Transkranielle Magnetstimulation des Motorkortex im Seitenvergleich : eine Probandenstudie

Knowledge about the organisation of the motorcortex plays a keyrole in understanding pathophysiological conditions and treatment of several cerebral diseases. Transcranial magnetic stimulation has been demonstrated many times as a precise and comfortable method for examine the organisation of the motorcortex. The lack of taking reference to the underlying neuroanatomical structures in normal transcranial magnetic stimulation can be successfully compensated by frameless stereotactic stimulation. Main objective of this study has been to get knowledge about the cortical representation and anatomical correlate of muscles of the lower and upper limb. Functional differences in cortical representation of these muscles referring to handedness and ipsilateral representation have been investigated especially. Knowledge about these two aspects in functional organisation of the motorcortex under healthy conditions is an important basis for understanding changes under pathological circumstances. By integrating frameless stereotaxis in transcranial magnetic mapping of the motorcortex the heterogenity of cortical motor representation has been set in reference to anatomical landmarks of the central region and it has been shown the anatomical landmark of the mapped functional epicenters of a representationareal is the sulcus centralis or the posterior slope of the precentral gyrus with is high density of corticospinal motoneurons and the sharp decraese of the potential course in between a representationareal refers to the pre- and postcentral gyrus. Moreover it has been shown that handedness has a functional correlate beside morphological differences in size of the preferred limb and the involved pyramidal tract. More distal muscles of the preferred upper limb have a larger representationareal than those more proximal. Even ipsilateral representation of muscles of the lower and upper limb have been found. Ipsilateral representation of the TA seemed to rise from the supplementary motorcortex of the paracentral gyrus. On the other side the ipsilateral representation of upper limb muscles seemed to rise from areas at the central sulcus where the normal contralateral representation is stored up. The results indicate that handedness and the consecutive differences in cortical representation are an expression of functional plasticity of the motorcortex. More investigation have to be done to understand motorcortex plasticity under pathological circumstances. The detection of ipsilateral representation in healthy subjects shows another dimension of the motorical system which is mainly involved in the reorganisation of motorical skills under pathological circumstances. The ipsilateral representation seems to be masked under healthy circumstances and only needed in performance of bilateral movements of spinal muscles and proximal limb.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2001

Author dc:creator

• Fruth, Martin

Contributors dc:contributor

• von Keyserlingk, Diedrich <Graf>

• info:eu-repo/classification/ddc/610
• Medizin

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-119076%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:57005