Recording ERPs at the Reading Brains Lab
First, we need to prepare to record your brain waves (EEG). This can take a pretty long time, anywhere from 30 to 50 minutes. Because this part might not be that interesting for you and you don’t need to do anything in particular while we are getting everything ready, we have some movies for you to choose from to watch while we are setting up the cap and the electrodes on your head. If you don’t want to watch a movie, that’s fine. We are happy to answer any questions that you might have at any time that you are in the Reading Brains Lab, so feel free to chat with us.
In order to prepare for recording ERPs, we place a stretchy elastic cap on your head (we even have differently colored caps for differently sized heads). The cap has little metal disks – electrodes – sewn into it. The electrodes are not dangerous and only listen in to the naturally ongoing electrical activity in your brain – they cannot add anything or take anything out or change anything in your brain. We place a little bit of gel in each electrode so that it can listen in more clearly.
We also place extra electrodes beside each of your eyes, below one eye on your cheek, and behind each ear. These electrodes are held on with stickers that are a little bit like a Band-Aid and a little bit like the reinforcing stickers used for three-ring notebook paper. We clean off your skin just where the stickers will go before we put each sticker on (to make sure that they stick to a clean surface) and after we take each sticker off (to wipe off any leftover gel).
When all of the electrodes have gel in them and all of them are clearly listening in to the electrical activity in your brain, we will stop the movie (if you were watching a movie) and ask you to move into the sound-attenuating booth. We record the ERPs in this booth because it is very quiet, which means that you will not be distracted when you are doing the experiment. There is a camera in the booth so that people outside the booth can see what is happening inside the booth even when the door is closed. There is also an intercom system in the booth so that you can communicate with people outside the booth even when the door is closed. You will be seated in a comfortable armchair in the booth during the experiment.
Once the cap and the electrodes are prepared and you are settled in the booth, we will show you a picture of your own brain waves (EEG) on a computer monitor in front of you.
Next, we will start the experiment (example). We will read you some instructions outlining exactly what will happen and what you need to do. If you have any questions, we are happy to answer them. We conduct lots of different kinds of experiments, but in all of them you will be asked to pay attention to sounds or words or pictures while your brain waves are being recorded. In some experiments, you may be asked to press a button in order to answer a question about the events that you saw or heard.
Information about the brain waves that we record while you are paying attention to the visual or auditory events is sent from the cap electrodes through a set of amplifiers in the booth to a computer outside the booth. A person sitting outside the booth will be watching your brain waves on a computer monitor as you are doing the experiment. We will save the brain wave information on disk and analyze it after you leave. The brain waves will help us to learn about how the brain processes different kinds of information.
When the experiment is over, we will remove the cap and the extra electrodes and clean up any electrode gel that might be left in your hair as best we can.
Nothing that we do in the ERP recording procedure at the Reading Brains Lab hurts at all.