Complementary roles of cortical oscillations in automatic and controlled processing during rapid serial tasks

Working memory-related frontal theta activity is decreased under acute stress

Cognitive control is essential for flexible, top-down, goal-directed behavior. Individuals with Internet gaming disorder (IGD) are characterized by impaired prefrontal cortex function and cognitive control. This results in an increase in stimulus-driven habitual behavior, particularly related to pathological gaming. In the present study, we investigated the electroencephalographic (EEG) activity in individuals with IGD. Twenty-four individuals with IGD and 35 healthy control (HC) subjects were recruited. We analyzed their EEG activity while the subjects played their favorite game (30–40 min duration). We compared the band power between the two groups. During gaming, the left frontal theta, alpha, and beta band activities were lower in subjects with IGD than in HCs. Moreover, the left frontal theta power negatively correlated with IGD severity. These results indicate that left frontal theta power could be used as a neurophysiological biomarker for the detection of diminished cognitive control patterns in individuals with IGD.

Age-related changes of frontal-midline theta is predictive of efficient memory maintenance

Rapid eye movement (REM) sleep and its main oscillatory feature, frontal theta, have been related to the processing of recent emotional memories. As memories constitute much of the source material for our dreams, we explored the link between REM frontal theta and the memory sources of dreaming, so as to elucidate the brain activities behind the formation of dream content. Twenty participants were woken for dream reports in REM and slow wave sleep (SWS) while monitored using electroencephalography. Eighteen participants reported at least one REM dream and 14 at least one SWS dream, and they, and independent judges, subsequently compared their dream reports with log records of their previous daily experiences. The number of references to recent waking-life experiences in REM dreams was positively correlated with frontal theta activity in the REM sleep period. No such correlation was observed for older memories, nor for SWS dreams. The emotional intensity of recent waking-life experiences incorporated into dreams was higher than the emotional intensity of experiences that were not incorporated. These results suggest that the formation of wakefulness-related dream content is associated with REM theta activity, and accords with theories that dreaming reflects emotional memory processing taking place in REM sleep.

Frontal EEG theta activity has been related to executive functions (i.e., goal‐directed behavior such as inhibition and flexibility of action). We studied the effects of morning nutritional status on frontal theta‐executive function relationships using stimulus‐locked responses [event‐related increases (ERS) and decreases (ERD) in synchronization] of 4‐6 Hz activity in a cued visual go/no‐go task in healthy, right‐handed children (8‐11 yrs. old; IQ > 80). Children were tested after overnight fasting (Phase 1), and again (Phase 2) after eating a standardized breakfast (n = 30; 15 males) or while continuing to fast (n = 30; 15 males). Performance measures‐accuracy and reaction time (RT)‐were obtained. Data were analyzed using ANOVA procedures with post‐hoc t‐tests. Response accuracy was similar across groups. Relative to Phase 1, RT slowed in Phase 2 for both groups, but the decrease was only significant for fasting females (p < .01). Consistent with increased executive function demands associated with response inhibition, ERS was greater to no‐go than go stimuli (p < .05) for both groups. Nutritional status did not significantly influence ERS responses in females, but Phase 2 responses to no‐go stimuli were decreased in fasting, but not fed, males (p < .05). These data suggest a greater sensitivity of frontal executive function processes to morning nutritional status in preadolescent males than females. (Supported by USDA ARS CRIS 6251‐51000‐002‐03S)

Midline theta dissociates agentic extraversion and anhedonic depression

Switch probability context (in)sensitivity within the cognitive control network

A distinct theta rhythm of EEG in the frontal midline area during performance of mental tasks has been called Fm theta. One of the characteristics of Fm theta is individual differences in its appearance. The effects of various mental tasks and its repetition on appearance of Fm theta were investigated. Adding, correcting wrong words, short-term memory (STM) and counting cubes were imposed 6 times on 7 male students who didn't generate Fm theta at the previous experiment. Counting cubes evoked more Fm theta than the other three mental tasks. In every task the first trial showed little Fm theta, and the appearance time of Fm theta was enhanced by repetition. Type I of Spielberger's State-Trait Anxiety Inventory (STAI-I) demonstrated a higher state anxiety level of the subjects at the first trial. It may be concluded that the amount of Fm theta corresponds to the level in concentration of attention.

Chapter 12 - Connectivity and local activity within the fronto-posterior brain network in schizophrenia

We used functional magnetic resonance imaging to evaluate functional activity in the brain of adolescents with spina bifida when performing selective attention and response inhibition tasks. We then compared the results to that of age-matched controls. Our results showed that adolescents with spina bifida had decreased frontal and superior parietal activation and more apparently low involvement of left brain hemisphere during these tasks. Our results indicated activation deficits and possibly abnormal functional organization in adolescents with spina bifida and associated pathologies such as hydrocephalus.

Brain oscillation and connectivity during a chemistry visual working memory task

Event Abstract Back to Event Cross-frequency analysis of MEG data applied to study functional connectivity Ole Jensen1* and Ali Mazaheri1 1 Donders Institute for Brain, Cognition and Behaviour, Netherlands Functional connectivity in the brain is typically studied by investigating task-dependent correlations between neuronal activation in different areas. Recent studies suggest that cross-frequency analysis based on power correlations in different frequency bands provide a robust methods for revealing functional connectivity. Two examples will be presented 1) In a Go-noGo MEG paradigm we found that frontal theta activity (5-8 Hz) was correlated to posterior alpha activity decreases (8-13 Hz). The cross-frequency correlation was stronger following noGo-errors compared to correct responses. Interestingly, strong pre-stimulus alpha activity was predictive of upcoming errors. This suggests that sources in frontal areas exercise a top-down drive altering the state of perceptual areas in order to reduce the chance of future errors. 2) MEG was applied to study oscillatory activity during mental rotation of limbs. During the task we found that central beta activity was depressed whereas posterior gamma activity increased. The gamma and beta activity correlated on a trial-by-trial basis during the task. This suggests that visual imagery during mental rotation relies on functional coupling between visual and motor areas. While this analysis was done on the sensors level we will demonstrate how it can be performed at source level as well using a beamformer technique. Our approach provides a conceptually new and promising way of studying functional in the human working brain.

Cortical oscillations serve as an index of both sensory and cognitive processes and represent one of the most promising candidates for training and targeting the top-down mechanisms underlying executive functions. Research findings suggest that theta (θ) oscillations (3–7 Hz) recorded over frontal-midline electrodes are broadly associated with a number of higher-order cognitive processes and may serve as the mechanistic backbone for cognitive control. Frontal-midline theta (FMθ) oscillations have also been shown to inversely correlate with activity in the default mode network (DMN), a network in the brain linked to spontaneous thought processes such as mind-wandering and rumination. In line with these findings, we previously observed increased FMθ oscillations in expert meditation practitioners during reported periods of focused-attention meditation practice when compared to periods of mind-wandering. In an effort to narrow the explanatory gap by directly connecting observed neurophysiological activity in the brain to the phenomenological nature of reported experience, we designed a methodologically novel and adaptive neurofeedback protocol with the aim of modulating FMθ while having meditation novice participants implement breath-focus strategies derived from focused-attention mediation practices. Participants who received eight sessions of the adaptive FMθ-meditation neurofeedback protocol were able to significantly modulate FMθ over frontal electrodes using focused-attention meditation strategies relative to their baseline by the end of the training and demonstrated significantly faster reaction times on correct trials during the n-back working memory task assessed before and after the FMθ-meditation neurofeedback protocol. No significant differences in frontal theta activity or behavior were observed in the active control participants who received age and gender matched sham neurofeedback. These findings help lay the groundwork for the development of brain training protocols and neurofeedback applications that aim to train features of the mental states and traits associated with focused-attention meditation.

Background: Frontal midline theta (FMT) oscillations (4–8 Hz) are strongly related to cognitive and executive control during mental tasks such as memory processing, arithmetic problem solving or sustained attention. While maintenance of temporal order information during a working memory (WM) task was recently linked to FMT phase, a positive correlation between FMT power, WM demand and WM performance was shown. However, the relationship between these measures is not well understood, and it is unknown whether purposeful FMT phase manipulation during a WM task impacts FMT power and WM performance. Here we present evidence that FMT phase manipulation mediated by transcranial alternating current stimulation (tACS) can block WM demand-related FMT power increase (FMTΔpower) and disrupt normal WM performance.Methods: Twenty healthy volunteers were assigned to one of two groups (group A, group B) and performed a 2-back task across a baseline block (block 1) and an intervention block (block 2) while 275-sensor magnetoencephalography (MEG) was recorded. After no stimulation was applied during block 1, participants in group A received tACS oscillating at their individual FMT frequency over the prefrontal cortex (PFC) while group B received sham stimulation during block 2. After assessing and mapping phase locking values (PLV) between the tACS signal and brain oscillatory activity across the whole brain, FMT power and WM performance were assessed and compared between blocks and groups.Results: During block 2 of group A but not B, FMT oscillations showed increased PLV across task-related cortical areas underneath the frontal tACS electrode. While WM task-related FMTΔpower and WM performance were comparable across groups in block 1, tACS resulted in lower FMTΔpower and WM performance compared to sham stimulation in block 2.Conclusion: tACS-related manipulation of FMT phase can disrupt WM performance and influence WM task-related FMTΔpower. This finding may have important implications for the treatment of brain disorders such as depression and attention deficit disorder associated with abnormal regulation of FMT activity or disorders characterized by dysfunctional coupling of brain activity, e.g., epilepsy, Alzheimer’s or Parkinson’s disease (AD/PD).

Results of several neuroimaging studies support the functional equivalence model, which states that motor imagery (MI) and motor execution (ME) involve the same processes, except for the final execution component. In contrast, the motor-cognitive model implies that MI additionally involves frontal executive control processes. However, according to some authors MI may actually be more comparable to motor preparation (MP). In the current electroencephalographic study, a version of the discrete sequence production paradigm was employed in which human participants initially had to prepare a sequence of five finger movements that subsequently had to be executed, imagined, or withheld. MI, ME, and MP were compared by computing event-related (de)-synchronization in the theta, alpha/mu, and beta bands. Results revealed a major increase in frontal theta power during MI as compared to ME and MP. At the end of the examined intervals, a posterior reduction in alpha power was present during ME and MP, but not during MI. Finally, above sensorimotor areas a decrease in beta power was observed that was most pronounced in the case of ME. The increase of frontal theta activity during MI may reflect increased effort, while the absence of a reduction in posterior alpha power suggests no major involvement of visuospatial attention and/or visual imagery. The present findings favor the motor-cognitive model, as it predicts extra involvement of frontal executive processes during MI.