Role of refractory period in homoclinic models of neural synchronization.
We study the properties of a homoclinic model of neuron by introducing a suitable one-dimensional map. We show that the system is characterized by a response time to external signals which is a decreasing function of the signal strength, in contrast to excitable models whose response time is signal-independent. In a one-dimensional array of these systems with bidirectional coupling, we observe a sudden transition to a synchronized state at a certain value of the coupling strength. The transition occurs when the response time of a site to the signals of the adjacent sites is of the order of refractory time. Near the transition, we find an intermittent behavior due to the competition between a turbulent and a synchronized state. The observed behavior distinguishes homoclinic systems from excitable systems.
Montina
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Dipartimento di fisica, Università di Firenze, via Sansone 1, 50019 Sesto Fiorentino (FI), Italy. almont@inoa.it
Mendoza
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Arecchi
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D000200:Action Potentials / Q000502:physiology; D003344:Cortical Synchronization; D008959:Models, Neurological; D009474:Neurons / Q000502:physiology*