title: Kepiński's functional structures, Kohonen's topological structures, aphasia and apraxia.
abstract: The concept of functional structures was introduced by Kepiński. At the Second Scandinavian Congress on Image Analysis in 1981 Kohonen provided evidence that the map of signals has the same topological order as the map of reactions. These topological concepts can be applied also to logical structures. The same is true also of functional structures described by Kepiński in schizophrenia, which may be created or destroyed, but their topological order remains unaltered. Functional structures change in obscuration and in hallucinogen-induced psychodelic states. Fixed pathological structures characterized by an altered topological order occur in paranoia. In the case of amnestic aphasia single elements of the topological functional structures fall out-these elements represent terms which patient is unable to recall. In motor aphasia, on the other hand, damage concerns the topological functional structures of speech related movements. In sensory aphasia damage concerns topological functional structures in the sensory area. In Goldstein's amnestic apraxia there is a loss of some elements of the topological functional structures governing the movements. In ideational apraxia the damage concerns topological functional structures representing entire sets of motor function and especially their creation. In ideomotor apraxia the respective topological functional structures are retained, albeit inaccessible, due to a disturbance in the motor association. In motor apraxia the damage seems to concern the topological functional structures governing precise movements and located at a lower level, i.e., closer to the effector. Constructive apraxia seems to result from the disturbed creation of the respective functional structures. Similarly the hypermotility of a maniacal type has a smooth and purposeful character, as far as the relation to a particular situation is concerned, which suggests that the respective topological functional structures are preserved. On the other hand, in the hyperkinetic phase of catatonic schizophrenia, in which the patient performs sequences of incoherent aimless movements without any relation to the current situation and environment, these structures are supposedly altered.
mesh_terms: D001037:Aphasia / Q000503:physiopathology*; D001039:Aphasia, Broca / Q000503:physiopathology; D001041:Aphasia, Wernicke / Q000503:physiopathology; D001072:Apraxias / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology*; D006801:Humans; D011381:Programming Languages