Bursting is a rapid signaling mode in neurons whereby clusters of two or more action potentials (spikes) are emitted as a single signaling event. A burst of two spikes is called a doublet, three spikes - triplet, four - quadruplet, etc. Burst mode is thought to be useful for signaling important events and routing information in the brain. In general, there are two types of bursting:
- Input-driven bursting, where strong excitatory inputs produce a rapid activation and burst of action potentials
- Intrinsic bursting, where voltage-gated ion channels intrinsic to the neuron convert brief suprathreshold inputs into long-lasting bursts of action potential output.
Some types of neurons are able to respond to current input by emitting an all- or non-burst response. This burst usually consists of a short phase of repeated action potentials, at a frequency of up to 350 Hz. This is followed by a prolonged refractory period. In contrast, neurons that fire tonically respond with action potentials at a rate proportional to the input current.
