De Schutter E, Steuber V
Computational Neuroscience Unit, Okinawa Institute of Science and Technology, Japan; Theoretical Neurobiology, University of Antwerp, Belgium.
Neuroscience. 2009 Sep 1;162(3):816-26. doi: 10.1016/j.neuroscience.2009.02.040. Epub 2009 Feb 26.
We review our recent experimental and modeling results on how cerebellar Purkinje cells encode information in their simple spike trains and present a theory of the function of pauses and regular spiking patterns. The regular spiking patterns were discovered in extracellular recordings of simple spikes in awake and anesthetized rodents, where it was shown that more than half of the spontaneous activity consists of short epochs of regular spiking. These periods of regular spiking are interrupted by pauses, which can be tightly synchronized among nearby Purkinje cells, while the spikes in the regular patterns are not. Interestingly, pauses are affected by long-term depression of the parallel fiber synapses. Both in modeling and slice experiments it was demonstrated that long-term depression causes a decrease in the duration of pauses, leading to an increase of the spike output of the neuron. Based on these results we propose that pauses in the simple spike train form a temporal code which can lead to a rebound burst in the target deep cerebellar nucleus neurons. Conversely, the regular spike patterns may be a rate code, which presets the amplitude of future rebound bursts.
我们回顾了近期关于小脑浦肯野细胞如何在其简单锋电位序列中编码信息的实验和建模结果，并提出了一个关于暂停和规则锋电位模式功能的理论。规则锋电位模式是在清醒和麻醉的啮齿动物的简单锋电位细胞外记录中发现的，结果表明超过一半的自发活动由规则锋电位的短时段组成。这些规则锋电位的时段被暂停打断，暂停在附近的浦肯野细胞之间可以紧密同步，而规则模式中的锋电位则不然。有趣的是，暂停会受到平行纤维突触长时程抑制的影响。在建模和切片实验中均表明，长时程抑制会导致暂停持续时间缩短，从而导致神经元锋电位输出增加。基于这些结果，我们提出简单锋电位序列中的暂停形成了一种时间编码，可导致目标小脑深部核团神经元的反弹爆发。相反，规则锋电位模式可能是一种速率编码，它预设了未来反弹爆发的幅度。
