Distortion of neural signals by spike coding.
Distortion of neural signals by spike coding.
复制标题
通过尖峰编码扭曲神经信号。
DOI：
10.1162/neco.2007.19.10.2797
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发表时间：
2007
影响因子：
2.9
通讯作者：
Andreou,AndreasG
中科院分区：
文献类型：
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作者：
Goldberg,DavidH;Andreou,AndreasG
模拟神经信号必须转换为尖峰序列，以便通过漏电轴突传输。这种尖峰编码和随后的解码会导致失真。我们通过推导尖峰链路的输入和输出之间的均方误差的近似表达式来量化这种失真。我们使用积分激发和泊松编码器将自然刺激转换为尖峰序列，并使用尖峰计数和尖峰间间隔解码器来生成刺激的重建。失真表达式使我们能够在大参数空间上比较这些尖峰编码方案。我们验证了积分点火编码器比泊松编码器更有效。两个编码器之间的差异随着刺激变异系数 (CV) 的增加而减小，此时，刺激引起的变异性压倒了泊松统计引起的变异性。当刺激 CV 较小时，尖峰间间隔解码器更优越，因为尖峰计数解码产生的失真主要由归因于尖峰计数的离散性质的项主导。在这种情况下，加性噪声对尖峰间隔解码器的影响比对尖峰计数解码器的影响更大。当刺激CV较大时，平均信号偏移远大于量化步长，尖峰计数解码更优越。
Analog neural signals must be converted into spike trains for transmission over electrically leaky axons. This spike encoding and subsequent decoding leads to distortion. We quantify this distortion by deriving approximate expressions for the mean square error between the inputs and outputs of a spiking link. We use integrate-and-fire and Poisson encoders to convert naturalistic stimuli into spike trains and spike count and inter-spike interval decoders to generate reconstructions of the stimulus. The distortion expressions enable us to compare these spike coding schemes over a large parameter space. We verify that the integrate-and-fire encoder is more effective than the Poisson encoder. The disparity between the two encoders diminishes as the stimulus coefficient of variation (CV) increases, at which point, the variability attributed to the stimulus overwhelms the variability attributed to Poisson statistics. When the stimulus CV is small, the interspike interval decoder is superior, as the distortion resulting from spike count decoding is dominated by a term that is attributed to the discrete nature of the spike count. In this regime, additive noise has a greater impact on the interspike interval decoder than the spike count decoder. When the stimulus CV is large, the average signal excursion is much larger than the quantization step size, and spike count decoding is superior.