At Which Low Amplitude Modulated Frequency Do Infants Best Entrain? A Frequency Tagging Study

Previous infant entrainment research has shown neural entrainment to a wide range of stimuli and amplitude modulated frequencies. However, it is unknown if infants neurally entrain more strongly to some frequencies more than others, and to which low amplitude modulated frequency infants show the strongest entrainment. The current study seeks to address this by testing the neural entrainment of N=23 4–6-month-old infants and N=22 control group adult caregivers while they listened to a range of sinusoidally amplitude modulated beep stimuli at rest (no sound), 2, 4, 6, 8, 10 and 12 Hz. Analysis examined differences across power and phase, regions of interest predetermined by previous literature and by segmented time windows. Results showed that the strongest entrainment was at 2Hz for both adult and infant participants; that there was no significant difference in power and phase, entrainment was occipital temporal and slightly left fronto-central in adults and right fronto-central and left occipito-temporal in infants, leading to some regions of interest used in previous studies being significant in infants and all regions of interest being significant in adults. Segmenting by time window did not show any significant increase or decrease in entrainment over time, but longer time windows showed a stronger entrainment response. In conclusion, it is important to choose appropriate stimulation frequencies when investigating entrainment between stimulation frequencies or across ages; whole head recording is recommended to see the full extent of activation; there is no preference on power vs phase analyses; and longer recordings show stronger effects. Author Contribution Statement Ives, J., conceptualisation, data collection and curation, formal analysis, methodology, writing – original draft; Labendzki, P., data collection and curation, formal analysis, writing – review & editing; Perapoch Amadó, M., data collection and curation, writing – review & editing; Greenwood, E., data collection and curation, participant recruitment, writing – review & editing; Viswanathan, N., data collection and curation, writing – review & editing; Northrop, T., data collection and curation, participant recruitment, writing – review & editing; Wass, S., conceptualisation, funding acquisition, methodology, project administration, supervision, writing – review & editing. Highlights 2Hz amplitude modulation stimulation showed the strongest neural entrainment We discuss power vs phase analyses of infant and adult frequency tagging responses We illustrate topographic differences in adult and infant neural responses ### Competing Interest Statement The authors have declared no competing interest.