电刺激大鼠尾壳核诱导丘脑外侧背核神经元出现与海马电图变化相关的特征性放电脉冲间隔(英文)

Characteristic neuronal firing interspike intervals in laterodorsal thalamic nuclei induced by tetanization of rat caudate putamen:possible relations to hippocampal electroencephalogram changes

本文旨在探讨电刺激右侧尾壳核(caudate putamen nucleus,CPu)对双侧丘脑外侧背核(laterodorsal thalamic nucleus,LD)单个 神经元放电和海马(hippocampus,HPC)电图瞬时时间编码形式的调制性影响。用21只雄性Sprague-Dawley大鼠(150-250 g),重 复急性强直电刺激(60Hz,2s,0．4-0．6mA)右侧尾壳核(acute tetanization of the right caudate putamen nucleus,ATRC)诱发大鼠癫痫模 型,4通道同步记录双侧LD神经元单位放电和双侧HPC深部电图。结果如下:重复施加ATRC可以诱导大鼠出现(1)双侧 LD-HPC癫痫电网络间的功能性环状联系。起始点为对侧LD神经元原发性单位后放电,随后出现同侧LD神经元原发性单位 后放电,然后呈现同侧HPC电图原发性后放电,最终引起对侧HPC电图脱同步化效应;(2)双侧LD神经元放电脉冲间隔 (interspike intervals,ISIs)散点分布形式与刺激前呈现镜像对称特征。对侧LD神经元原发性后放电的ISI点分布基于底层而且持 续时间较长,具有更加明显的突触可塑性特征:(3)随着ATRC串次的增加,对侧LD神经元原发性单位后放电间的爆发式放 电时程逐渐延长、可以募集增强海马电图同步化电活动;显现对侧LD神经元单个放电脉冲与HPC电γ电振荡(20-25 Hz)间 的锁相(phase—lock)和锁时(time-lock)关系。结果提示:ATRC町以募集形成具有联系的双侧LD神经元放电和HPC电图特征性 的神经信息编码形式,以对侧更加明显。这些跨越大脑半球、涉及多结构的功能性神经信息网络的建立很可能是癫痫发生、 发展和扩布的重要信息编码机制。

The purpose of the present work was to study the effect of acute tetanization of the right caudate putamen nucleus （ATRC） on single neuronal interspike intervals （ISIs） in both laterodorsal thalamic nuclei （LDi）, and electroencephalogram （EEG） wave interpeak intervals （IPIs） in both hippocampi （HPCi）. Experiments were performed on 21 male Sprague-Dawley rats weighing 150-250g. The seizures were induced by the ATRC （60 Hz, 2 s, 0.4-0.6 mA）. Quadruple recordings were simultaneously carried out： two for single unit recordings from both LDi, and two for EEG recordings from both HPCi. The ATRC induced： （1） An interactive epileptic electrical network reconstructed in bilateral HPCi, which was driven by primary afterdischarges of single LD neuron. （2） A symmetric mirror-like ISI spot distribution of the LD neuronal firing before and after tetanus. （3） Gradually prolonged LD neuronal discharge intermittence was coherent with synchronous hippocampal EEG activities on the contralateral side. （4） Single LD neuronal spikes were phase-and time-locked to 20-25 Hz gamma oscillations in contralateral HPC. It suggests a particular temporal code patterning of single LD neuronal firing and its relationships to hippocampal EEG wave code in time series, the latter implies the LD neuronal encoding mechanisms of ATRC-induced epileptic electrical network in bilateral HPCi.