Alpha and theta peak frequency track on- and off-thoughts

Abstract

Our thoughts are highly dynamic in their contents. At some points, our thoughts are related to external stimuli or tasks focusing on single content (on-single thoughts), While in other moments, they are drifting away with multiple simultaneous items as contents (off-multiple thoughts). Can such thought dynamics be tracked by corresponding neurodynamics? To address this question, here we track thought dynamics during post-stimulus periods by electroencephalogram (EEG) neurodynamics of alpha and theta peak frequency which, as based on the phase angle, must be distinguished from non-phase-based alpha and theta power. We show how, on the psychological level, on-off thoughts are highly predictive of single-multiple thought contents, respectively. Using EEG, on-single and off-multiple thoughts are mediated by opposite changes in the time courses of alpha (high in on-single but low in off-multiple thoughts) and theta (low in on-single but high in off-multiple thoughts) peak frequencies. In contrast, they cannot be distinguished by frequency power. Overall, these findings provide insight into how alpha and theta peak frequency with their phase-related processes track on- and off-thoughts dynamically. In short, neurodynamics track thought dynamics.

Reduced signal propagation elicited by frontal transcranial magnetic stimulation is associated with oligodendrocyte abnormalities in treatment-resistant depression

“…Furthermore, our finding that signal propagation from the left dlPFC to the salience network was reduced by 5 to 15 Hz in patients with TRD was also in line with the fact that 10 Hz rTMS treatment to the left dlPFC in TRD has a robust therapeutic effect. 8,49,50 Thus, both neural networks and frequency bands may be closely related in the therapeutic mechanism of rTMS in depression. In other words, reduced signal propagation in the θ and α bands from the left dlPFC to the salience network may reflect an underlying pathophysiology in TRD through which rTMS exerts its corrective therapeutic effect.…”

Resting-state EEG functional networks organization and individual differences in the task-unrelated thoughts: Greater Mind-Wanderers exhibit weaker default mode network integration

“…Notably, we do not know of the published studies that searched for the relationship between MW understood as a trait and the organization of functional networks reconstructed on the basis of source-space resting-state EEG. Previous EEG studies aimed inter alia at establishing links between MW and the theta/beta ratio [33], or generally a given frequency peak [34], and identifying EEG signature of off-task though using thought-probe method and ERP analysis [35,36]. The frequencyfocused investigations have produced quite divergent results suggesting that MW is associated with alpha [36, 37] delta and gamma [38] or by delta, theta and alpha bands [39].…”

“…First, the source signals from 40 ROIs were evaluated for each epoch. The source signals of each ROI were decomposed into the following ve frequency bands: delta (1-4Hz), theta (4-8 Hz), lower alpha (8-10 HZ), upper alpha (10-12 Hz), beta (12-30 Hz), and gamma (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45). This signal decomposition was accomplished by using a 6th order zero-phase Butterworth in nite impulse response (IIR) band-pass lter implemented in the MATLAB Signal Processing toolbox, with the cutoff frequencies equal to the borders of each frequency band.…”

Relationships between resting-state EEG functional networks organization and individual differences in mind wandering

“…Notably, we do not know of the published studies that searched for the relationship between MW understood as a trait and the organization of functional networks reconstructed on the basis of source-space resting-state EEG. Previous EEG studies aimed, inter alia, at establishing links between MW and the theta/beta ratio 33 , or generally a given frequency peak 34 , and identifying EEG signature of off-task though using thought-probe method and ERP analysis 35,36 . The frequency-focused investigations have produced quite divergent results suggesting that MW is associated with alpha 36,37 delta and gamma 38 or by delta, theta and alpha bands 39 .…”