Brain Study 7 - The Development of the Nervous System(truth or dare?)

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The Development of the Nervous System

 

(this problem with images is a thing to deal with!..bn)

 

Figure 3 shows a primitive nervous system. This system has been

around more than a half-billion years and is still used by many

primitive creatures. This is a reactive system, as are all nervous

systems. The sensor sees a condition, such as heat, light or touch,

and passes that information directly to a fixed process which

converts this real time information directly into a motor control

command. There are single-cell animals, for example, which live by

eating others. They move aimlessly around until they feel that they

have bumped into something and then start chomping away on whatever

is next to them. There are others that rely on light to power their

photo-synthesis energy system. These will sense which direction has

the most light and then swim toward it.

 

This decision module is fixed. It does not learn, it only reacts to

the current environment as reported by the sensor. It is not

intelligent. It is, instead, merely reactive. In electronic

engineering terms it is a state machine. With a given set of input

information, it produces a certain fixed response. The decision

mechanism is not an intellectual device which manipulates data while

judging its end effect, it is a fixed circuit which sums the input

data (some of which may be a summation done separately elsewhere) and

delivers a particular action command for each set of input data.

Evolution always builds on existing material. This miniature nervous

system set the pattern for all mobile life, billions of years ago. As

life became more complex, more terms (things to be considered in

decision making) were added to this decision matrix. An advanced

modern form of mobile life may have a decision matrix composed of

thousands of lessor decision mechanisms, each with hundreds or

perhaps thousands of other terms needed for the decision. As new

devices were added (arms, legs, etc.) and new sensors were added

(eyes, ears, nose, etc.) new terms were added into the decision

mechanism. The decision matrix is not a device which is located in

one place. It is diffused throughout the brain with major portions

located close to major complex functions.

 

Note! This form for the behavior controlling device is surmised from

observation and study of the evolution process. We do not know how

the brain works as yet. We do know however:

 

(1) Evolution does no planning. (2) Its mutations (changes) are

random, in general. (3) The mutations occur on existing material. (4)

Evolution does not develop functions not currently needed. (5) The

environment selects (allows to live) mutations which are helpful for

survival. These five statements together strongly imply the gradual

development of a decision system and as strongly denies the

possibility of the sudden invention of a super thinking machine which

the organism later advances into using.

The primitive nervous system works as we have described. Starting

with the lowest order of mobile animals and observing the change in

nervous systems from those to the most advanced (including man) there

are only gradual changes in system complexity. It is reasonable to

assume that evolution works the same in all species. Therefore man is

an extension of the same process.

As nervous systems became more complex through evolution, the new

functions were added to the old, so there is no reason to believe

that the methodology changed, nor is there evidence of any different

kind of structure.

In examining brain trauma (strokes and accidents), mainly through

autopsy after the patient's debilitation had been chronicled, the

existence of specialized portions of the brain can be demonstrated,

and has been known for a long time.

Physical measurement basis for these assumptions may be observed by

various forms of magnetic resonance imaging. See Magnetic Imaging

Techniques.