The sample E-Prime experiment provides the necessary interface commands to communicate with the D/A unit. The D/A unit provides the STMISOLA with the appropriate voltage levels to stimulate a subject. The system supports up to four STMISOLA (and includes one).
The Current Feedback Monitor Cable (CBLCFMA) is recommended for use with any voltage stimulator; to isolate CBLCFMA output, use INISO and HLT100C. Always make sure to place the electrodes on the participant at least 10 minutes before starting any electrical stimulation. Use a CBLCFMA to monitor and record the actual current delivered to the participant at ALL times. A large enough change in current delivered to the participant will alter the subjective perception of the stimulation. Thus, an unpleasant shock may become painful if more current starts being delivered or become ineffectual if less current is being delivered than during threshold identification. Changes in the levels of delivered current are due to changes in impedance. Changes in impedance could be due to a number of factors: gel saturating the skin over time; gel drying up – over longer period of times; hydration level of participant; sweating; decoupling of electrodes and skin due to motion artifacts; etc.
IMPORTANT! Read Safe Use of Electrical Stimulators – Application Note 257 for Comprehensive Safety Guidelines for Performing Electrical Stimulation on Subjects
MRI Usage Note
STMEPM should not be used in an MRI and is not for use in stimulating subjects who are to be placed in an MRI; see STMEPM-MRI for electrical stimulation in MRI or fMRI.
A largely equivalent replacement for MRI permits the same basic functionality as STMEPM, but is not subject to the same possible errant stimulation issues if a suitable patch panel filtering structure is not constructed. This substitute setup is restricted in terms of pulse width (2 ms max) and only voltage controlled voltage stimulation is possible. However, this substitute setup can generate stimulation of differing intensity under E-Prime control.
To use this TYPE of system for MRI applications, the following stimulation structure is recommended to be intrinisically safe, despite possible errors in user recording setup:
Replace the STMISOLA and its power supply with
- Isolated Power Supply IPS100C
- Stimulator Module STM100C
- Stimulus Isolation Adapter STMISOC
- Connection cable CBL100