Oscillatory Dynamics Underlying Perceptual Narrowing of Native Phoneme Mapping from 6 to 12 Months of Age
During the first months of life, human infants process phonemic elements from all languages similarly. However, by 12 months of age, as language-specific phonemic maps are established, infants respond preferentially to their native language. This process, known as perceptual narrowing, supports neural representation and thus efficient processing of the distinctive phonemes within the sound environment. Although oscillatory mechanisms underlying processing of native and non-native phonemic contrasts were recently delineated in 6-month-old infants, the maturational trajectory of these mechanisms remained unclear. A group of typically developing infants born into monolingual English families, …
Enhancement of Gamma Oscillations Indicates Preferential Processing of Native over Foreign Phonemic Contrasts in Infants
Young infants discriminate phonetically relevant speech contrasts in a universal manner, that is, similarly across languages. This ability fades by 12 months of age as the brain builds language-specific phonemic maps and increasingly responds preferentially to the infant's native language. However, the neural mechanisms that underlie the development of infant preference for native over non-native phonemes remain unclear. Since gamma-band power is known to signal infants' preference for native language rhythm, we hypothesized that it might also indicate preference for native phonemes. Using high-density electroencephalogram/event-related potential (EEG/ERP) recordings and source-localization…
Infant information processing and family history of specific language impairment: converging evidence for RAP deficits from two paradigms
An infant's ability to process auditory signals presented in rapid succession (i.e. rapid auditory processing abilities [RAP]) has been shown to predict differences in language outcomes in toddlers and preschool children. Early deficits in RAP abilities may serve as a behavioral marker for language-based learning disabilities. The purpose of this study is to determine if performance on infant information processing measures designed to tap RAP and global processing skills differ as a function of family history of specific language impairment (SLI) and/or the particular demand characteristics of the paradigm used. Seventeen 6- to 9-month-old infants from families with a history of specific l…
Time course of ERP generators to syllables in infants: A source localization study using age-appropriate brain templates
article i nfo Event-related potentials (ERPs) have become an important tool in the quest to understand how infants pro- cess perceptual information. Identification of the activation loci of the ERP generators is a technique that pro- vides an opportunity to explore the neural substrates that underlie auditory processing. Nevertheless, as infant brain templates from healthy, non-clinical samples have not been available, the majority of source localization studies in infants have used non-realistic head models, or brain templates derived from older children or adults. Given the dramatic structural changes seen across infancy, all of which profoundly affect the electrical fields measured with …
Change detection to tone pairs during the first year of life – Predictive longitudinal relationships for EEG-based source and time-frequency measures
Abstract Brain responses related to auditory processing show large changes throughout infancy and childhood with some evidence that the two hemispheres might mature at different rates. Differing rates of hemispheric maturation could be linked to the proposed functional specialization of the hemispheres in which the left auditory cortex engages in analysis of precise timing information whereas the right auditory cortex focuses on analysis of sound frequency. Here the auditory change detection process for rapidly presented tone-pairs was examined in a longitudinal sample of infants at the age of 6 and 12 months using EEG. The ERP response related to change detection of a frequency contrast, i…
Source localization of event-related potentials to pitch change mapped onto age-appropriate MRIs at 6 months-of-age
Auditory event-related potentials (ERPs) have been used to understand how the brain processes auditory input, and to track developmental change in sensory systems. Localizing ERP generators can provide invaluable insights into how and where auditory information is processed. However, age-appropriate infant brain templates have not been available to aid such developmental mapping. In this study, auditory change detection responses of brain ERPs were examined in 6-month-old infants using discrete and distributed source localization methods mapped onto age-appropriate magnetic resonance images. Infants received a passive oddball paradigm using fast-rate non-linguistic auditory stimuli (tone do…