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

Jingyu Hua,Annemarie Wolff,Jing Luo,Lin Yao,Yufeng Zang,Georg Northoff,Chang Liu,Xianliang Ge,Jianfeng Zhang

doi:10.1038/s42003-022-03146-w

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.

Highlights

Our thoughts are highly dynamic in their contents
We show no significant difference between off-multiple and on-single in both task-related accuracy and response time (RT), as well as between off task and on task, multiple-contents and single-content (RT: offmultiple vs. on-single: t = −0.299; on task vs. off task: t = −0.353; multiple-contents vs. single-content: t = −0.454, CR: off-multiple vs. on-single: z = 0.376; on task vs. off task: z = 0.207; multiplecontents vs. single-content: z = 0.379, all p > 0.05, see Fig. 2b, Supplementary Fig. 1)
Our results show that the two probes are highly correlated: when the first and second choices in probe 1 were chosen, participants were much more likely to choose the first choice in probe 2

Summary

Introduction

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). More dynamic oscillatory measures highlight the involvement of alpha[16,17,19–22] and theta frequency bands[16,21,23–27] during mind wandering These findings raise the question whether dynamic changes in alpha and theta frequency power can track the thought dynamic of on- and off-thoughts with their potentially different number of thought contents, i.e., single vs multiple. In addition to their power, neural activity in alpha and theta bands (and others) can be characterized by peak frequency sliding (FS) at specific points in millisecond time[28–31]. We hypothesize that alpha peak frequency, including its dynamic changes, i.e., sliding or change in peak frequency over time[30,31], may provide a candidate measure to track the number of thought contents during especially on-thoughts as form of externallyoriented cognition

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Discussion

Conclusion