Representation of the voice onset time (VOT) speech parameter in population responses within primary auditory cortex of the awake monkey

2003 ◽  
Vol 114 (1) ◽  
pp. 307-321 ◽  
Author(s):  
Mitchell Steinschneider ◽  
Yonatan I. Fishman ◽  
Joseph C. Arezzo
Keyword(s):  
Auditory Cortex ◽  
Voice Onset Time ◽  
Onset Time ◽  
Primary Auditory Cortex ◽  
Population Responses ◽  
Awake Monkey ◽  
The Voice

Speech-evoked activity in primary auditory cortex: effects of voice onset time

1994 ◽  
Vol 92 (1) ◽  
pp. 30-43 ◽  
Author(s):  
Mitchell Steinschneider ◽  
Charles E. Schroeder ◽  
Joseph C. Arezzo ◽  
Herbert G. Vaughan
Keyword(s):  
Auditory Cortex ◽  
Voice Onset Time ◽  
Onset Time ◽  
Primary Auditory Cortex ◽  
Evoked Activity

Temporal Encoding of the Voice Onset Time Phonetic Parameter by Field Potentials Recorded Directly From Human Auditory Cortex

1999 ◽  
Vol 82 (5) ◽  
pp. 2346-2357 ◽  
Author(s):  
Mitchell Steinschneider ◽  
Igor O. Volkov ◽  
M. Daniel Noh ◽  
P. Charles Garell ◽  
Matthew A. Howard
Keyword(s):  
Auditory Cortex ◽  
Voice Onset Time ◽  
Onset Time ◽  
Stop Consonant ◽  
Superior Temporal Gyrus ◽  
Response Patterns ◽  
Stop Consonants ◽  
Field Potentials ◽  
Heschl’S Gyrus ◽  
Heschl's Gyrus

Voice onset time (VOT) is an important parameter of speech that denotes the time interval between consonant onset and the onset of low-frequency periodicity generated by rhythmic vocal cord vibration. Voiced stop consonants (/b/, /g/, and /d/) in syllable initial position are characterized by short VOTs, whereas unvoiced stop consonants (/p/, /k/, and t/) contain prolonged VOTs. As the VOT is increased in incremental steps, perception rapidly changes from a voiced stop consonant to an unvoiced consonant at an interval of 20–40 ms. This abrupt change in consonant identification is an example of categorical speech perception and is a central feature of phonetic discrimination. This study tested the hypothesis that VOT is represented within auditory cortex by transient responses time-locked to consonant and voicing onset. Auditory evoked potentials (AEPs) elicited by stop consonant-vowel (CV) syllables were recorded directly from Heschl's gyrus, the planum temporale, and the superior temporal gyrus in three patients undergoing evaluation for surgical remediation of medically intractable epilepsy. Voiced CV syllables elicited a triphasic sequence of field potentials within Heschl's gyrus. AEPs evoked by unvoiced CV syllables contained additional response components time-locked to voicing onset. Syllables with a VOT of 40, 60, or 80 ms evoked components time-locked to consonant release and voicing onset. In contrast, the syllable with a VOT of 20 ms evoked a markedly diminished response to voicing onset and elicited an AEP very similar in morphology to that evoked by the syllable with a 0-ms VOT. Similar response features were observed in the AEPs evoked by click trains. In this case, there was a marked decrease in amplitude of the transient response to the second click in trains with interpulse intervals of 20–25 ms. Speech-evoked AEPs recorded from the posterior superior temporal gyrus lateral to Heschl's gyrus displayed comparable response features, whereas field potentials recorded from three locations in the planum temporale did not contain components time-locked to voicing onset. This study demonstrates that VOT at least partially is represented in primary and specific secondary auditory cortical fields by synchronized activity time-locked to consonant release and voicing onset. Furthermore, AEPs exhibit features that may facilitate categorical perception of stop consonants, and these response patterns appear to be based on temporal processing limitations within auditory cortex. Demonstrations of similar speech-evoked response patterns in animals support a role for these experimental models in clarifying selected features of speech encoding.

Complex tone processing in primary auditory cortex of the awake monkey. II. Pitch versus critical band representation

2000 ◽  
Vol 108 (1) ◽  
pp. 247-262 ◽  
Author(s):  
Yonatan I. Fishman ◽  
David H. Reser ◽  
Joseph C. Arezzo ◽  
Mitchell Steinschneider
Keyword(s):  
Auditory Cortex ◽  
Primary Auditory Cortex ◽  
Critical Band ◽  
Complex Tone ◽  
Awake Monkey

Variation in Voice Onset Time for Korean Stops

2006 ◽  
Vol 13 ◽  
pp. 1-16 ◽  
Author(s):  
David J. Silva
Keyword(s):  
United States ◽  
Native Speakers ◽  
Voice Onset Time ◽  
Onset Time ◽  
The United States ◽  
Age Group ◽  
Acoustic Data ◽  
Diachronic Change ◽  
Phonemic Level ◽  
The Voice

Abstract. Acoustic data elicited from 34 native speakers of Korean living in the United States pro-vide evidence for diachronic change in the voice onset time (VOT) of phrase-initial aspirated and lax stop phonemes. While older speakers produce aspirated and lax stops with clearly differentiated average VOT values, many younger speakers appear to have neutralized this difference, producing VOTs for aspirated stops that are substantially shorter than those of older speakers, and comparable to those for corresponding lax stops. The data further indicate that, within each age group, older speakers manifest sex-based differences in VOT while younger speakers do not. Despite this appar-ent shift in VOT values, the acoustic evidence suggests that all speakers in this study, regardless of age, continue to mark underlying differences between aspirated and lax stops in terms of stop closure and the fundamental frequency of the following vowel. It is concluded that the data point to a recent phonetic shift in the language, whereby VOT no longer serves as the primary cue to differentiate between lax and aspirated stops. There is not, however, evidence of any reorganization of the lan-guage as the phonemic level: the language's underlying lax ~ aspirated ~ tense contrasts endure.

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