Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy.
Department of Biomedical Sciences, Dental Sciences and Morphofunctional Imaging, University of Messina, Messina, Italy.
Behav Brain Res. 2021 Jul 23;410:113352. doi: 10.1016/j.bbr.2021.113352. Epub 2021 May 9.
High-frequency repeated transcranial magnetic stimulation (HF-rTMS) is a safe non-invasive neuromodulatory technique and there is a body of evidence shows that it can modulate plasticity in different brain areas. One of the most interesting application of HF-rTMS is the modulation of plasticity in primary motor cortex (M1) to promote recovery after brain injuries. However, the underlying mechanism by which HF-rTMS modulates motor cortex plasticity remain to be investigated. In this study, we investigated the effects of HF-rTMS treatment on morphological plasticity of pyramidal neurons in layer II/III (L2/3) of the primary motor cortex in mice. Our results show that the treatment did not increase anxiety in mice in the open field test and the elevated plus-maze test. Treated mice displayed increased total spine density in apical and basal dendrites, with a predominance of thin spines. The treatment also increased dendritic complexity, as assessed by Sholl analysis at both apical and basal dendrites. Collectively, the results show that HF-rTMS induced remarkable changes in dendritic complexity in primary motor cortex L2/3 connections which may strengthen corticocortical connections increasing integration of information across cortical areas. The data support the use of HF-rTMS as a circuit-targeting neuromodulation strategy.
高频重复经颅磁刺激（HF-rTMS）是一种安全的非侵入性神经调节技术，有大量证据表明它可以调节不同脑区的可塑性。HF-rTMS 的一个最有趣的应用是调节初级运动皮层（M1）的可塑性，以促进脑损伤后的恢复。然而，HF-rTMS 调节运动皮层可塑性的潜在机制仍有待研究。在这项研究中，我们研究了 HF-rTMS 治疗对小鼠初级运动皮层 L2/3 锥体神经元形态可塑性的影响。我们的结果表明，该治疗并未增加旷场试验和高架十字迷宫试验中小鼠的焦虑。治疗组小鼠在顶树突和基树突的总棘密度增加，以薄棘为主。该治疗还增加了 Sholl 分析在顶树突和基树突的分支复杂性。总之，这些结果表明，HF-rTMS 诱导了初级运动皮层 L2/3 连接中树突复杂性的显著变化，这可能增强了皮质间的连接，增加了跨皮质区域的信息整合。这些数据支持将 HF-rTMS 作为一种针对电路的神经调节策略。
