Almeida Rita, Ledberg Anders
Intitut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), C. Mallorca 183, 08036 Barcelona, Spain.
J Comput Neurosci. 2010 Feb;28(1):155-75. doi: 10.1007/s10827-009-0197-8. Epub 2009 Oct 28.
The temporal durations between events often exert a strong influence over behavior. The details of this influence have been extensively characterized in behavioral experiments in different animal species. A remarkable feature of the data collected in these experiments is that they are often time-scale invariant. This means that response measurements obtained under intervals of different durations coincide when plotted as functions of relative time. Here we describe a biologically plausible model of an interval timing device and show that it is consistent with time-scale invariant behavior over a substantial range of interval durations. The model consists of a set of bistable units that switch from one state to the other at random times. We first use an abstract formulation of the model to derive exact expressions for some key quantities and to demonstrate time-scale invariance for any range of interval durations. We then show how the model could be implemented in the nervous system through a generic and biologically plausible mechanism. In particular, we show that any system that can display noise-driven transitions from one stable state to another can be used to implement the timing device. Our work demonstrates that a biologically plausible model can qualitatively account for a large body of data and thus provides a link between the biology and behavior of interval timing.
事件之间的时间间隔常常对行为产生强大影响。这种影响的细节已在针对不同动物物种的行为实验中得到广泛描述。这些实验收集的数据的一个显著特征是它们通常具有时间尺度不变性。这意味着，当作为相对时间的函数绘制时，在不同持续时间间隔下获得的反应测量结果是一致的。在此，我们描述了一种关于间隔计时装置的生物学上合理的模型，并表明它在相当大的间隔持续时间范围内与时间尺度不变性行为是一致的。该模型由一组双稳态单元组成，这些单元在随机时间从一种状态切换到另一种状态。我们首先使用该模型的抽象形式来推导一些关键量的精确表达式，并证明在任何间隔持续时间范围内的时间尺度不变性。然后我们展示了该模型如何通过一种通用且生物学上合理的机制在神经系统中实现。特别是，我们表明任何能够显示由噪声驱动的从一个稳定状态到另一个稳定状态转变的系统都可用于实现计时装置。我们的工作表明，一个生物学上合理的模型能够定性地解释大量数据，从而在间隔计时的生物学与行为之间建立起联系。
