Nalecz Institute of Biocybernetics and Biomedical Engineering PAS, Warsaw, Poland.
Neurology Department of The Military Institute of Aviation Medicine, Warsaw, Poland.
Neurol Neurochir Pol. 2024;58(5):531-537. doi: 10.5603/pjnns.99567. Epub 2024 Sep 3.
Epilepsy is a disease characterized by abnormal paroxysmal bioelectrical activity in the brain cortex and subcortical structures. Seizures per se change brain metabolism in epileptic focus and in distal parts of the brain. However, interictal phenomena can also affect functional connectivity (FC) and brain metabolism in other parts of the brain.
We hypothesised that epilepsy affects functional connectivity not only among cortical, but also between subcortical, structures of the brain in a resting state condition.
Investigating functional connectivity in patients with epilepsy could provide insights into the underlying pathophysiological mechanisms. Better understanding may lead to more effective treatment strategies.
Functional connectivity was analysed in 35 patients with epilepsy and in 28 healthy volunteers. The group of patients was divided into generalised and focal epilepsy (temporal and extratemporal subgroups). Each patient and healthy volunteer underwent an fMRI resting-state session. During the study, EEG signals were simultaneously recorded with fMRI to facilitate the subsequent detection of potential interictal epileptiform discharges (IEDs). Their potential impact on BOLD signals was mitigated through linear regression. The data was processed and correlation coefficients (FC values) between the BOLD signal from selected structures of the central nervous system were determined and compared between study groups. The results were presented as significant differences in correlation coefficients between brain/subcortical structures in the epilepsy and control groups.
Lower FC values for the epilepsy group compared to the control group were shown for connections related to the MPFC, hippocampus, thalamus, amygdala, and the parahippocampal gyrus.
Epilepsy alters the functional connectivity of resting state subcortical networks. Patterns of pathological changes of FC differ between epilepsy subtypes, with predominant lower FC between the hippocampus, parahippocampal gyrus, amygdala and thalamus in patients with epilepsy.
This study suggests that epilepsy affects subcortical structures. Identifying distinct patterns of altered FC in epilepsy subtypes may help to tailor treatment strategies. Changes in FC detected by fMRI may precede clinical symptoms, aiding in the early diagnosis of cognitive and emotional disorders in focal epilepsy.
癫痫是一种以大脑皮层和皮层下结构异常阵发性生物电活动为特征的疾病。癫痫发作本身会改变癫痫灶和大脑其他部位的脑代谢。然而，发作间期现象也会影响大脑其他部位的功能连接（FC）和脑代谢。
我们假设癫痫不仅影响皮质结构之间，而且影响静息状态下大脑皮质下结构之间的功能连接。
研究癫痫患者的功能连接可以深入了解潜在的病理生理机制。更好的理解可能会导致更有效的治疗策略。
对 35 名癫痫患者和 28 名健康志愿者进行了功能连接分析。患者组分为全面性和局灶性癫痫（颞叶和颞外亚组）。每位患者和健康志愿者都接受了 fMRI 静息状态检查。在研究过程中，同时记录脑电图信号与 fMRI 以促进随后检测潜在的发作间期癫痫样放电（IEDs）。通过线性回归减轻其对 BOLD 信号的潜在影响。对数据进行处理，并确定所选中枢神经系统结构之间的 BOLD 信号的相关系数（FC 值），并在研究组之间进行比较。结果表示为癫痫组和对照组之间脑/皮质下结构之间相关系数的显著差异。
与对照组相比，癫痫组的 FC 值较低，与 MPFC、海马体、丘脑、杏仁核和海马旁回有关。
癫痫改变了静息状态下皮质下网络的功能连接。FC 病理性变化的模式在癫痫亚型之间有所不同，癫痫患者的海马体、海马旁回、杏仁核和丘脑之间的 FC 较低。
本研究表明癫痫会影响皮质下结构。识别癫痫亚型中改变的 FC 的独特模式可能有助于制定治疗策略。通过 fMRI 检测到的 FC 变化可能先于临床症状出现，有助于在局灶性癫痫中早期诊断认知和情感障碍。
