tDCS induced GABA change is associated with the simulated electric field in M1, an effect mediated by grey matter volume in the MRS voxel

Puonti, Oula; Clarke, William T.; Nettekoven, Caroline; Barron, Helen C.; Kolasinski, James; Hanayik, Taylor; Hinson, Emily L.; Berrington, Adam; Bachtiar, Velicia; Johnstone, Ainslie; Winkler, Anderson M.; Thielscher, Axel; Johansen‐Berg, Heidi; Stagg, Charlotte J.

doi:10.1016/j.brs.2022.07.049

Cited by 16 publications

(15 citation statements)

References 72 publications

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“…Still, when combined with voxel-based neuroimaging, there can be compelling reasons to use a cubical ROI. For instance, Nandi et al (2022) used a cubical ROI to extract E-field magnitude as this ROI matched the shape and size of the voxel they used for their magnetic resonance spectroscopy analyses [19].…”

Section: Resultsmentioning

confidence: 99%

“…While both metrics pursue a common goal, they do so in a substantially different manner. Whereas the ROI focuses on a specific, user-defined brain region (e.g., the left primary motor cortex [M1]) [17][18][19][20][21][22], a percentile whole-brain approach studies E-fields across the entire brain and does not restrict the analyses to any region [23][24][25]. Moreover, even within the same approach, wide methodological variations prevail.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, even within the same approach, wide methodological variations prevail. Some studies have quantified E-field magnitude within 3 spherical ROIs of considerably different radii, ranging between 0.5 and 45 mm, whereas others used different geometric shapes such as a cubical ROI [17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

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A Systematic Review and Large-Scale tES and TMS Electric Field Modeling Study Reveals How Outcome Measure Selection Alters Results in a Person- and Montage-Specific Manner

Hoornweder

Nuyts

Frieske

et al. 2023

Preprint

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Background: Electric field (E-field) modeling is a potent tool to examine the cortical effects of transcranial magnetic and electrical stimulation (TMS and tES, respectively) and to address the high variability in efficacy observed in the literature. However, outcome measures used to report E-field magnitude vary considerably and have not yet been compared in detail. Objectives: The goal of this two-part study, encompassing a systematic review and modeling experiment, was to provide an overview of the different outcome measures used to report the magnitude of tES and TMS E-fields, and to conduct a direct comparison of these measures across different stimulation montages. Methods: Three electronic databases were searched for tES and/or TMS studies reporting E-field magnitude. We extracted and discussed outcome measures in studies meeting the inclusion criteria. Additionally, outcome measures were compared via models of four common tES and two TMS modalities in 100 healthy younger adults. Results: In the systematic review, we included 118 studies using 151 outcome measures related to E-field magnitude. Structural and spherical regions of interest (ROI) analyses and percentile-based whole-brain analyses were used most often. In the modeling analyses, we found that there was an average of only 6% overlap between ROI and percentile-based whole-brain analyses in the investigated volumes within the same person. The overlap between ROI and whole-brain percentiles was montage- and person-specific, with more focal montages such as 4x1 and APPS-tES, and figure-of-eight TMS showing up to 73%, 60%, and 52% overlap between ROI and percentile approaches respectively. However, even in these cases, 27% or more of the analyzed volume still differed between outcome measures in every analyses. Conclusions: The choice of outcome measures meaningfully alters the interpretation of tES and TMS E-field models. Well-considered outcome measure selection is imperative for accurate interpretation of results, valid between-study comparisons, and depends on stimulation focality and study goals. We formulated four recommendations to increase the quality and rigor of E-field modeling outcome measures. With these data and recommendations, we hope to guide future studies towards informed outcome measure selection, and improve the comparability of studies.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Systematic Review and Large-Scale tES and TMS Electric Field Modeling Study Reveals How Outcome Measure Selection Alters Results in a Person- and Montage-Specific Manner

Hoornweder

Nuyts

Frieske

et al. 2023

Preprint

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“…The extension of the electrical field induced by TDCS is quite variable among subjects [ 29 ], so we cannot exclude an effect on the not stimulated hemisphere, which in any case was not enough to completely resolve the hemodynamic differences between patients and controls.…”

Section: Discussionmentioning

confidence: 99%

Effect of Single Session of Anodal M1 Transcranial Direct Current Stimulation—TDCS—On Cortical Hemodynamic Activity: A Pilot Study in Fibromyalgia

et al. 2022

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Transcranial direct current stimulation (TDCS) on the primary motor cortex (M1) has been reported to be effective in fibromyalgia (FM). Our previous works have shown hypometabolism of motor networks in FM using Functional Near Infrared Spectroscopy (fNIRS), which could contribute to pain symptoms. To investigate if a single Transcranial Direct Current Stimulation (TDCS) session can restore the reduced metabolism expected in FM patients, we compared metabolic activity in FM patients and controls during a finger-tapping task in basal condition, sham condition, and under anodal TDCS on M1. During the finger tapping task, a continuous wave 20 channel fNIRS system was placed across the bilateral central-frontal areas in 22 healthy controls and 54 FM patients. Subjects were randomly assigned to real TDCS or sham stimulation. The finger-tapping slowness did not change after real and sham stimulation. After real TDCS stimulation, FM patients showed an increased activation of cortical motor regions (t-statistic = −2.5246, p-value = 0.0125 for the stimulated hemisphere and t-statistic = −4.6638, p-value = 0.0001 for the non-stimulated hemisphere). The basal differences between FM and controls reverted after real TDCS, while this effect was not observed for sham stimulation. A single TDCS session of the cortical motor network seemed able to restore basic cortical hypometabolism in FM patients. Further studies could clarify the long-term effect of M1 stimulation on cortical metabolism, and its relevance in pain processing and clinical features.

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“…Compared with baseline, a decrease in glutamatergic activity was observed after application of cathodal stimulation [ 42 ], while combined glutamine and glutamate levels increased following anodal stimulation [ 40 ]. In addition, anodal tDCS over M1 induced local reductions in gamma-aminobutyric acid (GABA) concentrations, which, interestingly, were found to correlate with the estimated average electric field strength [ 43 , 44 ] and motor learning performance [ 45 , 46 ]. The association with behavioral outcomes may suggest that local changes in the levels of this inhibitory neurotransmitter, generated by transcranial electrical stimulation, facilitate the occurrence of glutamatergic plasticity, at least in M1 [ 47 ].…”

Section: Cerebellar Tdcs In Hereditary Ataxiasmentioning

confidence: 99%

The Therapeutic Potential of Non-Invasive and Invasive Cerebellar Stimulation Techniques in Hereditary Ataxias

Benussi

Batsikadze

França

et al. 2023

Cells

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The degenerative ataxias comprise a heterogeneous group of inherited and acquired disorders that are characterized by a progressive cerebellar syndrome, frequently in combination with one or more extracerebellar signs. Specific disease-modifying interventions are currently not available for many of these rare conditions, which underscores the necessity of finding effective symptomatic therapies. During the past five to ten years, an increasing number of randomized controlled trials have been conducted examining the potential of different non-invasive brain stimulation techniques to induce symptomatic improvement. In addition, a few smaller studies have explored deep brain stimulation (DBS) of the dentate nucleus as an invasive means to directly modulate cerebellar output, thereby aiming to alleviate ataxia severity. In this paper, we comprehensively review the clinical and neurophysiological effects of transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation (rTMS), and dentate nucleus DBS in patients with hereditary ataxias, as well as the presumed underlying mechanisms at the cellular and network level and perspectives for future research.

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tDCS induced GABA change is associated with the simulated electric field in M1, an effect mediated by grey matter volume in the MRS voxel

Cited by 16 publications

References 72 publications

A Systematic Review and Large-Scale tES and TMS Electric Field Modeling Study Reveals How Outcome Measure Selection Alters Results in a Person- and Montage-Specific Manner

A Systematic Review and Large-Scale tES and TMS Electric Field Modeling Study Reveals How Outcome Measure Selection Alters Results in a Person- and Montage-Specific Manner

Effect of Single Session of Anodal M1 Transcranial Direct Current Stimulation—TDCS—On Cortical Hemodynamic Activity: A Pilot Study in Fibromyalgia

The Therapeutic Potential of Non-Invasive and Invasive Cerebellar Stimulation Techniques in Hereditary Ataxias

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