Activation response and functional connectivity change in rat cortex after bilateral transcranial direct current stimulation—An exploratory study

Julia Boonzaier, Milou Straathof, Dirk Jan Ardesch, Annette van der Toorn, Gerard van Vliet, Caroline L. van Heijningen, Willem M. Otte, Rick M. Dijkhuizen*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Transcranial direct current stimulation (tDCS) is a noninvasive brain stimulation technique implicated as a promising adjunct therapy to improve motor function through the neuromodulation of brain networks. Particularly bilateral tDCS, which affects both hemispheres, may yield stronger effects on motor learning than unilateral stimulation. Therefore, the aim of this exploratory study was to develop an experimental model for simultaneous magnetic resonance imaging (MRI) and bilateral tDCS in rats, to measure instant and resultant effects of tDCS on network activity and connectivity. Naïve, male Sprague-Dawley rats were divided into a tDCS (n = 7) and sham stimulation group (n = 6). Functional MRI data were collected during concurrent bilateral tDCS over the sensorimotor cortex, while resting-state functional MRI and perfusion MRI were acquired directly before and after stimulation. Bilateral tDCS induced a hemodynamic activation response, reflected by a bilateral increase in blood oxygenation level-dependent signal in different cortical areas, including the sensorimotor regions. Resting-state functional connectivity within the cortical sensorimotor network decreased after a first stimulation session but increased after a second session, suggesting an interaction between multiple tDCS sessions. Perfusion MRI revealed no significant changes in cerebral blood flow after tDCS. Our exploratory study demonstrates successful application of an MRI-compatible bilateral tDCS setup in an animal model. Our results indicate that bilateral tDCS can locally modulate neuronal activity and connectivity, which may underlie its therapeutic potential.

Original languageEnglish
Pages (from-to)1377-1389
Number of pages13
JournalJournal of Neuroscience Research
Volume99
Issue number5
DOIs
Publication statusPublished - May 2021

Bibliographical note

Publisher Copyright:
© 2021 The Authors. Journal of Neuroscience Research published by Wiley Periodicals LLC.

Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.

Keywords

  • animal
  • magnetic resonance imaging
  • models
  • resting-state functional connectivity
  • transcranial direct current stimulation

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