Frontal Midline Theta Research Articles

Effects of Transcutaneous Vagus Nerve Stimulation (tVNS) on Conflict-Related Behavioral Performance and Frontal Midline Theta Activity

Several previous studies have highlighted the potential of transcutaneous vagus nerve stimulation (tVNS) to enhance executive control of action. In the present study, we tested for effects of tVNS on behavioral performance and frontal midline theta activity during response conflicts. Frontal midline theta reflects transient activation of the posterior midfrontal cortex in situations requiring increased executive control of action. It is an established marker for top-down action control. We carried out a combined behavioral and electroencephalography (EEG) within-subjects experimental study employing a cued go–no-go-change task. Twenty-two healthy young adults participated. We found that tVNS enhanced global behavioral accuracy, i.e., decreased the proportion of erroneous and missed responses, compared with sham (placebo) stimulation, and reduced conflict costs on behavioral performance in go/change response conflicts. Furthermore, in trials eliciting go/stop conflicts, frontal midline theta was enhanced under tVNS. These findings corroborate the potential of tVNS to enhance executive control of action. For the first time, we show an effect of tVNS on frontal midline theta activity, which suggests that tVNS specifically interacts with the neural mechanisms underlying action control. We conclude that tVNS is a promising method to enhance executive control and recommend the further investigation of tVNS as a candidate treatment of clinically relevant executive control deficits.

Error-Related Dynamics of Reaction Time and Frontal Midline Theta Activity in Attention Deficit Hyperactivity Disorder (ADHD) During a Subliminal Motor Priming Task.

Post-error slowing (PES) is an established performance monitoring readout. Several previous studies have found that PES is reduced in children and adolescents with attention-deficit hyperactivity disorder (ADHD). We analyzed reaction time data, along with electroencephalography (EEG) data, from a response priming experiment in children and adolescents with ADHD (N = 28) and typically developing (TD) controls (N = 15) between 10 and 17 years of age. We report dynamic reaction time changes before and after errors: whereas TD controls readjusted their response speed to their individual average speed after committing an error, this reaction time adjustment appeared to be delayed and decreased in ADHD patients. In the EEG, error trials were accompanied by increased frontal midline theta activity, which was attenuated in ADHD compared to TD. We conclude that PES has a different time course rather than being fully absent in ADHD and discuss relationships with our EEG findings and potential implications for performance monitoring in ADHD.

Recording mobile EEG in an outdoor environment reveals cognitive-motor interference dependent on movement complexity

Oftentimes we find ourselves in situations in which we need to perform concurrent motor and cognitive tasks like simple locomotion while being cognitively involved. In the present study, we investigated in how far cognitive and motor functioning interfere in an outdoor environment. Our participants performed an auditory oddball task while concurrently completing various motor tasks on the outside premises of our institute. Beside behavioural responses and subjective workload ratings, we also analysed electrophysiological data recorded with a 30-channel mobile EEG montage. We observed an increase of subjective workload and decrease of performance with increasing movement complexity. Accordingly, we also found a decrease in the parietal P3 amplitude as well as in frontal midline Theta power with higher motor load. These results indicate that an increased movement complexity imposes a higher workload to the cognitive system, which, in turn, effectively reduces the availability of cognitive resources for the cognitive task. Overall this experiment demonstrates the feasibility of transferring classical paradigms of cognitive research to real-world settings. The findings support the notion of shared resources for motor and cognitive functions by demonstrating distinct modulations of correlates of cognitive processes across different motor tasks.

Individuals with depression display abnormal modulation of neural oscillatory activity during working memory encoding and maintenance

PurposeTo investigate neural oscillatory activity supporting working memory (WM) processing in depressed individuals and healthy controls. MethodsForty-six participants with Major Depressive Disorder (MDD) and 41 healthy controls balanced on age, gender, and WM ability completed a Sternberg verbal WM task with concurrent electroencephalography recording. Oscillatory activity was calculated for upper alpha, theta, and gamma frequency bands during WM encoding and maintenance. ResultsWM performance did not differ between groups. When compared to healthy controls, depressed individuals displayed reduced frontal-midline theta power and increased occipital upper alpha power during WM encoding, and reductions in frontal-midline theta power and occipital gamma and upper alpha power during WM maintenance. Higher depression severity was associated with greater reductions upper alpha and gamma power during WM maintenance. ConclusionsDepressed individuals displayed prominent alterations in oscillatory activity during WM encoding and maintenance, indicating that the neural processes which support WM processing are altered in MDD even when no cognitive impairments are observed.

Atypical frontal midline theta activity during cognitive control in heroin addicts.

Deficiency in cognitive control has been proposed as a core issue in addictive behavior, and recent advancements in cognitive neuroscience have suggested that frontal midline theta is a mechanism for cognitive control. This study examined frontal midline theta deficits in patients with heroin dependence during a Go/No-go task which explicitly involved cognitive control. Electroencephalography readings were collected from 15 male heroin addicts and 17 demographically matched healthy controls during an equal probability Go/No-go task. The findings revealed that heroin addicts responded significantly slower to the Go stimulus as compared to the healthy control. Heroin addicts also showed less frontal midline theta modulations between the Go and No-go conditions. These findings provided further evidence toward understanding the nature of drug addiction-related cognitive dysfunction.

Wearing a bike helmet leads to less cognitive control, revealed by lower frontal midline theta power and risk indifference.

A recent study claims that participants wearing a bike helmet behave riskier in a computer-based risk task compared to control participants without a bike helmet. We hypothesized that wearing a bike helmet reduces cognitive control over risky behavior. To test our hypothesis, we recorded participants' EEG brain responses while they played a risk game developed in our laboratory. Previously, we found that, in this risk game, anxious participants showed greater levels of cognitive control as revealed by greater frontal midline theta power, which was associated with less risky decisions. Here, we predicted that cognitive control would be reduced in the helmet group, indicated by reduced frontal midline theta power, and that this group would prefer riskier options in the risk game. In line with our hypothesis, we found that participants in the helmet group showed significantly lower frontal midline theta power than participants in the control group, indicating less cognitive control. We did not replicate the finding of generally riskier behavior in the helmet group. Instead, we found that participants chose the riskier option in about half of trials, no matter how risky the other option was. Our results suggest that wearing a bike helmet reduces cognitive control, as revealed by reduced frontal midline theta power, leading to risk indifference when evaluating potential behaviors.

"Telling me not to worry…" Hyperscanning and Neural Dynamics of Emotion Processing During Guided Imagery and Music.

To analyze how emotions and imagery are shared, processed and recognized in Guided Imagery and Music, we measured the brain activity of an experienced therapist (“Guide”) and client (“Traveler”) with dual-EEG in a real therapy session about potential death of family members. Synchronously with the EEG, the session was video-taped and then micro-analyzed. Four raters identified therapeutically important moments of interest (MOI) and no-interest (MONI) which were transcribed and annotated. Several indices of emotion- and imagery-related processing were analyzed: frontal and parietal alpha asymmetry, frontal midline theta, and occipital alpha activity. Session ratings showed overlaps across all raters, confirming the importance of these MOIs, which showed different cortical activity in visual areas compared to resting-state. MOI 1 was a pivotal moment including an important imagery with a message of hope from a close family member, while in the second MOI the Traveler sent a message to an unborn baby. Generally, results seemed to indicate that the emotions of Traveler and Guide during important moments were not positive, pleasurably or relaxed when compared to resting-state, confirming both were dealing with negative emotions and anxiety that had to be contained in the interpersonal process. However, the temporal dynamics of emotion-related markers suggested shifts in emotional valence and intensity during these important, personally meaningful moments; for example, during receiving the message of hope, an increase of frontal alpha asymmetry was observed, reflecting increased positive emotional processing. EEG source localization during the message suggested a peak activation in left middle temporal gyrus. Interestingly, peaks in emotional markers in the Guide partly paralleled the Traveler's peaks; for example, during the Guide's strong feeling of mutuality in MOI 2, the time series of frontal alpha asymmetries showed a significant cross-correlation, indicating similar emotional processing in Traveler and Guide. Investigating the moment-to-moment interaction in music therapy showed how asymmetry peaks align with the situated cognition of Traveler and Guide along the emotional contour of the music, representing the highs and lows during the therapy process. Combining dual-EEG with detailed audiovisual and qualitative data seems to be a promising approach for further research into music therapy.

Converging electrophysiological evidence for a processing advantage of social over nonsocial feedback

We recently demonstrated a processing advantage of social versus nonsocial feedback stimuli in a western sample by assessing phase-locked neural responses. The current study extended our previous findings to another cultural sample (Chinese) to further test whether non-phase-locked neural oscillations also exhibit the social feedback processing advantage. Fifty-three Chinese volunteers performed a time estimation task with social and nonsocial feedback stimuli (matched for complexity) while electroencephalogram was recorded. Almost entirely replicating our previous results, feedback ERPs showed a processing advantage for social compared with nonsocial stimuli. Importantly, non-phase-locked oscillations also revealed this pattern. Frontal midline theta (FMΘ) oscillations differentiated between negative and positive feedback to a larger extent in response to social compared with nonsocial feedback. The current findings imply a rather universal effect of social stimulus characteristics during feedback processing and further corroborate the notion of social content as a distinct stimulus category.

Beta-gamma oscillation reveals learning from unexpected reward in learners versus non-learners

Beta-gamma oscillation has been demonstrated to be sensitive to unexpected reward feedback. However, it remains unclear whether beta-gamma activity manifests individual differences in reinforcement learning processing. Given that individuals differ largely in reinforcement learning tasks, we adapted the Friedland task and split subjects into two groups: learners who learned to choose the optimal card after training and non-learners who did not learn well. We used recorded electroencephalography signals to test the difference in brain activity between the learners and non-learners groups when participants conducted a time estimation task and received win and loss feedback in expected and unexpected conditions. The results revealed that the unexpected condition elicited a larger reward positivity amplitude than did the expected condition, but only in the learners group. No significant difference was found between the two groups for the expectancy effect on frontal-midline theta. The current results thus demonstrate that for learners, unexpected win feedback elicits a larger beta-gamma oscillation than expected win feedback, while this was not the case for non-learners. These results indicate that beta-gamma oscillation may reflect effective learning from positive reward prediction error, a finding that adds to the existing theories on learning processes.

Be Prepared: Tune to FM-Theta for Cognitive Control

Rhythmical brain activity around 5Hz can be observed in the prefrontal cortex under conditions requiring high levels of cognitive control. However, its temporal dynamics are still elusive. A recent research paper (Cooper et al. Neuroimage 2019;189:130-140) provides evidence that the temporal evolution of this frontal-midline theta activity reflects the style of cognitive control being implemented.

Eye fixation-related fronto-parietal neural network correlates of memory retrieval

Eye movements are considered to be informative with regard to the underlying cognitive processes of human beings. Previous studies have reported that eye movements are associated with which scientific concepts are retrieved correctly. Moreover, other studies have also suggested that eye movements involve the cooperative activity of the human brain's fronto-parietal circuits. Less research has been conducted to investigate whether fronto-parietal EEG oscillations are associated with the retrieval processing of scientific concepts. Our findings in this study demonstrated that the fronto-parietal network is indeed crucial for successful memory retrieval. In short, significantly lower theta augmentation in the frontal midline and lower alpha suppression in the right parietal region were observed at the 5th eye fixation for physics concepts that were correctly retrieved than for those that were incorrectly retrieved. Moreover, the visual cortex in the occipital lobe exhibits a significantly greater theta augmentation followed by an alpha suppression following each eye fixation, while a right fronto-parietal asymmetry was also found for the successful retrieval of presentations of physics concepts. In particular, the study results showed that eye fixation-related frontal midline theta power and right parietal alpha power at the 5th eye fixation have the greatest predictive power regarding the correctness of the retrieval of physics concepts.

Age-related differences in reallocating cognitive resources when dealing with interruptions

The ability to perform at a high level, even when the task at hand is interrupted by an unrelated secondary task, is central to human information processing. Executive control processes, in particular the reallocation of attentional resources, are crucial for coping with interruptions. Although the age-related decline in cognitive control functions is well described, the consequences of such changes for the ability to deal with interruptions are as of yet unclear. In the present study, we examined behavioral performance as well as electrophysiological parameters associated with executive control processes in older and younger participants using a nested task design: In one third of all trials, an ongoing working memory task was interrupted by a math task. We found that the impact of interruptions on primary task performance was more severe in the older age group. In the EEG, older adults showed stronger frontal midline theta activation and fronto-parietal connectivity in the theta range in response to the cue indicating the relevant attentional set. Younger participants, on the other hand, showed distinct and specific increases in cognitive control as indexed by frontal midline theta in response to the stimulus signaling an upcoming interruption. Overall, the results reveal strategic differences between the age groups, as older participants seem to prioritize the primary task more strongly. The data furthermore indicate that the combination of a rapid succession of events and the decreased ability to shift executive resources renders older adults’ performance particularly vulnerable to the occurrence of interruptions.

Challenge, motivation, and effort: Neural and behavioral correlates of self-control of difficulty during practice

Self-control of task-relevant parameters during practice results in superior learning. However, the mechanisms underlying this effect remain unclear. To investigate these effects, we collected frontal alpha asymmetry (ΔFAS) and midline frontal theta (ΔMFT). Sixty novice participants were randomized into a self-controlled group, controlling difficulty for each block in a videogame task, or a yoked group, with difficulty matched to a self-controlled counterpart. ΔMFT decreased with better performance and increased at higher levels of difficulty, but the effect of difficulty was moderated by group. There was also a Block x Group interaction for ΔMFT. Changing difficulty depended on a participant’s group and score, and participant engagement in the self-controlled group. This pattern of results suggests that self-controlled participants were better prepared to deal with more difficult environments. These data provide insight into the physiological factors that might explain self-controlled learning effects.

FMRI BOLD Correlates of EEG Independent Components: Spatial Correspondence With the Default Mode Network

Goal: We aimed to identify electroencephalographic (EEG) signal fluctuations within independent components (ICs) that correlate to spontaneous blood oxygenation level dependent (BOLD) activity in regions of the default mode network (DMN) during eyes-closed resting state.Methods: We analyzed simultaneously acquired EEG and functional magnetic resonance imaging (fMRI) eyes-closed resting state data in a convenience sample of 30 participants. IC analysis (ICA) was used to decompose the EEG time-series and common ICs were identified using data-driven IC clustering across subjects. The IC time courses were filtered into seven frequency bands, convolved with a hemeodynamic response function (HRF) and used to model spontaneous fMRI signal fluctuations across the brain. In parallel, group ICA analysis was used to decompose the fMRI signal into ICs from which the DMN was identified. Frequency and IC cluster associated hemeodynamic correlation maps obtained from the regression analysis were spatially correlated with the DMN. To investigate the reliability of our findings, the analyses were repeated with data collected from the same subjects 1 year later.Results: Our results indicate a relationship between power fluctuations in the delta, theta, beta and gamma frequency range and the DMN in different EEG ICs in our sample as shown by small to moderate spatial correlations at the first measurement (0.234 < |r| < 0.346, p < 0.0001). Furthermore, activity within an EEG component commonly identified as eye movements correlates with BOLD activity within regions of the DMN. In addition, we demonstrate that correlations between EEG ICs and the BOLD signal during rest are in part stable across time.Discussion: We show that ICA source separated EEG signals can be used to investigate electrophysiological correlates of the DMN. The relationship between the eye movement component and the DMN points to a behavioral association between DMN activity and the level of eye movement or the presence of neuronal activity in this component. Previous findings of an association between frontal midline theta activity and the DMN were replicated.

Go/no-go training affects frontal midline theta and mu oscillations to passively observed food stimuli

The mere perception of high-calorie food items can trigger strong action tendencies towards these foods. Go/no-go training has successfully been applied to reduce such action tendencies. This study investigated the electrophysiological mechanisms that may underlie the beneficial effects of go/no-go training on food consumption. EEG was measured while 19 participants passively observed pictures of food and non-food items, both before and after the go/no-go training. During training, 50% of the food and non-food items were consistently paired with a go/no-go response. After training, food items that had been associated with a response induced larger mu desynchronization at electrodes over sensorimotor regions, whereas food items that had been associated with withholding from responding induced larger increases in theta power at frontal midline electrodes. These findings suggest that the exerted cognitive control during go/no-go training with attractive food stimuli may become associated with these stimuli and signal the required level of control during subsequent encounters.

Electrophysiological measures reveal the role of anterior cingulate cortex in learning from unreliable feedback.

Although a growing number of studies have investigated the neural mechanisms of reinforcement learning, it remains unclear how the brain responds to feedback that is unreliable. A recent theory proposes that the reward positivity (RewP) component of the event-related brain potential (ERP) and frontal midline theta (FMT) power reflect separate feedback-related processing functions of anterior cingulate cortex (ACC). In the present study, the electroencephalogram (EEG) was recorded from participants as they engaged in a time estimation task in which feedback reliability was manipulated across conditions. After each response, they received a cue that indicated that the following feedback stimulus was 100%, 75%, or 50% reliable. The results showed that participants' time estimates adjusted linearly according to the feedback reliability. Moreover, presentation of the cue indicating 100% reliability elicited a larger RewP-like ERP component than the other cues did, and feedback presentation elicited a RewP of approximately equal amplitude for all of the three reliability conditions. By contrast, FMT power elicited by negative feedback decreased linearly from the 100% condition to 75% and 50% condition, and only FMT power predicted behavioral adjustments on the following trials. In addition, an analysis of Beta power and cross-frequency coupling (CFC) of Beta power with FMT phase suggested that Beta-FMT communication modulated motor areas for the purpose of adjusting behavior. We interpreted these findings in terms of the hierarchical reinforcement learning account of ACC, in which the RewP and FMT are proposed to reflect reward processing and control functions of ACC, respectively.

Mindfulness-based training with transcranial direct current stimulation modulates neuronal resource allocation in working memory: A randomized pilot study with a nonequivalent control group

Mindfulness-based training (MBT) and transcranial electrical stimulation (TES) methods such as direct current stimulation (tDCS) have demonstrated promise for the augmentation of cognitive abilities. The current study investigated the potential compatibility of concurrent “electrical” MBT and tDCS (or eMBT) by testing its combined effects on behavioral and neurophysiological indices of working memory (WM) and attentional resource allocation. Thirty-four healthy participants were randomly assigned to either a MBT task with tDCS group (eMBT) or an active control training task with sham tDCS (Control) group. Training lasted 4-weeks, with up to twenty MBT sessions and with up to eight of those sessions that were eMBT sessions. Electroencephalography was acquired during varying WM load conditions using the n-back task (1-, 2-, 3-back), along with performance on complex WM span tasks (operation and symmetry span) and fluid intelligence measures (Ravens and Shipley) before and after training. Improved performance was observed only on the 3-back and spatial span tasks for eMBT but not the Control group. During 3-back performance in the eMBT group, an increase in P3 amplitude and theta power at electrode site Pz was also observed, along with a simultaneous decrease in frontal midline P3 amplitude and theta power compared to the Control group. These results are consistent with the neural efficiency hypothesis, where higher cognitive capacity was associated with more distributed brain activity (i.e., increase in parietal and decrease in frontal amplitudes). Future longitudinal studies are called upon to further examine the direct contributions of tDCS on MBT by assessing the differential effects of electrode montage, polarity, current strength and a direct contrast between the eMBT and MBT conditions on performance and neuroimaging outcome data. While preliminary, the current results provided evidence for the potential compatibility of using eMBT to modulate WM capacity through the allocation of attention and its neurophysiological correlates.

Electrophysiological indices of anterior cingulate cortex function reveal changing levels of cognitive effort and reward valuation that sustain task performance

Successful execution of goal-directed behaviors often requires the deployment of cognitive control, which is thought to require cognitive effort. Recent theories have proposed that anterior cingulate cortex (ACC) regulates control levels by weighing the reward-related benefits of control against its effort-related costs. However, given that the sensations of cognitive effort and reward valuation are available only to introspection, this hypothesis is difficult to investigate empirically. We have proposed that two electrophysiological indices of ACC function, frontal midline theta and the reward positivity (RewP), provide objective measures of these functions. To explore this issue, we recorded the electroencephalogram (EEG) from participants engaged in an extended, cognitively-demanding task. Participants performed a time estimation task for 2 h in which they received reward and error feedback according to their task performance. We observed that the amplitude of the RewP, a feedback-locked component of the event related brain potential associated with reward processing, decreased with time-on-task. Conversely, frontal midline theta power, which consists of 4–8 Hz EEG oscillations associated with cognitive effort, increased with time-on-task. We also explored how these phenomena changed over time by conducting within-participant multi-level modeling analyses. Our results suggest that extended execution of a cognitively-demanding task is characterized by an early phase in which high control levels foster rapid improvements in task performance, and a later phase in which high control levels were necessary to maintain stable task performance, perhaps counteracting waning reward valuation.

Anxious gambling: Anxiety is associated with higher frontal midline theta predicting less risky decisions.

In this study, we address the effect of anxiety measured with the State-Trait Anxiety Inventory (STAI) on EEG and risk decisions. We selected 20 high and 20 low anxious participants based on their STAI trait scores in the upper or lower quartile of the norm distribution and implemented a risk game developed in our laboratory. We investigate if high anxious individuals exert more cognitive control, reflected in higher frontal midline theta (FMT) power when they make a risky decision, and if they act less risky compared to low anxious individuals. Participants played a risk game while we recorded their brain responses via EEG. High anxious participants played less risky compared to low anxious participants. Further, high anxious participants showed higher FMT power immediately before they chose one of two risk options, suggesting higher cognitive control during the decision time compared to low anxious participants. Via a mediation analysis, we show that the effect of anxiety on risk behavior is fully mediated by FMT power. Further, questionnaire responses revealed that high anxious participants rated risk situations as riskier compared to low anxious participants. We conclude that anxious individuals perceive risky situations as riskier and thus exert more cognitive control during their risk choices, reflected in higher FMT power, which leads to less risky decisions.

Stress-related deficits of older adults' spatial working memory: anEEG investigation of occipital alpha and frontal-midline thetaactivities.

Studies highlight cumulative life stress as a significant predictor of accelerated cognitive aging. This study paired electrophysiological with behavioral measures to explore how cumulative stress affects attentional and maintenance processes underpinning working memory retention. We collected electroencephalographic recordings from 60 individuals (30 older, 30 younger) reporting high or low levels of cumulative stress during the performance of a spatial Sternberg task. We measured mid-occipital alpha (8-12Hz) and frontal-midline theta (4-6Hz) as indicators of attentional and maintenance processes. Older, high-stress participants' behavioral performance lay significantly below than that of younger adults and low-stress older individuals. Impaired task performance coincided with reduced event-related synchronization in alpha and theta frequency ranges during memory maintenance. Electrophysiological findings suggest that older adults' reduced performance results from a stress-related impact on their ability to retain a stimulus in working memory and inhibit extraneous information from interfering with maintenance. Our results demonstrate the wide-ranging impact of cumulative stress on cognitive health and provide insight into the functional mechanisms disrupted by its influence.