Evidence map›Paper›PMID 30679770›Full record

Trial reportScientific reports2019

Can electric fields explain inter-individual variability in transcranial direct current stimulation of the motor cortex?

Ilkka Laakso, Marko Mikkonen, Soichiro Koyama, Akimasa Hirata, Satoshi Tanaka

Open access · goldAbstract readClinical Trial
PubMed Full text at PMC Publisher
In one paragraph

Trial report in Scientific reports, 2019. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 81 papers, 4 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
81citing papers in PubMed, 4 pooled it
11.5field-weighted citation impact, top 1% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

81 citing papers in PubMed, 4 syntheses or guidelines pooled it, 177 citations in OpenAlex.

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  19. Frontiers in neuroscience · 2026
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21 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

5 authors at 4 institutions in 2 countries.

Ilkka LaaksoDepartment of Electrical Engineering and Automation, Aalto University, Espoo, 02150, Finland. ilkka.laakso@aalto.fi.ORCID 0000-0002-8162-1356
Marko MikkonenDepartment of Electrical Engineering and Automation, Aalto University, Espoo, 02150, Finland.
Soichiro KoyamaFaculty of Rehabilitation, School of Health Sciences, Fujita Health University, Toyoake, 470-1192, Japan.
Akimasa HirataDepartment of Computer Science and Engineering, Nagoya Institute of Technology, Nagoya, 466-8555, Japan.
Satoshi TanakaLaboratory of Psychology, Hamamatsu University School of Medicine, Hamamatsu, 431-3192, Japan.
Aalto University · FIFujita Health University · JPHamamatsu University School of Medicine · JPNagoya Institute of Technology · JP

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

The effects of transcranial direct current stimulation (tDCS) on motor cortical excitability are highly variable between individuals. Inter-individual differences in the electric fields generated in the brain by tDCS might play a role in the variability. Here, we explored whether these fields are related to excitability changes following anodal tDCS of the primary motor cortex (M1). Motor evoked potentials (MEPs) were measured in 28 healthy subjects before and after 20 min sham or 1 mA anodal tDCS of right M1 in a double-blind crossover design. The electric fields were individually modelled based on magnetic resonance images. Statistical analysis indicated that the variability in the MEPs could be partly explained by the electric fields, subjects with the weakest and strongest fields tending to produce opposite changes in excitability. To explain the findings, we hypothesized that the likely locus of action was in the hand area of M1, and the effective electric field component was that in the direction normal to the cortical surface. Our results demonstrate that a large part of inter-individual variability in tDCS may be due to differences in the electric fields. If this is the case, electric field dosimetry could be useful for controlling the neuroplastic effects of tDCS.

Indexed as

Cortical ExcitabilityCross-Over StudiesDouble-Blind MethodElectric StimulationEvoked Potentials, MotorFemaleHumansMagnetic Resonance SpectroscopyMaleMotor CortexTranscranial Direct Current StimulationTranscranial Magnetic Stimulation

Identifiers

PMID30679770
PMCPMC6345748
OpenAlexW2912676447

What OpenQuestion holds

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Registered trials

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.