Newborns modulate and synchronise their Non-Nutritive Sucking behaviour to the temporal structure of sound

Abstract

Sensorimotor synchronization, the ability to align motor behaviour with the temporal structure of external stimuli, is thought to emerge gradually during development, but its origins remain unclear. Here, we investigated whether newborns can adapt their sucking behaviour and synchronise it to the temporal structure of auditory stimuli within the first days of life. Forty-one healthy full-term newborns (24-72 hours old) were exposed to two three-minute auditory streams differing in temporal structure: a highly structured stream with a stable temporal pattern and a highly variant stream with greater temporal variability, while their non-nutritive sucking (NNS) was continuously recorded. We assessed changes in NNS frequency and pressure and quantified NNS-sound coupling using magnitude-squared coherence at frequencies distinctive to each auditory stream. Structured stimulation promoted a more organised NNS, with more suck bursts than the variant stream, and increased sucking vigour, with a transiently higher suck peak rate during the first minute relative to the variant stream and greater suck pressure relative to silence. Coherence analyses revealed that coherence was selectively higher at the frequencies distinctive to each auditory stream, both for the structured and the highly variant stimulus. These findings show that, within hours of birth, NNS behaviour can selectively align with stimulus-specific temporal regularities, even when these are weakly predictable and lack a dominant periodicity. This early capacity to extract temporal structure and coordinate motor behaviour may provide a foundation for the subsequent development of sensorimotor synchronisation.