How is any action initiated in the brain?

We must individualize initiators and effectors sites of the action. Sometimes they are very close: in a reflex arc, termination of a sensory neuron transmits a signal which is projected directly on the motor neuron and trigger a contraction. Very few intermediaries.

Other situations are more complex: an idea formulated in the conscious space causes a cascade of reactions that can involve multiple nerve centers: locomotor action, visual search, linguistic communication, etc … It is quite difficult to determine the exact starting point an idea. They are linked in a thread of thought. However, after a time, concepts agglomerated in the global workspace which represents the consciousness become stable enough that derivative action is taken. Effectors will be the same motor neurons than in the reflex arc, but initiation has started at the top of the pyramid of mental organization.

In fact any level of mental organization is potentially initiator and effector of an action. Each of these levels of organization has indeed spontaneous activity and its own rules, which allow to codify simple concepts in more sophisticated concepts. Codification is dynamic and evolving under the influence of retro-controls, but has a stability range that ensures the consistency of functioning of the mind. A property that I call “blind independence.” When the spontaneous action is located low in the mental hierarchy, we call it reflexe or automation; when it is located at the top we call it habit.

Automations and habits are initiators more often than we are aware. Most of our daily actions have an unconscious starting point, in response to stimuli that consciousness does not even perceive. We do not consciously decide to have a meal, light a cigarette, open the car door to get into it … These have an unconscious initiation, from each neural group dedicated to the automation, and consciousness is simply notified. It does not feel thus because it is also subject to “blind independence.” It is after all only an additional level of organization.

This conscious upper level’s task shall be, like previous ones, to evaluate the result of the underlying automation. It built more elaborate representations to organize simple ideas that provide most of the way of our life. It restructures within limits these simple ideas when they appear to produce unfavorable results. But we know it is not easy to manipulate his unconscious. By that mastering consciousness has on the overall action plan of existence, we can name it the master of our destiny. While our daily actions are almost exclusively automations that activate others at all levels of the pyramid of our mind, whether to chase a mosquito, to satisfy an instinctive need, or open a book.

One thought on “How is any action initiated in the brain?”

  1. There may be a problem with the physical side of the initiation of a conscioue action. An “idea” is by definition immaterial and cannot affect the material world. In reality then the idea is only a subjective perception of processes (biochemical, electrophysiological,…) which take place in our brain. This would put in question the concept of “free will”. (Point of view of people like D. Swaab.)

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