1. A method comprising: maintaining, in a memory device, deterministic neural data for an electronic neuron of a neurosynaptic core circuit; receiving an incoming neuronal firing event targeting the neuron; generating, at a logic circuit, stochastic neural data by: obtaining a pseudo-random value; determining whether the deterministic neural data is less than the pseudo-random value; and forwarding a data value selected from multiple data values as the stochastic neural data based on whether the deterministic neural data is less than the pseudo-random value, wherein the selected data value comprises a first data value in response to determining the deterministic neural data is less than the pseudo-random value, and the selected data value comprises a second data value different from the first data value in response to determining the deterministic neural data is greater than or equal to the pseudo-random value; updating a membrane potential variable of the neuron based on the stochastic neural data; and generating an outgoing neuronal firing event in response to the neuron spiking, wherein the stochastic neural data controls frequency of the neuron spiking, such that the neuron spikes at an average firing rate proportional to a relative magnitude of the membrane potential variable.