Presumption of gating system by sodium activation gating model

Abstract

AbstractRecently, many studies have been reported on hardware neuron models for analyses of physiological nerve phenomena and for engineering applications of biological nerves. The ∧‐shaped transistor‐type hardware neuron model, reported by the authors earlier, simulates well the characteristics of neurons. Hence, the output pulse frequency is proportional to the input level above the threshold and the model is suitable also for engineering applications. Compared with the Hodgkin‐Huxley model which represents a phenomenal formula for the electrical phenomena of nervous excitation, however, the model reported here differs in saturation characteristics and time constants. For closer analyses of physiological nerve phenomena, a model which simulates more closely the characteristics of biological nerves is needed.This paper discusses the characteristics of sodium activation gates of nerve axon membranes and sets forth assumptions on the biological gate structure. For the discussion the authors divided the Na activation gate structure into a potential receptor and a channel gate, respective hardware models are tested with FETs, capacitors and resistors, and it was verified that the models closely simulate the electrical characteristics of the Na activation gate. Based on the results of the experiment, the following presumptions were made: (1) membrane potential is fed to the potential receptor through a high resistance and a capacitance exists between the membrane and the outside of the axon; (2) there are capacitances at both the open and closed positions of the potential receptor, and conductances are connected in parallel to them, thereby controlling the transition velocity by controlling transition of charged gate particles; (3) the channel gate is comprised of two conductances corresponding to the open status and closed status, and the conductances vary depending on respective voltages which vary in response to status change of the potential receptor.