How is the reflex?

We already know that the main law of the nervous system is the reflex. It was revealed more than 300 years ago by the famous philosopher and scientist Rene Descartes. If it is believed that the animal makes various movements because he has a soul, absolutely not connected with the body, Descartes made materialistic position that any action of the body is called that or other impact on the senses. Any such impact nerves carry in the brain ("just as we pull the rope that rang a bell at the other end"), and from there on the relevant nerves move certain muscles. Each response of the organism depends strictly on what part of the body and how easily provoked. Descartes compared the device nervous system and its work with the Royal gardens in the Netherlands. Their grottos and fountains were designed so that, stepping on certain tiles tracks, you was just a sudden change jet fountain, the appearance of new figures in their sculptural groups. For example, when approaching bathing Diana she was hiding and appeared Neptune, threatening his Trident. The idea that the movements of the animals do not depend on "free will", and from a strictly certain reasons, was exceptionally bold in those days and is immortal contribution of Descartes.
In the basis of reflex is the so-called reflex arc. From the receptor signals interpreted by them running to the corresponding nerve cell in the brain. This completes sensitive part of a reflex arc. Hereinafter, the signals are transferred to the motor cage, sending fiber to a particular muscle, gland, etc. This part reflex arc called motor or effector. It is clear that the transfer of excitation from the sensitive parts reflex arc to motor parts is possible only in case, if between them there is a relationship, that is, if they directly or through a number of intermediate cells are connected in their processes. This relationship is the basis of every reflex.
Usually physiologists study reflexes of the spinal cord on beheaded frog (with the same object of observations, we have already met in an interview 6). Hung her on a string, put paws animal various stimuli that receive specific answers. For example, if you bring to her paw a glass of acid, a frog after a few seconds, pulls the foot of the caustic solution. If you put her foot dipped in acid piece of paper, the frog will shake a paw, and if this does not work, reset the paper the other foot. Such actions beheaded frogs can really surprise ignorant man, seem to something reasonable. However, the point here is simply that the nervous system, even such a relatively low organized an animal, like a frog, took tens of millions of years of historical evolutionary development and in it during that time formed the nerve connection between the sensory and motor cells, healthy, and therefore seem reasonable.
Especially a lot to study the reflex as the basic law of the work of the spinal cord and certain areas of the brain made the father of Russian physiology I. M. Sechenov. Moreover, Sechenov put forward the idea that both the top Department of a brain bark of the big hemispheres - also works on the law of the reflex. It was of great importance, because with the activity of the cerebral cortex scientists materialists has long been associated mental life. However, specific laws work bark science did not know. Only I. P. Pavlov succeeded brilliantly to solve this problem.
Having made many important discoveries in physiology of several body systems, proving the leading role of the nervous system in management of the scientist moved to learning of the highest manifestations of the brain. He set a task to reveal the laws of functioning of a bark of the big hemispheres, to show what physiological basis of the so-called mental activity, which he proposed to call the higher nervous activity, to emphasize its relationship with the nervous system.