Multifocal Transcranial Direct Current Stimulation Modulates Resting-State Functional Connectivity in Older Adults Depending on the Induced Current Density

Kilian Abellaneda-Pérez; Lídia Vaqué-Alcázar; Ruben Perellón-Alfonso; Cristina Solé-Padullés; Núria Bargalló; Ricardo Salvador; Giulio Ruffini; Michael A Nitsche; Alvaro Pascual-Leone; David Bartrés-Faz

doi:10.3389/fnagi.2021.725013

Multifocal Transcranial Direct Current Stimulation Modulates Resting-State Functional Connectivity in Older Adults Depending on the Induced Current Density

Front Aging Neurosci. 2021 Nov 26:13:725013. doi: 10.3389/fnagi.2021.725013. eCollection 2021.

Authors

Kilian Abellaneda-Pérez^{1

2}, Lídia Vaqué-Alcázar^{1

2}, Ruben Perellón-Alfonso^{1

2}, Cristina Solé-Padullés^{1

2}, Núria Bargalló^{3

4}, Ricardo Salvador^{5

6}, Giulio Ruffini^{5

6}, Michael A Nitsche^{7

8}, Alvaro Pascual-Leone^{9

10

11}, David Bartrés-Faz^{1

2

11}

Affiliations

¹ Department of Medicine, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, Barcelona, Spain.
² Institute of Biomedical Research August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
³ Section of Neuroradiology, Department of Radiology, Diagnostic Image Center, Hospital Clinic of Barcelona, University of Barcelona, Barcelona, Spain.
⁴ Magnetic Resonance Image Core Facility (IDIBAPS), Barcelona, Spain.
⁵ Neuroelectrics, Cambridge, MA, United States.
⁶ Neuroelectrics, Barcelona, Spain.
⁷ Leibniz Research Centre for Working Environment and Human Factors, Dortmund, Germany.
⁸ Department of Neurology, University Medical Hospital Bergmannsheil, Bochum, Germany.
⁹ Hinda and Arthur Marcus Institute for Aging Research and Deanna and Sidney Wolk Center for Memory Health, Hebrew SeniorLife, Boston, MA, United States.
¹⁰ Department of Neurology, Harvard Medical School, Boston, MA, United States.
¹¹ Guttmann Brain Health Institute, Guttmann University Institute of Neurorehabilitation, Autonomous University of Barcelona, Badalona, Spain.

Abstract

Combining non-invasive brain stimulation (NIBS) with resting-state functional magnetic resonance imaging (rs-fMRI) is a promising approach to characterize and potentially optimize the brain networks subtending cognition that changes as a function of age. However, whether multifocal NIBS approaches are able to modulate rs-fMRI brain dynamics in aged populations, and if these NIBS-induced changes are consistent with the simulated electric current distribution on the brain remains largely unknown. In the present investigation, thirty-one cognitively healthy older adults underwent two different multifocal real transcranial direct current stimulation (tDCS) conditions (C1 and C2) and a sham condition in a crossover design during a rs-fMRI acquisition. The real tDCS conditions were designed to electrically induce two distinct complex neural patterns, either targeting generalized frontoparietal cortical overactivity (C1) or a detachment between the frontal areas and the posteromedial cortex (C2). Data revealed that the two tDCS conditions modulated rs-fMRI differently. C1 increased the coactivation of multiple functional couplings as compared to sham, while a smaller number of connections increased in C1 as compared to C2. At the group level, C1-induced changes were topographically consistent with the calculated electric current density distribution. At the individual level, the extent of tDCS-induced rs-fMRI modulation in C1 was related with the magnitude of the simulated electric current density estimates. These results highlight that multifocal tDCS procedures can effectively change rs-fMRI neural functioning in advancing age, being the induced modulation consistent with the spatial distribution of the simulated electric current on the brain. Moreover, our data supports that individually tailoring NIBS-based interventions grounded on subject-specific structural data might be crucial to increase tDCS potential in future studies amongst older adults.

Keywords: aging; electric current density; electric modeling; multifocal transcranial direct current stimulation; neuroimaging; non-invasive brain stimulation (NIBS); resting-state functional magnetic resonance imaging.