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

Dana Van Son,Peter Putman,Frances M De Blasio,Mischa De Rover,Robert J Barry,Willem Van Der Does

doi:10.1111/nyas.14180

Abstract

The ratio between frontal resting‐state electroencephalography (EEG) theta and beta frequency power (theta/beta ratio, TBR) is negatively related to cognitive control. It is unknown which psychological processes during resting state account for this. Increased theta and reduced beta power are observed during mind wandering (MW), and MW is related to decreased connectivity in the executive control network (ECN) and increased connectivity in the default mode network (DMN). The goal of this study was to test if MW‐related fluctuations in TBR covary with such functional variation in ECN and DMN connectivity and if this functional variation is related to resting‐state TBR. Data were analyzed for 26 participants who performed a 40‐min breath‐counting task and reported the occurrence of MW episodes while EEG was measured and again during magnetic resonance imaging. Frontal TBR was higher during MW than controlled thought and this was marginally related to resting‐state TBR. DMN connectivity was higher and ECN connectivity was lower during MW. Greater ECN connectivity during focus than MW was correlated to lower TBR during focus than MW. These results provide the first evidence of the neural correlates of TBR and its functional dynamics and further establish TBR's usefulness for the study of executive control, in normal and potentially abnormal psychology.

Highlights

Resting-state electroencephalography (EEG) provides measures of neural oscillatory activity in different frequency bands, such as the slow theta (4– 7 Hz) and faster beta (13–30 Hz)
default mode network (DMN) connectivity was higher and executive control network (ECN) connectivity was lower during mind wandering (MW)
We explored changes in the episodes. During the first (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] (2) MW-related changes in frontal theta/beta ratio (TBR) mediate a relationship between resting-state frontal TBR and attentional control (AC). (3) Functional connectivity within the ECN is stronger during focused episodes than during MW episodes, with the opposite pattern of functional connectivity within the DMN. (4) MWrelated EEG changes are positively correlated with MW-related changes of the functional connectivity within the DMN and negatively with changes of connectivity in the ECN

Summary

Introduction

Resting-state electroencephalography (EEG) provides measures of neural oscillatory activity in different frequency bands, such as the slow theta (4– 7 Hz) and faster beta (13–30 Hz). Research into the relation between TBR and AD(H)D has remained largely descriptive, —with the exception of studies that demonstrated that the administration of catecholamine agonists is therapeutic in AD(H)D through the restoration of suboptimal prefrontal cortical control (i.e., normalizing TBR2,5–8). This further suggests that high TBR scores may reflect the (frontal) cortical hypoactivity, which characterizes these disorders (e.g., Ref. 9).

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