Language-specific phoneme representations revealed by electric and magnetic brain responses

Abstract

There is considerable debate about whether the early processing of sounds depends on whether they form part of speech. Proponents of such speech specificity postulate the existence of language-dependent memory traces, which are activated in the processing of speech but not when equally complex, acoustic non-speech stimuli are processed. Here we report the existence of these traces in the human brain. We presented to Finnish subjects the Finnish phoneme prototype /e/ as the frequent stimulus, and other Finnish phoneme prototypes or a non-prototype (the Estonian prototype /õ/) as the infrequent stimulus. We found that the brain's automatic change-detection response, reflected electrically as the mismatch negativity (MMN), was enhanced when the infrequent, deviant stimulus was a prototype (the Finnish /ö/) relative to when it was a non-prototype (the Estonian /õ/). These phonemic traces, revealed by MMN, are language-specific, as /õ/ caused enhancement of MMN in Estonians. Whole-head magnetic recordings located the source of this native-language, phoneme-related response enhancement, and thus the language-specific memory traces, in the auditory cortex of the left hemisphere.

Electric brain responses to inappropriate harmonies during listening to expressive music

“…Because of the similarities between ERAN, RATN, MMN, and ELAN, these ERP components have been suggested as reflections of a highly adaptive, peri-sylvian system of auditory information processing (Koelsch et al, 2002(Koelsch et al, , 2001b, comprising the processing of single tones (Näätänen, 1992;Schröger, 1998), acoustic patterns (Schrö-ger, 1994, phonemes (Näätänen et al, 1997), tonal music (Koelsch et al, 2000b), and speech (Friederici, 1998). The early negativity elicited in the present experiment also appears to be part of this system, being most reminiscent to the ERAN.…”

Electrophysiological signatures: Magnetoencephalographic studies of the neural correlates of language impairment in autism spectrum disorders

“…In particular, it is hypothesized that the successful processing of polysyllabic speech elements and recognizing differences between syllabic tokens is critical for speech comprehension. An electrophysiological correlate of the detection of a change in sensory stimuli exists in the form of the mismatch negativity (MMN), described by Näätänen (2001Näätänen ( , 2003 and colleagues (Näätänen et al, 1987(Näätänen et al, , 1997. The MMN provides a measure of the pre-attentive detection of a difference in the attributes of an infrequently presented "deviant" stimulus as compared to the stimulus properties represented in the memory trace of the frequently presented "standard" stimuli.…”

“…It has been shown that the MMN response is greater in subjects for whom phonetic differences between stimuli cross a phoneme category boundary (Näätänen 2001) or is otherwise phonologically significant (Näätänen et al, 1997;Peltola et al, 2003;Winkler et al, 1990). As such, the MMN can be used to assess a subject's ability to detect change in linguistic stimuli.…”

Behavioral and electrophysiological evidence for the impact of regional variation on phoneme perception

“…This component is sensitive to changes not only in the acoustic characteristics of auditory stimuli (Näätänen, Simpson, & Loveless, 1982), but also to their phonological properties (for a review, Pulvermüller & Shtyrov, 2006). For example, Näätänen and collaborators (Näätänen et al, 1997) demonstrated MMN responses to phoneme changes when Finnish listeners heard the Finnish vowel /ö/ or the unknown Estonian vowel /õ/ in a list composed predominantly of the Finnish vowel /e/. A larger MMN amplitude was found when the Finnish vowel /ö/ served as the deviant stimulus than when the unknown Estonian vowel /õ/ was presented as the deviant stimulus despite the fact that the acoustic distance of the unknown Estonian vowel /õ/ from /e/ was larger than that for the deviant Finnish vowel /ö/.…”