From Big Medical Encyclopedia

DECORTICATION OF THE BRAIN (Latin the de-prefix extraction, destruction + cortex bark) — full or partial removal of a cerebral cortex. Full D. of m is used in fiziol, the researches on animals conducted for the purpose of studying of strukturnofunktsionalny bases of brain activity and value of bark of hemicerebrums in regulation of various functions of an organism. Partial D. of m, sometimes very extensive, are applied in clinic as a neurosurgical method of treatment of some diseases connected with dysfunctions of a cerebral cortex (see. Lobectomy , Topectomy ). The phenomena similar to frustration at D. to of m can be observed at an inborn anencephalia; such newborns are impractical.

Goltts (F. L. Goltz, 1881) was one of the first physiologists studying full and partial D.' influence of m on behavior of animals, works to-rogo played an important role in knowledge of functional value of bark of hemicerebrums. Experiments with use of a method of a decortication gained a classical impression about activity of various zones of bark of hemispheres, their value in analizatorny, effector and associative functions is established brain (see).

Full D. of m cause especially essential changes in behavior, than above in a phylogenetic row there is this species of an animal i.e. what more developed bark of hemicerebrums and a kortikalizirovana of function of a brain (see. Cerebral cortex ). Initial representation that with removal of bark at animals uslovnoreflektorny activity is completely excluded, was inexact. The possibility of production of simple conditioned reflexes at dekortitsirovanny animals was shown (cats, dogs).

Of of m has the essential shortcomings complicating obtaining authentic data on function of bark of hemispheres in complete activity of a brain. Emergence of extensive degenerative changes in subcrustal structures, the formation of a hem leading often to epileptic seizures, etc. concern to them. Therefore it is clear to find aspiration more perfect methods D. of of m. So, Buresh and Bureshova (J. Bures, O. of Buresova, 1968) successfully applied functional (reversible) D. of m, using a phenomenon of the extending Lean's depression.

Use of a method of reversible functional (cold) switching off showed that emergence of conditioned reflexes in surgically dekortitsirovanny animals is result of reorganization of brain activity. The emergency functional switching off of a neocortex (see. Very tectonics of a cerebral cortex ) leads to total disappearance of conditional reactions.

It is established also that bilateral functional switching off of certain areas of bark of hemispheres causes considerably big disturbances in behavior of animals, than operational removal of similar areas. This results from the fact that in the last cases experiments on animals are made later a certain term after surgical interventions, during to-rogo a brain is functionally reconstructed, and functions of a remote part of a brain are to a greater or lesser extent compensated. Thus, as a result of surgical D. the most reliable data can be obtained by of m only about those functions of remote area of bark of hemispheres which are not compensated for a long time.

Bibliography: Belenkov N. Yu. Conditioned reflex and subcrustal formations of a brain, M., 1965; it, New aspects of the structurally functional organization of a brain, Zhurn. vyssh. nervn. deyateln., t. 23, century 2, page 248, 1973, bibliogr.; Pavlov I. P. Lectures about work of big cerebral hemispheres, L. — M, 1937; Goltz F. Der Hund ohne Gross-hirn, Pfliigers Arch. ges. Physiol., Bd 51, S. 570, 1892; Lea o A. A. P. Spreading depression of activity in the cerebral cortex, J. Neurophysiol., v. 7, p. 359, 1944.

H. Yu. Belenkov.