Experimental observation of the stochastic bursting caused by coherence resonance in a neural pacemaker.

The inter-burst intervals (IBIs) of the stochastic bursting caused by the effect of coherence resonance (CR) in Hindmarsh-Rose model exhibited multiple mode and were approximately integer multiples of a basic IBI. A similar bursting pattern was found in the experiment on an experimental neural pacemaker perfused with solution whose extracellular calcium concentration ([Ca(2+) ](o) ) was lower than the normal level in which the firing pattern was period 1 spiking. The results verified the existence of the stochastic bursting and implied its CR mechanism. In addition, the distinction between the integer multiple bursting and the integer multiple spiking, another classical firing pattern caused by CR, was identified. The integer multiple bursting was generated in the parameter region where [Ca(2+) ](o) was lower than normal.