Opposing modulation of cortical and corticospinal excitability across movement-related beta stages
TL;DR
Combining individualized, state-targeted transcranial magnetic stimulation with electroencephalography and electromyography recordings during visually cued finger movements to probe excitability across movement-related beta-band dynamics reveals a fundamental dissociation between how intrinsic brain activity tunes local cortical excitability and corticospinal output in humans.
Abstract
Discrete voluntary movement depends on rapid changes in neural excitability across cortical and corticospinal circuits, yet how intrinsic movement-related neural states shape multi-level excitability remains unclear. Here, we combined individualized, state-targeted transcranial magnetic stimulation (TMS) with electroencephalography and electromyography recordings during visually cued finger movements to probe excitability across movement-related beta-band dynamics during two complementary experiments. Immediate transsynaptic cortical excitability closely tracked intrinsic beta dynamics, with attenuation of the second immediate TMS-evoked potential during beta desynchronization and recovery during the post-movement beta rebound. In contrast, corticospinal excitability showed the opposite pattern, with larger motor-evoked potentials during beta desynchronization and reduced responses during beta rebound. Together, these findings identify endogenous beta-state dynamics as a key regulator of movement-related cortical excitability and reveal a fundamental dissociation between how intrinsic brain activity tunes local cortical excitability and corticospinal output in humans.