As a part of a broader experiment, electrodes are applied to the inside of the participant's hand so as to measure skin conductance responses to food stimuli. Somehow these electrodes show rarely any and mostly no response at all. The electrodes system used is a Braindproducts GSR sensor system. I am currently using the TD 246 Skin Conductance Electrode Paste and a Brainvision ExG AUX amplifier. Since the amplifier works fine in other experiments, I expect the GSR system to be dysfunctional. Since I`m reluctant to replace the system prematurely, I´d love to hear about some tips and tricks in the neuroscience/psychology community that will help me get the system running or increase my chances of receiving a solid EDA signal.
Have you ruled out any mechanical errors? Simply holding the sensors against each other (or connecting them with any conductive substance) should show a large spike; If not then the electrodes themselves are simply faulty.
Additionally, you may want to make sure that any filters applied by the amplifier is compatible with the sensor.
If a mechanical fault is ruled out you could try measuring the EDA on a different region, e.g. the fingers.
Yes, fingers may be a better region to place the sensors.
But if you are thinking to try different equipment, you can consider using the Empatica E4 wristband. It may be pricier, but if budget allows, may be a more portable and less-invasive option.
Hi Jonathan,
It definitely doesn't sound like a problem with your amplifier. What type of electrodes are you using? Reusable electrodes are corrosive and they typically last only for one or two years if you're using them almost every day. Due to this reason, I recommend using pre-gelled disposable electrodes packed in individual pouches.
Also, it is very important to use the right type of gel. Isotonic recording gel with 0.5 saline solution is the right type of gel to use for GSR electrodes. When putting the gel, make sure that there's no air pocket inside. Poke several times with a cotton swab and make sure to remove any excess.
Good luck with your experiment!
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