中文摘要：

讨论了三维退化时滞微分系统的Hopf分支．通过分析其特征方程，发现当时滞穿越某些值时出现了分支．给出了寻找Hopf分支点的计算方法．

英文摘要：

This paper discusses the problem of Hopf bifurcation of three-neuron degenerate differential equations with delay. By analyzing the associated characteristic equation, it is found that Hopf bifurcation occurs when delay pass through a value. A formula for determining the direction of Hopf bifurcation is given.