The purpose of this Institutional Review Board-approved study is to see if mental functions take place during different levels of anesthesia, using a Food and Drug Administration (FDA) approved, commonly used drug (propofol). Imaging of the brain with fMRI will show areas in the brain involved in thinking at different levels of anesthesia. The fMRI exam works by registering blood flow to functioning areas while lying inside the magnet, which is a tube-shaped machine.
You will arrive to the study “fasting.” This means that you will not have had anything to drink for three hours before the appointment. A medical doctor will sit down with you and go over the procedures, ask you medical questions and give you a physical exam necessary for you to receive anesthetic.
The doctor will then put a small hollow tube called an intravenous (IV) line in a vein in your arm. An infusion pump will deliver the anesthetic (propofol). The drug will be given at two different doses for mild or deep sedation. The doctor will take two small blood samples to measure the amount of anesthetic in your blood stream.
In one scanning session, you will rest for 60 minutes. In another scanning session, you will hear sounds — pitches or names of people — through earphones. During the presentation of the words, a picture of your brain will be obtained with fMRI.
FMRI is a process by which images of the brain are obtained while the participant is engaged in some task. The method is "functional" in that the images show which areas of the brain are "working" the hardest during various tasks. This is in contrast to standard MRI scans, which produce images of the brain's shape and appearance.
Both types of MRI scanning use radio waves and a strong magnetic field to create the images. There is no radiation and no known risks when FDA guidelines are followed. MRI has been used in animal research since the 1940s and has had widespread clinical application since 1980. Medical College of Wisconsin investigators use the fMRI technique to study vision, hearing, language, motor function, memory, and other complex brain functions.
It is painless, although it is noisy and requires the participant to remain still for an extended period of time. The participant wears a helmet-like device that encases the FMRI magnetic coil. There is an intercom system in the scanner through which participants can be heard at all times, and the technicians in the adjacent control room use the intercom to inform participants each time a series of scans is about to begin. One cautionary note: the "tube" is somewhat narrow, and although it is open on both ends, some people do have a claustrophobic reaction to the scanner. Anyone who is aware of feeling uncomfortable in close quarters should not volunteer for this study. The scan takes about two hours. Total participation time, which includes filling out information forms and practicing the tasks to be performed, is typically five hours.
The doctor will trace the electrical activity of your heart (EKG), monitor your heart rate, blood pressure, amount of oxygen in your body, respiratory rate and expired gases. He or she will also measure your brain waves (EEG) to measure the different depths of anesthesia in your body. Finally, someone will give you a recognition test to see how well you remembered words once you are out of the scanner.
Payment for participation is $250, and participants may receive a print or digital picture of their brain upon request. If you are interested in participating, please read the Consent Form in the next web tab. This process requires you to submit personal information, including health information, which will be kept strictly confidential and available only to research personnel with security clearance.
If you are interested in enrolling, you may do so online. First, you will read and submit a web consent form to fill out the enrollment form. If you would prefer to enroll by speaking with the study coordinator on the telephone, please call 414-955-4956.
If the medical director determines that you are eligible for the study, you will be contacted. At that point, you will receive a new, hard copy consent form in the mail. This consent form will outline the procedure in greater detail; and it will explain the possible risks. A physician also will go over all of this again when you arrive at the study.