Case Report ARTICLE
Recovery from spatial hemineglect associated with intra- and transhemispheric functional connectivity changes in vestibular and visual cortex areas – a case study with caloric stimulation
- 1Department of neurology and German Center for Vertigo and Balance Disorders (DSGZ), Ludwig-Maximilians-Universität München, Germany
- 2German Center for Vertigo and Balance Disorders (DSGZ) and Graduate School for Systemic Neuroscience (GSN), Ludwig-Maximilians-Universität München, Germany
- 3Department of neurology and Graduate School for Systemic Neuroscience (GSN), Ludwig-Maximilians-Universität München, Germany
- 4Clinical Neuroscience, Ludwig-Maximilians-Universität München, Germany
- 5Department of neurology, German Center for Vertigo and Balance Disorders (DSGZ), Graduate School for Systemic Neuroscience (GSN) and Munich Cluster for Systems Neurology (SyNergy), Ludwig-Maximilians-Universität München, Germany
Objective: Vestibular signals are involved in higher cortical functions like spatial orientation and its disorders. Vestibular dysfunction contributes, for example, to spatial neglect which can be transiently improved by caloric stimulation. The exact roles and mechanisms of the vestibular and visual systems for the recovery of neglect is not yet known.
Methods: Resting state functional connectivity (fc) MRI was recorded in a patient with hemispatial neglect during the acute phase and after recovery six months later following a right MCA infarction before and after caloric vestibular stimulation. Seeds in the vestibular (parietal operculum OP2), the parietal (PPC; 7A, hIP3), and the visual cortex were used for the analysis.
Results: During the acute stage after caloric stimulation the fc of the right OP2 to the left OP2, the anterior cingulum, and the para/hippocampus was increased bilaterally (i.e., the vestibular network), while the interhemispheric fc was reduced between homologous regions in the visual cortex (VC). After six months similar fc increases in the vestibular network were found without stimulation. In addition, fc increases of the OP2 to the PPC and the VC were seen; interhemispherically this was true for both PPCs and for the right PPC to both VCs.
Conclusion: Improvement of neglect after caloric stimulation in the acute phase was associated with increased fc of vestibular cortex areas in both hemispheres to the para-hippocampus and the dorsal anterior cingulum, but simultaneously with reduced interhemispheric VC connectivity. This disclosed a, to some extent, similar but also distinct short-term mechanism (vestibular stimulation) of an improvement of spatial orientation compared to the long-term recovery of neglect.
Keywords: vestibular, neglect, visual, FC, OP2, transhemispheric, spatial, parietal
Received: 03 Oct 2017;
Accepted: 14 Feb 2018.
Edited by:Barry M. Seemungal, Imperial College London, United Kingdom
Reviewed by:Luca Passamonti, University of Cambridge, United Kingdom
Bjoern Machner, University of Lübeck, Germany
Copyright: © 2018 Conrad, Boegle, Ertl, Brandt and Dieterich. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: MD. Julian Conrad, Ludwig-Maximilians-Universität München, Department of neurology and German Center for Vertigo and Balance Disorders (DSGZ), Marchioninistr. 15, Munich, 80802, Bavaria, Germany, email@example.com