Nerve cells function as "inductors" (Mf p. 338) and contributes to govern the development of organs during fetal stage. It seems quite natural with the general view on nervous and nutrition systems as primary opposite vector fields that it is the interplay between these fields that differentiate organs. They are fields from the animal and vegetative poles of the gastrula, from 00- and 0-poles in terms of our model.
   On the molecular level, the same peptides may function as both transmitter substances in the nervous system and as digestive enzymes.

As said about glands the two vector fields meet and combine in hypothalamus with hypophysis and adrenal glands with tissues from both fields. Information goes there from the nervous signals to the chemical ones and blood stream of the nutrition system, an expression for the first inward direction of the nervous system (Ns).
   The origin of Ns from the 00-pole and inward direction seems revealed also in the fact that cortex of the brain primarily is a development of the sensory system (olfactory brain) - i.e. the inward directed signals.

The three kinds of stimuli, chemical → electric → mechanical, can be associated with matter →> charge →> motions →> in dimension degree (shortened d-degree) steps 3 → 2 → 1 → 0/00 in the dimension chain.
   In the propagation of nervous, electric signals the mediating chemical synapses can be interpreted as a binding force, as in the dimension model higher d-degree in relation to next lower one.

1. Polarizations within the nervous system:

The several polarities within Ns can be outlined in accordance with the elementary physical qualities interpreted as a dimension chain - with certain connections to the chain of levels in an organism:

Fig Ns-1

First polarization, step 5 →> 4, refers to the animal and vegetative poles of the embryo, commented above: Ns that develops from the animal pole (00) becomes the front end, position for brain - as the spinal cord stretches along the dorsal side - in opposition to vegetative pole, becoming back end and ventral side.

- Step 4 →> 3 implies the polarization of vector fields in inward - outward directions, in Ns the sensory and motor systems.

- Step 3 →> 2 as a polarization central - peripheral Ns follows mainly the differentiation of organs (level 3) and tissues (level 2): muscles versus guts, somatic versus visceral Ns. Cf. the interpretation of muscles, striated versus smooth ones as a polarization in step 3-2.
   The polarization has features of both the preceding ones; the opposite origins of organs and the outward / inward directions.
   Central Ns governs skeleton muscles, while the peripheral Ns governs not least the walls of blood vessels and intestines, walls as surfaces, and circumference of their inner space, an opposition also of the character mass - space, interpreted as polarity in step 3 - 2.

Secondarily the peripheral Ns gets polarized in the sympathetic and the parasympathetic Ns, an opposition which in function is related with both the main directions outwards/inwards and the next step: stimulation - inhibition.

- Step 2-1: Stimulation - Inhibition concerns charge over nerve cell membrane: hyperpolarization or depolarization of charge (proposed as a physical property of d-degree 2 in the model, relative mass when analyzed as of degree 3). It gets expressed in the design of different cell contacts in Ns.

- Step 1 →> 0/00: Frequency - Amplitude modulation concerns the electric signals of individual nerve cells and is connected with the elementary physical concepts Distance (amplitude, ~ distance from a basic line) and Time (1/f, frequency).

[The nervous system develops in similarity with other organs, e.g. the blood system, from individual cells to threads, nets and layers, through concentration of nerve cells to ganglions and via tube-shapes to the centered structure of the brain: in shapes      0 →1 → 2 → 3.]

2. Motor - Sensory systems:

Direction between the organism as center and its environment as anticenter is polarized in inward direction, sensory stimuli from outside, and outward direction, motor stimuli from inside. These main directions are also expressed in vertebra of the backbone, where motor nerves depart ventrally while sensory nerves enter dorsally.
   The 00-pole of the embryo becomes the dorsal side, its 0-pole the ventral side. The fact that sensory nerves enter from the dorsal side into the spinal marrow and that sensory areas are located dorsally in neural tube and brain is hardly a matter of course, sooner an expression of underlying dimensional rules. The principle in a vertebra:

Dimension degree 4:    Directions out-in.    4 horns.

Fig Ns-2-73-1

In accordance with the same geometry sensory signals in "afferent" fibers up to the brain pass through the posterior tract, i.e. along the dorsal side, while the "efferent" motor ways go ventrally in the anterior cerebrospinal tract.

Further, the switch-over stations in the sensory system are situated in ganglions outside vertebra, while motor ganglions lie inside in the spinal marrow: also a feature of the type anticenter versus center.
   (It could be observed that the ventral horns are thicker, more massive than the dorsal ones.)

Outside the vertebra and spinal ganglions sensory and motor nerves run together in shared pathways, which thus illustrate two-way direction (as of not polarized, two-way directed d-degree 4). These branch, as on a superposed level, in agreement with the same, underlying fundamental polarity, to dorsal and ventral sides:

      Fig Ns-3-73-2

It's a remarkable circumstance too that cortex of the brain, front end of the neural tube and secondary 00-pole of the embryo, develops out of the sensory regions.
   (The layer furthest out in cortex is also dendrites, the inward conducting extensions of the nerve cells.)
   The more ventral motor areas of cortex appear to be of a secondary kind with mostly a regulating function in relation to primary motor centers for movements deeper in the brain. This is another illustration of the underlying polarity center (0) and anticenter (00) and also to a certain degree of the polarity mass - shell in the brain, d-degrees 3-2.

Sensory and motor nerve cells:
In the dimension model step d-degree 4 →> 3 is hypothetically connected with an angle step 180° to 90°, where outward direction gives the radial component in d-degree 3, the inward direction the circular component, in terms of elementary geometries.
   These geometries can be found in the difference between motor nerve cells with axons, radially branched, outwards from the cell, and the sensory pseudo-unipolar cell which has its axon in straight angle to the cell:

   Fig Ns-4-75-1

Interneurons:
In this macrostructure of pathways the development of interneurons and reflex arcs may be interpreted as a result of a polarization towards a "perpendicular" relation in d-degree step 4 →> 3.
   It can be noted too that the stretch reflex doesn't have any interneurons, while the flexor reflex passes via several interneurons. Cf. flexing, bending as a turn towards curved structure.
   (Interneurons in the macrostructure of pathways have a certain similarity with dendrites on the cell level in its combining of signals from different directions - like an arc of a circle passes though a multitude of angles and coefficients of direction.)

      Fig Ns-5-75-2

The transition to circular structure and to rotation becomes most obvious in the "reverberating" circuits, closed chains of interneurons just in sensory, inward conducting pathways, where the signals can rotate self-propelled (Nf p.108).

      Fig Ns-6-75-3

Number of steps in transport of a signal:
Generally there seems to be about 4 neurons in the shortest sensory conductive pathways inwards to cortex of the brain, including the neurons in cortex. 5 with the receptor cell (MF p. 360): to compare with steps in a dimension chain 4 ←←←← 00.

Afferent pathways for sense of touch and proprioceptors:
→> 00: sensory receptor
→> 1: sensory neuron in spinal ganglion
→> 2: switch-over station in spinal marrow or in medulla oblongata
→> 3: thalamus
→> 4: cortex

Afferent pathways for sight and for hearing:
→> 00 receptor cells (cones and rods) and in the inner ear the hair cells
→> 1: bipolar cells* (sight) and from ear 1 nerve cell in a ganglion
→> 2: ganglion cell in retina and from ear 2 neurons in brain stem
→> 3: thalamus, sight and hearing
→> 4: cortex, sight and hearing
(*Apart from 2 layers of horizontally coupled cells moreover. See file Sight.)

A note about cranial nerves:
An invertebrate as the bristleworm has 6 pairs of cranial nerves. An early species of chordates as cyclostomes, whose brain already is divided in regions typical for vertebrates, has 10 pairs. From reptiles on there are 12 cranial nerves:

      Fig Ns-7

3. Somatic - Autonomous (Visceral) nervous system:

      Fig Ns-8

The polarization into somatic and visceral, autonomous Ns concerns directions in relation to governed organs in the body as a 3-dimensional whole:
   - the somatic Ns innervates striated muscles, i.e. in direction outwards in the chain of organs,
   - the visceral or peripheral nervous Ns innervate heart as center of the blood system and the smooth musculature in digestive canals, glands, blood vessels and so on, i.e. mostly organs in directions inwards the body.*
   The somatic Ns concerns external body posture and movements and external locomotion, the relation to environment, while the visceral Ns concerns the inner milieu of the body.

* The autonomous Ns innervates also such things as sweat glands in the skin and e.g. the pupils.

Muscles have in preceding files been proposed as derived in step 3-2 in the level chain of systems (s):

Fig Ns-9

In the chain of organs the polarity somatic - visceral muscles becomes a kind of border between "outward / inward" directions in the middle step:

   Fig Ns-10

The visceral system as inward directed in the mentioned sense cooperates with the sensory = inward directed system of the somatic one: visceral, preganglionic nerves get activated by inward conducting afferent nerves from both visceral and somatic organs

The autonomous system is in several respects secondary or "peripheral" in relation to the central one (CNS) - as a lower d-degree in relation to a higher one implies a further driven differentiation and a relation of the type anticenter to center in the dimension chain:
   The nerve cells in the sympathetic part of the peripheral system, sympathetic ganglion cells and chromaffin cells derive from the neural wall of the embryo, i.e. the anticenter to the neural plate and invaginating neural tube (Kz p. 116).
   Further, in the history of evolution the peripheral system is weakly developed in early chordates as cyclostomes and cartilaginous fishes, while it becomes more developed in bony fishes (Fc).
   It has also been shown that animals can manage without the sympathetic Ns, although less well (Nf p. 344).
   Intestines with origin from the vegetative 0-pole are as such primary in relation to skeleton musculature (from mesoderm), but from the aspect of the animal 00-pole the innervation of the inner organs comes later than that of the skeleton muscles, in this sense representing a later step.
   

Typical for the autonomous system is also that all motor pathways go via intermediate synapses, in this sense act more indirectly.
   In addition, the preganglionic motor neurons in the autonomous system corresponds in their function to interneurons in the central, somatic nervous system (Zf p.202), which gives one more reason to see the autonomous (or "vegetative" ) system as a secondary development according to the interpretation of interneurons above.

The position of visceral sympathetic neurons in the spinal chord between dorsal and ventral somatic centers may perhaps also be an expression for the secondary character of the autonomous system.

The autonomous system is to a great extent governed from hypothalamus and the marrow of adrenal (suprarenal) glands, organs out of the polar meeting between the nervous and the nutrition systems as primary vector fields (4a →> 4b).
   Hypothetically then the autonomous Ns could eventually have a deeper root than somatic Ns as a "resting", potential possibility, although developed later?

4. Sympathetic - Parasympathetic nervous systems:

The peripheral Ns polarizes in its turn in a corresponding way as the polarization somatic - visceral Ns into directions outwards - inwards in the body and also along the coordinate axis forwards - backwards:
   - the sympathetic system (SNS) is outward directed in promoting outer activity, preparation for defense, activated by stress and favors blood flows to skeleton muscles, heart, brain etc.,
   - the parasympathetic Ns (PNS) is inward directed towards intestines, favors blood flows to the digestive organs and depresses the heart activity etc.
   Hence, the sympathetic Ns stimulates mostly organs from mesoderm and ectoderm, outwards towards the 00-pole and environment, the parasympathetic Ns mostly organs from endoderm, inwards the 0-pole, seen from the aspect of tissue origins.

Regarding the spinal cord as a coordinate axis between head and tail, the parasympathetic nerves depart from the "outer" poles, from head and sacrum, in this sense from anticenters, while the sympathetic nerves depart from the central region:
   It's hard to find any natural cause for this arrangement, unless underlying dimensional aspects on directions are included.

   

Fig Ns-11-79

Parasympathetic ganglia have few mutual connections and their effect is local, limited to one organ (Nf p. 343). Cf. inward direction towards one 0-pole = towards one target. While sympathetic ganglia are mutually united through the sympathetic chains (or trunks) on each side of the spinal cord, and their effect is more general and unspecified - as outward direction from a 0-pole.

Position of ganglia as stations for transmission illustrates the same geometry, the typical center - anticenter relation: they lie in the sympathetic Ns near the vertebra, in the parasympathetic Ns further out, at the target organs as illustrated in the figure above.

In pupil reflexes of the eye the complementary effects of S- and P-systems show the radial versus circular polarity of d-degree 3 in the dimension model:
   - the parasympathetic nerves go to the ring-formed iris sphincter muscle for constriction of the pupil,
   - the sympathetic nerves go to radial muscles that widen the pupil.
It's perhaps the most typical illustration of the "postulates" in the model: of inward direction, equivalent with contraction (convergence) leading to circular structure in lower d-degree, and of outward direction as divergence (widening), leading to radial structure in lower d-degree.
   However, both P- and S-systems have double effects of widening - contraction, but mostly then divided on different, more or less complementary organs.

Further, the P-system increases secretion of electrolytes, the S-system increases secretion of organic substances (Mf).
   This difference could be regarded from the aspect of chemical phases: organic molecules as a 3-dimensional phase versus fluids as a 2-dimensional one with regard to bonds in the molecules. There is also a connection with the concepts mass versus charge as a d-degree relation of type 3 to 2 in the fundamental chain of physical qualities.

Number of departing S- and P-nerves from neck and backbone in humans:
(According to a figure in Kz p. 257. Accidental or not?)

S = 18
P 5+3 = 8

The 2x²-chain behind the periodic system:
      Fig Ns-12-18-8

5. Stimulation - Inhibition:

This polarity concerns charge, the quality that has been assumed defined in d-degree 2 in the dimension chain of physical properties. It works through hyper- or depolarizations over cell membranes. The quantity permeability as inversely proportional to charge gets localized to different canals in the membranes (d-degree 2) for different ions. Stimulation occurs through inflow of Na+ ions, inhibition probably through inflow of Cl- (Nf p. 111 f, 114). Hence, it would be a polarity between charges of the ions (or size?), not of directions.
   According to the loop version of a dimension chain we could have a connection between the polarization motor →←sensory signals in step 4 →> 3 and "the other way around" the stimulating-inhibiting system in step 2 ← 1.

     Fig Ns-13-81

Inhibition is in several respects characterized by features from the 00-pole - from anticenter.

In the history of evolution certain facts indicate that the polarization first concerns the membranes of receiving cells, i.e. in inward direction of the cells: the same transmitter, e.g. Acetylcholine, can have inhibiting effect on one cell, stimulating on another. It implies that the same sender cell can have activating or hampering effect on different cells, so in certain mollusks (Nf p. 118 f). (With the postulate in the model that the 00-pole and inward direction is the first polarizing force this circumstance could be taken as another indication that dimensional polarities are underlying the biochemical expressions for them.)

In mammals a division of functions is carried through so that certain cells are inhibiting, other stimulating in their outward activity - with different transmitters for stimulation and inhibition. It could be interpreted as a substantiation of polar functions towards superposed levels in accordance with the dimension model.
   Another example is the polarization that seems to occur in the brain during evolution between inhibiting and stimulating nuclei as striatum and pallidum.

Inhibition is mediated via interneuron between sensory and motor nerve cells (as if it were a polarization of the interval from sensory to motor cell, cf. the preceding figure).
   Geometrically it implies a development towards circular structure and loops in the conducting lines S - M, dimensionally as in steps 4 →> 3 →> 2,
   Such structures polarize further into stimulating and inhibiting interneurons.

The shortest, closed loop seems to be the self-inhibition of the motor α-neurons via interneurons (Renshaw-cells) to their own incoming signals.

   

Fig Ns-14-82-1

The polarization of muscles into antagonists, such as flexor- and stretch-muscles on opposite sides of limbs, seems expressed in mutual, reciprocal inhibition between the antagonists via interneurons. (Compare inside/outside as one geometrical definition of poles of d-degree 2 in the model in arrangement of muscles with stimulation - inhibition as a polarization in step 2 - 1.)

What is called "lateral inhibition" sideways exists on all levels in the nervous system and is principally perpendicular to in- and outgoing signals. (Cf. angle steps →> 180° →> 90°…, associated with d-degree steps 4 →> 3 ...)

      Fig Ns-15- 82-2

It's said that there exist few connections between columns that register different sensory types in cortex in the brain. Those that exist seem to be inhibiting ones. Branches from pyramidal cells in layer 5 go to star cells in layer 3 and 2, which sends inhibiting threads to pyramidal cells in adjacent columns, i.e. sideways (Nf p. 237, 254).
   In a corresponding way purkinje cells in the cerebellum inhibit one another via basket cells, whose threads are transversal to the espaliers of purkinje cells (Nf p. 300).
   The structure serves discrimination that implies sharpening of contrasts, borders, lines: cf. surfaces, d-degree 2 and lines 1. So for instance in retina in the eye.

      Fig Ns-16-82-3

We can find a similar principle in the vegetative world, where top shoots hamper the growth of side shoots through the substance auxin.

Lateral inhibition appears not only in eyes but also in other senses as in hearing and in skin (Nf p. 183): stimulation of the skin around the domain of a certain nerve cell hampers the signals from this. It's then an inhibition from anticenter inwards a center.

   Fig Ns-17-83-1

The inhibition between different kinds of sensory signals, i.e. between qualities, was mentioned above. One example is that touching can hamper signals of pain. Possibly however, this type could be a question of positions too, since they concern the same domain in the skin, although between different kinds of receptor cells. There is reason to suspect that the different senses are differentiations, mutually connected. (See about senses with aspects from the dimension model.)

A primary type of inhibition, where signals from anticenter via synapses hamper a motor signal from center is exemplified by the sensory Golgi organs in tendons at insertions of a muscle. (Cf. tendons as connective tissue on a tissue level referred to d-degree step 2 - 1 in earlier interpretations here.).
   Contraction of the muscle, implying stretching of tendons, leads to inhibiting signals via interneurons in the spinal chord to α-neurons of the muscles (Nf p. 206 f):

      Fig Ns-18-83-2

Muscle spindles, in the center of the muscle, are much more complex and directions of signals from center and anticenter the complementary ones: Outgoing (afferent) from the center of the spindle, to alpha-neurons in spinal chord, while incoming signals (efferent, from gamma-neurons) go to the ends at anticenters of the spindle. The central part of these fibers are not even contractile, only the ends at anticenter. Cf. contraction as directions inwards from 00-poles, outwards from 0-poles.
   The inhibiting function of the anticentric gamma-neurons seems not yet fully understood but is expressed as effecting the sensitivity of the spindle (Nf, Aph, Mf).

With the coordinate axes of the body in mind, Front - Back from Animal - Vegetative poles, there are several examples showing that inhibiting signals originate from the 00-pole or from secondary, superposed levels, which also as such represent anticenter in relation to underlying ones.

   Fig Ns-19-84

We have the already mentioned example that motor areas in cortex mostly have the function to regulate sensory inflow and therewith indirectly modulate motor outflows (Nf p. 264-265). While the essential stimulation to movements comes from inner centers in the brain and brainstem, from there to cortex and back.
   Inhibiting impulses from cortex have disappeared at spastic movements and released exciting impulses from the reticular formation and vestibular nuclei in the brainstem (LEL p. 133).
   The motor pyramidal pathways that go from cortex in the brain directly down to the spinal cord are physiologically younger than the other "extrapyramidal" pathways from inner centers in the brain, and they seem mostly to have a function to regulate distal fine motor ability (Fz p. 355). A big part of them go to interneurons from sensory spinal ganglia in the dorsal horns of the spinal cord.
   The pyramidal pathways can be cut off without loss of movability, not even loss of movements governed by the will. Only precision and velocity become weaker and slower (LEL p. 160).

In cerebellum (note its dorsal ~ anticenter location) the inhibition processes are dominating, while pathways for stimulation come from inner nuclei in the brainstem (Fig. Nf p. 282).

The polarity stimulation - inhibition can be regarded also as a specialization of the underlying polarity within the autonomous system in sympathetic - parasympathetic polarity, concerning stimulation - inhibition of blood flows to different organs.

According to certain observations (1978) inhibiting transmitters should lie in elliptic granules in the ends of axons, stimulating ones in round granules (Nf p. 117). Ellipses are polarized circles with two centers. Hence, also in such a detail, if the observation is correct, we could find a trait of the 00-/0-polarity.

6. Frequency - Amplitude modulation:

Amplitude and frequency are coupled entities in a sine wave, complementary energy forms as potential energy and kinetic energy. Potential energy = distance from a zero-line as 0-pole, kinetic energy passage through the zero-line per time unit. Hence the quantities are connected with distance and time respectively and this polarity is suggested as last step in polarizations within the nervous system.

     Fig Ns-20-90-2

In an atom the two energy forms are transformed into one another at absorption and re-emission. The amplitude of an electron orbit, distance from the nucleus, increases at absorption of radiation (inward direction) and becomes a measure of its energy. It translates into frequency of emitted radiation (outward direction) when the electrons fall back again to an inner orbit, the frequency depending on radial distances between different orbits.

In the nerve cell there is the same principle: incoming chemical signals become amplitude modulated in the cell membrane; outgoing electrical signals in the axons become frequency modulated.
   Geometrically it illustrates the poles circular - radial structure out of d-degree 3 in step 3 - 2 in the model: circular structure from inward direction connected with amplitude, radial structure from outward direction connected with frequency.
   (From the electrons point of view the description can seem reversed: outward jumps defining amplitudes,~ distances, d-degree 1, inward jumps giving the frequency, ~1/Time. Thus, we have a kind of pole exchange out/in between electrons and EM-waves as assumed in "d-degree 0/00" of motions in our model.)

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