Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, Texas, U.S.A; Yale University School of Medicine, New Haven, Connecticut, U.S.A.
Epilepsia. 2014 Jun;55(6):e50-5. doi: 10.1111/epi.12637. Epub 2014 May 6.
The thalamus has been implicated in various stages of medial temporal lobe epilepsy (MTLE) seizure evolution. The relative density and functional significance (in epileptogenesis) of thalamic projections to MTL subregions, however, remains to be determined. This study used structural and diffusion magnetic resonance imaging (MRI) to evaluate thalamic connection density with distinct MTL subregions in terms of location and volume. Nineteen MTLE patients with unilateral hippocampal sclerosis (HS; 12 right; 10 female) were compared to 19 age-matched controls. Five regions of interest (ROIs) per hemisphere were created in native space: thalamus, amygdala, entorhinal cortex, hippocampus, and parahippocampus. Separate probabilistic tractography analyses were performed between the thalamus and each ipsilateral MTL subregion (four per hemisphere). Individual connectivity profiles and regional volumes were assessed. The medial pulvinar consistently showed the highest connection density with the hippocampus in healthy controls and in MTLE patients. Decreased thalamic connected volume was observed for thalamohippocampal pathways in patients with MTLE, and indicates pathway-specific deafferentation. Regional hippocampal and thalamic atrophy was also observed, indicating gray and white matter loss in the thalamohippocampal pathway. Consistent localization of dense medial pulvinar (PuM) connectivity with the hippocampus suggests chronic PuM stimulation could modulate the MTLE seizure network. Decreased thalamic connected volume is a promising biomarker for epileptogenesis that merits longitudinal validation. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.
丘脑参与了内侧颞叶癫痫（MTLE）发作演变的各个阶段。然而，丘脑向 MTL 亚区的投射的相对密度和功能意义（在癫痫发生中）仍有待确定。本研究使用结构和弥散磁共振成像（MRI），根据位置和体积，评估了丘脑与不同 MTL 亚区的连接密度。19 例单侧海马硬化（HS）的 MTLE 患者（12 例右侧；10 例女性）与 19 名年龄匹配的对照者进行了比较。在原始空间中创建了每个半球的 5 个感兴趣区（ROI）：丘脑、杏仁核、内嗅皮层、海马体和海马旁回。在每个对侧 MTL 亚区（每个半球 4 个）之间进行了单独的概率追踪分析。评估了个体连接图谱和区域体积。在健康对照者和 MTLE 患者中，内侧丘系的内髓板始终与海马体表现出最高的连接密度。MTLE 患者的丘脑-海马体通路的连接体积减小，表明存在特定于通路的去传入。还观察到局部海马体和丘脑萎缩，表明在丘脑-海马体通路上存在灰质和白质损失。内侧丘系（PuM）与海马体之间存在高密度连接的一致定位表明，慢性 PuM 刺激可能调节 MTLE 发作网络。连接体积减小是癫痫发生的一个很有前途的生物标志物，值得进行纵向验证。本文的幻灯片摘要可在此处的支持信息部分下载。
