Cuesta Pablo, Ochoa-Urrea Manuela, Funke Michael, Hasan Omar, Zhu Ping, Marcos Alberto, López Maria Eugenia, Schulz Paul E, Lhatoo Samden, Pantazis Dimitrios, Mosher John C, Maestu Fernando
Department of Radiology, Rehabilitation and Physiotherapy, Complutense University of Madrid, Madrid, Spain.
Department of Neurology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, USA.
Brain Commun. 2022 Feb 3;4(2):fcac012. doi: 10.1093/braincomms/fcac012. eCollection 2022.
There is growing evidence for neuronal hyperexcitability in Alzheimer's disease. Hyperexcitability is associated with an increase in epileptiform activity and the disruption of inhibitory activity of interneurons. Interneurons fire at a high rate and are frequently associated with high-frequency oscillations in the gamma frequency band (30-150 Hz). It is unclear how hyperexcitability affects the organization of functional brain networks. A sample of 63 amnestic mild cognitive impairment patients underwent a magnetoencephalography resting-state recording with eyes closed. Twenty (31.75%) mild cognitive impairment patients had epileptiform activity. A cluster-based analysis of the magnetoencephalography functional connectivity revealed a region within the right temporal cortex whose global connectivity in the gamma frequency band was significantly reduced in patients with epileptiform activity relative to those without epileptiform activity. A subsequent seed-based analysis showed that this was largely due to weaker gamma band connectivity of this region with ipsilateral frontal and medial regions, and the upper precuneus area. In addition, this reduced functional connectivity was associated with higher grey matter atrophy across several cortical regions in the patients with epileptiform activity. These functional network disruptions and changes in brain physiology and morphology have important clinical implications as they may contribute to cognitive decline in mild cognitive impairment and Alzheimer's disease.
越来越多的证据表明，阿尔茨海默病存在神经元过度兴奋现象。过度兴奋与癫痫样活动增加以及中间神经元抑制活动的破坏有关。中间神经元高频放电，且经常与γ频段（30 - 150Hz）的高频振荡相关。目前尚不清楚过度兴奋如何影响功能性脑网络的组织。对63例遗忘型轻度认知障碍患者进行了闭眼静息态脑磁图记录。20例（31.75%）轻度认知障碍患者出现癫痫样活动。基于聚类的脑磁图功能连接分析显示，右侧颞叶皮质内有一个区域，相对于无癫痫样活动的患者，有癫痫样活动的患者在γ频段的全局连接性显著降低。随后基于种子点的分析表明，这主要是由于该区域与同侧额叶和内侧区域以及楔前叶上部区域的γ频段连接较弱。此外，这种功能连接性降低与有癫痫样活动患者多个皮质区域较高的灰质萎缩有关。这些功能网络破坏以及脑生理和形态学变化具有重要的临床意义，因为它们可能导致轻度认知障碍和阿尔茨海默病患者的认知衰退。
