Ponce-Alvarez Adrián, Kilavik Bjørg Elisabeth, Riehle Alexa
Institut de Neurosciences Cognitives de la Méditerranée, CNRS-Université de la Méditerranée, Marseille, France.
J Comput Neurosci. 2010 Aug;29(1-2):351-365. doi: 10.1007/s10827-009-0158-2. Epub 2009 May 16.
Spike time irregularity can be measured by the coefficient of variation. However, it overestimates the irregularity in the case of pronounced firing rate changes. Several alternative measures that are local in time and therefore relatively rate-independent were proposed. Here we compared four such measures: CV(2), LV, IR and SI. First, we asked which measure is the most efficient for time-resolved analyses of experimental data. Analytical results show that CV(2) has the less variable estimates. Second, we derived useful properties of CV(2) for gamma processes. Third, we applied CV(2) on recordings from the motor cortex of a monkey performing a delayed motor task to characterize the irregularity, that can be modulated or not, and decoupled or not from firing rate. Neurons with a CV(2)-rate decoupling have a rather constant CV(2) and discharge mainly irregularly. Neurons with a CV(2)-rate coupling can modulate their CV(2) and explore a larger range of CV(2) values.
峰电位时间不规则性可以通过变异系数来测量。然而，在放电率显著变化的情况下，它会高估不规则性。人们提出了几种在时间上局部且因此相对与速率无关的替代测量方法。在这里，我们比较了四种这样的测量方法：CV(2)、LV、IR和SI。首先，我们询问哪种测量方法对于实验数据的时间分辨分析最有效。分析结果表明，CV(2)的估计值变化较小。其次，我们推导了CV(2)对于伽马过程的有用特性。第三，我们将CV(2)应用于一只执行延迟运动任务的猴子运动皮层的记录，以表征可以被调制或不被调制、与放电率解耦或不解耦的不规则性。具有CV(2)-速率解耦的神经元具有相当恒定的CV(2)，并且主要不规则地放电。具有CV(2)-速率耦合的神经元可以调节它们的CV(2)并探索更大范围的CV(2)值。
