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If your question isn’t covered, learn more in EDA: Electrodermal Activity Applications, review EDA Signals & Measurements, or contact BIOPAC Support.
A: Data recorded from the same electrodes will look identical with one exception: the wireless system uses 12-bit A/D conversion before broadcasting the data, while the wired system uses 16-bit A/D conversion. This means you can detect much smaller changes in skin conductance with the wired system. The minimum resolution with the wireless system is 0.012 µS, while with the EDA100C amplifier it is several orders of magnitude smaller (because you can also change the gain and zero offset of the amplifier). For practical purposes, the resolution of the wireless system will be enough, but this is something to keep in mind if extremely sensitive measurements are necessary.
A: One of the best references is to look for publications that have employed the device and technology. BIOPAC products have been cited more than 45,700 times and over 2,630 times specifically for EDA. I would also check how the device is measuring the signal of interest and make sure that the technique is providing you with the data you require for the application. Many wearable devices are great for consumer use but not really suitable for research purposes. The BIOPAC BioNomadix product line has been proven in the lab and is now available for remote subject monitoring.
A: The following link will provide you with information about the MP36R hardware.
A: Just like with the EDA100C/GSR100C amplifiers, make sure you are in DC mode. You should also make sure the gain you are using is appropriate. Please contact us at support@biopac.com if you have specific questions.
A: Using the CAMSYS4 and CAMSYS8, you can record and synchronize 4 or 8 videos respectively. Furthermore, using the OUT103 led as a sync marker, there is no limit for how many external video cameras you can synchronize with AcqKnowledge and later link the footage to the software. See here. In addition to the multi camera setups there is also a High Frame Rate option for recording fast events.
A: The analysis approaches apply equally to data recorded with the MP36 system. The MP36R system comes with the AcqKnowledge software, which was used for the presentation. The BSL software comes with the regular MP36 system (part of our educational BSL package) but has fewer features as it is designed for teaching purposes. AcqKnowledge can open files created with the BSL/MP36 system and, therefore, you can analyze BSL data using the more advanced research software, AcqKnowledge.
A: It is possible, but please contact us so we can discuss your options.
BioNomadix Wireless EDA
A: No. EMG equipment records a biopotential voltage while EDA works by passing a current through the body and recording conductance. We have the BN-PPGED module to accomplish wireless EDA recordings.
A: The devices are factory calibrated but you can confirm the calibration by using known resistor values. Consult the Support Department for further information.
EDA Data recorded in MRI
A: Make sure that you are using the EDA100C-MRI with one of the BIOPAC MECMRI-TRANS filtered cable sets with suitable electrode leads and electrodes. The filter must be properly attached to the patch panel as per the instructions. The EDA100C-MRI does a nice job of eliminating/reducing gradient noise from the scanner and providing a good EDA signal.
A: Make sure that you are using one of our MECMRI-TRANS filtered cable sets with suitable electrode leads and electrodes. The filter should be securely fastened to the patch panel as described in our instructions. If you have everything connected according to our instructions, you should consult with our Support Department.
A: We recommend calibration outside the scanner room.
A: The easiest way it to go into Setup Data Acquisition and select Event Marking. This will allow you to select any Function Key and apply a label to the event mark. In this case, the label could say ‘Error’ and each time that particular Function Key is pressed, an event mark will be inserted with the label “Error” applied to it. The software will allow you to search and jump to any event mark in the file by accessing the Event Palette from the Toolbar. The following Event Marks screencast will provide you with a detailed demonstration of the event mark feature.
A: With the MP150 system and the STP100C module you can receive data from the parallel port or the StimTracker (and similar device) from any computer. You can send markers over the network to AcqKnowledge using Network Data Transfer (NDT) with NDT licenses. For virtual reality experiments we can provide sample code for how to send markers from Vizard to AcqKnowledge, as well as how to stream physiological data to the virtual reality computer in real-time.
A: If you use the STP100C and interface between the parallel port on the computer running E-prime, you can send digital markers from E-prime to the MP recording device. The Digital Input to Stim Events analysis option will convert the digital pulses from E-prime into unique events that AcqKnowledge can use for analysis. Click to watch the Digital Input to Stim screencast for additional information about this feature.
A: Digital channels 8-15 can be used to record markers from stimulus presentation software such as E-Prime, Presentation, and Experiment Center.
A: The Skin Conductance Level data will typically drop as a subject relaxes and this is quite normal. See A Guide for Analysing Electrodermal Activity (EDA) & Skin Conductance Responses (SCRs) for Psychological Experiments for a good section that covers this particular issue.
A: If you are looking at Skin Conductance Level during the baseline, you might see the level drop as the participant relaxes and gets used to the equipment. The important thing is ensure that the subject is relaxed and not engaged in anything during the baseline period. A period of 2-4 minutes should work for a baseline, but I would highly recommend consulting the literature to see what is appropriate for your application.
A: Yes, you can do this with the Scripting software. The following link will provide you with additional information about BIOPAC Basic Scripting. https://www.biopac.com/product/basic-scripting-licenses/
A: This is a function of latency + rise time + recovery time. We would suggest no less than 8-10 seconds, but this decision is ultimately the researchers. There are also publications on how to deal with analyzing EDA data when events are spaced very closely together; there certainly are some interesting solutions. We recommend that you consult the literature if you have to cut down on the inter-stimulus interval.
A: Handbook of Psychophysiology. John T. Cacioppo, Gary Berntson, Louis G. Tassinary states 1-3 seconds or 1-4 and I have always used that as my reference. The default setting in AcqKnowledge is 1-4 seconds, but you can change that as I demonstrated in the webinar. The same guide also mentions 0.05 for a threshold for detecting SCRs but is also goes on to say that this threshold was based around the use of legacy paper recording devices. The Society for Psychophysiological Research guideline paper recommends between .01 and .05, based on what the equipment can handle. As I demonstrated in the presentation, the software can reliably detect responses at the .01 level. However, I would definitely look closely at the guidelines and ensure that you are using the correct values.
EDA Stimuli plot
A: The example which included two digital channels with markers involved auditory stimulation. Two categories of sounds were played to the participant: recordings of screams and recordings of hand claps. They had similar dB levels.
A: Such a frequency of stimulation would be too much given the time it takes for responses to reach their peak and decay.
A: We can deliver a wide range of voltage or current stimulation, including even transcranial current stimulation (tDCS or tACS ). It is best to contact us at support@biopac.com since there are many details to consider when designing an experiment with electrical stimulation.
A: Here are two options for the MP150 System (similar options available for the MP36R):
a) Split the audio output of the computer and feed it directly into the system as an analog channel via the HLT100C and INISO. This would ensure optical isolation.
b) If using stimulus presentation software, send markers over the parallel port to the STP100C module.
There are more solutions available and if you need further information, please contact us at support@biopac.com
A: We have not experimented with this sufficiently. We recommend consulting with the literature.
A: This is a calibration issue. To fix existing data, contact us at support@biopac.com. For future recordings, make sure you perform the calibration with open circuit (electrodes not connected to the participant) at the start of the recording.
A: In our experience, about 10% of people are non-responders. If in doubt, you can always record some data from yourself when you encounter such a participant. If you use the same setup and same batch of electrodes and get responses yourself, but nothing from the participants, then you may have a non-responder. Also check the location where you are placing the electrodes for callused skin, cuts and abrasions because they will impact the quality of the signal.
A: By all means, the goal of such events is to share our knowledge with researchers.
A: Visit our website or conduct a Google scholar search for BIOPAC + GSR or BIOPAC + EDA. The search will return over a thousand results.
A: I would highly recommend performing a literature review for specifics.
A: I believe the participant was seated in a lab environment.
A: The STIMTRACKER (STK100) stimulus presentation marker USB interface offers one solution.
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