TY - JOUR
T1 - Evaluating the Effects of Model-Based Optimal Bipolar tDCS Configurations on Cortical Excitability
AU - Rampersad, Sumientra
AU - Jansen, Vincent
AU - van Asseldonk, Edwin
AU - Stegeman, Dick
PY - 2017
Y1 - 2017
N2 - Many positive effects of tDCS have been demonstrated, but these effects can be small or short-lived. Volume conduction modeling results have suggested that the effects of tDCS may improve by using different electrode placements. Some novel configurations have been put forward, but experimental validation is scarce. In a recent modeling study, optimal configurations were found for maximizing either the electric field strength or the electric field strength in the presumably most effective direction in a cortical target area. Configurations with two large electrodes were optimized as this is still the most widely available setup and this approach allows for a comparison with the conventional setup solely based on placement. In the current study, these optimal configurations were compared with the conventional configuration for motor cortex stimulation for their effects on neuronal excitability. Three tDCS configurations were compared in a randomized crossover design withtwenty healthy subjects. Corticospinal excitability was evaluated from electromyography of the right first dorsal interosseus muscle using single-pulse transcranial magnetic stimulation. Excitability was measured before and until 25 minutes after 15 minutes of 2 mA tDCS. The configuration that was optimized for field strength in the most effective direction produced significantly larger effects on a group level than the configuration optimized for absolute field strength, and slightly larger effects than the conventional configuration. However, individual differences were large and should be taken into account.
AB - Many positive effects of tDCS have been demonstrated, but these effects can be small or short-lived. Volume conduction modeling results have suggested that the effects of tDCS may improve by using different electrode placements. Some novel configurations have been put forward, but experimental validation is scarce. In a recent modeling study, optimal configurations were found for maximizing either the electric field strength or the electric field strength in the presumably most effective direction in a cortical target area. Configurations with two large electrodes were optimized as this is still the most widely available setup and this approach allows for a comparison with the conventional setup solely based on placement. In the current study, these optimal configurations were compared with the conventional configuration for motor cortex stimulation for their effects on neuronal excitability. Three tDCS configurations were compared in a randomized crossover design withtwenty healthy subjects. Corticospinal excitability was evaluated from electromyography of the right first dorsal interosseus muscle using single-pulse transcranial magnetic stimulation. Excitability was measured before and until 25 minutes after 15 minutes of 2 mA tDCS. The configuration that was optimized for field strength in the most effective direction produced significantly larger effects on a group level than the configuration optimized for absolute field strength, and slightly larger effects than the conventional configuration. However, individual differences were large and should be taken into account.
U2 - 10.1016/j.brs.2016.11.055
DO - 10.1016/j.brs.2016.11.055
M3 - Meeting Abstract
SN - 1935-861X
VL - 10
SP - E11-E12
JO - Brain stimulation
JF - Brain stimulation
IS - 1
M1 - 37
T2 - NYC Neuromodulation Conference 2015
Y2 - 9 January 2015 through 11 January 2015
ER -