by Tonny Mulder
In this tutorial you will perform a demo experiment and run some basic analyses.
Select what you want to do, by clicking on the pictures of your choice
In this tutorial you are going to perform a short demonstration experiment. The main reason for this demo experiment is to get you familiar with all the equipment and procedures. Take your time and take it seriously.
During the 'Motoriek Practicum' in your first year you already used the EEG_recorder program. Now you will get further familiar with EEG recording.
If the setup is not intact, now it's the time to build your EEG setup.
Visit the Setup page for information.
There are two main designs that are used in EEG experiments: Recording oscillations and recording ERPs. You will design an experiment wherein you will record both.
Use Stimulus Presenter to construct one task with three sub-tasks according to the design below. Have your participant perform these three sub-tasks accompanied by instruction slides:
Sub-task 1: Eliciting alpha oscillations, that are strong during rest
Sub-task 2: Eliciting Beta oscillations, that are strong during attention, concentration and calculation.
Both should have a duration of 1 minute in total and should be accompanied by proper controls and instruction slides.
Sub-task 3: Showing the participant 30 happy, 30 sad and 30 neutral faces in random order for one second each, recording ERPs. Download the pictures from CANVAS.
Use Stimulus Presenter to control your experiment. Construct relevant instruction slides for your participant.
Use Markers (DIO's) acccording to the flow chart below to synchronize events created in Stimulus Presenter with your EEG recording.
Then dry-run your experiment, before connecting a participant.. This will verify that everything runs properly and the markers are detected by the EEG-recorder: See next section!.
Note: for a dry run it isn't neccesary to present all faces or present a full duration of your alpha and Beta experiment. You can, for instance, dial down the number of repeats in your Stimulus Presenter program. This makes trouble shooting easy and fast!
The EEG Recorder software is already downloaded and available on your EEG_Recorder laptop.
The latest version = UvA_EEG_recorder-3.1.1_(4Jan_2021) is already available on the recording laptop.
To perform analysis on your own laptop: Download EEG_Recorder from CANVAS
This will be a dry run recording that will test the following:
NOTE: No participant is being recorded and electrodes are not connected. So the signal will be bad!!
NOTE: You wil check the quality of the signal after connecting a participant in the next section
Start EEG_Recorder in MATLAB (32bits)
Setting recording parameters
With all electrodes connected the signal can be tested. First select all EEG channels and Marker channels (DIOs) that are in use. (See figure below).
Figure: Example of the lower left panel of the EEG_Recorder. 'View EEG channels' and 'Select Markers to record' are interactive, 'DAQ settings' are default settings.
LIVE VIEW PANEL
In the ‘Live view’ panel you can adjust the settings of what is visible on your screen. These settings have no effect on the recorded data or what is eventually saved.
Figure: Example of the interactive ‘Live view’ panel of EEG_Recorder.
Starting and Stoping the RECORDING
Before starting the recording first some explanation about the right panel with which you control the recording.
Figure: The Clear/Start/Stop menu of EEG_Recorder.
Set the ‘Duration acquisition (s)’ to the time of your liking.
Now Start your recording and check if your markers are visible, trouble shoot if neccesary.
Connecting your participant.
If the task is ready AND running properly, connect a participant.
Setup a recording for Fz and Oz locations. In case you have a third electrode use Pz also. Fill the cap with the red recording electrodes, one yellow ground electrode on Cz and connect the blue earlobe reference when the cap is on the head of the participant. If necessary, use the setup page for reference
Fitting the cap.
Select the cap size that fits your subject.
The red cap has a medium fit and fits most people. The blue cap is the largest, and the green cap is the smallest. The cap should be tight enough so the electrodes are close to the scalp but still comfortable for the subject to wear. Let the subject put on the cap.
Orienting the cap
Gelling the electrodes
Time to test the recording setup :
In the following segments you will run EEG_Recorder for the first time, set the parameters, learn about its functionalities and make a test recording.
Use this signal check pipeline when you have a participant hooked up and you started your recording.
In this tutorial you will check the quality of your signal and examine the artifacts that may reside in your recording.
Check and discuss the results with your teaching assistent
PRESS START in the EEG_Recorder Window.
|1||The MobiLab is not plugged in||Cable is not connected||Press Clear, Plug MobiLab in, Press Start|
|2||The MobiLab is not switched ON||The MobiLab is not switched ON||Press Clear, Switch MobiLab ON, Press Start|
|3||The MobiLab is switched ON but LED is blinking red||The MobiLab batteries are dead||Press Clear, Change MobiLab Batteries, Press Start|
|4||The MobiLab is switched ON and LED is blinking green||Driver issue||Restart Matlab and EEG_Recorder and try again|
|5||None of the above||HELP!||Contact the assistant|
Now the recording should start
Continue with section: Recording started!
|1||ALL channels are bad||GammaBox is still OFF||Switch GammaBox ON|
|GammaBox is ON but no Green light||Change the battery for the GammaBox|
|Yellow ground electrode and/or blue reference electrode are not connected||Connect Ground and reference electrodes. Dont forget the GEL|
|No Gel into red recording electrodes||GEL all electrodes, make sure no air is trapped between the gel and the skull|
|ALL Electrode Plugs not properly connected to GammaBox||Push Plugs in to the hilt|
|Still none of the recording electrodes work||Change the Yellow grond and/or the Blue reference electrode|
|2||A few channels are bad, the rest is okay!||Ground and reference electrodes work, some recording electrodes don't.||GEL the faulty recording electrodes|
|Still a few recording electrodes don't work properly||Push Plugs of faulty electrodes into the GammaBox|
|Still a few recording electrodes don't work properly||Change the electrode (s) in question after discussing this with your teaching assistant|
Perform the experiment and save the recorded data:
If everything is set, start your DEMO recording.
The proper procedure to perform any recording is: