Measurements and models of electric fields in thein vivohuman brain during transcranial electric stimulation.
Transcranial electric stimulation aims to stimulate the brain by applying weak electrical currents at the scalp. However, the magnitude and spatial distribution of electric fields in the human brain are unknown. We measured electric potentials intracranially in ten epilepsy patients and estimated electric fields across the entire brain by leveraging calibrated current-flow models. When stimulating at 2 mA, cortical electric fields reach 0.8 V/m, the lower limit of effectiveness in animal studies. When individual whole-head anatomy is considered, the predicted electric field magnitudes correlate with the recorded values in cortical (r= 0.86) and depth (r= 0.88) electrodes. Accurate models require adjustment of tissue conductivity values reported in the literature, but accuracy is not improved when incorporating white matter anisotropy or different skull compartments. This is the first study to validate and calibrate current-flow models within vivointracranial recordings in humans, providing a solid foundation to target stimulation and interpret clinical trials.
Department of Biomedical Engineering, City College of the City University of New York, New York, United States.
Yu
Y
Huang
Comprehensive Epilepsy Center, New York University School of Medicine, New York, United States.
Anli A
AA
Liu
Department of Biomedical Engineering, City College of the City University of New York, New York, United States.
Belen
B
Lafon
Comprehensive Epilepsy Center, New York University School of Medicine, New York, United States.
Daniel
D
Friedman
Department of Neurology, Mayo Clinic, Rochester, United States.
Michael
M
Dayan
Comprehensive Epilepsy Center, New York University School of Medicine, New York, United States.
Xiuyuan
X
Wang
Department of Biomedical Engineering, City College of the City University of New York, New York, United States.
Marom
M
Bikson
Comprehensive Epilepsy Center, New York University School of Medicine, New York, United States.
Werner K
WK
Doyle
Comprehensive Epilepsy Center, New York University School of Medicine, New York, United States.
Orrin
O
Devinsky
Department of Biomedical Engineering, City College of the City University of New York, New York, United States.
Lucas C
0000-0003-4667-816X
LC
Parra
D001921:Brain / Q000528:radiation effects*; D004574:Electromagnetic Fields; D006801:Humans; D062206:Spatial Analysis; D065908:Transcranial Direct Current Stimulation
computational current-flow model; human; intracranial recordings; neuroscience; transcranial electric stimulation