痫样放电大鼠海马诱发场电位及癫痫脑电同步分析

【作者】 丁智勇；

【导师】 夏阳；

【作者基本信息】 电子科技大学 ， 生物医学工程， 2007， 硕士

【摘要】 癫痫是一种反复发作的神经元异常放电引起的暂时性中枢神经系统功能失常性疾病。海马在癫痫尤其是颞叶癫痫发作的起始及维持中扮演着重要的角色。迄今为止,癫痫发作的神经机制还未完全明了,对难治性癫痫的药物治疗还存在诸多困难。因此,探讨癫痫发生发展过程中神经电活动的动力学特征以及寻求有效药物的干预,具有重要的理论意义和临床应用价值。本论文通过建立匹鲁卡品(Pilocarpine)诱导的急性和慢性癫痫大鼠模型,分析癫痫发生发展过程中癫痫脑电的时空动力学变化,并探讨中药有效成分酸枣仁皂甙A (Jujuboside A, JuA)对癫痫神经元活动的影响。本课题的研究内容主要分为两个部分:1.麻醉状态下,通过腹腔注射匹鲁卡品,建立痫样放电大鼠模型,研究致痫前后大鼠皮层脑电(electrocorticogram,ECoG)、海马电图(electrohippocampogram,EHG)和海马诱发场电位(field evoked potentials,FEP)的变化以及JuA对上述神经电活动的影响。结果发现:致痫前后ECoG、EHG和海马FEP均存在显著性差异,同时JuA对致痫后的皮层脑电和海马电图的功率谱具有明显抑制作用(P<0.05),JuA对海马诱发场电位的影响主要表现为兴奋性突出后电位(excitatory postsynaptic potential,EPSP)斜率降低(P<0.05),而对群峰电位潜伏期的影响不明显,但其剂量依赖关系尚有待进一步研究。上述结果提示,在痫样放电过程中JuA对脑电和诱发场电位具有一定的抑制作用。2.腹腔注射匹鲁卡品,建立癫痫持续状态(Status epilepticus,SE)大鼠模型,采集了SE后一周内不同时间的ECoG和EHG,应用希尔伯特(Hilbert)同步方法分析癫痫持续状态后自由活动大鼠脑电信号的时空特征。结果显示:癫痫持续状态后,左右皮层和海马的同步性显著增强(P<0.05);在癫痫大发作后3小时达到高峰(P<0.01),24小时后同步性开始降低(P<0.05)。其中,各脑区脑电δ节律的变化趋势与前述的变化一致。提示希尔伯特(Hilbert)同步可以较好地刻画癫痫脑电的同步变化,并且δ节律的贡献有助于癫痫脑电的同步性变化。更多还原

【Abstract】 Epilepsy is a chronic disease characterized by recurrent episodic and central system dysfunction caused by abnormal discharge of neurons. The hippocampus occupies an important role in the beginning and development of epileptic seizures especially in partial seizures (e.g. TLE). So far, neural mechanism of epileptic seizures has not yet been fully understood. There are still many difficulties in refractory epilepsy drug treatment. Therefore, the research of epilepsy nerve activity and kinetic characteristics of effective drug intervention have important theoretical and clinical value.In this paper, through the establishment of pilocarpine-induced acute and chronic rat model of epilepsy, we analyze epilepsy seizure process of spatiotemporal dynamics EEG changes and explore JuA on epilepsy neurons activities. The subject of our research is divided into two parts:1. We establish the model of pilocarpine-induced epileptiform discharges rats by intraperitoneal injection of pilocarpine under anesthesia, study the change of ECoG、EHG、FEP of hippocampus and JuA’s impact on them in this course. The results show: there are significant differences among them after seizures and the power spectrum of ECoG and EHG are inhibited (P<0.05). It has great influence on EPSP (P<0.05) of hippocampus field evoked potentials, not as on PS latency. However, the dose-dependent relationship remains to be further analyzed These results suggest that in the process of epileptiform discharges JuA has the effect of inhibition on EEG and FEP2. By establishing pilocarpine-induced status epilepticus (SE) model, we collected the data in one week and analyzed the temporal-partial synchronization features of the EEG signals from different brain areas using freely moving rats after status epilepticus by Hilbert transform. It was found that synchronization between the cortex and hippocampus was significantly strengthened (P <0.05) and reached a peak after 3 hours after status epilepticus (P<0.01), then began to decrease at 24 hours (P<0.05). Among different rhythms, the changes ofδrhythm were very similar to total frequency domain. The results suggested that the synchronization analysis based on Hilbert transform might be used to describe the dynamics process of synchronization, andδrhythm might play a major role in EEG synchronization of epileptic rats.更多还原