ENV-420 Aversive Stimulation Current Test Package
Aversive stimulation is an important aspect of many behavioral studies. In today’s climate of increased awareness for the humane care and use of animals in research, the use of aversive stimulation usually requires specific scientific justification on the part of the researcher. Verifying that the levels of aversive stimulation appropriate for the intended purpose are actually delivered by the stimulator unit is now more important than ever.
Anyone who has attempted to measure current levels across a grid floor during aversive stimulation can appreciate that this task is not exactly a simple matter. For example, many people would like to measure the current across a grid floor when a test subject actually experience aversive stimulation. Unfortunately, one cannot simply attach standard multimeter leads to the grid rods and hope to measure current levels. Even measuring the current levels across grid rods or other electrodes when no test subject is present requires special purpose-designed equipment. A standard inexpensive multimeter, such as the type found in many laboratories for general troubleshooting purposes, is inadequate. These devices simply are not designed for measuring current in the circuits used to deliver scrambled current pulses across a grid floor.
Med Associates offers the ENV-420 Aversive Stimulation Current Test Package as an affordable solution to allow researchers to verify that their aversive stimulation equipment is functioning properly. This device is very simple to operate. The meter connects to a computer via an available USB port. The ENV-420 comes with a useful software application that functions as a digital current meter. The software shows an oscilloscope-like view of the current waveform that is measured, as well as the RMS current level. The meter connects to the grid rods, or other electrodes, using standard alligator clip leads, which are conveniently attached to the meter.
To measure current in your circuit with the ENV-420, simply clip the meter leads to the grid rods, or other electrodes, set the aversive stimulator to the desired current level, deliver a steady pulse of current, and observe the RMS current indicator on the computer monitor. This indicator should be close to the current setting on your aversive stimulator. For example, if you set the aversive stimulator to deliver 0.3 mA, the RMS current indicator in the ENV-420 software should read 0.3 mA. If no current is measured, or if the current is significantly different from your intended setting, a problem may be present at some point in the system.
Common problems that may be indicated when current measurements do not match expectations include:
- grid rods that are not properly connected
- grid rods that are shorted out
- current range setting on the aversive stimulator was set to the wrong level (for example, 0-10 mA instead of 0-1 mA)
- “Dummy Load” set to IN position instead of OUT position
- ENV-420 leads placed incorrectly
- faulty aversive stimulator unit
Contact Med Associates Sales Department at 802-527-9724 for more information, or if you would like to add an ENV-420 Stimulation Current Test Package to your laboratory.
