Simulation of restricted neural networks with reprogrammable neurons

A network model is described which is composed of reprogrammable neurons, incorporating the following design features: (1) spikes can be generated by a model representing repetitive firing at axon (and dendritic) trigger zones; (2) active responses (plateau potentials; delaying mechanisms) are simulated with Hodgkin-Huxley-type kinetics; (3) synaptic interactions, both spike-mediated and nonspiking chemical (chemotonic), simulate transmitter release and binding to postsynaptic receptors; facilitation and antifacilitation of spike-mediated postsynaptic potentials (PSPs) are included; (4) chemical pools are used to simulate second messenger systems, trapping ions in extracellular spaces, and electrogenic pumps, as well as biochemical reaction chains of quite general character; modulation of any of the parameters of any compartment can be effected through the pools; and (5) intracellular messengers of three kinds are simulated explicitly: those produced by voltage-gated processes (e.g. Ca), those dependent on transmitter (or hormone) binding; and those dependent on other internal messengers (e.g. internally released Ca; enzymatically activated pathways)