Emergence of coupling-induced oscillations and broken symmetries in   heterogeneously driven nonlinear reaction networks
  Many natural systems including the brain comprise coupled non-uniformly stimulated elements. In this paper we show that heterogeneously driven networks of excitatory-inhibitory units exhibit striking collective phenomena, including spontaneous oscillations upon coupling. On varying the coupling strength a novel transition is seen wherein the pattern symmetries of stimulated and unstimulated groups undergo mutual exchange. The system exhibits coexisting chaotic and non-chaotic attractors - an intriguing result in view of earlier reports of varying degrees of chaoticity in the brain. 
Varsha Sreenivasan, Shakti N. Menon and Sitabhra Sinha
nlin.AO cond-mat.dis-nn q-bio.NC