Effects of cerebellar transcranial direct current stimulation on cerebellar-brain inhibition in humans: A systematic evaluation

Giorgi Batsikadze; Zeynab Rezaee; Dae-In Chang; Marcus Gerwig; Stefan Herlitze; Anirban Dutta; Michael A Nitsche; Dagmar Timmann

doi:10.1016/j.brs.2019.04.010

Effects of cerebellar transcranial direct current stimulation on cerebellar-brain inhibition in humans: A systematic evaluation

Brain Stimul. 2019 Sep-Oct;12(5):1177-1186. doi: 10.1016/j.brs.2019.04.010. Epub 2019 Apr 22.

Authors

Giorgi Batsikadze¹, Zeynab Rezaee², Dae-In Chang³, Marcus Gerwig⁴, Stefan Herlitze⁵, Anirban Dutta², Michael A Nitsche⁶, Dagmar Timmann⁴

Affiliations

¹ Department of Neurology, Essen University Hospital, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany. Electronic address: giorgi.batsikadze@uk-essen.de.
² Department of Biomedical Engineering, University at Buffalo, Buffalo, NY, 14260, USA.
³ Department of Neurology, Essen University Hospital, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany; Department of Psychiatry and Psychotherapy, LVR-Hospital Essen, Faculty of Medicine, University of Duisburg-Essen, Virchowstrasse 174, 45147, Essen, Germany.
⁴ Department of Neurology, Essen University Hospital, University of Duisburg-Essen, Hufelandstraße 55, 45147, Essen, Germany.
⁵ Department of General Zoology and Neurobiology, Ruhr-University Bochum, Universitätsstraße 150, 44780, Bochum, Germany.
⁶ Department of Psychology and Neurosciences, Leibniz Research Centre for Working Environment and Human Factors, Ardeystraße 67, Dortmund, Germany; Department of Neurology, University Medical Hospital Bergmannsheil, Bochum, Germany.

PMID: 31040077
DOI: 10.1016/j.brs.2019.04.010

Abstract

Background: Cerebellar transcranial direct current stimulation (ctDCS) is increasingly used to modulate cerebellar excitability and plasticity in healthy subjects and various patient populations. ctDCS parameters are poorly standardized, and its physiology remains little understood. Our aim was to compare the physiological effects of three different non-target electrode positions (buccinator muscle, supraorbital region, deltoid muscle).

Methods: In the first experiment, physiological after-effects of ctDCS were compared based on cerebellar-brain inhibition (CBI) in a group of 15 healthy right-handed participants. In the second experiment, CBI after-effects of ctDCS were assessed using different transcranial magnetic stimulation (TMS) intensities in 14 participants (CBI recruitment curve). The electric field distribution was calculated for each of the electrode montages based on a single anatomically accurate head model.

Results: Anodal and cathodal ctDCS polarities significantly decreased cerebellar-brain inhibition (CBI) with no substantial differences between the montages. Lower cerebellar TMS intensities resulted in decreased CBI following cathodal and increased CBI after anodal ctDCS. Computational modeling revealed minor differences in the electric field distribution between non-target electrode positions based on the effect size.

Conclusion: Our results show that the non-target electrode position has no significant impact on modeling results and physiological ctDCS after-effects. The recruitment of the cerebellar-M1 connection, however, varied depending on ctDCS polarity and cerebellar transcranial magnetic stimulation intensity, possibly due to diverse effects on different cell populations in the cerebellar cortex. This may be one of the reasons why ctDCS effects on functional measures are difficult to predict.

Keywords: Cerebellar-brain inhibition; Cerebellum; Neuroplasticity; Transcranial direct current stimulation; Transcranial magnetic stimulation.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Cerebellum / physiology*
Female
Humans
Male
Neural Inhibition / physiology*
Random Allocation
Transcranial Direct Current Stimulation / methods*
Young Adult