An Efficient Method for Computing Synaptic Conductances Based on a Kinetic Model of Receptor Binding

Synaptic events are often formalized in neural models as stereotyped, time-varying conductance waveforms. The most commonly used of such waveforms is the a-function (Rall 1967): where gsyn is the synaptic conductance and to is the time of transmitter release. This function peaks at a value of lle at t = to + 7, and decays exponentially with a time constant of 7. When multiple events occur in succession at a single synapse, the total conductance at any time is a sum of such waveforms calculated over the individual event times. There are several drawbacks to this method. First, the relationship to actual synaptic conductances is based only on an approximate correspondence of the time-course of the waveform to physiological recordings of the postsynaptic response, rather than plausible biophysical mechanisms. Second, summation of multiple waveforms can be cumbersome, since each event time must be stored in a queue for the duration of the waveform and necessitates calculation of an additional exponential during