theta activity is related to a specific aspect of conflict-related theta activity, mainly in superior frontal regions and in the supplemental motor area (SMA, BA6) in particular. The signal decomposition showed that only stimulus-related, but not motor-response-related coding levels in the EEG signal and the event-related total theta activity were associated with resting theta activity. This specificity of effects may explain why the association between resting state theta activity and overt conflict monitoring performance may not be as strong as often assumed. The results suggest that resting state theta activity is particularly important to consider for input integration processes during cognitive control.

Resting-state EEG Dynamics Reveals Differences in Network Organization and its Fluctuation between Frequency Bands

Functional connectivity in EEG resting-state is not stable but fluctuates considerably. The aim of this study was to investigate how efficient information flows through a network, i.e. how resting-state EEG networks are organized and whether this organization it also subject to fluctuations. Differences of the network organization (small-worldness), degree of clustered connectivity, and path length as an indicator of how information is integrated into the network across time was compared between theta, alpha and beta bands. We show robust differences in network organization (small-worldness) between frequency bands. Fluctuations in network organization were larger in the theta, compared to the alpha and beta frequency. Variation in network organization and not the frequency of fluctuations differs between frequency bands. Furthermore, the degree of clustered connectivity and its modulation across time is the same across frequency bands, but the path length revealed the same modulatory pattern as the small-world metric. It is therefore the interplay of local processing efficiency and global information processing efficiency in the brain that fluctuates in a frequency-specific way. Properties of how information can be integrated is subject to fluctuations in a frequency-specific way in the resting-state. The possible relevance of these resting-state EEG properties is discussed including its clinical relevance.

Acute Alcohol Effects on Response Inhibition Depend on Response Automatization, but not on GABA or Glutamate Levels in the ACC and Striatum

Alcohol increases GABAergic signaling and decreases glutamatergic signaling in the brain. Variations in these neurotransmitter levels may modulate/predict executive functioning. Matching this, strong impairments of response inhibition are one of the most consistently reported cognitive/behavioral effects of acute alcohol intoxication. However, it has never been investigated whether baseline differences in these neurotransmitters allow to predict how much alcohol intoxication impairs response inhibition, and whether this is reflected in neurophysiological measures of cognitive control. We used MR spectroscopy to assess baseline (i.e., sober) GABA and glutamate levels in the anterior cingulate cortex (ACC) and striatum in n = 30 healthy young males, who were subsequently tested once sober and once intoxicated (1.01 permille). Inhibition was assessed with the sustained attention to response task (SART). This paradigm also allows to examine the effect of different degrees of response automatization, which is a known modulator for response inhibition, but does not seem to be substantially impaired during acute intoxication. As a neurophysiological correlate of response inhibition and control, we quantified EEG-derived theta band power and located its source using beamforming analyses. We found that alcohol-induced response inhibition deficits only occurred in the case of response automatization. This was reflected by decreased theta band activity in the left supplementary motor area (SMA), which may reflect modulations in the encoding of a surprise signal in response to inhibition cues. However, we did not find that differences in baseline (i.e., sober) GABA or glutamate levels significantly modulated differences in the size of alcohol-induced inhibition deficits.

On the relevance of EEG resting theta activity for the neurophysiological dynamics underlying motor inhibitory control

The modulation of theta frequency activity plays a major role in inhibitory control processes. However, the relevance of resting theta band activity and of the ability to spontaneously modulate this resting theta activity for neural mechanisms underlying inhibitory control is elusive. Various theoretical conceptions suggest to take these aspects into consideration. In the current study, we examine whether the strength of resting theta band activity or the ability to modulate the resting state theta activity affects response inhibition. We combined EEG-time frequency decomposition and beamforming in a conflict-modulated Go/Nogo task. A sample of N = 66 healthy subjects was investigated. We show that the strength of resting state theta activity modulates the effects of conflicts during motor inhibitory control. Especially when resting theta activity was low, conflicts strongly affected response inhibition performance and total theta band activity during Nogo trials. These effects were associated with theta-related activity differences in the superior (BA7) and inferior parietal cortex (BA40). The results were very specific for total theta band activity since evoked theta activity and measures of intertrial phase coherency (phase-locking factor) were not affected. The data suggest that the strength of resting state theta activity modulates processing of a theta-related alarm or surprise signal during inhibitory control. The ability to voluntarily modulate theta band activity did not affect conflict-modulated inhibitory control. These findings have important implications for approaches aiming to optimize human cognitive control.