Gilbert Mike, Rasmussen Anders
School of Psychology, University of Birmingham, Birmingham, UK.
Department of Experimental Medical Science, Lund University, Lund, Sweden.
R Soc Open Sci. 2025 Mar 26;12(3):241665. doi: 10.1098/rsos.241665. eCollection 2025 Mar.
We present a theory of the inner layer of the cerebellar cortex, the granular layer, where the main excitatory input to the cerebellum is received. We ask how input signals are converted into an internal code and what form that has. While there is a computational element, and the ideas are quantified with a computer simulation, the approach is primarily evidence-led and aimed at experimenters rather than the computational community. Network models are often simplified to provide a noiseless medium for sophisticated computations. We propose, with evidence, the reverse: physiology is highly adapted to provide a noiseless medium for straightforward computations. We find that input data are converted to a hyper low-resolution internal code. Information is coded in the joint activity of large cell groups and therefore has minimum spatial dimensions-the dimensions of a code group. The conversion exploits statistical effects of random sampling. Code group dimensions are an effect of topography, cell morphologies and granular layer architecture. The activity of a code group is the smallest unit of information but not the smallest unit of code-the same information is coded in any random sample of signals. Code in this form is unexpectedly wasteful-there is a huge sacrifice of resolution-but may be a solution to fundamental problems involved in the biological representation of information.
我们提出了一种关于小脑皮质内层即颗粒层的理论，小脑在此接收对其主要的兴奋性输入。我们探讨输入信号是如何转换为一种内部编码的，以及该编码的形式是什么。虽然存在一个计算元素，并且这些想法通过计算机模拟进行了量化，但该方法主要以证据为导向，目标受众是实验人员而非计算领域的群体。网络模型常常被简化，以提供一个用于复杂计算的无噪声介质。我们有证据表明情况恰恰相反：生理学高度适应于提供一个用于简单计算的无噪声介质。我们发现输入数据被转换为一种超低分辨率的内部编码。信息编码于大细胞群体的联合活动中，因此具有最小的空间维度——一个编码组的维度。这种转换利用了随机抽样的统计效应。编码组维度是拓扑结构、细胞形态和颗粒层结构的一种效应。一个编码组的活动是信息的最小单位，但不是编码的最小单位——相同的信息在信号的任何随机样本中都有编码。这种形式的编码出人意料地浪费——分辨率有巨大牺牲——但可能是解决信息生物学表征中所涉及的基本问题的一种方案。
