Neuronale Grundlagen der visuomotorischen Verarbeitung bei Normalprobanden und bei Albinismus

Autor :Barbara Wolynski
Herkunft :OvGU Magdeburg, Fakultät für Naturwissenschaften
Datum :01.09.2015
Dokumente :
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Typ :Dissertation
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Kurzfassung :The visual information we receive is vital not only to our perception of the environment, it also affects our reactions to external influences. Understanding the neural processes involved in converting visual information into motor action is therefore a primary interest in neurophysiology. In this study, two approaches were taken to further the understanding of visuo-motor integration in humans. Using functional magnetic resonance imaging (fMRI), relevant cortical regions were identified in healthy subjects. Then, the functionality and plasticity of visuo-motor processing in the presence of abnormal visual input was examined in patients with albinism. The fMRI analysis in healthy subjects demonstrated that an extensive occipito-parieto-frontal network is activated in visuo-motor processing. The lateralization properties and the functional connectivity of the cortical responses supported the following functional specificity: a) visual processing in the occipital lobe and the posterior intraparietal sulcus (IPS), b) visuo-motor planning in the anterior IPS and the frontal eye fields (FEF) and c) motor action in FEF, pre- and supplementary motor areas, and in the primary motor cortex. The results of the patient study suggest that in albinism, abnormal visual field representation can be found in areas beyond the primary visual cortex, namely the middle temporal cortex and in the intraparietal sulcus. This indicatedthat the abnormal visual representation in area V1 is not suppressed or compensated in further processing, but that it is propagated to higher tier visual areas. Despite this visual abnormality, there was no indication of impaired processing for subsequent visually induced motor actions. The hit rates achieved in the visuo-motor paradigm by the albinotic patients did not differ significantly from that of healthy subjects. Further, there was no significant deviation from normal lateralization patterns in the cortical responses of the motor and somatosensory systems. It is concluded that the abnormal representation is made available to visuo-motor integration. Possibly, this is achieved via adaptive mechanisms directly affecting the areas involved in the visuo-motor integration.
Schlagwörter :Albinismus, intraparietaler Sulcus, visueller Kortex, Reorganisation, Lateralisation, visuomotorische Integration
Rechte :Dieser Text ist urheberrechtlich geschützt
Größe :134 S.
Erstellt am :28.03.2011 - 13:21:34
Letzte Änderung :28.03.2011 - 13:21:59
MyCoRe ID :HALCoRe_document_00010366
Statische URL :http://edoc.bibliothek.uni-halle.de/servlets/DocumentServlet?id=10366