Plasticity in Developing Brain: Active Auditory Exposure Impacts Prelinguistic Acoustic Mapping

Abstract

A major task across infancy is the creation and tuning of the acoustic maps that allow efficient native language processing. This process crucially depends on ongoing neural plasticity and keen sensitivity to environmental cues. Development of sensory mapping has been widely studied in animal models, demonstrating that cortical representations of the sensory environment are continuously modified by experience. One critical period for optimizing human language mapping is early in the first year; however, the neural processes involved and the influence of passive compared with active experience are as yet incompletely understood. Here we demonstrate that, while both active and passive acoustic experience from 4 to 7 months of age, using temporally modulated nonspeech stimuli, impacts acoustic mapping, active experience confers a significant advantage. Using event-related potentials (ERPs), we show that active experience increases perceptual vigilance/attention to environmental acoustic stimuli (e.g., larger and faster P2 peaks) when compared with passive experience or maturation alone. Faster latencies are also seen for the change discrimination peak (N2*) that has been shown to be a robust infant predictor of later language through age 4 years. Sharpening is evident for both trained and untrained stimuli over and above that seen for maturation alone. Effects were also seen on ERP morphology for the active experience group with development of more complex waveforms more often seen in typically developing 12-to 24-month-old children. The promise of selectively "fine-tuning" acoustic mapping as it emerges has far-reaching implications for the amelioration and/or prevention of developmental language disorders.

WISC-V Use in Societal Context

“…One parent, when asked if she spoke to her young infant or read to her preschool children, simply said "I didn't know I should do that." Such clinical observations are consistent with research showing that vocabulary development of young children varies as a function of maternal speech frequency (Hoff, 2003), and that language development can be enhanced through active exposure to quality auditory stimuli in infancy (Benasich, Choudhury, Realpe-Bonilla, & Roesler, 2014). Parents living in poverty spend less time talking and reading to young children, which negatively impacts the prelinguistic process of acoustic mapping in infancy, and exposes them to fewer new words during later, critical periods of language development.…”

Musical intervention enhances infants’ neural processing of temporal structure in music and speech

“…In the current study, we focused specifically on learning to extract higher level temporal information (i.e., temporal structure) from the intervention designed to simulate naturalistic music learning. Previous studies have suggested the significant role temporal information plays in speech perception and the impact of training using modified speech or nonspeech sounds to help infants and children prioritize specific temporal information, which may in turn enhance speech processing (35)(36)(37)(38). However, the cross-domain generalization demonstrated here has not previously been tested or reported in young infants from music learning to speech processing.…”

Three- and four-dimensional mapping of speech and language in patients with epilepsy

“…Currently available models, primarily based on the results of lesions, non-invasive neurophysiology, and neuroimaging, suggest that variable language-processing functions emerge at distinct regions at different ages, and gradually grow or disappear in a heterogeneous manner (Minagawa-Kawai et al , 2011; Benasich et al 2014; Skeide and Friederici, 2016). Although the developmental timeline for the emergence of different language functions has been outlined, the neurobiological basis for this timeline is poorly understood.…”