This is an exercise in speculation. Traditionally, speculation is allowed free reign when discussing how the nervous system works. So, this is speculation, do not look for truth.
Today, the nervous system is made of individual neurons that communicate by /electrochemical means. Such a nervous system is best described by discrete electrical components. Therefore; I envisioned how such a nervous system might work. Certainly, no one has attempted to demonstrate how the nervous system does work. So, why not speculate?
We are interested in the nervous system, not the soul (mind). There has been too much idle chatter about the soul (mind). Descartes would have a soul (mind) with causal powers. The Princess Elizabeth would have none of that. I stand with the Princess. If the soul (mind) has no causal powers, it is irrelevant to our speculations. The subjective half of experience has no place in nervous system organization.
We see the neuron as a leaky integrator It integrates incoming charges, at the same time, the integral leaks out. When income sufficiently exceeds outgo, an axonal pulse is released. Many reject such simplicity, I find it sufficient. We add a few time-dependent parameters that described the neuron=92s readiness to fire, to acquire synapses, to shed synapses, to grow new axonal branches.
We feel that the neurons are precisely ordered throughout the nervous system, ordered by the genome. When Hubel and Wiesel began there work, there was no reason to believe that area seventeen of the neocortex had any more organization than a bowl of oatmeal. They managed to find the rules by which it is organized, and demonstrated a cortex of precise connection. Why should we expect to find otherwise in other areas of the neocortex? If we cannot find the rules by which another area is organized, that only tells us that we must look harder. We should expect to find a place for every neuron, and every neuron in its place. The genome, together with the RNA, makes the rules.
The first thing about the nervous system that interests us is the motor program generators. These are clusters of neurons in the spinal column and hindbrain, that produce the exquisitely sequenced axonal pulses that, when they arrive at the muscle fibers, produce a motor acts. The life of an organism is a succession of such motor acts. Each motor act requires the initiation of a motor program generator. Without these motor acts, the organism is nothing but an inert lump; the motor program generators give it life.
But we must avoid thinking of the motor program as an organ. It is anything but. It is the output of a group of neurons that corresponds to the muscle fibers that will execute the motor acts. This motor program moves through the nervous system, now in the form of axonal pulses, and now in the form of excited neurons.
The motor program generator may be likened to the player piano roll that produces music. The sequenced axonal pulses are the equivalent of the puffs of air that flow through the perforations in the roll. When the puffs arrive at the piano keys, music ensues. When the axonal pulses arrive at the muscle fibers, we walk and talk. A motor program generator can be ignited by centers in the hindbrain, it can also be ignited by sensory input.
As the motor program proceeds through the nervous system, it is smoothed by the cerebellum. It continues to the ventral anterior- ventral lateral nuclei of the thalamus. Here the impulses of the motor program come under the influence of the neurons of the thalamic reticular nucleus. If these neurons are activated by the confluence of current sensory input and synaptic strengthening due to previous bad results, the motor program is halted. If not, it proceeds to the motor and pre-motor cortex and executes.
As an extra capability, the thalamic reticular nucleus can halt the inward flow of sensory signals at the lateral geniculate (vision), the medial geniculate (audio), and the ventral-posterior nuclei (somatosensory system). Simultaneously and selectively, all motor programs can be halted at the VA-VL somplex. Released from the tyranny of the rush of sensory input, the neurons of the neocortex can freely associate. This is called =93thinking=94.
Ray