Lüthi A, McCormick D A
Section of Neurobiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
Neuron. 1998 Mar;20(3):553-63. doi: 10.1016/s0896-6273(00)80994-0.
Thalamocortical networks can generate both normal and abnormal patterns of synchronized network activity, such as spindle waves and spike-and-wave seizures. These periods of synchronized discharge are often separated by a silent, refractory phase of between 5 and 20 s. In vitro investigations have demonstrated that this refractory period is due in large part to the persistent activation of the hyperpolarization-activated cation current Ih in thalamocortical cells. Here, we show that increases in [Ca2+]i due to rebound Ca2+ bursts result in persistent activation of Ih resulting from a positive shift in the activation curve of this current. The dynamical upregulation and persistent activation of Ih is the critical determinant of the time course of the refractory period. These findings demonstrate that periodicity in neural network oscillations may be generated through an interaction between the electrophysiological properties and intracellular signaling pathways of the constituent neurons.
丘脑皮质网络能够产生同步网络活动的正常和异常模式，如纺锤波和棘波癫痫发作。这些同步放电的时期通常被5到20秒的静息、不应期隔开。体外研究表明，这种不应期在很大程度上是由于丘脑皮质细胞中超极化激活阳离子电流Ih的持续激活所致。在这里，我们表明，由于反弹Ca2+爆发导致的[Ca2+]i增加会导致Ih的持续激活，这是由于该电流激活曲线的正向偏移所致。Ih的动态上调和持续激活是不应期时间进程的关键决定因素。这些发现表明，神经网络振荡的周期性可能是通过组成神经元的电生理特性和细胞内信号通路之间的相互作用产生的。
