Corticospinal excitability depends on hemodynamic brain state: a study using optical neuroimaging-triggered, brain-state-dependent stimulation

Zhang, Jack Jiaqi, Zeng, Roy Rongyue, Wang, Siqing, Xiong, Siqi, Luo, Xue, Wang, Zi, Lin, Ruixuan, Zhang, Bella Bingbing, Kranz, Georg S., Miller, Tiev, Kwong, Patrick W.H., Lorentz, Lukas, Shaikh, Usman Jawed, Bai, Zhongfei, Lührs, Michael, Binkofski, Ferdinand, Mathiak, Klaus, Mehler, David M.A. and Fong, Kenneth N.K. 2026. Corticospinal excitability depends on hemodynamic brain state: a study using optical neuroimaging-triggered, brain-state-dependent stimulation. Journal of Neurorestoratology , p. 100342. 10.1016/j.jnrt.2026.100342

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Abstract

Background This study aimed to investigate whether a neural interface, which utilizes functional near-infrared spectroscopy (fNIRS) to trigger transcranial magnetic stimulation (TMS) based on real-time hemodynamic signals, can modulate corticospinal excitability more effectively than brain-state-independent stimulation. Methods We developed an fNIRS-TMS interface that acquired oxyhemoglobin concentrations from the supplementary motor area (SMA) during kinesthetic motor imagery (KMI). In the brain-state-independent condition, participants performed continuous KMI while TMS pulses were delivered irrespective of their brain state. In the fNIRS-guided state-dependent condition, TMS was triggered to elicit motor evoked potentials (MEPs) only when real-time fNIRS signals from the SMA exceeded a predetermined activation threshold. MEP amplitudes were compared between conditions in both healthy and post-stroke participants. Results In 20 healthy participants, a generalized estimating equation adjusted for VAS revealed that SMA-fNIRS-guided TMS produced significantly larger MEP amplitude compared to the brain-state-independent TMS (p = 0.010). Parameter estimates indicated that MEP amplitude was lower in the brain-state-independent condition compared to that collected during the brain-state-dependent condition (B = −0.109, SE = 0.042, 95% CI: [−0.192, −0.026]). However, no significant difference between the two conditions was observed in the included eight patients with subcortical ischemic stroke. Above the individual activation threshold, higher hemodynamic signal levels were associated with lower MEP amplitude (r = −0.15, p = 0.027). Conclusion The fNIRS-TMS interface shows preliminary technical feasibility for developing brain-state-dependent stimulation to probe and modulate brain function. Whether the absence of brain-state-dependent facilitation of SMA in post-stroke participants reflects impaired SMA-to-M1 facilitatory connectivity, and whether restoring such facilitation is clinically beneficial, warrant further investigation.

Item Type:	Article
Date Type:	Published Online
Status:	In Press
Schools:	Schools > Psychology
Publisher:	Dove Medical Press
ISSN:	2324-2426
Date of First Compliant Deposit:	19 October 2026
Date of Acceptance:	5 October 2026
Last Modified:	19 Oct 2026 10:00
URI:	https://orca.cardiff.ac.uk/id/eprint/190278

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