Recent electrophysiological results imply that the duration of the stimulus onset asynchrony in eyeblink conditioning is encoded by a mechanism intrinsic to the cerebellar Purkinje cell. This raises the general question - how is quantitative information (durations, distances, rates, probabilities, amounts, etc.) transmitted by spike trains and encoded into engrams? The usual assumption is that information is transmitted by firing rates. However, rate codes are energetically inefficient and computationally awkward. A combinatorial code is more plausible. If the engram consists of altered synaptic conductances (the usual assumption), then we must ask how numbers may be written to synapses. It is much easier to formulate a coding hypothesis if the engram is realized by a cell-intrinsic molecular mechanism.

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编码问题

最近的电生理结果表明，眨眼条件下刺激开始不同步的持续时间是由小脑浦肯野细胞固有的机制编码的。这就提出了一个普遍的问题——定量信息（持续时间、距离、速率、概率、数量等）是如何由尖峰列车传输并编码成印迹的？通常的假设是信息是通过发射率传输的。然而，速率代码在能量上效率低下并且在计算上笨拙。组合代码更合理。如果印迹由改变的突触电导组成（通常的假设），那么我们必须问如何将数字写入突触。如果印迹是通过细胞内在分子机制实现的，则制定编码假设要容易得多。