A computer program for simulating a network of interacting neurons. I. Organization and physiological assumptions.

Abstract PABLO is the most recent version of a series of digital-computer programs designed to simulate interacting neurons. Programmed in FORTRAN, it is organized to jump from event to event; the state variables are updated only when necessary as, for example, when an impulse arrives at a synapse. The neuron model allows absolute and relative refractoriness, linear or nonlinear summation of synaptic potentials, pacemaker activity, and, post-inhibitory rebound. Synaptic mechanisms include quantal release of transmitter, synaptic noise, and facilitation or antifacilitation. Neurons can be connected by axons, terminating in synapses, in any specified fashion. Each axon segment has its own conduction time and probability of failure to transmit an impulse. Output of PABLO is the set of times of impulse production or arrival in specified network components; these times are available for display or statistical analysis by any of a number of other, compatible programs. Part I describes the overall organization of the program and the physiological assumptions it embodies.