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A Mode Control Model of a Neuron's Axon and Dendrites

1970; Taylor & Francis; Volume: 1; Issue: 1 Linguagem: Inglês

10.3109/00207457009147617

1563-5279

Charles J. Swigert,

Photoreceptor and optogenetics research

The ability of a neuron network to process information depends upon the ability of the individual neurons to transport impulses and to control the transport process in other neurons. The propagated action potential seen at the axon has been shown to be dependent upon the excitable characteristic of the neural membrane. Propagation of signals in the dendrites, where synaptic inputs are most likely processed, presents a puzzle. If the dendrite membrane is passive, it would satisfy the diffusion equation. Extra-cellular recordings of systems indicate that the dendrites are partially excitable and can conduct spikes. Further, electrical stimulation of the reticular formation or specific thalamic nuclei suggest that the conduction process can be modified in the dendrites of cortical cells. A neuron model is described which demonstrates many of the observed transport and control properties of dendrite and axon membrane. The Mode Control model is based upon a simple extension of Fitzhugh's BVP model. Lateral transport over the membrane has been introduced by applying Kirchhoff's laws. Reinterpreting the variables, the influence of membrane potential, pH, and calcium ions can be identified. Modification of the voltage-current characteristic of the membrane model can change the axon model to a dendrite model. The dendrite model possesses a diffusion equation mode, a wave equation mode and a pulse mode. Signals are transferred in the wave and pulse mode and blocked in the diffusion mode. The dendrite's mode is controlled by the “resting” level of depolarization. Experimental evidence tends to confirm these phenomena.