Bragin Anatol, Wilson Charles L, Engel Jerome
Neurology Neurobiology Brain Research Institute, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA.
Epilepsia. 2003 Sep;44(9):1233-7. doi: 10.1046/j.1528-1157.2003.18503.x.
Fast ripples (FRs) are interictal, pathological, high-frequency oscillations in the 200- to 600-Hz range, which can be recorded from limbic regions capable of generating spontaneous seizures in rodent models of epilepsy and in human mesial temporal lobe epilepsy. To evaluate the spatial stability of FR-generating brain areas over long periods, we monitored interictal FR oscillations in rats with chronic recurrent spontaneous seizures.
After unilateral intrahippocampal injection of kainic acid, 22 rats were video monitored until spontaneous behavioral seizures occurred, and then implanted with multiple hippocampal, dentate gyrus, and entorhinal cortex microelectrodes. Electrophysiological monitoring of microelectrode sites was carried out during daily 8-h recordings for periods ranging from 6 to 98 days.
Interictal FRs were recorded from discretely localized areas, adjacent to non-FR-generating areas in dentate gyrus and entorhinal cortex. The location of interictal FR oscillations remained fixed, and the electrophysiological pattern of FRs remained the same over the time of our study. For the duration of monitoring, sites initially recording interictal FRs continued to display FR oscillations, and sites that initially did not record FRs never demonstrated FR activity. A direct relation was seen between the total number of electrode contacts recording interictal FRs and the frequency of spontaneous seizure generation (p < 0.0001).
These results suggest that interictal FRs reflect abnormal discharges from a fixed pathologic substrate imbedded within less-epileptogenic tissue, and that spontaneous seizure frequency is dependent on the extent and distribution of this pathologic substrate.
快速涟漪（FRs）是发作间期的病理性高频振荡，频率范围在200至600赫兹之间，可在癫痫啮齿动物模型以及人类内侧颞叶癫痫中能够产生自发性癫痫发作的边缘区域记录到。为了评估长时间内产生FR的脑区的空间稳定性，我们监测了慢性复发性自发性癫痫大鼠的发作间期FR振荡。
在单侧海马内注射海人酸后，对22只大鼠进行视频监测直至出现自发性行为性癫痫发作，然后植入多个海马、齿状回和内嗅皮质微电极。在每天8小时的记录期间，对微电极部位进行电生理监测，记录时长从6天到98天不等。
在齿状回和内嗅皮质中与非FR产生区域相邻的离散定位区域记录到发作间期FRs。发作间期FR振荡的位置保持固定，并且在我们的研究期间FR的电生理模式保持不变。在监测期间，最初记录发作间期FRs的部位持续显示FR振荡，而最初未记录到FRs的部位从未表现出FR活动。记录发作间期FRs的电极触点总数与自发性癫痫发作频率之间存在直接关系（p < 0.0001）。
这些结果表明，发作间期FRs反映了嵌入较少致痫性组织内的固定病理基质的异常放电，并且自发性癫痫发作频率取决于该病理基质的范围和分布。
