Vecchio Fabrizio, Di Iorio Riccardo, Miraglia Francesca, Granata Giuseppe, Romanello Roberto, Bramanti Placido, Rossini Paolo Maria
Brain Connectivity Laboratory, IRCCS San Raffaele-Pisana, Via Val Cannuta, 247, 00166, Rome, Italy.
Department Geriatrics, Neurosciences, Orthopedics, Policlinic A. Gemelli, Institute of Neurology, Catholic University, Rome, Italy.
Exp Brain Res. 2018 Apr;236(4):1117-1127. doi: 10.1007/s00221-018-5200-z. Epub 2018 Feb 13.
Transcranial direct current stimulation (tDCS) is a non-invasive technique able to modulate cortical excitability in a polarity-dependent way. At present, only few studies investigated the effects of tDCS on the modulation of functional connectivity between remote cortical areas. The aim of this study was to investigate-through graph theory analysis-how bipolar tDCS modulate cortical networks high-density EEG recordings were acquired before and after bipolar cathodal, anodal and sham tDCS involving the primary motor and pre-motor cortices of the dominant hemispherein 14 healthy subjects. Results showed that, after bipolar anodal tDCS stimulation, brain networks presented a less evident "small world" organization with a global tendency to be more random in its functional connections with respect to prestimulus condition in both hemispheres. Results suggest that tDCS globally modulates the cortical connectivity of the brain, modifying the underlying functional organization of the stimulated networks, which might be related to changes in synaptic efficiency of the motor network and related brain areas. This study demonstrated that graph analysis approach to EEG recordings is able to intercept changes in cortical functions mediated by bipolar anodal tDCS mainly involving the dominant M1 and related motor areas. Concluding, tDCS could be an useful technique to help understanding brain rhythms and their topographic functional organization and specificity.
经颅直流电刺激（tDCS）是一种能够以极性依赖方式调节皮质兴奋性的非侵入性技术。目前，仅有少数研究探讨了tDCS对远程皮质区域之间功能连接调制的影响。本研究的目的是通过图论分析，研究双相tDCS如何调制皮质网络。在14名健康受试者的优势半球初级运动皮质和运动前皮质进行双相阴极、阳极和假tDCS刺激前后，采集了高密度脑电图记录。结果显示，双相阳极tDCS刺激后，与刺激前相比，两个半球的脑网络呈现出不太明显的“小世界”组织，其功能连接在整体上更趋于随机。结果表明，tDCS对大脑皮质连接进行整体调制，改变了受刺激网络的潜在功能组织，这可能与运动网络及相关脑区的突触效率变化有关。本研究表明，脑电图记录的图分析方法能够检测到主要涉及优势M1和相关运动区域的双相阳极tDCS介导的皮质功能变化。总之，tDCS可能是一种有助于理解脑节律及其地形功能组织和特异性的有用技术。
