FUNCTIONAL MRI OF MEMORY IN TEMPORAL LOBE EPILEPSY

本研究项目将应用功能磁共振成像（fMRI）这一新兴技术来解决中颞叶癫痫（MTLE）患者面临的临床问题和提出的理论问题。越来越多的证据表明，内侧颞叶（MTL）是物质特异性的；显性MTL专门用于言语记忆，非显性MTL专门用于视觉空间记忆。MTLE患者经常表现出与癫痫灶偏侧相关的细微的内容特异性记忆缺陷，但通常保持良好的整体记忆功能。这表明内侧颞叶硬化患者将正常侧化的记忆功能重组到对侧颞叶颞叶。本研究将验证以下假设：(1)当记忆系统参与特定内容的任务时，可能在正常人中看到离散的、偏侧特异性的左右颞叶颞叶皮层激活；(2)颞叶癫痫患者根据其致痫灶的位置对颞叶记忆激活区域进行了特殊的重组。为了验证这些假设，我们将开发语言和非语言任务，这些任务能够选择性地激活健康志愿者的显性或非显性MTL。这些范例随后将适用于癫痫患者，他们将在执行特定记忆处理任务时进行成像。将对颞叶切除术前后的患者进行研究，并将其与基线记忆缺陷、颈动脉内淀粉样蛋白测试和术后结果进行相关性研究。功能重组将被定义为偏离法线所观察到的预期侧性。这项工作的成功完成将达到双重目标，即在fmri的新领域培养候选人-这是她研究技能的重要新维度-并进一步了解MTLE患者的神经心理变化。

This research project will apply the emerging technology of functional magnetic resonance imaging (fMRI) to clinical problems faced by, and theoretical questions raised in, patients with mesial temporal lobe epilepsy (MTLE). Converging lines of evidence suggest that the mesial temporal lobe (MTL) is material specific; the dominant MTL is specialized for verbal memory and the non-dominant MTL is specialized for visuo-spatial memory. Patients with MTLE frequently exhibit subtle content-specific memory deficits related to the laterality of the epileptogenic focus, but generally maintain good overall memory function. This implies that patients with mesial temporal sclerosis reorganize normally lateralized memory functions to the contralateral MTL. This study will test the hypotheses that: (1) discrete, laterality-specific, activation of the left and right MTL may be seen in normals when engaging memory systems with content- specific tasks and (2) patients with temporal lobe epilepsy have particular reorganization of memory-activated regions of the temporal lobe based on the location of their epileptogenic foci. To test the hypotheses, we will develop verbal and non-verbal tasks that are able to selectively activate the dominant or non- dominant MTL in healthy volunteers. These paradigms will then be adapted for use in epilepsy patients who will be imaged as they perform the specific memory processing tasks. Patients will be studied both before and after temporal lobectomy, and correlation will be made to baseline memory deficits, intracarotid amytal testing, and post-operative outcome. Functional reorganization will be defined as a deviation from the expected laterality as observed in normals. The successful completion of this work will accomplish the dual goals of training the candidate in the new area of fMRI-an important new dimension to her research skills-and of furthering understanding of neuropsychological changes patients with MTLE.