Kimura Ikko, Hayashi Masamichi J, Amano Kaoru
Center for Information and Neural Networks (CiNet), Advanced ICT Research Institute, National Institute of Information and Communications Technology, Suita, Japan.
Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.
Imaging Neurosci (Camb). 2024 Aug 12;2. doi: 10.1162/imag_a_00264. eCollection 2024.
It remains unclear whether repetitive stimulation of a single brain area immediately alters brain microstructure. Thus, we investigated the immediate changes in human brain microstructures following repetitive extrinsic excitation of the left primary motor cortex (M1) through quadri-pulse stimulation (QPS). Sixteen right-handed healthy adults underwent excitatory (QPS5) and inhibitory (QPS50) QPS. Diffusion magnetic resonance imaging (MRI) and resting-state functional MRI were conducted before and after QPS to detect microstructural and functional changes, respectively. No significant alterations in microstructural indices after QPS5 or QPS50 were observed in the cerebral cortex. The functional connectivity (FC) between the bilateral M1 was significantly decreased after QPS5, while it was not significantly modulated after QPS50. Microstructural changes exhibited no significant correlation with this FC change in any region after QPS5 or QPS50. Although no significant FC change was observed following QPS50, these results may suggest that repetitive stimulation of a single brain area can be insufficient to induce immediate microstructural alterations. This would be supported by demonstrating the lack of microstructural changes after QPS together with changes in cortical excitability of the stimulated region.
单一脑区的重复刺激是否会立即改变脑微观结构仍不清楚。因此，我们通过四脉冲刺激（QPS）对左侧初级运动皮层（M1）进行重复性外在刺激，研究了人脑微观结构的即时变化。16名右利手健康成年人接受了兴奋性（QPS5）和抑制性（QPS50）QPS。在QPS前后分别进行扩散磁共振成像（MRI）和静息态功能MRI，以检测微观结构和功能变化。在QPS5或QPS50后，未观察到大脑皮层微观结构指标有显著改变。QPS5后双侧M1之间的功能连接性（FC）显著降低，而QPS50后未观察到显著调节。在QPS5或QPS50后，任何区域的微观结构变化与这种FC变化均无显著相关性。尽管QPS50后未观察到显著的FC变化，但这些结果可能表明，对单一脑区的重复刺激可能不足以立即引起微观结构改变。刺激区域皮质兴奋性的变化以及QPS后微观结构变化的缺乏将支持这一观点。
