Autonomic and neural activity dynamically couple during infant attention

Abstract The developing brain does not regulate attention in isolation, but coordinates with the body’s peripheral signals. However, empirical research quantifying the dynamic interplay between neural oscillations and autonomic signals during infancy is lacking. Here, we provide the first evidence of real-time coupling between cortical activity and parasympathetic tone in 3-month-old infants during a sustained attention task. Using simultaneous EEG and ECG, we extracted continuous time series of respiratory sinus arrhythmia (RSA) and EEG power across theta, alpha, and beta bands. Cross-correlation and generalized additive mixed models revealed frequency- and region-specific coupling: theta and alpha power were positively linked to RSA, peaking when RSA preceded neural activity while beta power showed inverse coupling. Coupling was strongest for theta power in the frontal cortex and predicted the magnitude of sustained attention. Notably, RSA–neural coupling peaked immediately prior to the onset of sustained attention while the infant was orienting to the stimulus. These findings evidence a dynamic, bidirectional autonomic-neural signal attunement that scaffolds attention from the earliest months of life.