A case study in the functional consequences of scaling the sizes of realistic cortical models
A case study in the functional consequences of scaling the sizes of realistic cortical models
复制标题
缩放现实皮质模型尺寸的功能后果的案例研究
DOI：
10.1371/journal.pcbi.1007198
复制
发表时间：
2019
影响因子：
4.3
通讯作者：
L. Young
中科院分区：
文献类型：
--
作者：
Madhura R. Joglekar;Logan Chariker;R. Shapley;L. Young
神经科学模型有着广泛的尺度和特异性，从平均场速率模型到大规模的尖峰神经元网络。简单性与现实性、多功能性和计算速度之间存在潜在的权衡。本文是关于大规模的皮层网络模型，我们解决的问题是可扩展性之一：缩小细胞密度会影响网络再现皮层动力学和功能的能力吗？我们研究了这个问题，使用以前构建的现实模型的猴子视觉皮层是真实的大小。将细胞密度逐渐减少到50倍，我们研究了模型行为的变化。没有参数调整的尺寸减小是灾难性的。令人惊讶的是，由理论算法引导的突触权重的相对较小的补偿恢复了平均放电率和基本功能，例如比真实的皮层小10-20倍的模型的方向选择性。在简化模型的皮层中，并非所有的都是正常的：细胞内动力学获得了一种不同于真实的神经元的特征，尽管传递前馈输入的能力保持不变，但简化模型显示出需要皮层神经元之间动力学相互作用的功能缺陷的迹象。这些发现并不局限于视觉皮层的模型，建模者应该意识到伴随尺寸减小的潜在问题。这项研究的更广泛的意义包括稳态维持放电率的重要性，以及前馈与循环动力学的功能后果，这些想法可能会揭示其他物种和遭受细胞损失的系统。
Neuroscience models come in a wide range of scales and specificity, from mean-field rate models to large-scale networks of spiking neurons. There are potential trade-offs between simplicity and realism, versatility and computational speed. This paper is about large-scale cortical network models, and the question we address is one of scalability: would scaling down cell density impact a network’s ability to reproduce cortical dynamics and function? We investigated this problem using a previously constructed realistic model of the monkey visual cortex that is true to size. Reducing cell density gradually up to 50-fold, we studied changes in model behavior. Size reduction without parameter adjustment was catastrophic. Surprisingly, relatively minor compensation in synaptic weights guided by a theoretical algorithm restored mean firing rates and basic function such as orientation selectivity to models 10-20 times smaller than the real cortex. Not all was normal in the reduced model cortices: intracellular dynamics acquired a character different from that of real neurons, and while the ability to relay feedforward inputs remained intact, reduced models showed signs of deficiency in functions that required dynamical interaction among cortical neurons. These findings are not confined to models of the visual cortex, and modelers should be aware of potential issues that accompany size reduction. Broader implications of this study include the importance of homeostatic maintenance of firing rates, and the functional consequences of feedforward versus recurrent dynamics, ideas that may shed light on other species and on systems suffering cell loss.
影响因子：
13.9
作者：
Froemke RC
通讯作者：
Froemke RC
影响因子：
5.3
作者：
Chariker, Logan;Shapley, Robert;Young, Lai-Sang
通讯作者：
Young, Lai-Sang