Impact of tDCS on brain metabolites in the left DLPFC in healthy subjects
Poster No:
101
Submission Type:
Abstract Submission
Authors:
Aldo Soldini1, Gizem Vural2, Frank Padberg3, Eva Mezger1, Julian Melcher1, Sophia Stoecklein1, Lucia Bulubas3, Antonia Šušnjar4, Daniel Keeser3
Institutions:
1LMU Klinikum, Munich, Bavaria, 2LMU Klinikum, Munich, Other, 3Department of Psychiatry and Psychotherapy, University Hospital LMU, Munich, Germany, 4Purdue University, West Lafayette, IN
First Author:
Co-Author(s):
Introduction:
Transcranial Direct Current Stimulation (tDCS) is emerging as a non-invasive brain stimulation (NIBS) technique for modulating cortical brain activity, with potential implications in cognitive enhancement and treatment in psychiatry. Current knowledge on tDCS primarily pertains to its neurophysiological effects, encompassing motor-eveoked potentials, cognitive studies, EEG investigations, and fMRI research; however, there is limited understanding regarding its impact on brain metabolites in the dorsolateral prefrontal cortex (DLPFC), a target region for NIBS in mental disorder. The aim of this double-blind, placebo-controlled investigation was to explore the impacts of prefrontal tDCS on neurotransmitter levels, specifically glutamine/glutamate (Glx), N-Acetylaspartate (NAA), and gamma-aminobutyric acid (GABA) in the left dorsolateral prefrontal cortex (DLPFC), utilizing a combined tDCS/MRS approach in a sample of healthy volunteers.
Methods:
A total of 41 healthy individuals (19 females; mean age: 25) underwent bifrontal active (2 mA for 20 min) or sham tDCS targeting the left (anode: F3) and right (cathode: F4) DLPFC within a 3 Tesla Siemens Prisma MRI scanner, utilizing a neuroConn DC-Stimulator MR device. In vivo magnetic resonance spectroscopy (MRS) was employed to monitor neurometabolic changes before, during, and after tDCS administration. A Siemens vendor and MEGA-PRESS sequence specific basis set was used for linear-combination modeling deployed in LC Model software. A single voxel, positioned underneath F3, was utilized to quantify metabolite levels at four 10-minute measurement time points at baseline, during the first and second 10 minutes of stimulation and after the stimulation. LCModel (Linear Combination Model, Version 6.3-1R), a reliable and model-free method for analyzing brain metabolites, was employed. For in vivo data, eddy current correction and water scaling were applied. Furthermore, we utilized Osprey (version 2.5.0) for voxel registration and tissue segmentation. Statistical analyses were conducted using the R programming language (version 4.2.2) in R Studio (version 2022.12.0.353: R Development Core Team, 2008).
Results:
There was a significant increase in Glx levels during active tDCS compared to sham tDCS. This effect was still detectable during the 10 min post- stimulation period. Three-way interaction was not ssignificant for GABA and NAA between stimulation conditions and , time points, however, sex and sex-specific variations were observed in GABA and NAA metabolites.
Conclusions:
This concurrent tDCS-MRS study demonstrates that a single session of anodal tDCS of the left DLPFC has acute effects on Glx levels at the target site, whereas effects on GABA and NAA were not detected. Further studies should investigate sex effects in larger samples and compare the acute effects in health and disease.
Brain Stimulation:
Non-invasive Electrical/tDCS/tACS/tRNS
TDCS 1
Novel Imaging Acquisition Methods:
MR Spectroscopy 2
Physiology, Metabolism and Neurotransmission :
Physiology, Metabolism and Neurotransmission Other
Keywords:
GABA
Glutamate
Other - Transcranial direct current stimulation (tDCS); MR Spectroscopy; Dorsolateral prefrontal cortex (DLPFC)
1|2Indicates the priority used for review
Provide references using author date format
Dickler, M. (2018). Online effects of transcranial direct current stimulation on prefrontal metabolites in gambling disorder. Neuropharmacology, 131, 51-57.
Mezger, E. (2021). Effects ofbifrontal transcranial direct current stimulation on brain glutamate levels and resting state connectivity: multimodal MRI data for the cathodal stimulation site. European archives of psychiatry and clinical neuroscience, 271(1), 111-122.
Friston, K. J. (1994). Statistical parametric maps in functional imaging: a general linear approach. Human brain mapping, 2(4), 189-210.