Başar E, Schmiedt-Fehr C, Mathes B, Femir B, Emek-Savaş D D, Tülay E, Tan D, Düzgün A, Güntekin B, Özerdem A, Yener G, Başar-Eroğlu C
Istanbul Kultur University, Brain Dynamics, Cognition and Complex Systems Research Center, Istanbul, Turkey.
Bremen University, Institute of Psychology and Cognition Research, Bremen, Germany.
Int J Psychophysiol. 2016 May;103:135-48. doi: 10.1016/j.ijpsycho.2015.02.004. Epub 2015 Feb 7.
The application of the concept and methods of brain oscillations has been an important research area in neurosciences. In the last decades, besides the application in cognitive processes, the study of changes in brain oscillations in diseases has also become an important focal point of research. In the present paper, some remarkable examples in three different diseases are taken into consideration: 1) schizophrenia (SZ), 2) Alzheimer's disease (AD), 3) bipolar disorders (BD). In the current literature, decreased oscillations in cortical recordings are observed in most of the pathologies. For example, decrease of gamma activity in SZ, decrease of delta activity in almost all diseases, as well as frequency shifts in alpha and the lower frequencies were recorded. However, there are also paradoxical cases in which an increase of oscillatory activities is observed. In BD, whereas alpha activity is greatly decreased, a huge increase of beta activity is observed. Or, in SZ, a paradoxical increase of gamma activity can be observed during cognitive loading. We also observed paradoxical changes in the analysis of connectivity. In AD, we find that alpha, delta, and theta coherences between distant parts of the cortex are greatly decreased, whereas in the gamma band, event-related coherences attain very high values. The comparison of the results and paradoxical changes in diseases may lead to important conclusions related to the web of oscillations and neurotransmitters. In turn, we could gain new insights to approach "brain function", in general.
脑振荡概念和方法的应用一直是神经科学领域的一个重要研究方向。在过去几十年里，除了在认知过程中的应用，疾病中脑振荡变化的研究也已成为一个重要的研究焦点。在本文中，我们考虑了三种不同疾病中的一些显著例子：1）精神分裂症（SZ），2）阿尔茨海默病（AD），3）双相情感障碍（BD）。在当前的文献中，在大多数病理情况下都观察到皮层记录中的振荡减少。例如，SZ中γ活动减少，几乎所有疾病中δ活动减少，以及α和更低频率的频率偏移也有记录。然而，也存在一些矛盾的情况，即观察到振荡活动增加。在BD中，α活动大幅减少，而β活动却大幅增加。或者，在SZ中，在认知负荷期间可以观察到γ活动的矛盾性增加。我们在连通性分析中也观察到了矛盾的变化。在AD中，我们发现皮层远距离部分之间的α、δ和θ相干性大大降低，而在γ波段，事件相关相干性达到非常高的值。对疾病结果和矛盾变化的比较可能会得出与振荡网络和神经递质相关的重要结论。反过来，总体而言，我们可以获得关于理解“脑功能”的新见解。
