Spectral-temporal EEG dynamics of speech discrimination processing in infants during sleep

BMC Neuroscience

Research Article

Kaylee Watson¹  Christine Yoshinaga-Itano²  Phillip M. Gilley²  Kristin Uhler³ 

[1] Department of Speech, Language, and Hearing Sciences, University of Colorado, Boulder, Boulder, CO, USA;Institute of Cognitive Science, University of Colorado, Boulder, Boulder, CO, USA;Marion Downs Center, Denver, CO, USA;University of Colorado School of Medicine, Aurora, CO, USA;

关键词: EEG;    Auditory evoked potentials;    Mismatch negativity;    Speech discrimination;    Infants;    Sleep;    Surprise;   

DOI  :  10.1186/s12868-017-0353-4

 received in 2016-03-25, accepted in 2017-03-09,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundOddball paradigms are frequently used to study auditory discrimination by comparing event-related potential (ERP) responses from a standard, high probability sound and to a deviant, low probability sound. Previous research has established that such paradigms, such as the mismatch response or mismatch negativity, are useful for examining auditory processes in young children and infants across various sleep and attention states. The extent to which oddball ERP responses may reflect subtle discrimination effects, such as speech discrimination, is largely unknown, especially in infants that have not yet acquired speech and language.ResultsMismatch responses for three contrasts (non-speech, vowel, and consonant) were computed as a spectral-temporal probability function in 24 infants, and analyzed at the group level by a modified multidimensional scaling. Immediately following an onset gamma response (30–50 Hz), the emergence of a beta oscillation (12–30 Hz) was temporally coupled with a lower frequency theta oscillation (2–8 Hz). The spectral-temporal probability of this coupling effect relative to a subsequent theta modulation corresponds with discrimination difficulty for non-speech, vowel, and consonant contrast features.DiscussionThe theta modulation effect suggests that unexpected sounds are encoded as a probabilistic measure of surprise. These results support the notion that auditory discrimination is driven by the development of brain networks for predictive processing, and can be measured in infants during sleep. The results presented here have implications for the interpretation of discrimination as a probabilistic process, and may provide a basis for the development of single-subject and single-trial classification in a clinically useful context.ConclusionAn infant’s brain is processing information about the environment and performing computations, even during sleep. These computations reflect subtle differences in acoustic feature processing that are necessary for language-learning. Results from this study suggest that brain responses to deviant sounds in an oddball paradigm follow a cascade of oscillatory modulations. This cascade begins with a gamma response that later emerges as a beta synchronization, which is temporally coupled with a theta modulation, and followed by a second, subsequent theta modulation. The difference in frequency and timing of the theta modulations appears to reflect a measure of surprise. These insights into the neurophysiological mechanisms of auditory discrimination provide a basis for exploring the clinically utility of the MMRTF and other auditory oddball responses.

【 授权许可】

CC BY   
© The Author(s) 2017

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