Fig. 7.

Emergence of the frontal-midline theta oscillation in development (A) Example participant (age 10) who demonstrated alpha and theta oscillations in frontal-midline and parietal-midline clusters. Theta power was greater in the frontal-midline (red trace), whereas alpha power was greater in the parietal-midline (blue trace). (B) Frontal-midline power spectra for all participants with the slope of the aperiodic signal removed. Dots indicate the peak frequency for each participant. We observed a number of anterior theta peaks in younger participants and anterior alpha peaks in older participants, possibly due to the confounding influence of volume conduction. We therefore conducted our analyses on peak theta power, since this is likely to reflect greater proximity to the true origin of resting theta power in children versus adults. (C) Logistic regression of the site of aperiodic signal corrected peak theta power with age. Spatially-normalized (z-scored) theta topography averaged over participants with greater power in anterior (D) and posterior (E) electrodes. (Insert in C) Difference in z-scored theta power between participants with greater anterior versus posterior power. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article).