Neural oscillations suggest periodicity encoding during auditory beat processing in the premature brain

When exposed to rhythmic patterns with temporal regularity, adults exhibit an inherent

ability to extract and anticipate an underlying sequence of regularly spaced beats,

which is internally constructed, as beats are experienced even when no events occur

at beat positions (e.g., in the case of rests). Perception of rhythm and synchronization

to periodicity is indispensable for development of cognitive functions, social

interaction, and adaptive behavior.We evaluated neural oscillatory activity in premature

newborns (n = 19, mean age, 32 ± 2.59 weeks gestational age) during exposure

to an auditory rhythmic sequence, aiming to identify early traces of periodicity encoding

and rhythm processing through entrainment of neural oscillations at this stage

of neurodevelopment. The rhythmic sequence elicited a systematic modulation of

alpha power, synchronized to expected beat locations coinciding with both tones

and rests, and independent of whether the beat was preceded by tone or rest. In

addition, the periodic alpha-band fluctuations reached maximal power slightly before

the corresponding beat onset times. Together, our results show neural encoding of

periodicity in the premature brain involving neural oscillations in the alpha range that

are much faster than the beat tempo, through alignment of alpha power to the beat

tempo, consistent with observations in adults on predictive processing of temporal

regularities in auditory rhythms.