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Updated: Jun 13, 2026
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Bilateral Assessment of the Corticospinal Pathways of the Ankle Muscles Using Navigated Transcranial Magnetic Stimulation
Published on: February 19, 2019
Cortico-conus motor conduction time (CCCT) for leg muscles
Hideyuki Matsumoto1, Ritsuko Hanajima, Yuichiro Shirota
1Department of Neurology, Division of Neuroscience, Graduate School of Medicine, The University of Tokyo, Japan. hideyukimatsumoto@mail.goo.ne.jp
Summary
Magnetic stimulation accurately measures cortico-conus motor conduction time (CCCT) in leg muscles. This novel method assesses corticospinal tract function without peripheral influence.
Area of Science:
- Neuroscience
- Neuromuscular Physiology
Background:
- Assessing corticospinal tract (CST) integrity is crucial for diagnosing neurological disorders affecting motor function.
- Current methods for evaluating CST function in leg muscles can be influenced by peripheral nerve conduction.
- A method to isolate the central motor conduction time to the conus medullaris is needed.
Purpose of the Study:
- To measure the conduction time from the motor cortex to the conus medullaris (cortico-conus motor conduction time, CCCT) for leg muscles.
- To evaluate the utility of magnetic stimulation for assessing CCCT.
Main Methods:
- Recorded motor evoked potentials (MEPs) from tibialis anterior muscles in 51 healthy volunteers.
- Utilized a Magnetic Activated Transducer System (MATS) coil for magnetic stimulation at the conus medullaris/proximal cauda equina.
- Measured cortical latency via transcranial magnetic stimulation and calculated CCCT by subtracting conus latency from cortical latency.
Main Results:
- MATS coil stimulation successfully evoked reproducible MEPs in all participants.
- Reliable CCCT data was obtained for all tested tibialis anterior muscles.
- The method demonstrated feasibility in healthy subjects.
Conclusions:
- MATS coil stimulation is a viable technique for obtaining CCCT data in healthy individuals.
- This novel approach offers a valuable tool for evaluating corticospinal tract function in leg muscles.
- The CCCT measurement is not affected by peripheral nerve conduction, enhancing its diagnostic utility.
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