Heart Rate Variability (HRV)-Guided Transcranial Direct Current Stimulation (tDCS)

tDCS will be delivered using the 1x1 Mini CT tDCS device. For active tDCS, the device is programmed to ramp up to 2.0 mA (for 30 seconds), provide constant current throughout the session (29 minutes), and then ramp down (for 30 seconds) at the end. Participants will receive 10 sessions of tDCS over the course of this study on weekdays (M-F).

Sham tDCS will be delivered using the 1x1 Mini CT tDCS device. For sham tDCS, the device is programmed to ramp up to 2.0 mA (for 30 seconds) followed by a ramp down (30 seconds), with no current delivery for 28 minutes, and then ramp up (for 30 seconds) and down (for 30 seconds) at the end. Participants will receive 10 sessions of sham tDCS over the course of this study on weekdays (M-F).