Adaptation

As already noted above, the rate of rise of irritation is one of the most essential parameters of excitability. If you act on nerve DC gradually increasing intensity, then in force, even, many times greater than the threshold, it is possible not to get excited. Nernst (W. Herst, 1904) called this phenomenon " accommodation *.
A similar effect is observed and the effects on nerve DC for a long time: the nerve stops responding. Motor nerves faster accommoderait than sensitive. So, for example, thin nerve fibers, which are considered to be the conductors of pain sensitivity, almost no accommoderait.
According to the majority opinion of the authors, adaptation is a process, which aims to eliminate the effect that causes the nerve incumbent on him factor. If the stimulus causes agitation, the adaptation prevents the appearance of this excitement. If the cathode increases anxiety, adaptation reduced it. Anode reduces anxiety - adaptation seeks to increase it. Adaptation is equally common and characteristic reaction of any excitable education and excitement. Adaptation is active reaction of tissue, but acting in the opposite direction to the excitement. It occurs as soon as it begins to act irritation regardless of the strength of the stimulus. Lorente de No (1949) observed the reaction of adaptation to the current force in 400 times weaker than the threshold. It manifests itself and runs the more, the faster and stronger effect the stimulus. But while it starts to work immediately after the application of irritation, she grows more slowly than excitement. So if irritation grows fast, cool, adaptation is not able to prevent impulse: the rate of flow processes leading to the emergence of agitation, more speed adaptation. On the contrary, at a very slow rise in the intensity of irritation excitation may not occur: the rate of development of adaptation in these cases, equal to the rate of processes of excitation.
Different receptors have different adaptive capacity. Some of them adapt quickly, others slowly. To the last, in particular, include pain receptors. In slowly adapting the receptors generating potential may remain unchanged for many minutes and maintained so long time flow of information centre.

* Is there any difference between the accommodation and adaptation or are synonymous? According to literary data, some authors believe these terms are unambiguous, others give a different meaning. Speaking about the accommodation of the eye, we mean the ability of the lens to adjust to the vision at different distances from the eye. Adaptation is about the same eyes we understand the adaptation of the visual receptors for vision at different illumination. In other instances these terms indicated same physiological phenomenon, but localized in different parts of the analyzer. When talking about nerve fibers, used more often, the term "accommodation", and receptor use a conventional term "adaptation".