EEG Phase Amplitude Coupling Strength and Phase Preference: Association with Age over the First Three Years After Birth

Abstract

Phase-amplitude coupling (PAC), the coupling of the phase of slower electrophysiological oscillations with the amplitude of faster oscillations, is thought to facilitate dynamic integration of neural activity in the brain. Though the brain undergoes dramatic change and development during the first few years of life, how PAC changes through this developmental period has not been extensively studied. Here, we examined PAC through electroencephalography (EEG) data collected during an awake, eyes-open EEG collection paradigm in 98 children between the ages of 3 months and 3 years. We employed non-parametric clustering methods to identify areas of significant PAC across a range of frequency pairs and electrode locations, and examined how PAC strength and phase preference develops in these areas. We found that PAC, primarily between the alpha-beta and gamma frequencies, was positively correlated with age from early infancy to early childhood (p = 2.035 x 10⁻⁶). Additionally, we found gamma over anterior electrodes coupled with the rising phase of the alpha-beta waveform, while gamma over posterior electrodes coupled with the falling phase of the alpha-beta waveform; this regionalized phase preference became more prominent with age. This opposing trend may reflect each region’s specialization towards feedback or feedforward processing, respectively, suggesting opportunities for back translation in future studies.

Significance Statement

The brain undergoes significant development during infancy and early childhood, enabling the emergence of higher-level cognition. Phase-amplitude coupling (PAC) is thought to support the integration of information within the brain. Our data suggest PAC increases from 3 months to 3 years of age. We additionally report the anterior and posterior electrodes show opposing forms of PAC; this regional phase preference also increases with age of EEG collection. These findings help set the stage for future analyses of PAC in young children with neurodevelopmental disorders, in which development of biomarkers during early life is a burgeoning field and measures of cross-frequency coupling may offer new promise.