Phase-Amplitude Coupling Between EEG Cortical Oscillations and Respiration: An Exploratory Study

Cortical oscillatory patterns are associated with a wide range of functions, including attention, motor functions, and memory. Selective modulation of different cortical oscillations is of interest in many brain-computer interface (BCI) and neurofeedback paradigms. Recent findings have suggested that respiration plays a role in modulating higher-frequency electrocortical activity. However, these previous works have mostly relied on invasive neuroimaging modalities, and the relationship between respiration and cortical oscillations recorded non-invasively though imaging techniques, including electroencephalography (EEG), remains underreported. In this study, we explore phase-amplitude coupling (PAC) between the phase of respiration signals and amplitude of EEG band power across several frequency bands. We recorded simultaneous EEG and respiration effort from nine healthy participants during an auditory task and applied a PAC algorithm to explore coupling between respiration phase and EEG band power amplitude. We observed significant PAC in at least three channels and one frequency band across all nine participants. Specifically, respiration-gamma PAC was observed in at least three channels in five of nine participants, while a similar pattern was observed in respiration-alpha PAC in four of nine participants. These findings reinforce previous observations in invasive studies of widely distributed respiration-cortical gamma PAC while suggesting that alpha band oscillations may also be modulated by respiration in some individuals. These results contribute to better understanding of the role of respiration in higher brain functions and could inform future neurofeedback paradigms that integrate respiration tracking.