Wen Quan, Chklovskii Dmitri B
Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
J Neurophysiol. 2008 May;99(5):2320-8. doi: 10.1152/jn.00280.2007. Epub 2008 Feb 27.
Over hundreds of millions of years, evolution has optimized brain design to maximize its functionality while minimizing costs associated with building and maintenance. This observation suggests that one can use optimization theory to rationalize various features of brain design. Here, we attempt to explain the dimensions and branching structure of dendritic arbors by minimizing dendritic cost for given potential synaptic connectivity. Assuming only that dendritic cost increases with total dendritic length and path length from synapses to soma, we find that branching, planar, and compact dendritic arbors, such as those belonging to Purkinje cells in the cerebellum, are optimal. The theory predicts that adjacent Purkinje dendritic arbors should spatially segregate. In addition, we propose two explicit cost function expressions, falsifiable by measuring dendritic caliber near bifurcations.
在数亿年的时间里，进化优化了大脑的设计，以在将与构建和维护相关的成本降至最低的同时，最大化其功能。这一观察结果表明，人们可以使用优化理论来合理化大脑设计的各种特征。在这里，我们试图通过在给定的潜在突触连接性条件下最小化树突成本，来解释树突棘的尺寸和分支结构。仅假设树突成本随着总树突长度以及从突触到胞体的路径长度增加，我们发现分支状、平面状和紧凑状的树突棘，比如小脑浦肯野细胞的树突棘，是最优的。该理论预测相邻的浦肯野树突棘在空间上应该是分离的。此外，我们提出了两个明确的成本函数表达式，可通过测量分支点附近的树突直径来进行验证。
