Center (neuroanatomy)

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In neuroanatomy and neurophysiology , the term center (derived from ancient Greek τ ‚κέντρον to kentron , German 'sting' , then the spiked stick or the" center of the circle "at which the tip of the circle is attached) denotes an association of nerve cells that form a working group to process afferent neural stimuli and convert them into efferent neural impulses. In this way, overarching tasks that are important for the entire organism can be better managed, especially those of better adaptation to constantly changing environmental conditions ( cerebrospinal nervous system ). Synonyms are cerebral cortex field, field, = Latin area or Kern = Latin nucleus . While the reflex model is decisive for the “center” and thus has a strictly defined physiological meaning, the term “core” is more in purely anatomical use, especially for the gray origin, switching or end nuclei of a nerve pathway . (a) (a)

Reflex model

The center thus corresponds to the reflex concept or the model of the reflex arc . The nervous center in humans and vertebrates is the result of a long development that led to the development of a central nervous system (CNS). (b) Anatomically and topographically, the CNS can be separated from the peripheral nervous system as an organ system within the skull and spinal canal . Functionally, both parts form a unit. Both parts are called a system insofar as they are composed of differently differentiated nerve cells ( neuron theory ). The model of centralization described by Heinz Werner is also effective within the central nervous system. The central nervous system is therefore not to be understood as a uniform functional association, but as an association of different centers that only come into mutual connection with one another in the course of development. These centers are hierarchically structured and divided into higher and lower centers. The highest centers are also connected with one another. (a) Regardless of the level of the hierarchical system at which such a center is located, it is referred to as a center if it has a specific effect on a certain organ or organ system. (a) This also corresponds to the definition of Hans Winterstein (1879–1963), who assumes a center as part of the CNS when it is of decisive importance for the occurrence of a central nervous process. Carl Wernicke described the function of higher centers as part of a psychological reflex arc . The Wernicke Center was named after him. A number of individual fluctuations arise in the maturation and formation of the furrows and convolutions of the brain. There is no complete correspondence between different brain surfaces, not even between the left and right hemispheres of a brain.

Projection centers, association centers

Projection centers are associated with "deeper" centers or organs. Association centers connect centers “at the same level” on the neural level. There are not only connections between somatosensory and somatomotor nerves and between viscerosensitive and visceromotor nerves, but also between the cerebrospinal and autonomic nervous systems. (b) (c)

Cerebrospinal nervous system

Examples of sensory centers are:

Examples of motor centers are:

The map of the cerebral cortex gives a detailed overview of the various brain centers or fields.

Autonomic Nervous System

Examples of vegetative centers are:

The neural vegetative centers are closely linked. So far they could only be identified electrophysiologically, not morphologically. (c)

Pathological anatomy

Pathological focal or even referred to as "focal" changes of organs or other tissues may be similar as in neuroanatomical centers is the case, lead to long-term effects affecting parts of the body or the whole body. This can of course occur if the corresponding centers are damaged. (b) As such a center, the gyrus praecentralis (anterior central turn) is of clinical importance for the entire voluntary motor function . The clinical picture of damage in such cases corresponds to that of " central paralysis ". The term “central” does not only refer to the gray neuroanatomical centers themselves, but also delimits all damage within the CNS from the ailments that occur in more peripheral nerves. It not only relates to the gray matter of the neuroanatomical centers, but also applies to damage to the white matter in the CNS and thus its nerve tracts. Thus “central” is an ambiguous term. The precentral turn corresponds to Area 4 according to Korbinian Brodmann (1868–1918), see also the map of the cortex .

criticism

Both the reflex model and the conception of the circle or the spherical surface (as periphery) and its center (as center) connected with the derivation of the term “center” represent abstractions . Neurobiological centers cannot anatomically be understood as “punctiform” entities . There is almost always a whole "field" of spatially structured further instances involved. This applies both horizontally to the same hierarchical level of a respective center in relation to other similarly structured centers and vertically to the gradual formation of a “higher” center in the course of development history . Already in chap. Reflex model was dealt with ontogenetic ideas, according to which “higher” centers develop from “lower” preliminary stages. This always takes place according to the principle of influencing an ever increasing number of specific reactions through the centralized structure. (d)

The multitude of specific reactions requires a multitude of corresponding centers that work together in the sense of an interrelationship . A center is therefore always dependent on a system of other nervous units. The nervous apparatus works as a nervous system. This aspect of integration is also taken into account by a further definition of the nervous center, which speaks of an “anatomically circumscribed area of ​​the CNS or ... several such areas in the sense of the center constellation”. The concept of field was introduced by Gestalt psychology , cf. especially the term isomorphism . (b) The field term has proven to be fruitful for the description of neuropsychological syndromes in the context of the primary, secondary and tertiary cortical fields, see also the explanation of these field terms based on vision . (a) From the point of view of the image of the circle, the concept of the field includes not only the area of the circle as the sum of all "lower" instances between the periphery ( receptor ) and the "highest" instance (center of the circle), but also the area outside the circle as a sphere the environment . One speaks therefore not only of association centers and projection centers , etc., but also of association fields and projection fields, etc. The localization thinking of neurology is rather questionable in psychology if it occurs without taking into account the services of the totality of the cortical fields. (a) (e)

Individual evidence

  1. ↑ center . In: Hermann Triepel : The anatomical names. Your derivation and pronunciation . 26th edition. Verlag von JF Bergmann, Munich 1962, edited by Robert Herrlinger , p. 21.
  2. ↑ a b Norbert Boss (Ed.): Roche Lexicon Medicine . 2nd Edition. Hoffmann-La Roche AG and Urban & Schwarzenberg, Munich, 1987, ISBN 3-541-13191-8 :
    (a) p. 1851 f. to Lemma “center”;
    (b) p. 759 on Lemma “Herd”,
    cf. a. downloadable text 5 2003 of the online lexicon .
  3. ↑ a b c d e Alfred Benninghoff , Kurt Goerttler : Textbook of Human Anatomy. Shown with preference given to functional relationships . Volume 3: Nervous System, Skin and Sensory Organs . 7th edition. Urban & Schwarzenberg, Munich, 1964:
    (a) p. 109 on Stw. “Orientation within the environmental sphere”;
    (b) p. 106 on head. “Building functional structures in the development series”;
    (c) p. 129 to Stw. “Connections in the spinal cord and in the spinal ganglia”;
    (d) p. 106 on head. “History of development” as in (b);
    (e) p. 292 to Stw. "strict localization theory".
  4. ↑ Peter R. Hofstätter (Ed.): Psychology . The Fischer Lexikon, Fischer-Taschenbuch, Frankfurt am Main 1972, ISBN 3-436-01159-2 , p. 102 on "Centralization".
  5. ↑ a b Wilhelm Karl Arnold u. a. (Ed.): Lexicon of Psychology . Bechtermünz, Augsburg 1996, ISBN 3-86047-508-8 :
    (a) Sp. 2686 f. to Lex.-Lemma: “Central nervous system”, Stw. “hierarchical structure”;
    (b) Col. 599–600 on lexical lemmas: "Field" and "Field theory".
  6. ↑ a b c Robert F. Schmidt (Ed.): Outline of Neurophysiology. 3. Edition. Springer, Berlin 1979, ISBN 3-540-07827-4 :
    (a) p. 249 on “Definition of the term› center ‹” and on chap. "Central nervous regulation of the vegetative effectors by the spinal cord and brain stem";
    (b) p. 282 (incl. illus.) on section “Association cortex - projection cortex”;
    (c) p. 249 see (a).
  7. ↑ Hermann Rein , Max Schneider : Introduction to Human Physiology . 15th edition. Springer, Berlin 1964; P. 553 on “Definition of the center by Hans Winterstein”, p. 625 f. to the tax "localization".
  8. ↑ Carl Wernicke : The aphasic symptom complex . A psychological study on an anatomical basis. Breslau: M. Cohn & Weigert 1874.
  9. ^ Hermann Voss , Robert Herrlinger : Taschenbuch der Anatomie . Volume III: nervous system, sensory system, skin system, increment system . 12th edition. VEB Gustav-Fischer, Jena 1964; P. 52 to chap. "Furrows and Convolutions of the Hemispheres".
  10. ↑ a b Hans Walter Gruhle : Understanding Psychology . Experiential theory. 2nd edition, Georg Thieme, Stuttgart 1956; P. 4 to district “brain center, focus, focus”.
  11. ^ Fritz Broser : Topical and clinical diagnosis of neurological diseases. 2nd edition, U&S, Munich 1981, ISBN 3-541-06572-9 ; P. 134 to chap. 2–9, district “central paralysis”.
  12. ^ Zetkin-Schaldach: Dictionary of Medicine . dtv, Munich and Georg Thieme, Stuttgart 1980, ISBN 3-423-03029-1 (dtv) and ISBN 3-13-382206-3 (Thieme); S. 1547 on Wb.-Lemma "Centers".
  13. ^ A b Karl Jaspers : General Psychopathology. 9th edition. Springer, Berlin 1973, ISBN 3-540-03340-8 :
    (a) p. 131 on Stw. “Neuropsychological Syndrome”; P. 414 on district “center”;
    (b) pp. 157 ff., 403, 408 f. to Stw. "Localization problem".