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Cortical neuromagnetic fields preceding voluntary jaw movements.
Y Shibukawa1, M Shintani, T Kumai
1Oral Health Science Center, Tokyo Dental College, Chiba 261-8502, Japan. yshibuka@tdc.ac.jp
Journal of Dental Research
|June 26, 2004
Summary
This study located the source of brain activity preceding voluntary jaw movements. The primary motor cortex was identified as being bilaterally involved in planning and executing these movements.
Area of Science:
- Neuroscience
- Motor Control
- Brain Imaging
Background:
- Slow cortical potentials, specifically readiness potentials (RPs), are known to precede voluntary movements.
- The precise cortical origin of the RP for jaw movements, however, remains unlocalized.
Purpose of the Study:
- To identify the specific cortical regions responsible for the central programming of voluntary, bilaterally symmetrical jaw movements.
- To localize the neuromagnetic counterpart of the RP, known as the readiness field (RF).
Main Methods:
- Used magnetoencephalography (MEG) to detect the readiness field (RF) preceding jaw movements.
- Analyzed the timing and location of RFs relative to electromyograms (EMGs) of jaw muscles.
Main Results:
- Readiness fields (RFs) were detected bilaterally in the fronto-lateral region, preceding muscle activity by hundreds of milliseconds.
- The current sources of the RFs were localized to the precentral gyrus bilaterally.
- RFs appeared significantly earlier than the excitability increase in pyramidal tract neurons.
Conclusions:
- The primary motor cortex is bilaterally engaged in both the central programming and execution of symmetrical voluntary jaw movements.
- This finding contributes to understanding the neural basis of complex motor control.