Periodic and aperiodic neural activity displays age-dependent changes across early-to-middle childhood

Abstract

The neurodevelopmental period spanning early-to-middle childhood represents a time of significant growth and reorganisation throughout the cortex. Such changes are critical for the emergence and maturation of a range of social and cognitive processes. Here, we utilised both eyes open and eyes closed resting-state electroencephalography (EEG) to examine maturational changes in both oscillatory (i.e., periodic) and non-oscillatory (aperiodic, ‘1/ f -like’) activity in a large cohort of participants ranging from 4-to-12 years of age (N = 139, average age=9.41 years, SD=1.95). The EEG signal was parameterised into aperiodic and periodic components, and linear regression models were used to evaluate if chronological age could predict aperiodic exponent and offset, as well as well as peak frequency and power within the alpha and beta ranges. Exponent and offset were found to both decrease with age, while aperiodic-adjusted alpha peak frequency increased with age; however, there was no association between age and peak frequency for the beta band. Age was also unrelated to aperiodic-adjusted spectral power within either the alpha or beta bands, despite both frequency ranges being correlated with the aperiodic signal. Overall, these results highlight the capacity for both periodic and aperiodic features of the EEG to elucidate age-related functional changes within the developing brain.

Time-resolved parameterization of aperiodic and periodic brain activity

“…However, it remains unclear whether these effects are independent or related; a recent analysis of the same dataset showed that the amplitude of alpha oscillations around a non-zero mean voltage influence baseline cortical excitability (Studenova et al, 2021)—an effect observable in part through variations of the aperiodic exponent (Gao et al, 2017). We also observed both slower alpha-peak centre frequencies and smaller aperiodic exponents in the older age group (Figure 4B), in agreement with previous literature on healthy aging (Cellier et al, 2021; Donoghue et al, 2020; Hill et al, 2022; Ostlund et al, 2022; Schaworonkow & Voytek, 2021).…”

“…These parameters are physiologically meaningful: current constructs consider the offset as reflecting neuronal population spiking, and the exponent as related to the integration of synaptic currents (Voytek & Knight, 2015) and reflecting the balance between excitatory (E) and inhibitory (I) currents (i.e., the larger the exponent, the stronger the inhibition; Chini et al, 2021; Gao et al, 2017; Waschke et al, 2021). Aperiodic neural activity is ubiquitous throughout the brain (He, 2014); it differentiates healthy aging (Cellier et al, 2021; Donoghue et al, 2020; Hill et al, 2022; Ostlund et al, 2022; Schaworonkow & Voytek, 2021; Voytek et al, 2015), and is investigated as a potential marker of neuropsychiatric conditions (Molina et al, 2020) and epilepsy (van Heumen et al, 2021). Though the study of aperiodic neural activity has recently advanced, unanswered questions remain about its functional relevance, which requires an expanded toolkit to track their evolution across time and the broadest possible expressions of behaviour.…”

Sleep EEG in young people with 22q11.2 deletion syndrome: a cross-sectional study of slow-waves, spindles and correlations with memory and neurodevelopmental symptoms

“…We also observed that the slope and intercept of the aperiodic part of the signal reduced with age, similar to previously reported findings in awake resting state EEG in children and adolescents (Hill et al, 2022), and aging adults (Voytek et al, 2015). The slope of the 1/f component of the EEG has also been associated with changes in level of arousal across different sleep stages, with REM being associated with the steepest slopes (Kozhemiako et al, 2021;Lendner et al, 2020).…”

Decomposing the role of alpha oscillations during brain maturation

“…Due to comparatively small sample sizes in these studies, it remains unclear whether the aperiodic-adjusted alpha power truly remains stable in this period of life or whether too little statistical power was provided to detect changes in this newly emerging measure of alpha power. Furthermore, conventional measures of total and relative alpha power were either not reported ( Cellier et al, 2021 ; Hill et al, 2022 ), or did not show any relation to age ( He et al, 2019 ). Hence, comparisons and integration of these results with the large body of literature investigating maturational changes in total and relative alpha power remain limited.…”