Developmental trajectories of EEG aperiodic and periodic components: Implications for understanding thalamocortical development during infancy

Abstract

The time-course of developing brain circuits plays a fundamental role in brain maturation and later cognitive functioning, but thus far has been poorly characterized in humans. Here, aperiodic and periodic EEG power features were examined from longitudinal EEGs collected from 592 healthy 2-44 month-old infants, revealing age-dependent nonlinear changes suggestive of distinct milestones in early brain maturation. Consistent with the transient developmental progression of thalamocortical circuitry, we observe the presence and then absence of periodic alpha and high beta peaks across the three-year period, as well as the emergence of a low beta peak (12-20Hz) after six months of age. We present preliminary evidence that the emergence of the low beta peak is associated with thalamocortical connectivity sufficient for anesthesia-induced alpha coherence. Together, these findings suggest that early age-dependent changes in alpha and beta periodic peaks may reflect the state of thalamocortical network development.

Alterations in aperiodic and periodic EEG activity in young children with Down syndrome

“…Several aspects of theta peaks observed in preschoolers with DS are remarkably similar to what we have previously reported in very young neurotypical infants. In a longitudinal analysis of developmental trajectories of periodic power we have previously observed the presence of both theta and alpha peaks in ∼70% of infants between 2 and 4-months-old, however by 6-months-old, the majority of infants displayed a single peak, usually in the theta range that then increased in frequency with age 4 . In Figure 3C, we show the similarities between average periodic power from the DS group and average periodic power from 2-4 month-olds.…”

“…The aperiodic 1/f signal can be described by its offset and slope, both provided by SpecParam. Here we define the aperiodic offset as the aperiodic power at 2.5Hz, as we have observed high levels of error in SpecParam estimates at frequencies below 2.5Hz 4 . To determine the periodic power spectra, the SpecParam estimated aperiodic signal was subtracted from the absolute power spectrum.…”

“…Electroencephalography (EEG) provides a non-invasive measure of network level brain activity and is well-tolerated in both children and adults with neurodevelopmental and genetic disorders 3 . Across early development, resting state EEG activity, as reflected in the EEG power spectrum, undergoes significant change 4–8 as inhibitory networks and thalamocortical circuits are established and mature 9–12 .…”

Aperiodic and Hurst EEG exponents across early human brain development: a systematic review

“…Furthermore, there is currently no consensus on whether at the earliest point in infant development E:I balance tilts more towards excitation or inhibition, as AE measure coverage in this window is limited. Wilkinson et al (2023)’s data suggests that all regional AEs but temporal AEs increase during infancy, whilst temporal AE decreases prior to a nadir∼400 days, before increasing. Overall, these data and our findings agree that infant AE maxima are in the posterior channels overlaying occipital regions.…”

“…In toddlerhood, gaps in characterising AE are more significant, which impedes the interpretation of a qualitative ‘trajectory’ of AE development thereafter (particularly given the complex patterns of AE variability observed in childhood). A preprint by Wilkinson et al ., (2023) partially addresses this toddler AE gap, charting resting AE from 2-44 months, highlighting considerably flatter spectra than we observe here, with AE rising from 1.00 to 1.20 (0-1200 days) and age-sex interactions being evident. Evidence from this work suggests that AE increases persist through infancy and toddlerhood.…”