Schematic of the dynamical processes that occur within and between neural populations.

Gray circles are quantities associated with interactions between populations (i.e., a and b), while white circles are quantities associated with a population (i.e., a or b). Spike-rate fields ϕab arriving at neurons of type a from ones of type b are modulated by the synaptic dynamics, and undergo dendritic dynamics to produce postsynaptic subpotentials Vab. These contributions are linearly summed in the dendritic tree, eventually resulting in charging currents at the soma that give rise to the soma potential Va, after allowing for capacitive effects and leakage. Action potentials generated at the axonal hillock are averaged over a population of neurons. Then, when the mean soma voltage exceeds a threshold, the mean firing rate Qa of the population is obtained via a nonlinear response function. Finally, the pulses propagate away across the axonal tree and the dendrites of the receiving population c as the set of average spike-rate fields ϕca. Note that self-connections with b = a or c = a are included.