Gnosis (neuropsychology)

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With Gnosis (derived from ancient Greek γνῶσις : Gnosis : "[ER-] knowledge") is in the Neuropsychology meant an ability with which the importance of the seen, what is heard or Getastetem etc. is detected. This ability of the recognition of sensory stimuli is the result of integrative neural processing of experience to experience or to experience with very specific individual qualitative "coloring" or "tone" ( Qualia ).

Neuroanatomy

Neuroanatomically, gnosis is a result of the activity of secondary sensory centers . They are located in the immediate vicinity of the primary centers responsible for stimulus processing. Gnostic disorders of the secondary centers are as mindblindness or auditory agnosia referred etc., as the cortical blindness and deafness or as the primary centers cortical blindness or beef numbness , etc.

Already here the critical question arises of the justification in the delimitation of such differently specialized centers. Is it a matter of different elementary capabilities of nerve cells or a special organic interaction of cell groups? The problem here is similar to the subject of neuron theory , to which reference must be made in this context. It is not only a question of whether the entire cerebral cortex is involved or only individual centers. It is also about the interaction of elementary parts of the brain, the neurons , for example in neural networks . In practice, therefore, a reductionist or atomistic, i.e. H. purely scientific point of view in the sense of a strict doctrine of localization . In these concerns, epistemological considerations also play a role, according to which subjective factors play a decisive role that an objective psychology cannot or only with difficulty - u. a. with the help of introspection - are accessible. It is understandable that, due to physiological experiments, little can be learned about subjective functions, since the experimenter often regards the individual behavior as a disturbing deviation from the rule.

Example agnosia

The problem of localization can be demonstrated using the example of agnosias , i. H. in the event of a loss of gnostic performance B. by localizable cerebral bleeding or tumors.

According to the basics of association psychology, agnosia is not defined as a failure of the centers, but as a conduction disorder. The so-called Flechsig's rule goes back to Paul Flechsig (1847–1929) , according to which only association fields and not primary cortical areas are connected by commissure fibers . Primary and secondary centers can thus be anatomically differentiated from one another. This rule is a prerequisite for a more conceptual and predominantly theoretical diverse demarcation between differently localized centers and the nervous pathways that connect them . Centers are viewed as points of intersection between the corresponding nervous pathways. Such purely theoretical schemes, from which various possibilities of damage can be read, are for example the Lichtheim scheme (1884) and the Liepmann scheme (1908). They are called "classical aphasia teachings" and are based on the distinction between damage to the centers of the cerebral cortex or the corresponding pathways. With this exclusion of damage types, these teachings are no longer recognized today.

Criticism is appropriate because centers are not punctiform and disease processes that can be localized in space often also affect the centers at the same time. On the other hand, there is often the clinical impression that in neuropsychological disease processes, functions only partially fail and thus the impression of intact centers only appears to exist. This is often related to the fact that, as a result of a disruption or failure of a center, the other centers that are further away but functionally involved are not affected due to the localization of the disorder and partially compensate for the failure.

But this is the starting point of a criticism presented by Gestalt psychology , which is based on a field theory . The schemes of diverse disorder patterns formed on the basis of association psychology are more of theoretical and didactic interest today and often do not correspond to the clinically observable cases in their delimitations and distinctions. The diverse and often difficult to detect interaction of different centers or brain sections is not taken into account here. So is z. B. to pay attention to the fact that naming disorders often occur in so-called agnosias. Agnosias are therefore often associated with apraxias . The patient has the relevant knowledge, but cannot communicate it. In addition to these clinical difficulties, there is also the fact that tertiary centers show no clear effects and successes in the experimental stimulation. That is why they used to be called "mute".

Naming of the agnosias

The term "agnosia" was introduced in 1891 by Sigmund Freud (1856–1939). In his neuropathological work, Freud did not understand agnosia to be a conduction disorder, but rather the failure of the primary and secondary centers. However, the view of Heinrich Lissauer (1861-1891) has prevailed . A year earlier - in 1890 - he described a case of soul blindness in which only the higher functions of cognition were disturbed, not vision itself, because the patient could not correctly conceptually designate objects but could almost correctly describe them. (Example: A coffee cup is described as a "drinking thing".)

As abarognosis the inability referred to estimate the weight.

Individual evidence

  1. ↑ a b c d Alfred Benninghoff and Kurt Goerttler : Textbook of Human Anatomy. Shown with preference given to functional relationships. 3rd volume nervous system, skin and sensory organs. Urban and Schwarzenberg, Munich 7 1964; P. 292 ff. - on tax "Gnosis".
  2. ^ A b c Klaus Poeck : Neurology . Springer, Berlin 8 1992, ISBN 3-540-53810-0 ; P. 142 - to Stw. "Flechsig rule".
  3. ↑ Uwe Henrik Peters : Dictionary of Psychiatry and Medical Psychology . Urban & Schwarzenberg, Munich 3 1984; P. 43 f. - to Lemma: "classical aphasia".
  4. ↑ Karl Jaspers : General Psychopathology . Springer, Berlin 9 1973, ISBN 3-540-03340-8 ; Pp. 143 f., 168 ff. - on tax “Agnosia”.
  5. ↑ Sigmund Freud : On the conception of aphasia. A critical study. Deuticke, Vienna, Leipzig 1891.
  6. ↑ Heinrich Lissauer : A case of soul blindness, together with a contribution to the theory of the same . In: Archives for Psychiatry and. Nervenkrankheiten , Vol. 21 (1890), pp. 222-270.