微观和宏观尺度下海马体癫痫发作期间的细胞类型特异性网络。

Cell-type-specific networks during hippocampal seizures at the micro- and macroscale.

作者信息

Wang Jiaoyang, Yan Jiaqing, Li Donghong, He Shipei, Li Xiaonan, Xing Yue, Lai Huanling, Gui Yue, Zhang Nannan, Huang Wenyao, Yang Xiaofeng

机构信息

Department of Neurology, The First Affiliated Hospital, Guangzhou Medical University, Guangzhou 510120, China.

Guangzhou National Laboratory, Guangzhou 510005, China.

出版信息

Brain. 2025 Jan 23. doi: 10.1093/brain/awaf024.

Abstract

Epilepsy is a network disorder, involving neural circuits at both the micro- and macroscale. While local excitatory-inhibitory imbalances are recognized as a hallmark at the microscale, the dynamic role of distinct neuron types during seizures remain poorly understood. At the macroscale, interactions between key nodes within the epileptic network, such as the central median thalamic nucleus (CMT), are critical to the, hippocampal epileptic process. However, precise mechanisms underlying these interactions remain unclear. In this study, we investigated the microcircuit dynamics within the seizure onset zone and secondary spreading regions, as well as the network connectivity between the hippocampus and the CMT, using a 4-aminopyridine (4-AP) induced hippocampal seizure model. Rats were allocated into three experimental groups. The first group used a 3D tetrode array to monitor hippocampal seizure activity and microcircuit dynamics, including seizure propagation across the macroscale network. In the second group, a chemical lesion was induced in the CMT to assess its impact on hippocampal seizures. In the third group, chemogenetic techniques were used to selectively suppress pyramidal neurons in the CMT and observe changes in neural network connectivity between the CMT and hippocampus during seizures. Offline single-unit sorting was performed using KlustaKwik and further analysis was conducted with CellExplorer. At seizure onset, the narrow interneurons exhibited increased firing rates, initiating recruitment of other neurons, followed by increased activity in pyramidal neuron. Wide interneurons also showed heightened activity subsequent to pyramidal neurons. Interneurons played a more prominent role in the microcircuit during seizures compared to baseline. The CMT exhibited characteristic seizure activity and a decrease in narrow interneuron activity, whereas the cortex did not display seizure activity during hippocampal seizures. Lesioning the CMT resulted in the loss of the tonic component of hippocampal seizures and reduced overall neuronal activity in the hippocampal. Selective suppression of CMT pyramidal neurons resulted in shortened hippocampal seizures while preserving the tonic component. Narrow interneuron activity remained unchanged, while pyramidal neuron and wide interneuron activity significantly decreased. Our findings underscore the critical role of interneurons in the micronetwork of the seizure onset zone and secondary spreading region. Narrow interneurons were particularly vital in seizure initiation, whereas wide interneurons may contribute to seizure termination within the onset zone but not in the secondary spreading region. Pyramidal neurons in the CMT influence hippocampal seizures by modulating of both hippocampal pyramidal neurons and wide interneurons.

摘要

癫痫是一种网络疾病,涉及微观和宏观尺度的神经回路。虽然局部兴奋-抑制失衡被认为是微观尺度的一个标志,但不同神经元类型在癫痫发作期间的动态作用仍知之甚少。在宏观尺度上,癫痫网络内关键节点之间的相互作用,如中央中丘脑核(CMT),对海马癫痫过程至关重要。然而,这些相互作用背后的确切机制仍不清楚。在本研究中,我们使用4-氨基吡啶(4-AP)诱导的海马癫痫模型,研究了癫痫发作起始区和继发扩散区域内的微电路动力学,以及海马与CMT之间的网络连接性。将大鼠分为三个实验组。第一组使用3D四极管阵列监测海马癫痫活动和微电路动力学,包括癫痫在宏观网络中的传播。第二组在CMT中诱导化学损伤,以评估其对海马癫痫的影响。第三组使用化学遗传学技术选择性抑制CMT中的锥体神经元,并观察癫痫发作期间CMT与海马之间神经网络连接性的变化。使用KlustaKwik进行离线单单元分类,并使用CellExplorer进行进一步分析。在癫痫发作开始时,窄型中间神经元的放电率增加,开始募集其他神经元,随后锥体神经元的活动增加。宽型中间神经元在锥体神经元之后也表现出活动增强。与基线相比,中间神经元在癫痫发作期间的微电路中发挥了更突出的作用。CMT表现出特征性的癫痫活动,窄型中间神经元活动减少,而在海马癫痫发作期间皮质未显示癫痫活动。损伤CMT导致海马癫痫发作的强直成分丧失,并降低海马中的整体神经元活动。选择性抑制CMT锥体神经元导致海马癫痫发作缩短,同时保留强直成分。窄型中间神经元活动保持不变,而锥体神经元和宽型中间神经元活动显著降低。我们的研究结果强调了中间神经元在癫痫发作起始区和继发扩散区域的微网络中的关键作用。窄型中间神经元在癫痫发作起始中尤为重要,而宽型中间神经元可能有助于癫痫发作起始区内的发作终止,但在继发扩散区域则不然。CMT中的锥体神经元通过调节海马锥体神经元和宽型中间神经元来影响海马癫痫发作。

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