Transcranial Direct Current Stimulation (tDCS), High Definition Transcranial Direct Current Stimulation (HD-tDCS), and Transcranial Alternating Current Stimulation (tACS) are forms of electrical stimulation to effect neuro-modulation in the brain. These stimulation methods employ the use of low level (typically under 2 ma) current applied to selected regions of the brain via surface electrodes placed on the scalp. Direct current is unipolar, alternating current is bipolar.
For tDCS/tACS studies, use the STMISOLA Constant Current or Voltage Linear Isolated Stimulator, which is ideally suited to perform this type of stimulation. At lower current levels (up to ~2 ma), the DC output current can be held for an arbitrarily long period of time.See More...
The STMISOLA will support arbitrarily long, constant, non-varying, direct output currents, so long as the associated voltage compliance is 100 VDC or less. The tDCS level is adjusted by holding a stable voltage to the control voltage input of the STMISOLA. This control voltage can be set in AcqKnowledge, to be output to STMISOLA via MP160/150 analog output.
BIOPAC is unaware of safety concerns related to this procedure, however it is our understanding that tDCS or HD-tDCS are investigative protocols. As a safety precaution, please verify output currents prior to any subject measurements. There are no known measurement impacts when performing tDCS with other BIOPAC equipment.