Division of Neurology, Department of Medicine, University of Toronto, Division of Brain, Imaging and Behavior - Systems Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, M5T 2S8, Canada; Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.
Division of Neurology, Department of Medicine, University of Toronto, Division of Brain, Imaging and Behavior - Systems Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, M5T 2S8, Canada; Monash Alfred Psychiatry Research Centre, Monash University Central Clinical School and The Alfred, Melbourne, 3004, Australia.
Neuroimage. 2017 Sep;158:48-57. doi: 10.1016/j.neuroimage.2017.06.048. Epub 2017 Jun 29.
Network connectivity measured with resting state functional magnetic resonance imaging (rsfMRI) has revealed the contribution of distinct cerebellar lobules to an array of brain wide networks sub-serving motor and cognitive processes. As distinct cerebellar lobules form relatively accessible nodes of different brain networks, this raises the possibility for site-specific modulation of network connectivity using non-invasive brain stimulation techniques such as transcranial magnetic stimulation (TMS). Continuous theta burst transcranial magnetic stimulation (cTBS) induces long-lasting inhibition of cortical areas. Although previous studies have shown that cTBS of the lateral cerebellum modulates motor cortical excitability and improves symptoms in several movement disorders, the effect on cognitive domains has not been examined. We explored the immediate effects of cTBS in a sham-controlled study on the strength of intrinsic functional connectivity between cerebellar and cortical motor and cognitive regions in 12 participants. Lateral cerebellar cTBS significantly decreased functional connectivity with frontal and parietal cognitive regions, while connectivity with motor regions remained unaltered. Sham stimulation had no effect on either motor or cognitive connectivity. These results show that inhibitory cerebellar stimulation reduces intrinsic functional connectivity between different cortical areas, in keeping with the known connectivity pattern of the cerebellum. The results highlight the plasticity of cerebello-cerebral networks and indicate for the first time that this functional connectivity can be downregulated using an inhibitory neurostimulation paradigm. This may shed light on the pathophysiology of network dysfunction and is a potential treatment for cognitive and movement disorders.
利用静息态功能磁共振成像（rsfMRI）测量的网络连通性揭示了不同小脑叶对一系列广泛的大脑网络的贡献，这些网络服务于运动和认知过程。由于不同的小脑叶形成了相对可接近的不同大脑网络的节点，这就为使用非侵入性脑刺激技术（如经颅磁刺激（TMS））来特异性地调节网络连通性提供了可能性。连续 theta 爆发经颅磁刺激（cTBS）诱导皮质区域的长时间抑制。尽管先前的研究表明，外侧小脑的 cTBS 调节运动皮质兴奋性并改善了几种运动障碍的症状，但尚未检查其对认知领域的影响。我们在一项假刺激对照研究中，在 12 名参与者中探索了 cTBS 对小脑和皮质运动及认知区域之间内在功能连通性强度的即时影响。外侧小脑 cTBS 显著降低了与额叶和顶叶认知区域的功能连通性，而与运动区域的连通性保持不变。假刺激对运动或认知连通性均无影响。这些结果表明，抑制性小脑刺激可降低不同皮质区域之间的内在功能连通性，这与小脑的已知连通模式一致。结果突出了小脑-大脑网络的可塑性，并首次表明可以使用抑制性神经刺激范式来下调这种功能连通性。这可能有助于阐明网络功能障碍的病理生理学，并为认知和运动障碍的治疗提供了新的思路。
