Transcranial Direct Current Stimulation (tDCS) and High Definition Transcranial Direct Current Stimulation (HD-tDCS) 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), unipolar, direct current applied to selected regions of the brain via surface electrodes placed on the scalp.
For tDCS 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.
tDCS can be used in conjunction with fMRI and transcranial magnetic stimulation (TMS)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 MP150 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.