| We studied a mechanism of spike adding in bursting activity in a reduced model of the leech heart interneuron.As the control parameter of the model,that is the activation kinetics of a slow potassium current is shifted towards depolarized potential values,the system undergoes a sequence of spike-adding bifurcations.We show that in the vicinity of these bifurcation the system is extremely sensitive to random perturbations which lead to chaotic behavior.We study influence of weak noise on bursting regime to mimic situation occurring in experiments,where fluctuations are inevitable.Addition of weak noise to the model leads to chaotic behavior in a wide parameter ranges,where the number of spikes per burst fluctuates in a random manner.This behavior was assayed with entropies of spike numbers and Lyapunov exponent. |
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