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Types of Nervous System in Man, Their Heredity and Evolution

Published online by Cambridge University Press:  08 February 2018

S. Davidenkov*
Affiliation:
Leningrad

Extract

The theory concerning the various types of nervous system in man, generally acknowledged by Russian neurologists, is based on the principles established by Pavlov in his investigations on conditioned reflexes in dogs. It was Pavlov and his collaborators who succeeded in establishing that all variations in the nervous types of dog are due to three main differences. These differences may consist in varying intensity in the essential processes (excitation and inhibition), peculiar to the nerve cell of the cerebral cortex, with the result that some specimens are of a stronger, others of a weaker nervous type. There may also be differences in the degree of equilibrium attained between the two processes, with the result that some specimens are well balanced, while others are unbalanced. Finally the differences may consist in the rate at which the nerve cell is able to pass from one state to the other, in the rate at which the concentration of the excitation or inhibition process is reached after the primary phase of irradiation, and in the rate at which the excitation process becomes extinct within a cell after the action of the stimulus has ceased. As a result of these latter differences some specimens may be more mobile, others more inert. At the same time it was established that the differences with respect to all these three functions could develop independently of one another, owing to which fact the resulting typologic combinations are extremely varied.

Type
Part I.—Original Articles
Copyright
Copyright © Royal College of Psychiatrists, 1947 

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