NON-LINEAR FEEDBACK MODEL OF NEURONAL POPULATIONS IN HIPPOCAMPAL CA1 REGION
NON-LINEAR FEEDBACK MODEL OF NEURONAL POPULATIONS IN HIPPOCAMPAL CA1 REGION
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DOI：
10.1152/jn.1982.47.5.845
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发表时间：
1982-01-01
影响因子：
2.5
通讯作者：
LEUNG, LWS
中科院分区：
文献类型：
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作者：
LEUNG, LWS
1. 提出了海马CAl区域局部相互作用的集总电路模型。每个神经元群在拉普拉斯域中用线性微分方程或线性传递函数表示。神经元群之间的相互作用由增益因子表示。抑制性中间神经元对锥体细胞的反复抑制是重要的相互作用，表现为不对称的双向饱和增益曲线。模型的输入是锥体细胞的正角或反角输入和脑干的强直输入。输出是锥体细胞和中间神经元的反应。2. 该模型通过海马细胞内和细胞外记录的数据进行评估。细胞外记录包括平均诱发电位（AEPs）、单一刺激后时间直方图（pths）和自发性脑电图（EEG）。由于海马的规则结构，预计细胞外电位与局部神经元群的平均细胞内电位相对应。3. 在深度麻醉下，所有由电击引起的海马传入神经反应都以锥体细胞的长时间抑制而结束。该模型进一步预测了抑制持续时间随刺激强度的增加而增加，并得到了实验验证。4. 在清醒的大鼠中，特别是在伴有海马theta节律的行为（如行走）时，CAl区域传入输入刺激引起的aep以20-50周期/s的频率振荡。在该模型中，假设来自脑干的兴奋性偏压使局部电路线性化，导致与实验结果相似的振荡反应。5. 波谱分析发现，在大鼠的不同行为过程中，40 ~ 70 Hz海马脑电图的功率和共振都发生了变化。除了theta节律外，在给定高斯白噪声输入的情况下，对模型输出的分析显示出与活体脑电图相似的功率谱。在某些行为（如行走）中，40-70 Hz EEG功率的增加是通过假设脑干调制偏置使局部CAl电路线性化来重现的。后一种情况是产生振荡性aep和高频脑电图的基础。6. 当反复的兴奋-抑制反馈非常大时，模型产生的极限循环为50-65 cycles/s。极限环被认为是一种特殊类型的高频（50-65周期/秒）海马后放电的原因，这种放电发生在输入通路的破伤风后。模型的幅值、频率、波形与实验数据相似。7. 综上所述，海马体的非线性循环兴奋-抑制反馈模型解释并整合了各种现有的实验数据。该模型进一步预测了可以通过实验验证的结果。
1. A lumped-circuit model is proposed for the local interactions within the hippocampal CAl region. Each neuronal population is represented by a linear differential equation or a linear transfer function in the Laplace domain. Interactions between neuronal populations are represented by gain factors. Recurrent inhibition of pyramidal cells by the inhibitory interneurons is the important interaction represented by an asymmetric, bidirectionally saturating gain curve. The inputs to the model are orthodromic or antidromic inputs to the pyramidal cells and a tonic input from the brain stem. The outputs are the response ot pyramidal cells and interneurons. 2. The model is evaluated by data of intracellular and extracellular recordings from the hippocampus. Extracellular recordings consist of the average evoked potentials (AEPs), unitary poststimulus time histograms (PSTHs), and the spontaneous electroencephalogram (EEG). On account of the regular structure of the hippocampus, extracellular potentials are expected to correspond to the average intracellular potential among a local neuronal population. 3. Under deep anesthesia, all neuronal responses evoked by an electrical shock to the hippocampal afferents end in a prolonged inhibition of pyramidal cells. The model further predicts that the duration of inhibition increases with stimulus intensity, which is verified experimentally. 4. In the awake rat, especially during behaviors accompanied by a hippocampal theta rhythm (e.g., walking), the AEPs evoked by stimulation of afferent input to the CAl region were oscillatory with a frequency of 20-50 cycles/s. In the model an excitatory bias from the brain stem is assumed to linearize the local circuits, resulting in oscillatory responses similar to those obtained experimentally. 5. As observed by spectral analysis, the hippocampal EEG of the frequency 40-70 Hz varied in power and resonance during various behaviors of the rat. Except for the theta rhythm, analysis of the output(s) of the model given a Gaussian white-noise input showed similar power spectra as the EEG in vivo. The increase in power of the 40-70 Hz EEG in some behaviors, e.g., walking, is reproduced by assuming that during such behaviors a modulating bias from the brain stem linearizes the local CAl circuits. This latter circumstances underlies the generation of oscillatory AEPs and the high-frequency EEG. 6. When recurrent excitatory-inhibitory feedback is very large, the model produces a limit cycle of 50-65 cycles/s. The limit cycle is suggested to be the cause of a particular type of high-frequency (50-65 cycles/s) hippocampal afterdischarge that occurs after tetanization of the input pathways. The amplitude, frequency, and waveform of the model generated and experimental data are similar. 7. In conclusion, a nonlinear recurrent excitatory-inhibitory feedback model of the hippocampus explains and integrates various existing experimental data. The model further predicts results that can be experimentally tested.