Early maturation of sound duration processing in the infant brain

Abstract

AbstractThe ability to process sound duration is crucial already at a very early age for laying the foundation for the main functions of auditory perception, such as object perception and music and language acquisition. With the availability of age-appropriate structural anatomical templates, we can reconstruct EEG source activity with much-improved reliability. The current study capitalized on this possibility by reconstructing the sources of event-related potential (ERP) waveforms sensitive to sound duration in four- and nine-month-old infants. Infants were presented with short (200 ms) and long (300 ms) sounds equiprobably delivered in random order. Two temporally separate ERP waveforms were found to be modulated by sound duration. Generators of these waveforms were mainly located in primary and secondary auditory area and other language-related regions, such as the superior temporal and the inferior frontal gyri. The results show marked developmental changes between four and nine months, partly reflected by scalp-recorded ERPs, but appearing in the underlying generators in a far more nuanced way. The results also confirm the feasibility of the application of anatomical templates in developmental populations.