Oscillation encoding of individual differences in speech perception

Abstract

Individual differences in second language (L2) phoneme perception (within the normal population) have been related to/nspeech perception abilities, also observed in the native language, in studies assessing the electrophysiological response/nmismatch negativity (MMN). Here, we investigate the brain oscillatory dynamics in the theta band, the spectral correlate of/nthe MMN, that underpin success in phoneme learning. Using previous data obtained in an MMN paradigm, the dynamics of/ncortical oscillations while perceiving native and unknown phonemes and nonlinguistic stimuli were studied in two groups/nof participants classified as good and poor perceivers (GPs and PPs), according to their L2 phoneme discrimination abilities./nThe results showed that for GPs, as compared to PPs, processing of a native phoneme change produced a significant/nincrease in theta power. Stimulus time-locked analysis event-related spectral perturbation (ERSP) showed differences for the/ntheta band within the MMN time window (between 70 and 240 ms) for the native deviant phoneme. No other significant/ndifference between the two groups was observed for the other phoneme or nonlinguistic stimuli. The dynamic patterns in/nthe theta-band may reflect early automatic change detection for familiar speech sounds in the brain. The behavioral/ndifferences between the two groups may reflect individual variations in activating brain circuits at a perceptual level.