de Ruyter van Steveninck R R, Lewen G D, Strong S P, Koberle R, Bialek W
NEC Research Institute, 4 Independence Way, Princeton, NJ 08540, USA.
Science. 1997 Mar 21;275(5307):1805-8. doi: 10.1126/science.275.5307.1805.
To provide information about dynamic sensory stimuli, the pattern of action potentials in spiking neurons must be variable. To ensure reliability these variations must be related, reproducibly, to the stimulus. For H1, a motion-sensitive neuron in the fly's visual system, constant-velocity motion produces irregular spike firing patterns, and spike counts typically have a variance comparable to the mean, for cells in the mammalian cortex. But more natural, time-dependent input signals yield patterns of spikes that are much more reproducible, both in terms of timing and of counting precision. Variability and reproducibility are quantified with ideas from information theory, and measured spike sequences in H1 carry more than twice the amount of information they would if they followed the variance-mean relation seen with constant inputs. Thus, models that may accurately account for the neural response to static stimuli can significantly underestimate the reliability of signal transfer under more natural conditions.
为了提供有关动态感觉刺激的信息，发放脉冲的神经元中动作电位的模式必须是可变的。为确保可靠性，这些变化必须可重复地与刺激相关。对于果蝇视觉系统中对运动敏感的神经元H1，匀速运动会产生不规则的脉冲发放模式，并且对于哺乳动物皮层中的细胞，脉冲计数的方差通常与均值相当。但是，更自然的、随时间变化的输入信号会产生在时间和计数精度方面都更具可重复性的脉冲模式。变异性和可重复性是用信息论的概念来量化的，并且H1中测量到的脉冲序列所携带的信息量比在恒定输入下遵循方差-均值关系时多两倍以上。因此，可能准确解释对静态刺激的神经反应的模型在更自然的条件下可能会显著低估信号传递的可靠性。
