JOURNAL ARTICLE

Effects of language experience and stimulus context on the neural organization and categorical perception of speech

Gavin M Bidelman, Chia-Cheng Lee
NeuroImage 2015 October 15, 120: 191-200
26146197
Categorical perception (CP) represents a fundamental process in converting continuous speech acoustics into invariant percepts. Using scalp-recorded event-related brain potentials (ERPs), we investigated how tone-language experience and stimulus context influence the CP for lexical tones-pitch patterns used by a majority of the world's languages to signal word meaning. Stimuli were vowel pairs overlaid with a high-level tone (T1) followed by a pitch continuum spanning between dipping (T3) and rising (T2) contours of the Mandarin tonal space. To vary context, T1 either preceded or followed the critical T2/T3 continuum. Behaviorally, native Chinese showed stronger CP as evident by their steeper, more dichotomous psychometric functions and faster identification of linguistic pitch patterns than native English-speaking controls. Stimulus context produced shifts in both groups' categorical boundary but was more exaggerated in native listeners. Analysis of source activity extracted from primary auditory cortex revealed overall stronger neural encoding of tone in Chinese compared to English, indicating experience-dependent plasticity in cortical pitch processing. More critically, "neurometric" functions derived from multidimensional scaling and clustering of source ERPs established: (i) early auditory cortical activity could accurately predict listeners' psychometric speech identification and contextual shifts in the perceptual boundary; (ii) neurometric profiles were organized more categorically in native speakers. Our data show that tone-language experience refines early auditory cortical brain representations so as to supply more faithful templates to neural mechanisms subserving lexical pitch categorization. We infer that contextual influence on the CP for tones is determined by language experience and the frequency of pitch patterns as they occur in listeners' native lexicon.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read
26146197
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"