An event-related fMRI investigation of voice-onset time discrimination.

Full Abstract

The discrimination of voice-onset time, an acoustic-phonetic cue to voicing in stop consonants, was investigated to explore the neural systems underlying the perception of a rapid temporal speech parameter. Pairs of synthetic stimuli taken from a [da] to [ta] continuum varying in voice-onset time (VOT) were presented for discrimination judgments. Participants exhibited categorical perception, discriminating 15-ms and 30-ms between-category comparisons and failing to discriminate 15-ms within-category comparisons. Contrastive analysis with a tone discrimination task demonstrated left superior temporal gyrus activation in all three VOT conditions with recruitment of additional regions, particularly the right inferior frontal gyrus and middle frontal gyrus for the 15-ms between-category stimuli. Hemispheric differences using anatomically defined regions of interest showed two distinct patterns with anterior regions showing more activation in the right hemisphere relative to the left hemisphere and temporal regions demonstrating greater activation in the left hemisphere relative to the right hemisphere. Activation in the temporal regions appears to reflect initial acoustic-perceptual analysis of VOT. Greater activation in the right hemisphere anterior regions may reflect increased processing demands, suggesting involvement of the right hemisphere when the acoustic distance between the stimuli are reduced and when the discrimination judgment becomes more difficult.

Author information

Author/s: Hutchison, Emmette R (ER); Blumstein, Sheila E (SE); Myers, Emily B (EB);

Affiliation: Brown University, Department of Neuroscience, 185 Meeting Street, Providence, RI 02912, USA.

Grants: DC 006220 (Agency:NIDCD NIH HHS) ; R01 DC006220-03 (Agency:NIDCD NIH HHS) ; R01 DC006220-04 (Agency:NIDCD NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't

Journal: NeuroImage (Neuroimage), published in United States. (Language: eng)

Reference: 2008-Mar; vol 40 (issue 1) : pp 342-52

Dates: Created 2008/02/11; Completed 2008/04/23; Revised 2009/03/03;

PMID: 18248740, status: MEDLINE (last retrieval date: 3/10/2009, IMS Date: )

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