Temporal Interference Methods for Non-invasive Deep Brain Stimulation, Study 1.1

"Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using alternating current frequencies (e.g., 2000 Hz and 2020 Hz) at up to 2 mA per electrode. This stimulation creates a beat frequency interference pattern (e.g., 20 Hz) that focally stimulates deep brain regions without activating overlying cortex.~For the NAcc TI Active condition, 2000Hz will be administered in one channel and 2020Hz in the other. These frequencies will be administered in 2 minutes on/2 minutes off cycles with a 30 second ramp up and ramp down beginning at the start of each 2 minute period."

"Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using alternating current frequencies (e.g., 2000 Hz and 2020 Hz) at up to 2 mA per electrode. This stimulation creates a beat frequency interference pattern (e.g., 20 Hz) that focally stimulates deep brain regions without activating overlying cortex.~For the NAcc TI Sham condition, 2000Hz will be administered in one channel and 2020Hz in the other. These frequencies will be administered in 2 minutes on/2 minutes off cycles, however, instead of the 30 second ramp up and ramp down at the beginning of each 2 minute period (as seen in the Active TI condition), the stimulation in the NAcc TI Sham condition will immediately ramp down as soon as it reaches 2mA after ramp up."

"Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using the same current frequencies at up to 2 mA per electrode.~For the NAcc No-TI Active condition, 2000Hz will be administered in both channels. These frequencies will be administered in 2 minutes on/2 minutes off cycles with a 30 second ramp up and ramp down beginning at the start of each 2 minute period."

"Non-invasive electrical brain stimulation delivered through two sets of scalp electrodes using the same current frequencies at up to 2 mA per electrode.~For the NAcc No-TI Sham condition, 2000Hz will be administered in both channels. These frequencies will be administered in 2 minutes on/2 minutes off cycles, however, instead of the 30 second ramp up and ramp down at the beginning of each 2 minute period (as seen in the NAcc No-TI Active condition), the stimulation in the NAcc No-TI Sham condition will immediately ramp down as soon as it reaches 2mA after ramp up."