COMPUTER-SIMULATION OF THE SEGMENTAL NEURAL NETWORK GENERATING LOCOMOTION IN LAMPREY BY USING POPULATIONS OF NETWORK INTERNEURONS
COMPUTER-SIMULATION OF THE SEGMENTAL NEURAL NETWORK GENERATING LOCOMOTION IN LAMPREY BY USING POPULATIONS OF NETWORK INTERNEURONS
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DOI：
10.1007/bf00203132
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发表时间：
1992-11-01
影响因子：
1.9
通讯作者：
LANSNER, A
中科院分区：
文献类型：
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作者：
HELLGREN, J;GRILLNER, S;LANSNER, A
对实验建立的七鳃鳗产生游泳的局部脊髓神经网络进行了真实的计算机模拟。使用网络中间神经元群体，其中细胞特性（如细胞大小和膜电导（包括电压依赖性离子通道））随机分布在实验获得的平均值周围，突触电导（红藻氨酸/AMPA、NMDA、甘氨酸）和延迟也是如此。与之前使用的更简单的子样本模型相比，该群体模型在更宽的频率范围内显示出更稳健的突发活动，并且神经元间活动的模式是合适的。相互抑制的强度对于突发频率的调节起着非常重要的作用，只需改变抑制偏向就可以覆盖整个生理范围。在爆发的较低频率范围内，节段性兴奋性中间神经元提供稳定性，电压依赖性 NMDA 受体的激活也提供稳定性。通过后超极化 (AHP) 求和的尖峰频率适应充当主要的突发终止因素，并且在较低速率下，NMDA 受体激活赋予膜特性。外侧中间神经元对于突发终止并不是至关重要的。然而，它们对于在例如转向和扶正反应期间引起快速爆发终止可能特别重要。多种细胞因素相结合，在整个频率范围内提供安全稳定的运动模式。
Realistic computer simulations of the experimentally established local spinal cord neural network generating swimming in the lamprey have been performed. Populations of network interneurons were used in which cellular properties, like cell size and membrane conductance including voltage dependent ion channels were randomly distributed around experimentally obtained mean values, as were synaptic conductances (kainate/AMPA, NMDA, glycine) and delays. This population model displayed more robust burst activity over a wider frequency range than the more simple subsample model used previously, and the pattern of interneuronal activity was appropriate. The strength of the reciprocal inhibition played a very important role in the regulation of burst frequency, and just by changing the inhibitory bias the entire physiological range could be covered. At the lower frequency range of bursting the segmental excitatory interneurons provide stability as does the activation of voltage dependent NMDA receptors. Spike frequency adaptation by means of summation of afterhyperpolarization (AHP) serves as a major burst terminating factor, and at lower rates the membrane properties conferred by the NMDA receptor activation. The lateral interneurons were not of critical importance for the burst termination. They may, however, be of particular importance for inducing a rapid burst termination during for instance steering and righting reactions. Several cellular factors combine to provide a secure and stable motor pattern in the entire frequency range.