NetStim

NetStim is a presynaptic spike generator used in the NEURON simulation environment to produce trains of action potentials for synaptic stimulation. It serves as an artificial source of spikes that can be connected to one or more synapses through NetCon objects, delivering presynaptic input to a neuron or network model. NetStim is commonly employed to study how postsynaptic cells respond to different firing patterns and to test network dynamics under controlled input.

The behavior of NetStim is governed by several parameters. Interval specifies the mean inter-spike interval in milliseconds and determines the regularity of the train. Start sets the time, in milliseconds, at which the first spike is emitted. Number controls how many spikes will be generated; a value of 0 typically means an infinite train. Noise introduces randomness into spike timing; a zero value yields perfectly regular timing, while nonzero values produce irregular spike times. By adjusting interval, start, number, and noise, NetStim can produce regular trains, as well as stochastic or Poisson-like spike sequences, depending on the desired simulation scenario.

In practice, NetStim is used by creating a NetStim object, configuring its parameters, and connecting it to a target synapse via a NetCon, which transmits each emitted spike to drive the postsynaptic element. NetStim is a versatile tool for modeling external or artificial presynaptic input and for exploring how varying input patterns influence neuronal and network behavior.