Department of Biology, University of Crete, Heraklion, Crete, Greece.
PLoS Comput Biol. 2010 Dec 16;6(12):e1001038. doi: 10.1371/journal.pcbi.1001038.
The in vivo activity of CA1 pyramidal neurons alternates between regular spiking and bursting, but how these changes affect information processing remains unclear. Using a detailed CA1 pyramidal neuron model, we investigate how timing and spatial arrangement variations in synaptic inputs to the distal and proximal dendritic layers influence the information content of model responses. We find that the temporal delay between activation of the two layers acts as a switch between excitability modes: short delays induce bursting while long delays decrease firing. For long delays, the average firing frequency of the model response discriminates spatially clustered from diffused inputs to the distal dendritic tree. For short delays, the onset latency and inter-spike-interval succession of model responses can accurately classify input signals as temporally close or distant and spatially clustered or diffused across different stimulation protocols. These findings suggest that a CA1 pyramidal neuron may be capable of encoding and transmitting presynaptic spatiotemporal information about the activity of the entorhinal cortex-hippocampal network to higher brain regions via the selective use of either a temporal or a rate code.
在体 CA1 锥体神经元的活动在规则放电和爆发之间交替，但这些变化如何影响信息处理尚不清楚。使用详细的 CA1 锥体神经元模型，我们研究了远端和近端树突层的突触输入的时间和空间排列变化如何影响模型响应的信息含量。我们发现，两层激活之间的时间延迟充当兴奋性模式之间的开关：短延迟诱导爆发，而长延迟降低放电。对于长延迟，模型响应的平均放电频率可区分远端树突分支的空间聚类与扩散输入。对于短延迟，模型响应的起始潜伏期和尖峰间隔序列可以根据不同的刺激方案，将输入信号准确地分类为时间上接近或遥远、空间上聚类或扩散。这些发现表明，CA1 锥体神经元可能能够通过选择性使用时间或速率编码，将来自内嗅皮层-海马网络活动的突触前时空信息编码并传递到更高的大脑区域。
