1998 Fiscal Year Final Research Report Summary
Central processing from speech recognition to vocalization
| Project/Area Number |
09671742
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Otorhinolaryngology
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
FUJIKI Nobuya Kyoto University Graduate School of Medicine, Department of Hearing and Speech Science, Instructor, 医学研究科, 助手 (20271009)
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| Co-Investigator(Kenkyū-buntansha) |
NAGAMINE Takashi Kyoto University Graduate School of Medicine, Department of Brain Pathophysiolog, 医学研究科, 助手 (10231490)
NAITO Yasushi Kyoto University Graduate School of Medicine, Department of Hearing and Speech S, 医学研究科, 講師 (70217628)
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| Project Period (FY) |
1997 – 1998
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| Keywords | auditory language / Magnetoencephalography / superior temporal gyrus / visual language / visual cortex / temporo-parieto-occipital region / Broca's area / supplementary motor area |
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| Research Abstract |
To evaluate, an auditory language processing, we measured auditory evoked magnetic fields elicited by a speech sound and non speech sounds using magnetoencephalography. N100m latency of a pure tone, the fundamental frequency of which was 170 Hz, was longer than that of a white noise, a Japanese vowel sound and a produced complex sound which included power of F0, F1, F2 and F3 peak of the vowel sound. Equivalent current dipole (ECD) elicited by each stimulus was estimated in the superior temporal gyrus and there was no significant difference of the location between each other. Although the ECD moment was larger over the right hemisphere than the left hemisphere, the difference of the ECD moments between these stimuli was significant over the left hemisphere. This finding imply that phonological processing is performed mainly in the left auditory cortex, which seems to be dominant in language processing.
Regarding a visual language processing, event-related magnetic fields (ERFs) were rec
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orded when normal subjects were presented with a rectangle, a Japanese Kanji character and an unreadable character followed by silent reading only if Kanji character was presented. The ERF averages for the Kanji and unreadable characters were larger than that for the rectangle at latencies of about 100 ms in the visual cortex and 200 ms in the temporo-parieto-occipital region. This observation suggests that the first stage of visual word processing might arise in the occipital lobe. This observation suggests that the first stage of visual language processing might arise in the visual, cortex.
Event-related magnetic fields (ERFs) were also recorded when the subjects were presented with Japanese Kanji characters followed by vocalizations. The ERF were observed at latencies of about 100 ms in the visual cortex and 200 ms in the temporo-parieto-occipital region which is so-called Wernicke's area. In some cases, the ERFs were also seen on the frontal lobe at the latencies from 200 ms to 400 ms and the ECDs were estimated in Broca's area, its right hemisphere homologue and the supplementary motor area. These findings suggests that parallel processing might occur in the frontal cortex during vocalizations. Less
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