Wilson Marcus T, Barry Melissa, Reynolds John N J, Crump William P, Steyn-Ross D Alistair, Steyn-Ross Moira L, Sleigh James W
J Biol Phys. 2010 Jun;36(3):245-59. doi: 10.1007/s10867-009-9180-x. Epub 2009 Dec 4.
We study the dynamics of the transition between the low- and high-firing states of the cortical slow oscillation by using intracellular recordings of the membrane potential from cortical neurons of rats. We investigate the evidence for a bistability in assemblies of cortical neurons playing a major role in the maintenance of this oscillation. We show that the trajectory of a typical transition takes an approximately exponential form, equivalent to the response of a resistor-capacitor circuit to a step-change in input. The time constant for the transition is negatively correlated with the membrane potential of the low-firing state, and values are broadly equivalent to neural time constants measured elsewhere. Overall, the results do not strongly support the hypothesis of a bistability in cortical neurons; rather, they suggest the cortical manifestation of the oscillation is a result of a step-change in input to the cortical neurons. Since there is evidence from previous work that a phase transition exists, we speculate that the step-change may be a result of a bistability within other brain areas, such as the thalamus, or a bistability among only a small subset of cortical neurons, or as a result of more complicated brain dynamics.
我们通过对大鼠皮层神经元膜电位进行细胞内记录，研究皮层慢振荡低发放状态和高发放状态之间转换的动力学。我们调查了皮层神经元集合中双稳态在维持这种振荡中起主要作用的证据。我们表明，典型转换的轨迹呈近似指数形式，等同于电阻 - 电容电路对输入阶跃变化的响应。转换的时间常数与低发放状态的膜电位呈负相关，其值大致等同于在其他地方测量的神经时间常数。总体而言，结果并不强烈支持皮层神经元双稳态的假设；相反，它们表明振荡的皮层表现是皮层神经元输入阶跃变化的结果。由于先前的工作有证据表明存在相变，我们推测这种阶跃变化可能是其他脑区（如丘脑）内双稳态的结果，或者仅是一小部分皮层神经元之间的双稳态的结果，或者是更复杂脑动力学的结果。
