Transcranial direct current stimulation: a computer-based human model study.
OBJECTIVE
Interest in transcranial direct current stimulation (tDCS) in clinical practice has been growing, however, the knowledge about its efficacy and mechanisms of action remains limited. This paper presents a realistic magnetic resonance imaging (MRI)-derived finite element model of currents applied to the human brain during tDCS.


METHODS
Current density distributions were analyzed in a healthy human head model with varied electrode montages. For each configuration, we calculated the cortical current density distributions. Analogous studies were completed for three pathological models of cortical infarcts.


RESULTS
The current density magnitude maxima injected in the cortex by 1 mA tDCS ranged from 0.77 to 2.00 mA/cm(2). The pathological models revealed that cortical strokes, relative to the non-pathological solutions, can elevate current density maxima and alter their location.


CONCLUSIONS
These results may guide optimized tDCS for application in normal subjects and patients with focal brain lesions.
Wagner
Tim
T
Center for Non-invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA. twagner@mit.edu <twagner@mit.edu>
Fregni
Felipe
F
Fecteau
Shirley
S
Grodzinsky
Alan
A
Zahn
Markus
M
Pascual-Leone
Alvaro
A
D001921:Brain / Q000502:physiology*; D003198:Computer Simulation; D004574:Electromagnetic Fields; D020342:Finite Element Analysis; D006257:Head / Q000502:physiology*; D006801:Humans; D008959:Models, Neurological; D011829:Radiation Dosage; D011874:Radiometry / Q000379:methods*; D012542:Scattering, Radiation; D050781:Transcranial Magnetic Stimulation / Q000379:methods*