Laboratory of Animal and Human Physiology, Department of Biological Applications and Technology, Faculty of Health Sciences, University of Ioannina, Ioannina, Greece.
Department of Neuroanatomy, Faculty of Medicine, Institute of Anatomy and Cell Biology, University of Freiburg, Freiburg, Germany.
Epilepsia Open. 2022 Dec;7(4):608-615. doi: 10.1002/epi4.12633. Epub 2022 Aug 8.
To investigate the effect of generating mechanism on the relationship between interictal-like epileptiform discharges (IEDs) and the underlying High Frequency Oscillations (HFOs; Ripples, R, and Fast Ripples, FR).
Synchronous spontaneous IEDs were recorded from the CA1 area of hippocampal slices from adult rats, perfused by Mg -free ACSF (n = 41slices/14 animals) or 4-aminopyridine (50 μM, n = 37slices/16 animals); IED filtering revealed Rs and FRs and several metrics were calculated and compared (amplitude, duration, relative onset, time lag, % overlap, peak frequency, peak power, FR/R).
Longer IEDs and higher 1st Population Spike (PS) amplitude in Mg -free ACSF (vs 4-AP; P < .001, P < .001) correlated with longer duration and higher amplitude Rs (P < .0001, P = .001) and longer duration FRs (P < .001). In both media, Rs and FRs appeared before IED onset with Rs preceding FRs; R- and FR-IED lag (P = .008, P = .01) as well as R-FR lag (P = .04) were significantly longer in Mg -free ACSF vs in 4-AP. R peak frequency and power were higher in Mg -free ACSF, while no such differences were observed in FRs. Inter-model differences were mostly reflected in Rs, not FRs, suggesting that mechanisms unique to R generation are more active in Mg -free ACSF vs in 4-AP. FRs appeared to contribute equally to IEDs irrespective of generating mechanism.
Several of the metrics used, particularly those regarding the timing between HFOs and IEDs, appear to correlate with the synchronizing mechanism and we propose that they may be useful when investigating antiepileptic substance effects on neuronal network activity.
探究棘波样放电（IEDs）与高频振荡（HFOs；锐波、R 和快锐波、FR）之间的关系与产生机制的关系。
从成年大鼠海马脑片 CA1 区同步记录 Mg 自由 ACSF（n=41 片/14 只动物）或 4-氨基吡啶（50μM，n=37 片/16 只动物）灌流的自发 IEDs；对 IED 进行滤波，得到 Rs 和 FRs，并计算和比较了几种指标（幅度、持续时间、相对起始、时间滞后、重叠百分比、峰值频率、峰值功率、FR/R）。
Mg 自由 ACSF 中 IED 持续时间较长且第一群体峰（PS）幅度较高（与 4-AP 相比；P < .001，P < .001），与 Rs 持续时间较长且幅度较高（P < .0001，P=0.001）和 FRs 持续时间较长相关（P < .001）。在两种介质中，Rs 和 FRs 均在 IED 起始前出现，且 Rs 先于 FRs 出现；Rs 和 FR 与 IED 起始的滞后（P=0.008，P=0.01）以及 Rs 和 FR 之间的滞后（P=0.04）在 Mg 自由 ACSF 中显著长于 4-AP。Mg 自由 ACSF 中的 R 峰值频率和功率较高，而 FRs 中则没有观察到这种差异。模型间的差异主要反映在 Rs 上，而不是 FRs 上，这表明在 Mg 自由 ACSF 中与 R 产生相关的机制比 4-AP 中更为活跃。FRs 似乎对 IEDs 的贡献是相等的，而与产生机制无关。
所使用的几种指标，特别是那些与 HFOs 和 IEDs 之间的时间关系相关的指标，似乎与同步化机制相关，我们提出它们可能在研究抗癫痫物质对神经元网络活动的影响时有用。
