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Motor planning center for speech articulation in the normal human brain
1Research Institute for Electronic Science, Hokkaido University, Sapporo, Japan.
Neuroreport
|April 20, 1999
Summary
Researchers pinpointed the brain's speech control center using magnetoencephalography (MEG). This study reveals the left insula's role in the articulatory programming of speech movements before sound production.
Area of Science:
- Neuroscience
- Cognitive Science
- Speech Motor Control
Background:
- Understanding the neural basis of speech production is crucial for diagnosing and treating speech disorders.
- The precise location of the speech articulation coordination center in the dominant hemisphere remains an area of active research.
Purpose of the Study:
- To identify the specific brain region responsible for coordinating speech movements.
- To investigate the temporal dynamics of neural activity preceding speech articulation.
Main Methods:
- Magnetoencephalography (MEG) was used to measure brain activity in right-handed subjects.
- Subjects pronounced various words while MEG signals were recorded from the left frontal area.
- Source localization of MEG signals was performed using individual magnetic resonance images (MRIs).
Main Results:
- A significant neural response was detected 120-320 ms before speech sound onset.
- The localized dipole sources of this response were found in the superior region of the left insula.
- The onset of the brain response preceded perioral muscle activity by approximately 100 ms.
Conclusions:
- The deep frontal region, specifically the left insula, plays a key role in the articulatory programming of speech.
- These findings contribute to understanding the neural mechanisms underlying voluntary speech production.