Modeling the effects of anesthesia on the electroencephalogram
Modeling the effects of anesthesia on the electroencephalogram
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DOI：
10.1103/physreve.71.041902
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发表时间：
2005-04-01
影响因子：
2.4
通讯作者：
Liley, DTJ
中科院分区：
文献类型：
--
作者：
Bojak, I;Liley, DTJ
在全身麻醉期间观察到的脑电图（EEG）的变化是用电气活性的生理平均场理论建模的。为此，引入了突触后冲动反应的参数化，该反应考虑了麻醉剂对神经配体门控离子通道的药理作用。然后确定了这种改进理论的参数集，这些参数集尊重已知的解剖约束，并预测人类受试者通常遇到的平均发射率和功率谱。通过对代表整个人皮层的网格上的八个非线性，二维偏微分方程的平行模拟，可以证明线性近似足以预测一系列定量EEG变量。最终选择了超过70,000个合理的参数集，并以刻板的吸入全一麻醉性异氟烷进行模拟诱导。因此，确定了86个参数集，表现出强大的“双相”升高，这在实验中经常观察到这一特征。一项敏感性研究表明，即使在低药剂浓度下，这种“双相”行为也可以区分。最后，将我们的结果与其他小组的先前工作进行了简短的比较，并提供了与实验数据的未来展望。
Changes to the electroencephalogram (EEG) observed during general anesthesia are modeled with a physiological mean field theory of electrocortical activity. To this end a parametrization of the postsynaptic impulse response is introduced which takes into account pharmacological effects of anesthetic agents on neuronal ligand-gated ionic channels. Parameter sets for this improved theory are then identified which respect known anatomical constraints and predict mean firing rates and power spectra typically encountered in human subjects. Through parallelized simulations of the eight nonlinear, two-dimensional partial differential equations on a grid representing an entire human cortex, it is demonstrated that linear approximations are sufficient for the prediction of a range of quantitative EEG variables. More than 70 000 plausible parameter sets are finally selected and subjected to a simulated induction with the stereotypical inhaled general anesthetic isoflurane. Thereby 86 parameter sets are identified that exhibit a strong "biphasic" rise in total power, a feature often observed in experiments. A sensitivity study suggests that this "biphasic" behavior is distinguishable even at low agent concentrations. Finally, our results are briefly compared with previous work by other groups and an outlook on future fits to experimental data is provided.