Periodic behaviour versus chaos

chaos (Olsen Degn, 1977 Olsen, 1979, 1983 Aguda Larter, 1991 Geest et al., 1992 Steinmetz et al, 1993), and hard excitation (Aguda, Hofmann-Frisch Olsen, 1990). 

In each of the models studied here, the domains of chaos and birhythmicity are much more reduced than the domain of complex periodic oscillations, which is itself smaller than the domain where simple periodic oscillations occur. This observation, which is corroborated by results obtained on the occurrence of complex oscillations in multi-looped negative feedback systems (Glass Malta, 1990), accounts for 

Link with the evolution to chaos through the periodic forcing of an 

The appearance of complex autonomous behaviour due to the interaction between two endogenous oscillatory mechanisms can be related to 

Whereas chaos and complex oscillations in the models studied here result from the interaction between two endogenous oscillators, in these experiments and in the associated models they result from the coupling between an endogenous oscillator and a periodic extem d source, as indicated by the analysis of normal forms for such a situation (Baesens Nicolis, 1983). Evidence for autonomous chaos has nevertheless been obtained in molluscan neurons (Holden et al, 1982 Hayashi Ishizuka, 1992). 

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