Diao Xiaoying, Lu Qian, Qiao Lei, Gong Youhui, Lu Xiao, Feng Min, Su Panpan, Shen Ying, Yuan Ti-Fei, He Chuan
Department of Rehabilitation Medicine, The Affiliated Jiangsu Shengze Hospital of Nanjing Medical University, Suzhou, China.
Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Front Neurosci. 2022 Feb 17;16:788538. doi: 10.3389/fnins.2022.788538. eCollection 2022.
Intermittent theta burst stimulation (iTBS) is an effective stimulus for long-term potentiation (LTP)-like plasticity. However, iTBS-induced effects varied greatly between individuals. Ample evidence suggested that an initial decrease in local γ-aminobutyric acid (GABA) or enhancement in -methyl-D-aspartate (NMDA) facilitation neurotransmission is of vital importance for allowing LTP-like plasticity to occur. Therefore, we aimed to investigate whether the individual level of GABA or NMDA receptor-mediated activity before stimulation is correlated with the after-effect in cortical excitability induced by iTBS.
Fifteen healthy volunteers were recruited for the present study. We measured short-interval intracortical inhibitory (SICI), long-interval intracortical inhibitory (LICI), and intracortical facilitation (ICF), which index GABA receptor-, GABA receptor-, and glutamate receptor-mediated activity, respectively, in the cortex before conducting iTBS. After iTBS intervention, the changes of motor-evoked potential (MEP) amplitude were taken as a measure for cortical excitability in response to iTBS protocol.
There was a significant negative correlation between the amount of SICI measured before iTBS and the after-effect of iTBS-induced LTP-like plasticity at the time points of 5, 10, and 15 min after inducing iTBS. A multiple linear regression model indicated that SICI was a good predictor of the after-effect in cortical excitability induced by iTBS at 5, 10, and 15 min following stimulation.
The present study found that GABA receptor-mediated activity measured before stimulation is negatively correlated with the after-effect of cortical excitability induced by iTBS. SICI, as the index of GABA receptor-mediated activity measured before stimulation, might be a good predictor of iTBS-induced LTP-like plasticity for a period lasting 15 min following stimulation.
间歇性θ波爆发刺激（iTBS）是一种诱导长时程增强（LTP）样可塑性的有效刺激。然而，iTBS诱导的效应在个体间差异很大。大量证据表明，局部γ-氨基丁酸（GABA）的初始减少或N-甲基-D-天冬氨酸（NMDA）易化性神经传递的增强对于LTP样可塑性的发生至关重要。因此，我们旨在研究刺激前GABA或NMDA受体介导的活性的个体水平是否与iTBS诱导的皮质兴奋性后效应相关。
本研究招募了15名健康志愿者。在进行iTBS之前，我们测量了短间隔皮质内抑制（SICI）、长间隔皮质内抑制（LICI）和皮质内易化（ICF），它们分别代表皮质中GABA受体介导的活性、GABA受体介导的活性和谷氨酸受体介导的活性。iTBS干预后，运动诱发电位（MEP）幅度的变化被用作衡量对iTBS方案的皮质兴奋性的指标。
在iTBS诱导后5、10和15分钟时间点，iTBS前测量的SICI量与iTBS诱导的LTP样可塑性的后效应之间存在显著负相关。多元线性回归模型表明，SICI是刺激后5、10和15分钟iTBS诱导的皮质兴奋性后效应的良好预测指标。
本研究发现，刺激前测量的GABA受体介导的活性与iTBS诱导的皮质兴奋性后效应呈负相关。SICI作为刺激前测量的GABA受体介导活性的指标，可能是刺激后15分钟内iTBS诱导的LTP样可塑性的良好预测指标。
