States, traits, and the resting state EEG task aftereffect

Abstract

Background

Historically, resting state electroencephalogram (rsEEG) measures have been considered indices of stable traits. However, recent research has indicated that rsEEG measures change after an individual has performed a task. These task aftereffects raise several questions regarding the task parameters needed to facilitate task aftereffects. This study aimed to set a foundation to answer these questions by creating a baseline of rsEEG changes observed within a healthy college aged sample before and after a classic cognitive task.

Methods

The sample consisted of 34 undergraduate students. rsEEG data were recorded in alternating states of eyes open and closed before and after a standard oddball paradigm task.

Results

Results indicated that timepoint (e.g. before and after study) had no significant effect or interaction with eye status when measuring peak alpha amplitude and frequency. When analyzing classic frequency bands, there was an interaction between eye status and timepoint for delta at electrode Fz, but no main effect of timepoint. This was the only interaction within the classic frequency bands. Frontal alpha and beta asymmetries shifted rightwards after the task, but had fair to poor reliability. Theta/beta ratio was significantly higher after the task.

Conclusions

Theta/beta ratio was the only measure that met criteria for both a good experimental dependent variable and stable individual difference variable due to its high reliability. To our knowledge this is the first time these common rsEEG variables have been simultaneously assessed for consistent within-subject effects and reliable between-subject differences.