Fig. 2

Schematic diagrams of the network structures of the six 3-node biochemical oscillator models. Each model includes three nodes (X, Y, and Z) and nine possible interactions (Lxx, Lxy, Lxz, Lyx, Lyy, Lyz, Lzx, Lzy, and Lzz). The term ‘Lpq’ denotes an interaction in which node P is influenced by node Q. For instance, Lxy denotes an interaction in which node X is influenced by node Y. The figure shows the six network structures: a simple NFO; b activator-amplified NFO; c inhibitor-amplified NFO; d type 1 incoherently-amplified NFO; e type 2 incoherently-amplified NFO; and (f) type 3 incoherently-amplified NFO in order of appearance