Goldenkoff Elana R, Deluisi Joseph A, Destiny Danielle P, Lee Taraz G, Michon Katherine J, Brissenden James A, Taylor Stephan F, Polk Thad A, Vesia Michael
School of Kinesiology, University of Michigan, Ann Arbor, MI, United States.
Department of Psychology, University of Michigan, Ann Arbor, MI, United States.
Front Neurosci. 2023 Oct 26;17:1198222. doi: 10.3389/fnins.2023.1198222. eCollection 2023.
Repetitive transcranial magnetic stimulation (TMS) is widely used in neuroscience and clinical settings to modulate human cortical activity. The effects of TMS on neural activity depend on the excitability of specific neural populations at the time of stimulation. Accordingly, the brain state at the time of stimulation may influence the persistent effects of repetitive TMS on distal brain activity and associated behaviors. We applied intermittent theta burst stimulation (iTBS) to a region in the posterior parietal cortex (PPC) associated with grasp control to evaluate the interaction between stimulation and brain state. Across two experiments, we demonstrate the immediate responses of motor cortex activity and motor performance to state-dependent parietal stimulation. We randomly assigned 72 healthy adult participants to one of three TMS intervention groups, followed by electrophysiological measures with TMS and behavioral measures. Participants in the first group received iTBS to PPC while performing a grasping task concurrently. Participants in the second group received iTBS to PPC while in a task-free, resting state. A third group of participants received iTBS to a parietal region outside the cortical grasping network while performing a grasping task concurrently. We compared changes in motor cortical excitability and motor performance in the three stimulation groups within an hour of each intervention. We found that parietal stimulation during a behavioral manipulation that activates the cortical grasping network increased downstream motor cortical excitability and improved motor performance relative to stimulation during rest. We conclude that constraining the brain state with a behavioral task during brain stimulation has the potential to optimize plasticity induction in cortical circuit mechanisms that mediate movement processes.
重复经颅磁刺激（TMS）在神经科学和临床环境中被广泛用于调节人类皮层活动。TMS对神经活动的影响取决于刺激时特定神经群体的兴奋性。因此，刺激时的脑状态可能会影响重复TMS对远端脑活动和相关行为的持续影响。我们将间歇性θ波爆发刺激（iTBS）应用于与抓握控制相关的顶叶后皮质（PPC）区域，以评估刺激与脑状态之间的相互作用。在两个实验中，我们证明了运动皮层活动和运动表现对状态依赖性顶叶刺激的即时反应。我们将72名健康成年参与者随机分配到三个TMS干预组之一，随后进行TMS电生理测量和行为测量。第一组参与者在同时执行抓握任务时接受对PPC的iTBS。第二组参与者在无任务的休息状态下接受对PPC的iTBS。第三组参与者在同时执行抓握任务时接受对皮质抓握网络外的顶叶区域的iTBS。我们比较了每次干预后一小时内三个刺激组中运动皮层兴奋性和运动表现的变化。我们发现，与休息时的刺激相比，在激活皮质抓握网络的行为操作期间进行顶叶刺激可增加下游运动皮层兴奋性并改善运动表现。我们得出结论，在脑刺激期间通过行为任务来限制脑状态有可能优化介导运动过程的皮质回路机制中的可塑性诱导。
