Strange patterns in one ring of Chen oscillators coupled to a "buffer' cell

We study curious dynamical patterns appearing in networks of one ring of cells coupled to a buffer' cell. Depending on how the cells in the ring are coupled to the buffer' cell, the full network may have a nontrivial group of symmetries or a nontrivial group of interior' symmetries. This group is Z(3) in the unidirectional case and D-3 in the bidirectional case. We simulate the coupled cell systems associated with the networks and obtain steady states, rotating waves, quasiperiodic behavior, and chaos. The different patterns seem to arise through a sequence of Hopf, period-doubling, and period-halving bifurcations. The behavior of the systems with exact symmetry are similar to the ones with interior' symmetry. The network architecture appears to explain some features, whereas the properties of the Chen oscillator, used to model cells' internal dynamics, may explain others. We use XPPAUT and MATLAB to numerically compute the relevant states.