Computational Models of Transcranial Direct Current Stimulation

• Published in: Clinical EEG and neuroscience Vol. 43; no. 3; pp. 176 - 183
• Main Authors: Bikson, Marom, Rahman, Asif, Datta, Abhishek
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.07.2012; SAGE PUBLICATIONS, INC
• Subjects: Action Potentials - physiology; Action Potentials - radiation effects; Animals; Automation; Brain; Brain - physiology; Brain - radiation effects; Brain research; Computer Simulation; Defects; Electrodes; Humans; Models, Neurological; Neural networks; Neurons - physiology; Neurons - radiation effects; Neurosciences; Software; Studies; Transcranial Magnetic Stimulation - methods; computer model; tDCS; transcranial electrical stimulation; forward model; current density; current flow; electric field; FEM
• ISSN: 1550-0594; 2169-5202
• DOI: 10.1177/1550059412445138

During transcranial direct current stimulation (tDCS), controllable dose parameters are electrode number (typically 1 anode and 1 cathode), position, size, shape, and applied electric current. Because different electrode montages result in distinct brain current flow patterns across the brain, tDCS dose parameters can be adjusted, in an application-specific manner, to target or avoid specific brain regions. Though the tDCS electrode montage often follows basic rules of thumb (increased/decreased excitability “under” the anode/cathode electrode), computational forward models of brain current flow provide more accurate insight into detailed current flow patterns and, in some cases, can even challenge simplified electrode-placement assumptions. With the increased recognized value of computational forward models in informing tDCS montage design and interpretation of results, there have been recent advances in modeling tools and a greater proliferation of publications.  In addition, the importance of customizing tDCS for potentially vulnerable populations (eg, skull defects, brain damage/stroke, and extremes of age) can be considered. Finally, computational models can be used to design new electrode montages, for example, to improve spatial targeting such as high-definition tDCS. Pending further validation and dissemination of modeling tools, computational forward models of neuromodulation will become standard tools to guide the optimization of clinical trials and electrotherapy.