Skip to main content
Log in

The effect of tissue anisotropy on the radial and tangential components of the electric field in transcranial direct current stimulation

  • Original Article
  • Published:
Medical & Biological Engineering & Computing Aims and scope Submit manuscript

Abstract

Transcranial direct current stimulation (tDCS) is considered to be a promising technique for noninvasive brain stimulation and brain disease therapy. Recent studies have investigated the distribution of the electric field (EF) magnitude over gyri and sulci and the effect of tissue homogeneity with isotropic electrical conductivities. However, it is well known that the skull and white matter (WM) are highly anisotropic electrically, requiring investigations of their anisotropic effects on the magnitude and the directional components of the induced EF due to the high dependency between neuromodulation and the EF direction. In this study, we investigated the effects of the skull and WM anisotropy on the radial and tangential components of the EF via gyri-specific high-resolution finite element head models. For tDCS, three configurations were investigated: the conventional rectangular pad electrode, a 4(cathodes) +1(anode) ring configuration, and a bilateral configuration. The results showed that the skull anisotropy has a crucial influence on the distribution of the radial EF component. The affected cortical regions by the radial EF were reduced about 22 % when considering the skull anisotropy in comparison with the regions with the skull isotropy. On the other hand, the WM anisotropy strongly alters the EF directionality, especially within the sulci. The electric current tends to flow radially to the cortical surface with the WM anisotropy. This effect increases the affected cortical areas by the radial EF component within the sulcal regions. Our results suggest that one must examine the distribution of the EF components in tDCS, not just the magnitude of the EF alone.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9

Similar content being viewed by others

References

  1. Akhtari M, Bryant HC, Mamelak AN, Flynn ER, Heller L, Shih JJ, Mandelkern M, Matlachov A, Ranken DM, Best ED, DiMauro MA, Lee RR, Sutherling WW (2002) Conductivities of three-layer live human skull. Brain Topogr 14(3):151–167

    Article  CAS  PubMed  Google Scholar 

  2. Akin JE (2010) Finite element analysis concepts: via SolidWorks. World Scientific, USA

    Book  Google Scholar 

  3. Bijsterbosch JD, Barker AT, Lee K-H, Woodruff PWR (2012) Where does transcranial magnetic stimulation (TMS) stimulate? Modeling of induced field maps for some common cortical and cerebellar targets. Med Biol Eng Comput 50(7):671–681

    Article  PubMed  Google Scholar 

  4. Borckardt JJ, Bikson M, Frohman H, Reeves ST, Datta A, Bansal V, Madan A, Barth K, George MS (2012) A pilot study of the tolerability and effects of high-definition transcranial direct current stimulation (HD-tDCS) on pain perception. J Pain 13(2):112–120

    Article  PubMed  Google Scholar 

  5. Brunoni AR, Nitsche MA, Bolognini N, Bikson M, Wanger T, Merabet L, Edwards DJ, Valero-Cabre A, Rotenberq A, Pascual-Leone A, Ferrucci R, Priori A, Boggio PS, Fregni F (2012) Clinical research with transcranial direct current stimulation (tDCS): challenges and future directions. Brain Stimul 5(3):175–195

    Article  PubMed Central  PubMed  Google Scholar 

  6. DaSilva AF, Volz MS, Bikson M, Fregni F (2011) Electrode positioning and montage in transcranial direct current stimulation. J Vis Exp 51:1–12

    Google Scholar 

  7. Datta A, Bansal V, Diaz J, Patel J, Reato D, Bikson M (2009) Gyri-precise head model of transcranial direct current stimulation: improved spatial focality using a ring electrode versus conventional rectangular pad. Brain Stimul 2(4):201–207

    Article  PubMed Central  PubMed  Google Scholar 

  8. Deng ZD, Lisanby SH, Peterchev AV (2011) Electric field strength and focality in electroconvulsive therapy and magnetic seizure therapy: a finite element simulation study. J Neural Eng 8(1):1–13

    Article  Google Scholar 

  9. Dmochowski JP, Datta A, Bikson M, Su Y, Parra LC (2011) Optimized multi-electrode stimulation increases focality and intensity at target. J Neural Eng 8(4):1–16

    Article  Google Scholar 

  10. Dogdas B, Shattuck DW, Leahy RM (2005) Segmentation of skull and scalp in 3-D human MRI using mathematical morphology. Hum Brain Mapp 26(4):273–285

    Article  PubMed  Google Scholar 

  11. Fang Q, Boas DA (2009) Tetrahedral mesh generation from volumetric binary and gray-scale images. In: IEEE international symposium on biomedicine imaging, pp 1142–1145

  12. Fregni F, Boggio PS, Santos MC, Lima M, Vieira AL, Rigonatti SP, Silva MT, Barbosa ER, Nitsche MA, Pascual-Leone A (2006) Noninvasive cortical stimulation with transcranial direct current stimulation in Parkinson’s disease. Mov Disord 21(10):1693–1702

    Article  PubMed  Google Scholar 

  13. Fregni F, Thome-Souza S, Nitsche MA, Freedman SD, Valente KD, Pascual-Leone A (2006) A controlled clinical trial of cathodal DC polarization in patients with refractory epilepsy. Epilepsia 47(2):335–342

    Article  PubMed  Google Scholar 

  14. Hesse S, Wemer C, Schonhardt EM, Bardeleben A, Jenrich W, Kirker SG (2007) Combined transcranial direct current stimulation and robot-assisted arm training in subacute stroke patients: a pilot study. Restor Neurol Neurosci 25(1):9–15

    CAS  PubMed  Google Scholar 

  15. http://surfer.nmr.mgh.harvard.edu/

  16. Hummel FC, Cohen LG (2006) Non-invasive brain simulation: A new strategy to improve neurorehabilitation after stroke? Lancet Neurol 5(8):708–712

    Article  PubMed  Google Scholar 

  17. Janssen AM, Oostendorp TF, Stegeman DF (2014) The effect of local anatomy on the electric field induced by TMS: evaluation at 14 different target sites. Med Biol Eng Comput 52(10):873–883

    Article  PubMed  Google Scholar 

  18. Johnson CR (1997) Computational and numerical methods for bioelectric field problems. Crit Rev Biomed Eng 25(1):1–81

    Article  CAS  PubMed  Google Scholar 

  19. Kim S, Kim T-S, Zhou Y, Singh M (2003) Influence of conductivity tensors on the scalp electrical potential: study with 2-D finite element models. IEEE Trans Nucl Sci 50(1):133–138

    Article  Google Scholar 

  20. Lee WH, Seo HS, Kim SH, Cho MH, Lee SY, and Kim T-S (2009) Influence of white matter anisotropy on the effects of transcranial direct current stimulation: a finite element study. In: International conference on biomedicine engineering IFMBE proceedings, vol 23, pp 460–464

  21. Miranda PC, Lomarev M, Hallet M (2006) Modeling the current distribution during transcranial direct current stimulation. Clin Neurophysiol 117(7):1623–1629

    Article  PubMed  Google Scholar 

  22. Miranda PC, Mekonnen A, Salvador R, Ruffini G (2013) The electric field in the cortex during transcranial current stimulation. NeuroImage 70:48–58

    Article  PubMed  Google Scholar 

  23. Nitsche MA, Paulus W (2000) Excitability changes induced in the human motor cortex by transcranial direct current stimulation. J Physiol 527(3):633–639

    Article  PubMed Central  CAS  PubMed  Google Scholar 

  24. Nitsche MA, Boggio PS, Fregni F, Pascual-Leone A (2009) A treatment of depression with transcranial direct current stimulation (tDCS): a review. Exp Neurol 219(1):14–19

    Article  PubMed  Google Scholar 

  25. Radman T, Ramos RL, Brumberg JC, Bikson M (2009) Role of cortical cell type and morphology in subthreshold and suprathreshold uniform electric field stimulation in vitro. Brain Stimul 2(4):215–228

    Article  PubMed Central  PubMed  Google Scholar 

  26. Rampersad SM, Stegeman DF, Oostendorp TF (2013) Single-layer skull approximations perform well in transcranial direct current stimulation modeling. IEEE Trans Neural Syst Rehabil Eng 21(3):346–353

    Article  PubMed  Google Scholar 

  27. Rattay F (1986) Analysis of models for external stimulation of axons. IEEE Trans Biomed Eng 33(10):974–977

    Article  CAS  PubMed  Google Scholar 

  28. Sadleir RJ, Vannorsdall TD, Schretlen DJ, Gordon B (2010) Transcranial direct current stimulation (tDCS) in a realistic head model. NeuroImage 51(4):1310–1318

    Article  PubMed  Google Scholar 

  29. Shahid S, Wen P, and Ahfock T (2011) Effect of fat and muscle tissue conductivity on cortical currents—a tDCS study. In: International conference on complex medical engineering, 211–215

  30. Suh HS, Kim SH, Lee WH and Kim T-S (2009) Realistic simulation of transcranial direct current stimulation via 3-D high-resolution finite element analysis: effect of tissue anisotropy. In: Conference proceedings of IEEE engineering in medicine and biology society, pp 638–641

  31. Suh HS, Lee WH, Cho YS and Kim T-S (2010) Reduced spatial focality of electrical field in tDCS with ring electrodes due to tissue anisotropy. In: Conference proceedings of IEEE engineering in medicine and biology society, pp 2053–2056

  32. Suh HS, Lee WH, Kim T-S (2012) Influence of anisotropic conductivity in the skull and white matter on transcranial direct current stimulation via an anatomically realistic finite element head model. Phys Med Biol 57(21):6961–6980

    Article  PubMed  Google Scholar 

  33. Tang Y, Hojatkashani C, Dinov ID, Sun B, Fan L et al (2010) The construction of a Chinese MRI brain atlas: a morphometric comparison study between Chinese and Caucasian cohorts. NeuroImage 51:33–41

    Article  PubMed Central  PubMed  Google Scholar 

  34. Valle A, Roizenblatt S, Botte S, Zaghi S, Riberto M, Tufik S, Boggio PS, Fregni F (2009) Efficacy of anodal transcranial direct current stimulation (tDCS) for the treatment of fibromyalgia: results of a randomized, sham-controlled longitudinal clinical trial. J Pain Manag 2(3):353–361

    PubMed Central  PubMed  Google Scholar 

  35. Wanger T, Fregni F, Fecteau S, Grodzinsky A, Zhan M, Pascual-Leone A (2007) Transcranial direct current stimulation: a computer-based human model study. NeuroImage 35(3):1113–1124

    Article  Google Scholar 

  36. Wolters CH, Anwander A, Tricoche X, Weinstein D, Koch MA, MacLeod RS (2006) Influence of tissue conductivity anisotropy on EEG/MEG field and return current computation in a realistic head model: a simulation and visualization study using high-resolution finite element modeling. NeuroImage 30(3):813–826

    Article  CAS  PubMed  Google Scholar 

  37. Ye H, Cotic M, Fehlings MG, Carlen PL (2011) Transmembrane potential generated by a magnetically induced transverse electric field in a cylindrical axonal model. Med Biol Eng Comput 49:107–119

    Article  PubMed  Google Scholar 

Download references

Acknowledgments

This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MEST) (2014R1A2A2A09052449).

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Tae-Seong Kim.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Metwally, M.K., Han, S.M. & Kim, TS. The effect of tissue anisotropy on the radial and tangential components of the electric field in transcranial direct current stimulation. Med Biol Eng Comput 53, 1085–1101 (2015). https://doi.org/10.1007/s11517-015-1301-z

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s11517-015-1301-z

Keywords

Navigation