Universität zu Köln

Volz, Lukas J. ORCID: 0000-0002-0161-654X, Sarfeld, Anna-Sophia, Diekhoff, Svenja, Rehme, Anne K., Pool, Eva-Maria ORCID: 0000-0001-8007-9588, Eickhoff, Simon B. ORCID: 0000-0001-6363-2759, Fink, Gereon R. ORCID: 0000-0002-8230-1856 and Grefkes, Christian ORCID: 0000-0002-1656-720X (2015). Motor cortex excitability and connectivity in chronic stroke: a multimodal model of functional reorganization. Brain Struct. Funct., 220 (2). S. 1093 - 1108. HEIDELBERG: SPRINGER HEIDELBERG. ISSN 1863-2661

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Abstract

Cerebral ischemia triggers a cascade of cellular processes, which induce neuroprotection, inflammation, apoptosis and regeneration. At the neural network level, lesions concomitantly induce cerebral plasticity. Yet, many stroke survivors are left with a permanent motor deficit, and only little is known about the neurobiological factors that determine functional outcome after stroke. Transcranial magnetic stimulation (TMS) and magnetic resonance imaging (MRI) are non-invasive approaches that allow insights into the functional (re-) organization of the cortical motor system. We here combined neuronavigated TMS, MRI and analyses of connectivity to investigate to which degree recovery of hand function depends on corticospinal tract (CST) damage and biomarkers of cerebral plasticity like cortical excitability and motor network effective connectivity. As expected, individual motor performance of 12 stroke patients with persistent motor deficits was found to depend upon the degree of CST damage but also motor cortex excitability and interhemispheric connectivity. In addition, the data revealed a strong correlation between reduced ipsilesional motor cortex excitability and reduced interhemispheric inhibition in severely impaired patients. Interindividual differences in ipsilesional motor cortex excitability were stronger related to the motor deficit than abnormal interhemispheric connectivity or CST damage. Multivariate linear regression analysis combining the three factors accounted for more than 80 % of the variance in functional impairment. The inter-relation of cortical excitability and reduced interhemispheric inhibition provides direct multi-modal evidence for the disinhibition theory of the contralesional hemisphere following stroke. Finally, our data reveal a key mechanism (i.e., the excitability-related reduction in interhemispheric inhibition) accounting for the rehabilitative potential of novel therapeutic approaches which aim at modulating cortical excitability in stroke patients.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Volz, Lukas J. UNSPECIFIED orcid.org/0000-0002-0161-654X UNSPECIFIED Sarfeld, Anna-Sophia UNSPECIFIED UNSPECIFIED UNSPECIFIED Diekhoff, Svenja UNSPECIFIED UNSPECIFIED UNSPECIFIED Rehme, Anne K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Pool, Eva-Maria UNSPECIFIED orcid.org/0000-0001-8007-9588 UNSPECIFIED Eickhoff, Simon B. UNSPECIFIED orcid.org/0000-0001-6363-2759 UNSPECIFIED Fink, Gereon R. UNSPECIFIED orcid.org/0000-0002-8230-1856 UNSPECIFIED Grefkes, Christian UNSPECIFIED orcid.org/0000-0002-1656-720X UNSPECIFIED
URN:	urn:nbn:de:hbz:38-406710
DOI:	10.1007/s00429-013-0702-8
Journal or Publication Title:	Brain Struct. Funct.
Volume:	220
Number:	2
Page Range:	S. 1093 - 1108
Date:	2015
Publisher:	SPRINGER HEIDELBERG
Place of Publication:	HEIDELBERG
ISSN:	1863-2661
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language TRANSCRANIAL MAGNETIC STIMULATION; SUBCORTICAL STROKE; BRAIN-STIMULATION; INTERHEMISPHERIC DIFFERENCES; NETWORK CONNECTIVITY; EVOKED-POTENTIALS; ENHANCE RECOVERY; HAND; INHIBITION; AREAS Multiple languages Anatomy & Morphology; Neurosciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/40671