School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, PO Box 376, P.C. 54124, Thessaloniki, Greece.
Institute for Biomagnetism and Biosignalanalysis, University of Münster, Malmedyweg 15, P.C. D-48149, Münster, Germany.
Sci Rep. 2019 Oct 29;9(1):15452. doi: 10.1038/s41598-019-51747-z.
The present study used resting state MEG whole-head recordings to identify how chronic tonal tinnitus relates to altered functional connectivity of brain's intrinsic cortical networks. Resting state MEG activity of 40 chronic tinnitus patients and 40 matched human controls was compared identifying significant alterations in intrinsic networks of the tinnitus population. Directed functional connectivity of the resting brain, at a whole cortex level, was estimated by means of a statistical comparison of the estimated phase Transfer Entropy (pTE) between the time-series of cortical activations, as reconstructed by LORETA. As pTE identifies the direction of the information flow, a detailed analysis of the connectivity differences between tinnitus patients and controls was possible. Results indicate that the group of tinnitus patients show increased connectivity from right dorsal prefrontal to right medial temporal areas. Our results go beyond previous findings by indicating that the role of the left para-hippocampal area is dictated by a modulation from dmPFC; a region that is part of the dorsal attention network (DAN), as well as implicated in the regulation of emotional processing. Additionally, this whole cortex analysis showed a crucial role of the left inferior parietal cortex, which modulated the activity of the right superior temporal gyrus, providing new hypotheses for the role of this area within the context of current tinnitus models. Overall, these maladaptive alterations of the structure of intrinsic cortical networks show a decrease in efficiency and small worldness of the resting state network of tinnitus patients, which is correlated to tinnitus distress.
本研究使用静息态 MEG 全头记录来确定慢性音调性耳鸣如何与大脑固有皮质网络的功能连接改变相关。比较了 40 名慢性耳鸣患者和 40 名匹配的正常人的静息态 MEG 活动，确定了耳鸣人群固有网络的显著改变。通过 LORETA 重建的皮质激活时间序列之间估计相位传递熵 (pTE) 的统计比较，估计静息大脑的定向功能连接，在整个皮质水平上。由于 pTE 确定了信息流的方向，因此可以对耳鸣患者和对照组之间的连接差异进行详细分析。结果表明，耳鸣患者组显示右侧背侧前额叶到右侧内侧颞区的连接增加。我们的结果超越了先前的发现，表明左侧海马旁回区域的作用是由 dmPFC 调制决定的；该区域是背侧注意网络 (DAN) 的一部分，并且与情绪处理的调节有关。此外，这项全皮质分析显示左侧下顶叶皮层起着至关重要的作用，它调节了右侧上颞叶的活动，为该区域在当前耳鸣模型中的作用提供了新的假设。总的来说，这些固有皮质网络结构的适应性改变表明，耳鸣患者的静息态网络效率和小世界特性降低，这与耳鸣困扰有关。
