Connectivity between supplementary motor complex and primary motor cortex: a dual-coil paired-pulse TMS study

SUMMARYIn recent years, dual-coil paired-pulse transcranial magnetic stimulation (ppTMS) has garnered interest for its potential in elucidating neural circuit dynamics. In this study, the dual-coil ppTMS was utilized to assess the effective connectivity between the supplementary motor complex (SMC) and the primary motor cortex (M1) in humans. A robust facilitatory connection between the SMC and M1 was observed, manifested as a 19% increase in mean peak-to-peak motor-evoked potentials following preconditioning of SMC 7 ms prior to M1 stimulation. Importantly, the facilitatory influence of SMC only occurred when the preconditioning stimulation was administered 4 cm anterior to Cz but not when applied at 5-cm, 6-cm, or 7-cm distance. While previous work has focused on demonstrating important temporal dynamics for SMC-M1 plasticity, the present findings highlight a critical contribution of spatial specificity for modulation of SMC-M1 circuitry.Graphical abstractHighlightsThe conditioned stimulus induced larger MEPs compared to the unconditioned stimulusThe connectivity between SMC and M1 diminished when the SMC coil was moved forwardFindings highlight the importance of spatial specificity for modulation of SMC-M1 circuitry

Kim, H., Lei, Y., Bao, S., Huynh, A. T., Buchanan, J. J., Bernard, J. A., Brown, J. C., & Wright, D. L.

Kim, Hakjoo||Lei, Yuming||Bao, Shancheng||Huynh, Angelina T||Buchanan, John J||Bernard, Jessica A||Brown, Joshua C||Wright, David L

Connectivity between supplementary motor complex and primary motor cortex: a dual-coil paired-pulse TMS study Institutional Repository Document