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Abstract:
Frequency, intensity and duration are three essential factors
underlying the auditory perception and discrimination in speech.
The present experimental design aimed on investigation of
neurocognitive processes triggered by temporal aspects of syllable
duration in a word-like pattern. We recorded electrophysiological
signals of the perception of syllable duration in context of
tri-syllabic monomorphemic consonant vowel items. Vowel quality was
always /a/ with either a voiced /d/ or an unvoiced /t/ consonant.
The stimuli were naturally produced by a German female speaker with
an initial or medial stress. Analyses showed that increased
duration was the main correlate of syllable stress. Hence, the two
consonant conditions consisted of comparable CVCVCV patterns. These
four items were presented in a mismatch negativity design with an
infrequent item in a fixed template of 8 to 10 items. The
distractor task was to count the number of items and to overlook
item changes. Preliminary ERP data suggest that the stimulus onset
of the initial syllable was always reflected by an early
negativity, most distinct for the deviant conditions. The
comparison of the ERP response to initial versus medial stressed
items seems to reflect the syllable boundaries by enhanced
positivity most eminent in the infrequent item, reflecting the
existence of neuronal memory trace for durational changes of speech
sounds.
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