Neuroscience 2004 Abstract
| Presentation Number: | 752.13 |
|---|---|
| Abstract Title: | Cortical activities related to noise-vocoded speech intelligibility measured by functional magnetic resonance imaging. |
| Authors: |
Tachibana, R.*1
; Riquimaroux, H.1
1Sensory and Cognitive Neurosci. Res. Lab., Grad. Sch. of Engin., Doshisha Univ, Kyotanabe, Japan |
| Primary Theme and Topics |
Sensory Systems - Auditory -- Auditory cortex: Perception, cognition, and action |
| Secondary Theme and Topics | Cognition and Behavior<br />- Human Cognition, Behavior, and Anatomy<br />-- Language |
| Session: |
752. Auditory Cortex IV Poster |
| Presentation Time: | Tuesday, October 26, 2004 1:00 PM-2:00 PM |
| Location: | San Diego Convention Center - Hall A-H, Board # T4 |
| Keywords: | AMPLITUDE ENVELOPE, SPEECH PERCEPTION, NEUROPLASTICITY |
The brain activity involved in perception of spectrally degraded but intelligible processed speech was studied by using functional magnetic resonance imaging, fMRI. Japanese spoken sentences were spectrally divided into four bands, and then the amplitude envelope was extracted from each band, which was used to modulate noise of the same bandwidth. This processing severely reduced the spectral resolution but preserved the amplitude envelope of each band. Previous studies demonstrated that the present processed speech sound called noise-vocoded speech sound, NVS, was almost unintelligible without any training, but it became intelligible at about 80% level after a brief training. Moreover, prosodic characteristics, such as accents or intonations, normally carried by spectral information were found to be correctly perceived with NVS without F0 or formants. The findings suggest that the brain reconstructs essential cues from the envelope cues to make sentences intelligible. Thus, the neural circuits for making NVS intelligible appear to be different from those for the natural speech sounds, NAS. In the present study, the cortical function for NVS perception was investigated by comparing data with NVS to those with NAS before and after a 3-day training by means of fMRI. Results showed distinct differences between activities with NAS and NVS. The typical pattern of passive listening was illustrated in the condition of NAS, but the activation involved in NVS lay broadly on various cortical areas, including the area involved in NAS. This observation demonstrates a complementary and more active process for speech comprehension using the temporal envelope cues.
Supported by This research supported by a grant to RCAST at Doshisha Univ. from MEXT, Innovative Cluster Creation Project by MEXT.
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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