Alle Henrik, Geiger Jörg R P
Independent Hertie Research Group, Max-Planck-Institute for Brain Research, D-60528 Frankfurt, Germany.
Curr Opin Neurobiol. 2008 Jun;18(3):314-20. doi: 10.1016/j.conb.2008.08.006.
In the mammalian cortex, the classic view assumes that the output information of a neuron is encoded in rather stereotyped action potentials, which provide an all-or-none or digital way of communication between cell body and axonal boutons. A role for subthreshold signal propagation within cortical axons has largely been ignored. Recent achievements of direct recordings from axonal structures in the hippocampus and neocortex extended the classic view by the observation that subthreshold-graded signals propagate down the axon over distances of up to 1 mm. At certain synapses, these analog axonal signals modulate action-potential-dependent transmitter release, thereby enabling a hybrid code of information transmission in local cortical circuits.
在哺乳动物的皮层中，传统观点认为神经元的输出信息是通过相当刻板的动作电位进行编码的，动作电位提供了一种细胞体和轴突终扣之间全或无的、数字化的通信方式。皮层轴突内阈下信号传播的作用在很大程度上被忽视了。最近在海马体和新皮层的轴突结构上进行直接记录的成果扩展了传统观点，观察到阈下分级信号可沿轴突向下传播长达1毫米的距离。在某些突触处，这些模拟轴突信号会调节依赖动作电位的递质释放，从而在局部皮层回路中实现信息传递的混合编码。
