Effects of tDCS dose and electrode montage on regional cerebral blood flow and motor behavior

Anant B Shinde; Karl D Lerud; Fanny Munsch; David C Alsop; Gottfried Schlaug

doi:10.1016/j.neuroimage.2021.118144

Effects of tDCS dose and electrode montage on regional cerebral blood flow and motor behavior

Neuroimage. 2021 Aug 15:237:118144. doi: 10.1016/j.neuroimage.2021.118144. Epub 2021 May 12.

Authors

Anant B Shinde¹, Karl D Lerud², Fanny Munsch³, David C Alsop³, Gottfried Schlaug⁴

Affiliations

¹ Department of Neurology, Baystate Medical Center - UMass Medical School, Springfield, MA 01107, USA; Department of Biomedical Engineering and Institute of Applied Life Sciences, UMass Amherst, Amherst, MA 01003, USA. Electronic address: anantshinde@umass.edu.
² Department of Neurology, Baystate Medical Center - UMass Medical School, Springfield, MA 01107, USA.
³ Department of Radiology, MRI Research, Beth Israel Deaconess Medical Center and Harvard Medical School Boston, MA 02215, USA.
⁴ Department of Neurology, Baystate Medical Center - UMass Medical School, Springfield, MA 01107, USA; Department of Biomedical Engineering and Institute of Applied Life Sciences, UMass Amherst, Amherst, MA 01003, USA; Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School Boston, MA 02215, USA.

Abstract

We used three dose levels (Sham, 2 mA, and 4 mA) and two different electrode montages (unihemispheric and bihemispheric) to examine DOSE and MONTAGE effects on regional cerebral blood flow (rCBF) as a surrogate marker of neural activity, and on a finger sequence task, as a surrogate behavioral measure drawing on brain regions targeted by transcranial direct current stimulation (tDCS). We placed the anodal electrode over the right motor region (C4) while the cathodal or return electrode was placed either over a left supraorbital region (unihemispheric montage) or over the left motor region (C3 in the bihemispheric montage). Performance changes in the finger sequence task for both hands (left hand: p = 0.0026, and right hand: p = 0.0002) showed a linear tDCS dose response but no montage effect. rCBF in the right hemispheric perirolandic area increased with dose under the anodal electrode (p = 0.027). In contrast, in the perirolandic ROI in the left hemisphere, rCBF showed a trend to increase with dose (p = 0.053) and a significant effect of montage (p = 0.00004). The bihemispheric montage showed additional rCBF increases in frontomesial regions in the 4mA condition but not in the 2 mA condition. Furthermore, we found strong correlations between simulated current density in the left and right perirolandic region and improvements in the finger sequence task performance (FSP) for the contralateral hand. Our data support not only a strong direct tDCS dose effect for rCBF and FSP as surrogate measures of targeted brain regions but also indirect effects on rCBF in functionally connected regions (e.g., frontomesial regions), particularly in the higher dose condition and on FSP of the ipsilateral hand (to the anodal electrode). At a higher dose and irrespective of polarity, a wider network of sensorimotor regions is positively affected by tDCS.

Keywords: Arterial spin labeling; Bihemispheric electrical stimulation; Motor learning; Neural excitability; Sensorimotor network; rCBF change; tDCS.

Publication types

Research Support, N.I.H., Extramural

MeSH terms

Adult
Cerebrovascular Circulation / physiology*
Female
Fingers
Humans
Magnetic Resonance Imaging
Male
Motor Activity / physiology*
Nerve Net / physiology*
Sensorimotor Cortex / physiology*
Spin Labels
Transcranial Direct Current Stimulation* / methods

Substances

Spin Labels

Abstract

Publication types

MeSH terms

Substances

Grants and funding