Temporal lobe epilepsy alters spatio-temporal dynamics of the hippocampal functional network
Temporal lobe epilepsy alters spatio-temporal dynamics of the hippocampal functional network
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DOI：
10.1016/j.nicl.2020.102254
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发表时间：
2020-01-01
影响因子：
4.2
通讯作者：
Rogers, Baxter P.
中科院分区：
文献类型：
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作者：
Morgan, Victoria L.;Chang, Catie;Rogers, Baxter P.
内侧颞叶癫痫(TLE)的特征是起源于海马区的一过性异常电活动。本研究的目的是利用3T磁共振成像技术对41例单侧MTLE患者(28例右侧，13例左侧)和56例健康对照组进行功能连接性(FC)标测，研究MTLE患者海马区网络连接性的动态时空波动。在整个扫描过程中，使用滑动60-S窗口计算动态FC。这与使用整个10分钟功能MRI扫描计算的静态FC以及海马区功能MRI信号的变化进行了比较。四种状态的健康海马区动态FC被识别，并与TLE患者进行比较。TLE患者在这四种状态之间波动，但与癫痫灶同侧的海马体在以较低的前额叶和顶叶FC为特征的状态下比主要的健康状态花费更多的时间。处于这种状态的时间增加与静态功能障碍增加和海马区功能MRI信号变化增加有关。总体而言，这项工作提供的证据表明，MTLE患者海马区癫痫灶信号波动的方差增加可能导致fMRI扫描中健康FC网络动力学的中断，从而导致静态海马FC的减少。这些改变导致TLE患者双侧前额区和顶区的海马区连通性降低，这可能与这些患者的行为和认知障碍有关。因此，表征单个患者在不同时间尺度上的海马区动力学特征可能提供更具体的网络损害的时空轮廓，这可能与TLE的海马区功能障碍有关。
Mesial temporal lobe epilepsy (TLE) is characterized by transient abnormal electrical activity originating in the hippocampus. The objective of this study was to characterize dynamic spatio-temporal fluctuations in hippocampal network connectivity in mTLE using functional connectivity (FC) mapping in 41 unilateral mTLE patients (28 right, 13 left) and 56 healthy control participants using 3T MRI. Dynamic FC was computed across the scan using sliding 60-s windows. This was compared to static FC computed using the whole 10-min functional MRI scan, and to the variance in the hippocampal functional MRI signal. Four states of healthy hippocampal dynamic FC were identified and compared to TLE patients. TLE patients fluctuated between these four states, but the hippocampus ipsilateral to the seizure focus spent more time in a state distinguished by lower prefrontal and parietal FC than the dominant healthy state. Increased time spent in this state was associated with increased impairment in static FC and increased variance in the hippocampal functional MRI signal. Overall, this work provides evidence that increases in variance in signal fluctuations occurring at the seizure focus in the hippocampus in patients with mTLE may contribute to disruptions in healthy FC network dynamics within an fMRI scan that contribute to decreases in static hippocampal FC. These alterations result in decreased hippocampal connectivity to bilateral prefrontal and parietal regions in TLE which may be related to behavior and cognitive impairments in these patients. Therefore, characterization of an individual patient's hippocampal dynamics at different time scales may provide more specific spatio-temporal profiles of network impairment that may be related to hippocampal dysfunction in TLE.