Neural entrainment to auditory stimuli and language development: The BabyRhythm Project

The BabyRhythm Project: Neural oscillations and early language development. Dr Adam Attaheri

The synchronization of cortical oscillations with different patterns of temporal information in the speech signal may be key in how the brain processes language. Our current research focuses on individual differences between infants in the entrainment of low frequency neural oscillations (delta band, ~2Hz, and theta band, ~5 Hz) in early development to both speech and non-speech inputs. In spoken language, a 2Hz rhythm reflects the production of stressed syllables, which are produced approximately twice a second across languages. Modulation energy in the delta band (0.9 – 2.5 Hz) is increased in infant directed speech compared to adult directed speech, and across languages lullabies and nursery rhymes also converge on a 2 Hz beat rate. Our hypothesis is that accurate entrainment to a 2 Hz "beat" may provide a foundational entrainment rate across languages, offering a rhythmic skeleton upon which other language units (words, syllables, rhyme, phonemes) may be scaffolded.
To test this, we are conducting a longitudinal assessment of infants from 2 months to 2.5 years of age. Our primary measures use EEG to measure oscillatory entrainment to different inputs (simple drum beat, rhythmic repetition of syllable ‘ta’ and phrasal prosody via nursery rhymes). We focus on the neural accuracy of low-frequency phase locking (entrainment) and phase alignment at delta and theta rates, across the first year of life (2-11 months). The infants are followed up between 12 and 30 months, using a range of phonological, morphological and vocabulary assessments. By tracking longitudinal measures through development, we can assess the importance of individual differences in neural entrainment in predicting later language outcomes. Our visit is motivated by our current interest in using envelope reconstruction using the mTRF toolbox, to assess neural entrainment to nursery rhymes, as a predictor of language outcomes.
In this talk, I will give an introduction to the BabyRhythm project, and will present early results suggesting that from 8 weeks of age the infant brain is showing increased 2 Hz power in response to drum beats and syllable repetition presented at 2 Hz. I will also present evidence to suggest an increase in phase locking and inter-trial coherence in response to 2Hz drum beats and syllable repetition.


The BabyRhythm Project: A motor perspective. Dr Sinead Rocha

The BabyRhythm project emphasises the importance of neural entrainment to auditory stimuli for language development. However, strong links have also been shown between the alignment of rhythmic movement to auditory rhythms (sensorimotor synchronization; SMS), and language skill. We are therefore investigating SMS in the same BabyRhythm infant population using Motion Capture technology. Our novel longitudinal observations of rhythmic movement will be ground-breaking both in terms of tracking the development of SMS over time, and in relating motor and neural entrainment measurements within the same infant cohort. I will give an overview of the measures we are collecting and present our preliminary findings.