The spiking component of oscillatory extracellular potentials in the rat hippocampus.
The spiking component of oscillatory extracellular potentials in the rat hippocampus.
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DOI：
10.1523/jneurosci.0656-12.2012
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发表时间：
2012-08-22
期刊：
影响因子：
--
通讯作者：
Koch C
中科院分区：
文献类型：
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作者：
Schomburg EW;Anastassiou CA;Buzsáki G;Koch C
当使用颅内电记录监测神经活动时，研究人员通常认为信号有两个主要组成部分：来自电极附近神经元的快速动作电位（AP）和较慢的局部场电位（LFP），后者被认为由整合的突触后电流主导。更大体积的组织。通常，对于大多数脑节律，观察到信号功率随着频率增加而降低。大鼠海马中的100-200 Hz振荡，包括“快速伽马”或“快速伽马”振荡和尖波波纹（SPW-R），是一个例外，其显示在该频带内功率随频率增加。我们采用了详细的生物物理模型，研究在大鼠CA 1快速振荡的细胞外电位的组成。我们发现，突触后电流表现出降低的能力，产生大幅度的振荡信号在高频率，而相位调制尖峰显示相反的趋势。我们的估计表明，AP和突触后电流贡献了140-200 Hz波纹中包含的功率的相似比例，并且两者结合产生了与体内SPW-R非常相似的信号。AP产生的信号大部分来自距离记录点超过100 μm的神经元，无论它们是否包含可识别的AP，波纹都表现出类似的强度。此外，AP可以在90-150 Hz的窄带中从有节奏地放电的锥体神经元产生大量的功率。因此，高频LFP通常可以包含局部细胞组装激活的特征。
When monitoring neural activity using intracranial electrical recordings, researchers typically consider the signals to have two primary components: fast action potentials (AP) from neurons near the electrode, and the slower local field potential (LFP), thought to be dominated by postsynaptic currents integrated over a larger volume of tissue. In general, a decrease in signal power with increasing frequency is observed for most brain rhythms. 100–200 Hz oscillations in the rat hippocampus, including ‘fast gamma’ or ‘epsilon’ oscillations and sharp wave-ripples (SPW-R), are one exception, showing an increase in power with frequency within this band. We have employed detailed biophysical modeling to investigate the composition of extracellular potentials during fast oscillations in rat CA1. We find that postsynaptic currents exhibit a decreasing ability to generate large amplitude oscillatory signals at high frequencies, whereas phase-modulated spiking shows the opposite trend. Our estimates indicate that APs and postsynaptic currents contribute similar proportions of the power contained in 140–200 Hz ripples, and the two combined generate a signal that closely resembles in vivo SPW-Rs. Much of the AP-generated signal originates from neurons further than 100 μm from the recording site, consistent with ripples appearing similarly strong regardless of whether or not they contain recognizable APs. Additionally, substantial power can be generated in the 90–150 Hz epsilon band by the APs from rhythmically firing pyramidal neurons. Thus, high frequency LFPs may generally contain signatures of local cell assembly activation.