Session Information
Date: Tuesday, September 24, 2019
Session Title: Neurophysiology
Session Time: 1:45pm-3:15pm
Location: Les Muses Terrace, Level 3
Objective: To explore the effects of quadripulse stimulation (QPS) over the supplementary motor area (SMA) in the healthy humans.
Background: Repetitive transcranial magnetic stimulation (rTMS) has been applied as a treatment of various neurologic diseases. In Parkinson disease (PD), some meta-analysis indicated that rTMS over the primary motor cortex (M1) or SMA improve motor symptoms. Both high frequency (HF) and low frequency (LF) rTMS improve the PD symptoms, but the effect of rTMS is highly variable among individuals. The interindividual variability of QPS was reported to be lower compared with other rTMS protocols, offering a potential of therapeutic use of QPS in PD. However, it is unclear whether QPS over SMA could indeed induce cortical excitability changes. Based on these, we assessed the effect of QPS over SMA in healthy individuals.
Method: Ten healthy volunteers (8 men, 2 women, mean age 28.9 ± 5.2 years) participated in this experiment. We evaluated motor-evoked potentials (MEPs), short interval intracortical inhibition (SICI) and intracortical facilitation (ICF) before and after QPS over left SMA. MEPs were recorded from the right first dorsal interosseous (FDI) muscle at rest. TMS pulse was set at intensity of 90% active motor threshold (AMT) for FDI. Interstimulus interval (ISI) was 5 or 50ms (QPS-5 or 50). Sham stimulation was performed as placebo. Participants received all rTMS patterns (QPS-5, QPS-50, and Sham stimulation) in random order at an interval of at least one week (washout time).
Results: QPS-50 induced MEP size reduction for 30min after the intervention. In contrast, neither QPS-5 nor sham stimulation induced any significant MEP changes. Neither SICI nor ICF was affected by any QPS interventions.
Conclusion: We, here, showed QPS over SMA induced heterotopic LTD like plasticity in the primary motor cortex (M1). In contrast, QPS over M1 induced bi-directional, homotopic plasticity in M1. The present results suggest that we should not simply extrapolate the results of rTMS over M1 to other cortical areas.
To cite this abstract in AMA style:
K. Sato, M. Hamada, Y. Shirota, S. Kodama, Y. Sugiyama, Y. Ugawa, C. Hosoda, T. Toda. QPS over the supplementary motor area induced cortical excitability changes in human primary motor cortex: Comparison with Placebo effect [abstract]. Mov Disord. 2019; 34 (suppl 2). https://www.mdsabstracts.org/abstract/qps-over-the-supplementary-motor-area-induced-cortical-excitability-changes-in-human-primary-motor-cortex-comparison-with-placebo-effect/. Accessed May 9, 2025.« Back to 2019 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/qps-over-the-supplementary-motor-area-induced-cortical-excitability-changes-in-human-primary-motor-cortex-comparison-with-placebo-effect/