2022 Fiscal Year Annual Research Report
Development of a neuromodulation method for facilitation of corticospinal plasticity
| Project/Area Number |
20K19412
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| Research Institution | Osaka University |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | neuromodulation / theta burst stimulation / spinal cord stimulation / rehabilitation |
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| Outline of Annual Research Achievements |
The objective of this research is to understand mechanisms of neuroplasticity though synchronization of cortical commands and peripheral sensory feedback. Non-invasive brain stimulation was applied as theta burst stimulation (TBS) either via intermittent TBS (iTBS) facilitatory or continuous TBS (cTBS) inhibitory protocols. Afferent networks were activated using neuromuscular electrical stimulation (NMES) of muscles or recruitment of the cervical dorsal roots sensory fibers through transcutaneous spinal cord stimulation (tSCS). First, iTBS facilitatory or cTBS inhibitory cortical priming was applied before delivery of upper-limb muscle NMES. Our results showed that facilitatory cortical priming using iTBS followed by NMES was most effective in significantly facilitating corticospinal networks. We then showed that short duration iTBS facilitatory activation applied at the same time using synchronized frequencies affects corticospinal excitability immediate after the intervention. Finally, we tested the effects of the duration of concurrent synchronized iTBS-NMES interventions on corticospinal excitably and showed that longer durations interventions could elicit longer-lasting effects. In parallel, we have been developing a method for activation of cervical spinal dorsal roots through tSCS. We showed both using computer simulations and experimental findings evidence that sensory fibers in the dorsal roots can be activated before motor fibers. Moreover, we showed selectivity and sensitivity of recruitment of upper-limb motor pools with different cervical stimulation locations.
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