HHMI, Department Biological Sciences, Columbia University, New York, NY 10027, USA.
Neuron. 2011 Sep 8;71(5):772-81. doi: 10.1016/j.neuron.2011.07.024.
Dendritic spines receive most excitatory connections in pyramidal cells and many other principal neurons. But why do neurons use spines, when they could accommodate excitatory contacts directly on their dendritic shafts? One suggestion is that spines serve to connect with passing axons, thus increasing the connectivity of the dendrites. Another hypothesis is that spines are biochemical compartments that enable input-specific synaptic plasticity. A third possibility is that spines have an electrical role, filtering synaptic potentials and electrically isolating inputs from each other. In this review, I argue that, when viewed from the perspective of the circuit function, these three functions dovetail with one another to achieve a single overarching goal: to implement a distributed circuit with widespread connectivity. Spines would endow these circuits with nonsaturating, linear integration and input-specific learning rules, which would enable them to function as neural networks, with emergent encoding and processing of information.
树突棘接收来自于锥体神经元和其他许多主要神经元的大多数兴奋性连接。但是，既然神经元的树突干也可以容纳兴奋性接触，那么它们为什么还要使用树突棘呢？一种观点认为，树突棘用于与经过的轴突连接，从而增加树突的连接性。另一种假说认为，树突棘是生化隔室，能够实现输入特异性突触可塑性。第三种可能性是，树突棘具有电作用，可以滤过突触电位，并使输入彼此之间相互隔离。在这篇综述中，我认为，从电路功能的角度来看，这三个功能彼此吻合，共同实现一个总体目标：构建具有广泛连接的分布式电路。树突棘将为这些电路提供非饱和、线性整合和输入特异性学习规则，从而使它们能够作为神经网络发挥作用，对信息进行新的编码和处理。
