Makra Péter, Menyhárt Ákos, Bari Ferenc, Farkas Eszter
Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary.
Front Physiol. 2018 Nov 8;9:1512. doi: 10.3389/fphys.2018.01512. eCollection 2018.
Cortical spreading depolarisation (CSD) is a transient disruption of ion balance that propagates along the cortex. It has been identified as an important factor in the progression of cerebral damage associated with stroke or traumatic brain injury. We analysed local field potential signals during CSD in old and young rats to look for age-related differences. We compared CSDs elicited under physiological conditions (baseline), during ischaemia and during reperfusion. We applied short-time Fourier transform and a windowed implementation of multifractal detrended fluctuation analysis to follow the electrophysiological signature of CSD. Both in the time-dependent spectral profiles and in the multifractal spectrum width, CSDs appeared as transient dips, which we described on the basis of their duration, depression and recovery slope and degree of drop and rise. The most significant age-related difference we found was in the depression slope, which was significantly more negative in the beta band and less negative in the delta band of old animals. In several parameters, we observed an attenuation-regeneration pattern in reaction to ischaemia and reperfusion, which was absent in the old age group. The age-related deviation from the pattern took two forms: the rise parameter did not show any attenuation in ischaemic conditions for old animals, whilst the depression slope in most frequency bands remained attenuated during reperfusion and did not regenerate in this age group. Though the multifractal spectrum width proved to be a reliable indicator of events like CSDs or ischaemia onset, we failed to find any case where it would add extra detail to the information provided by the Fourier description.
皮质扩散性抑制（CSD）是一种沿皮质传播的离子平衡短暂破坏。它已被确定为与中风或创伤性脑损伤相关的脑损伤进展中的一个重要因素。我们分析了老年和幼年大鼠在CSD期间的局部场电位信号，以寻找与年龄相关的差异。我们比较了在生理条件下（基线）、缺血期间和再灌注期间诱发的CSD。我们应用短时傅里叶变换和多重分形去趋势波动分析的加窗实现来追踪CSD的电生理特征。在时间相关的频谱轮廓和多重分形谱宽度方面，CSD均表现为短暂下降，我们根据其持续时间、下降程度、恢复斜率以及下降和上升程度对其进行了描述。我们发现的最显著的与年龄相关的差异在于下降斜率，在老年动物的β波段中下降斜率明显更负，而在δ波段中则较不明显。在几个参数中，我们观察到对缺血和再灌注的反应呈现出衰减 - 再生模式，而老年组中不存在这种模式。与年龄相关的模式偏差有两种形式：老年动物在缺血条件下上升参数没有任何衰减，而在再灌注期间大多数频段的下降斜率仍保持衰减且在该年龄组中未恢复。尽管多重分形谱宽度被证明是CSD或缺血发作等事件的可靠指标，但我们未能找到任何情况表明它能为傅里叶描述提供的信息增添额外细节。
