Functional redundancy of the premotor network in hemispherotomy patients

  • Objective: Using multimodal imaging, we tested the hypothesis that patients after hemispherotomy recruit non-primary motor areas and non-pyramidal descending motor fibers to restore motor function of the impaired limb. Methods: Functional and structural MRI data were acquired in a group of 25 patients who had undergone hemispherotomy and in a matched group of healthy controls. Patients’ motor impairment was measured using the Fugl-Meyer Motor Assessment. Cortical areas governing upper extremity motor-control were identified by task-based functional MRI. The resulting areas were used as nodes for functional and structural connectivity analyses. Results: In hemispherotomy patients, movement of the impaired upper extremity was associated to widespread activation of non-primary premotor areas, whereas movement of the unimpaired one and of the control group related to activations prevalently located in the primary motor cortex (all p ≤ 0.05, FWE-corrected). Non-pyramidal tracts originating in premotor/supplementary motor areas and descending through the pontine tegmentum showed relatively higher structural connectivity in patients (p < 0.001, FWE-corrected). Significant correlations between structural connectivity and motor impairment were found for non-pyramidal (p = 0.023, FWE-corrected), but not for pyramidal connections. Interpretation: A premotor/supplementary motor network and non-pyramidal fibers seem to mediate motor function in patients after hemispherotomy. In case of hemispheric lesion, the homologous regions in the contralesional hemisphere may not compensate the resulting motor deficit, but the functionally redundant premotor network.
Author:Conrad Prillwitz, Bastian David, Gottfried Schlaug, Thomas Deller, Johannes Schramm, Robert Lindenberg, Elke HattingenORCiDGND, Bernd Weber, Rainer Surges, Christian Erich Elger, Theodor Rüber
Parent Title (English):Annals of Clinical and Translational Neurology
Place of publication:Chichester [u.a.]
Document Type:Article
Date of Publication (online):2021/08/04
Date of first Publication:2021/08/04
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2022/03/24
Page Number:13
First Page:1796
Last Page:1808
This work was supported by grants from the BONFOR research commission of the medical faculty of the University of Bonn (2017-6-02 and 2016-8-07). CCP and BD are recipients of fellowships from Bischöfliche Studienförderung Cusanuswerk. TR is supported by the Hessian Ministry of Research and Art's LOEWE initiative. The authors thank Esra Aslim for technical assistance in figure creation. Finally, the authors are grateful for the kind support provided by the Verein zur Förderung der Epilepsieforschung e.V. in Bonn.
Dewey Decimal Classification:6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit
Licence (German):License LogoCreative Commons - Namensnennung-Nicht kommerziell - Keine Bearbeitung 4.0