Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, UK.
MRI Unit, Epilepsy Society, Buckinghamshire, UK.
Epilepsia. 2022 Oct;63(10):2597-2622. doi: 10.1111/epi.17370. Epub 2022 Aug 2.
Temporal lobe epilepsy (TLE) affects brain networks and is associated with impairment of episodic memory. Temporal and extratemporal reorganization of memory functions is described in functional magnetic resonance imaging (fMRI) studies. Functional reorganizations have been shown at the local activation level, but network-level alterations have been underinvestigated. We aim to investigate the functional anatomy of memory networks using memory fMRI and determine how this relates to memory function in TLE.
Ninety patients with unilateral TLE (43 left) and 29 controls performed a memory-encoding fMRI paradigm of faces and words with subsequent out-of-scanner recognition test. Subsequent memory event-related contrasts of words and faces remembered were generated. Psychophysiological interaction analysis investigated task-associated changes in functional connectivity seeding from the mesial temporal lobes (MTLs). Correlations between changes in functional connectivity and clinical memory scores, epilepsy duration, age at epilepsy onset, and seizure frequency were investigated, and between connectivity supportive of better memory and disease burden. Connectivity differences between controls and TLE, and between TLE with and without hippocampal sclerosis, were explored using these confounds as regressors of no interest.
Compared to controls, TLE patients showed widespread decreased connectivity between bilateral MTLs and frontal lobes, and increased local connectivity between the anterior MTLs bilaterally. Increased intrinsic connectivity within the bilateral MTLs correlated with better out-of-scanner memory performance in both left and right TLE. Longer epilepsy duration and higher seizure frequency were associated with decreased connectivity between bilateral MTLs and left/right orbitofrontal cortex (OFC) and insula, connections supportive of memory functions. TLE due to hippocampal sclerosis was associated with greater connectivity disruption within the MTL and extratemporally.
Connectivity analyses showed that TLE is associated with temporal and extratemporal memory network reorganization. Increased bilateral functional connectivity within the MTL and connectivity to OFC and insula are efficient, and are disrupted by greater disease burden.
颞叶癫痫（TLE）影响脑网络，并与情景记忆损伤有关。功能磁共振成像（fMRI）研究描述了颞叶和颞外记忆功能的重组。已经在局部激活水平上显示了功能重组，但网络水平的改变尚未得到充分研究。我们旨在使用记忆 fMRI 研究记忆网络的功能解剖结构，并确定其与 TLE 中的记忆功能的关系。
90 名单侧 TLE 患者（43 名左侧）和 29 名对照者进行了面孔和单词的记忆 fMRI 编码范式，并随后进行了扫描仪外识别测试。生成了单词和面孔记忆的后续记忆事件相关对比。使用内侧颞叶（MTL）的功能连接种子进行心理生理相互作用分析，以研究任务相关的功能连接变化。研究了功能连接变化与临床记忆评分、癫痫持续时间、癫痫发病年龄和发作频率之间的相关性，以及与更好记忆和疾病负担相关的功能连接变化。使用这些混杂因素作为无兴趣回归，探索了 TLE 与对照组之间以及 TLE 伴和不伴海马硬化之间的连接差异。
与对照组相比，TLE 患者双侧 MTL 与额叶之间的连接普遍减少，双侧前 MTL 之间的局部连接增加。双侧 MTL 内的内在连接与左右 TLE 患者的扫描仪外记忆表现更好相关。癫痫持续时间较长和发作频率较高与双侧 MTL 与左/右眶额皮质（OFC）和岛叶之间的连接减少相关，这些连接支持记忆功能。由海马硬化引起的 TLE 与 MTL 内和颞外的连接中断更大有关。
连接分析表明，TLE 与颞叶和颞外记忆网络重组有关。双侧 MTL 内的功能连接增加以及与 OFC 和岛叶的连接增加是有效的，并且会因疾病负担增加而受到干扰。
