Marder E
Volen Center, Brandeis University, Waltham, Massachusetts 02254, USA.
Annu Rev Neurosci. 1998;21:25-45. doi: 10.1146/annurev.neuro.21.1.25.
Neurons and synapses display a rich range of time-dependent processes. Which of these are critical to understanding specific integrative functions in the brain? Computational methods of various kinds are used to understand how systems of neurons interact to produce behavior. However, these models often assume that neuronal dynamics and synaptic strengths are fixed. This review presents some recent models that illustrate that short-term synaptic plasticity mechanisms such as facilitation and depression can have important implications for network function. Other features of synaptic transmission such as multi-component synaptic potentials, cotransmission, and neuromodulation with obvious potential computational implications are presented. These examples illustrate that synaptic strength and intrinsic properties in networks are continuously varying on numerous time scales as a function of the temporal patterns of activity in the network. Thus, both firing frequency of the neurons in a circuit, and the modulatory environment determine the intrinsic and synaptic properties that produce behavior.
神经元和突触表现出一系列丰富的时间依赖性过程。其中哪些对于理解大脑中的特定整合功能至关重要？人们运用各种计算方法来理解神经元系统如何相互作用以产生行为。然而，这些模型常常假定神经元动力学和突触强度是固定不变的。本综述介绍了一些近期的模型，这些模型表明诸如易化和抑制等短期突触可塑性机制可能对网络功能具有重要影响。还介绍了突触传递的其他特征，如多成分突触电位、共同传递以及具有明显潜在计算意义的神经调制。这些例子说明，网络中的突触强度和内在特性会随着网络活动的时间模式在众多时间尺度上持续变化。因此，回路中神经元的放电频率以及调制环境都决定了产生行为的内在和突触特性。
