|Age:||18 to 35 years old|
|Keywords:||Transcranial Direct Current Stimulation, EEG, brain stimulation, cognition|
If you choose to participate in this study you will complete up to four sessions.
Interview Session: During the interview session we will ask you questions about your personality, speech, mood, living situation, medical history, and any past or present drug or alcohol use. We will also ask you about experiences such as hearing voices, seeing visions or having trouble with your thinking. You may skip any question on the questionnaire or in the interview that you do not wish to answer. If you are female, you will be given a urine pregnancy test to determine that you are not pregnant. If you are found to be pregnant you will be not be able to participate in the study. This is because it is unknown whether the study device may harm a fetus. This session will last about 1 hour.
tDCS/EEG Sessions: At the beginning of each tDCS/EEG session you will complete a urine drug screen. This is to check for any drugs (e.g., marijuana, cocaine) that may be in your body that could affect the study results. We will not tell anyone the results of your drug screen without your permission. The results will not become part of your medical record. It is your choice if you wish to tell someone the results from this drug screen. Results from this drug screen will not prevent you from doing the study. If your drug screen is positive we will ask you to reschedule your appointment. Next you will get 20 minutes of tDCS stimulation. tDCS is “transcranial direct current stimulation”. This is a safe method of applying a small electrical current to your brain using small electrodes. We will place two tDCS electrodes on your head. The electrodes apply a low electrical current to stimulate your brain. You will receive either “active” or “sham” tDCS stimulation at each session.
Active stimulation is when the electrical current is applied for the 20 minutes. The electrical current strength will be a maximum of 2 milliamperes (mA). This is similar to the output of a 9-volt battery. Sham stimulation is when the electrical current is applied for the first minute and then switched off. We will not tell you which type of stimulation you are receiving. This is to prevent biased performance on the task.
The type of stimulation you get during a given session will be chosen by chance, like flipping a coin. Neither you nor the researchers will choose what type of stimulation you get during a session. Over the course of the study, you will complete all types of stimulation (active and sham), in randomized order. Neither you nor the researchers will know which type of stimulation you are getting at a given session.
We will ask about your mood before and after stimulation. We will monitor you until your mood has returned to normal. During stimulation you will complete a short cognitive task. We will also ask you about any physical sensations that you are experiencing. If you experience unpleasant physical sensations we will stop stimulation. After stimulation you will complete the brain wave recording (EEG). Several locations on your head and face will be cleansed (alcohol may be used) and tin or silver and plastic disks (electrodes) will be attached to those locations with either a sticker or an elastic cap that you will wear. Between your skin and the electrodes, a small amount of electrode jelly will be applied to make good contact.
During EEG recording, you will sit in a comfortable chair and your brain waves will be recorded while you complete cognitive tasks. These tasks will involve looking at a computer screen where different types of stimuli will be presented. These will be figures, symbols, numbers, letters, words or sentences. You will be asked to respond to these by pressing a button, reading aloud what you see on screen or generating your own verbal responses, or picking from among a group of answers on the screen.
At the conclusion of EEG recording, the electrodes and elastic cap will be removed and the area where the electrodes were located will be cleansed. Preparation of the sensors typically takes about 30 minutes, and recording time will take up to 1.5 hours.
MRI Scan: At the end of the last tDCS/EEG session, you may complete an MRI magnetic resonance imaging) recording after the EEG recording. The MRI machine uses magnetic waves to take pictures inside the body. The waves are not harmful. The MRI machine is a large hollow round tube. In an MRI, you will lie comfortably on your back on a table inside the machine while pictures are taken of your brain. The MRI images allow us to see how well your brain functions while you are responding to the computer tasks. You will hear noises during the scan, and wear earplugs so the noises aren’t too loud. You will always be able to talk with the operator or technologist during the study. The MRI session includes 15 minutes of preparation before getting in the scanner. The actual time you will be in scanner will be about 1 hour.
Have any questions or want to learn more? Leave your contact details below and the research team will reach out to you.