Neuron electrochemical processes cause axon impulse instantaneous frequency, average frequency, and frequency changes, and synapse neurotransmitter-packet release rate {coding and sensations}. Impulses and packets are discrete and make digital code. Summing, averaging, synaptic transmission, transmitter binding, feedback, neuron interactions, and neurohormones blur digital code to make essentially analog code.
Stimuli transfer kinetic energy to receptors, which require a minimum (threshold) energy to respond. Light photons collide with, and transfer kinetic energy to, retinal photoreceptors {stimulus energy and receptors}. Photons have energy E that depends on electric-field frequency f: E = h * f, where h is Planck constant. Blue-light-photon-energy to red-light-photon-energy ratio is approximately 1.75. Photoreceptors have maximum-sensitivity wavelength and respond less to higher and lower wavelengths.
To cause one nerve impulse, neuron input must make neuron membrane potential higher than threshold potential. Below threshold, neuron axon has no impulse, equivalent to 0. Above threshold, neuron axon has one impulse, equivalent to 1. Neuron thresholds split instantaneous input-value range into two output opposites, to make intensity categories {thresholds as category boundaries}. Thresholds convert analog signals to digital signals. Neuron series with increasing thresholds can indicate increasing accumulations/intensities and so categories. Thresholds are the lowest level of meaning: yes or no, present or not, true or false.
After receiving sufficient stimulus input, axon-impulse-frequency and synapse-neurotransmitter-packet-release rates typically increase from baseline level, peak, then decrease to baseline, making one wave {neurochemical waves and sensations}, which has 2-millisecond to 20-millisecond time interval. Because they involve few axon impulses, single waves cannot have amplitude or frequency modulation. Neuron-assemblies have coordinated waves that make neuron-assembly activity patterns, to code stimulus intensity, quality, and location.
1-Consciousness-Speculations-Sensation-Biology
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Date Modified: 2022.0225