A Model for Mutual Excitation in a Neuron Population in Olfactory Bulb

The glomerular neurons are small cells in the olfactory bulb which form numerous synaptic connections with each other and with the output neurons of the bulb, the mitral-tufted cells. They form in the mass two anatomical feedback loops, one within the population, the other between the populations of glomerular and mitral-tufted cells. The poststimulus time (PST) histograms of single glomerular neurons on afferent electrical stimulation are monotonic, always with initial increase in induced pulse probability at varying latency of onset, implying that interactions are mutually excitatory. A differential equation is developed to represent the dynamics of afferent temporal dispersion and positive feedback in a neural population. The solutions of the equation are used to generate curves fitted to the PST histograms. The required numerical values for the coefficients are similar to those found for other bulbar neurons, which implies that the particular properties of neurons in the population arise-from the topology of connections and not from the single neurons.