TRACING SEIZURE PATHWAYS USING QUANTITATIVE EEG

皮层下元素的场电位以及皮层脑电图通过将神经活动定位到特定的丘脑核，为研究癫痫提供了强有力的工具。对这些记录进行新颖的定量分析的初步数据提供了有价值的信息，说明在癫痫发作期间，完整的大脑中单个皮质下中心的选择性参与。一个原始的和令人兴奋的结果是，前丘脑（An）属于哺乳丘脑束（MTT）是戊四唑（PTZ）诱发癫痫发作时电活动传播的关键门户。在MTT的药理学和电刺激研究结合的实验中，我们希望在一个重要的神经学领域推进我们的理解。我们建议：1)利用部分相干分析及其统计方法，验证AN皮层下电活动与皮层的关联程度高于与MTT无关的丘脑中心的假设。我们将扩展我们的研究，包括使用双谱和交叉双谱对CTX-AN连接的非线性贡献。使用原始的时间延迟估计方法，我们将显示癫痫发作从中脑中心传播到皮层。我们还将记录沿着MTT前进的扣押的确切延迟时间。2)确定一种已知的化学抗惊厥药乙thosuximide （ESM）对PTZ发作期间皮层和皮层下中枢之间的脑电图反应的影响。我们将展示如何通过ESM的应用改变特定皮层下区域的皮层下电参与水平和传播延迟。3)验证电刺激a激活MTT沿线区域的假设。利用放射自显影术，我们将研究高频电刺激对癫痫发作活动的抑制作用。我们还将展示ESM在低频电刺激AN时阻断癫痫发作表达。总体目标是更好地了解全身性癫痫在其主要激活区的功能解剖和机制，并帮助发现有效的抗惊厥治疗方法。

The field potentials of subcortical elements as well as the cortical EEG provide powerful tools for the study of epilepsy by enabling localization of neural activity to a specific thalamic nucleus. Preliminary data from novel, quantitative analysis of these recordings provide valuable information about the selective involvement of individual subcortical centers in the intact brain during seizure episodes. An original and exciting result has been that the anterior thalamus (AN) belonging to the mammillothalamic tract (MTT) is a critical gateway in the propagation of electrical activity during pentylenetetrazol (PTZ)- induced seizure episodes. in experiments coupling pharmacological and electrical stimulation studies of the MTT, we hope to advance our understanding in an important neurological area. We propose: 1) To test the hypothesis that the subcortical electrical activity from AN shows a higher level of association with cortex than a thalamic center unaffiliated with the MTT using the method of partial coherence analysis and its statistics. We will expand our studies to include the non linear contributions to the CTX-AN connection using the bispectrum and cross-bispectrum. Using original methods of time delay estimation, we will show that the seizure travels from the midbrain centers to cortex. We will also document the exact delay times of the advancing seizure along the MTT. 2) TO identify the effects of a known chemical anticonvulsant, ethosuximide (ESM), on EEG responses during PTZ seizures between cortex and subcortical centers. We will show how the level of subcortical electrical involvement and propagation delays are altered in specific subcortical areas with the application of ESM. 3) To test the hypothesis that electrical stimulation of AN activate's areas along the MTT. Using autoradiography we will investigate the inhibition of seizure activity produced by high frequency electrical stimulation. We will also show that ESM blocks seizure expression during low frequency electrical stimulation of AN. The overall goal is to obtain a better understanding of the functional anatomy and mechanisms underlying generalized epilepsy in its principal activation zones and to help discover effective anticonvulsant treatments for its remedy.