Frontal EEG theta/beta ratio during mind wandering episodes

Abstract

Background: In resting-state EEG, the ratio between frontal power in the slow theta frequency band and the fast beta frequency band (the theta/beta ratio, TBR) has previously been negatively related to attentional control. Also, increased theta and reduced beta power were observed during mind wandering (MW) compared to episodes of focused attention. Thus, increased resting-state frontal TBR could be related to MW, suggesting that previously observed relationships between TBR and attentional control could reflect MW episodes increasing the average resting state TBR in people with low attentional control. Goals: To replicate and extend the previous theta and beta MW effects for frontal TBR recordings and test if MW related changes in frontal TBR are related to attentional control. Methods: Twenty-six healthy participants performed a 40-minute breath-counting task, after a baseline EEG recording, while EEG was measured and participants indicated MW episodes with button presses. Results: Frontal TBR was significantly higher during MW episodes than during on-task periods. However, no relation between frontal TBR and attentional control was found. Conclusions: This confirms that frontal TBR varies with MW episodes and that previous frontal TBRattentional control relations might be related to MW, though no direct evidence was found for this hypothesis.

Electroencephalography theta/beta ratio covaries with mind wandering and functional connectivity in the executive control network

“…We recently replicated this study and similarly found higher frontal TBR during the MW episodes compared with the task-focused periods. 34 These results support a hypothesis that relations between restingstate TBR and EC might reflect the brain dynamics, which occur when participants engage in MW or related states of reduced cognitive control during the resting-state measurement. This warrants a comparison between EEG-based TBR and functional magnetic resonance imaging (fMRI)−based localization of the corresponding cortical and subcortical activity.…”

“…The ECN is active during cognitive tasks involving demanding top-down processes, including working memory (WM), mental calculation, and spatial WM, 43 and this network is associated with goal-directed AC. 42,44,45 In summary, states of MW versus controlled attention have been associated with increased TBR 33,34 and with decreased activity in brain areas that are involved in EC, 35 but in separate studies. Together, these findings support the hypothesis that low TBR reflects a state of increased top-down cognitive control, involving functional connectivity in the ECN, whereas high TBR reflects uncontrolled thought and functional connectivity in the DMN.…”

“…Breath-counting task The breath-counting task was as in van Son et al; 34 based on Braboszcz and Delorme. 33 Participants were asked to count their breath cycles (one inhalation and one exhalation) from 1 to 10 and then start from 1 again (with eyes closed).…”

“…Prior to performance of the task, participants were instructed to bring their focus back to breath-counting after pressing the button. To retain consistency with the procedure of Braboszcz and Delorme, 33 and subsequently van Son et al, 34 a passive auditory oddball was presented during the task and debriefing questions were presented at the end of each block as it is possible that this might influence the occurrence of MW episodes. The oddball-related EEG and fMRI data were not of interest here and so participants were instructed to ignore the tones.…”

“…13,17 We tested the following hypotheses: (1) Frontal TBR is higher during MW episodes than during focused episodes, and this MW-related change is related to resting-state (i.e., baseline) frontal TBR. We also explored changes in the EEG delta and alpha bands, as MW-related changes in these bands were observed in van Son et al 34 and Braboszcz and Delorme. 33…”