Clearwater J M, Rennie C J, Robinson P A
School of Physics, University of Sydney, New South Wales 2006, Australia.
J Theor Biol. 2008 Dec 7;255(3):287-98. doi: 10.1016/j.jtbi.2008.08.010. Epub 2008 Aug 19.
A recent continuum model of the large scale electrical activity of the thalamocortical system is generalized to include cholinergic modulation. The model is examined analytically and numerically to determine the effect of acetylcholine (ACh) on its steady states, linear stability, spectrum, and temporal responses. Changing the ACh concentration moves the system between zones of one, three, and five steady states, showing that neuromodulation of synaptic strength is a possible mechanism by which multiple steady states emerge in the brain. The lowest firing rate steady state is always stable, and subsequent fixed points alternate between stable and unstable. Increasing ACh concentration changes the form of the spectrum. Increasing the tonic level of ACh concentration increases the magnitudes of the N100 and P200 in the evoked response potential (ERP), without changing the timing of these peaks. Driving the system with a pulse of cholinergic activity results in a transient increase in the firing rate of cortical neurons that lasts over 10s. Step-like increases in cortical ACh concentration cause increases in the firing rate of cortical neurons, with rapid responses due to fast acting nicotinic receptors and slower responses due to muscarinic receptor suppression of intracortical connections.
一种最近的丘脑皮质系统大规模电活动连续模型被推广以纳入胆碱能调制。对该模型进行了分析和数值研究，以确定乙酰胆碱（ACh）对其稳态、线性稳定性、频谱和时间响应的影响。改变ACh浓度会使系统在一、三、五个稳态区域之间移动，表明突触强度的神经调制是大脑中出现多个稳态的一种可能机制。最低放电率稳态始终稳定，随后的固定点在稳定和不稳定之间交替。增加ACh浓度会改变频谱的形式。增加ACh浓度的强直水平会增加诱发反应电位（ERP）中N100和P200的幅度，而不会改变这些峰值的时间。用胆碱能活动脉冲驱动系统会导致皮质神经元放电率短暂增加，持续超过10秒。皮质ACh浓度的阶梯式增加会导致皮质神经元放电率增加，由于快速作用的烟碱受体而产生快速反应，以及由于毒蕈碱受体对皮质内连接的抑制而产生较慢反应。
