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Exp Neurol. 2017 Nov;297:50-61. doi: 10.1016/j.expneurol.2017.07.013. Epub 2017 Jul 25.

The differentiated networks related to essential tremor onset and its amplitude modulation after alcohol intake.

Author information

1
Nuffield Department of Clinical Neurosciences, MRC Brain Network Dynamics Unit, University of Oxford, Oxford, United Kingdom; Department of Neurology, University Hospital Cologne, Cologne, Germany. Electronic address: david.pedrosa@staff.uni-marburg.de.
2
Department of Neurology, University Hospital Cologne, Cologne, Germany.
3
Nuffield Department of Clinical Neurosciences, MRC Brain Network Dynamics Unit, University of Oxford, Oxford, United Kingdom.
4
Department of Neurology, University Hospital Cologne, Cologne, Germany; SAGE Center for the Study of the Mind, University of California, Santa Barbara, USA.
5
Max-Planck Institute for Neurological Research Cologne, Cologne, Germany.
6
Department of Neurology, University Hospital Cologne, Cologne, Germany; Department of Neurology, University Hospital Marburg, Marburg, Germany.

Abstract

The dysregulation of endogenous rhythms within brain networks have been implicated in a broad range of motor and non-motor pathologies. Essential tremor (ET), classically the purview of a single aberrant pacemaker, has recently become associated with network-level dysfunction across multiple brain regions. Specifically, it has been suggested that motor cortex constitutes an important node in a tremor-generating network involving the cerebellum. Yet the mechanisms by which these regions relate to tremor remain a matter of considerable debate. We sought to discriminate the contributions of cerebral and cerebellar dysregulation by combining high-density electroencephalography with subject-specific structural MRI. For that, we contrasted ET with voluntary (mimicked) tremor before and after ingestion of alcohol to regulate the tremorgenic networks. Our results demonstrate distinct loci of cortical tremor coherence, most pronounced over the sensorimotor cortices in healthy controls, but more frontal motor areas in ET-patients consistent with a heightened involvement of the supplementary motor area. We further demonstrate that the reduction in tremor amplitude associated with alcohol intake is reflected in altered cerebellar - but not cerebral - coupling with movement. Taken together, these findings implicate tremor emergence as principally associated with increases in activity within frontal motor regions, whereas modulation of the amplitude of established tremor relates to changes in cerebellar activity. These findings progress a mechanistic understanding of ET and implicate network-level vulnerabilities in the rhythmic nature of communication throughout the brain.

KEYWORDS:

Beamformer; DICS; Essential tremor; MRI

PMID:
28754506
PMCID:
PMC5584663
DOI:
10.1016/j.expneurol.2017.07.013
[Indexed for MEDLINE]
Free PMC Article

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