Krembil Neuroscience Center & Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada.
Epilepsia. 2013 May;54(5):809-18. doi: 10.1111/epi.12098. Epub 2013 Jan 29.
The clinical relevance of resting state functional connectivity in neurologic disorders, including mesial temporal lobe epilepsy (mTLE), remains unclear. This study investigated how connectivity in the default mode network changes with unilateral damage to one of its nodes, the hippocampus (HC), and how such connectivity can be exploited clinically to characterize memory deficits and indicate postsurgical memory change.
Functional magnetic resonance imaging (fMRI) resting state scans and neuropsychological memory assessments (Warrington Recognition Tests for Words and Faces) were performed on 19 healthy controls, 20 patients with right mTLE, and 18 patients with left mTLE. In addition, postsurgical fMRI resting state and memory change (postsurgical memory performance-presurgical memory performance) data were available for half of these patients.
Patients with mTLE showed reduced connectivity from the posterior cingulate cortex (PCC) to the epileptogenic HC and increased PCC connectivity to the contralateral HC. Stronger PCC connectivity to the epileptogenic HC was associated with better presurgical memory and with greater postsurgical memory decline. Stronger PCC connectivity to the contralateral HC was associated with less postsurgical memory decline. Following surgery, PCC connectivity to the remaining HC increased from presurgical values and showed enhanced correlation with postsurgical memory function. It is notable that this index was superior to others (hippocampal volume, preoperative memory scores) in explaining variance in memory change following surgery.
Our results demonstrate the striking clinical significance of the brain's intrinsic connectivity in evaluating cognitive capacity and indicating the potential of postsurgical cognitive morbidity in patients with mTLE.
静息态功能连接在神经疾病中的临床相关性尚不清楚，包括内侧颞叶癫痫（mTLE）。本研究旨在探讨默认模式网络中连接的变化如何随着其节点之一海马（HC）的单侧损伤而改变，以及这种连接如何在临床上被利用来描述记忆缺陷，并指示术后记忆变化。
对 19 名健康对照者、20 名右侧 mTLE 患者和 18 名左侧 mTLE 患者进行功能磁共振成像（fMRI）静息态扫描和神经心理学记忆评估（沃灵顿识别测试单词和面孔）。此外，这些患者中的一半还提供了术后 fMRI 静息态和记忆变化（术后记忆表现-术前记忆表现）的数据。
mTLE 患者表现出从后扣带回皮质（PCC）到致痫性 HC 的连接减少，以及 PCC 到对侧 HC 的连接增加。PCC 与致痫性 HC 的连接越强，术前记忆越好，术后记忆下降越大。PCC 与对侧 HC 的连接越强，术后记忆下降越少。手术后，PCC 与剩余 HC 的连接从术前值增加，并与术后记忆功能的相关性增强。值得注意的是，该指标在解释 mTLE 患者手术后记忆变化的方差方面优于其他指标（海马体积、术前记忆评分）。
我们的结果表明，大脑内在连接在评估认知能力和指示 mTLE 患者术后认知发病率方面具有显著的临床意义。
