What is fMRI?

With fMRI technology, we can determine which part of the brain is active during a given task by comparing (at least) two experimental conditions. When a part of the brain is active, it requires more oxygen. The body delivers more oxygen to active regions of the brain by increasing the blood flow to that region. We can compare the differences in blood flow between our two conditions to find regions that are associated with one task and not the other. We are able to detect these differences with MRI because there is a difference in the magnetization properties of oxygenated and deoxygenated blood (that is, blood that has not been used and blood that has been used by the brain.)

Here are a couple of web sites that you can refer to if you would like a more detailed explanation of fMRI. Please feel free to ask us any questions that you might have.

1. MRI textbook by Joseph P. Hornak, Ph.D. --http://www.cis.rit.edu/htbooks/mri/

3. MRI Tutor Web Site -- http://www.mritutor.org/mritutor/index.html

The fMRI experience

To see pictures of the scanner, hear the sound it makes and see what you have to do as a subject, have a look at the online subject orientation:

http://cnl.web.arizona.edu/orientation.htm

It is important to us that you know what to expect when you participate in an MRI study. This material will describe what participating in our fMRI study will be like. Please read carefully and consider whether or not you will be able to participate.

Most of the studies that take place in our lab are about 2 hours long. The actual amount of time in the MRI scanner is around 90 minutes. During this time, you will be lying on your back on the scanner bed. The scanner bed will move inside of a large donut-shaped magnet. Some people feel claustrophobic being inside of the enclosed space of the magnet, but most are okay. If you have any back problems or think that you will not be able to lie comfortably on the bed for 90 minutes, it is not recommended that you participate in an fMRI study. It is necessary for you to keep perfectly still during the entire time you are in the scanner because the MRI is very sensitive to movement of any kind. We will make you as comfortable as possible. We have found that the best way to stay still is to be able to relax comfortably inside the scanner.

We need to make you aware that we share the scanner with the clinical staff. It is always possible that the clinical scanning will take longer than planned, or that an emergency case will arise. For that reason, it is often necessary for us to postpone or reschedule our appointments for studies. We will make every attempt to get you into the scanner at the time that we had originally planned with you, but sometimes it is out of our hands. Please keep in mind that we may need to make some last minute scheduling changes with you.

When you get to the hospital, we will have you sign a consent form that details exactly what your involvement in our study requires. We will then go through the MRI checklist with you a second time as a safety precaution. The MRI scanner is within a strong magnetic field. For that reason, it is important that you do not have any metal in or on your body. Before entering the scanning area you will need to remove everything from your pockets and all metal items you may be wearing (belts, jewelry,nicotine patches etc.). We have a locker for you to store these items in. At this point you will enter the MRI suite.

For some studies we may have you run through a practice trial on the computer in order to familiarize you with the task you will be performing before you enter the scanner. Once you are ready, we will bring you into the scanning room and you will lie down on the scanner table. A plastic encased coil is placed over your head (This is the head coil or "bird cage"). In many of our experiments we have you wear goggles and/or headphones so we can provide you with instructions and show you stimuli.

Throughout your scan, the MRI scanner will be taking many pictures of your brain. It is very important that you keep your head still during the scans. We use small foam pillows to help you keep your head still.

The magnet makes loud knocking sounds while it is acquiring images. Because of this we will have you put earplugs in your ears. You will also be wearing headphones with a microphone attached so that we can communicate with each other in between the scans.

The typical scanning session has 3 parts: 1) the structural localizers 2) the functional scans and 3) high resolution structural scans.

First we collect two brief scans called "localizers." These scans only take a couple of minutes to collect. The pictures of your brain collected here are used to plan the rest of the scans.

The second part is the functional scans. These scans are taken while you are engaged in the experiment and tell us which areas of your brain are active. Depending on the experiment, 2-8 runs will be collected. Instructions will be given to you both before you go into the scanner, and just before the functional runs begin. During the functional scans, many pictures are taken of your brain (17 images across your brain may be taken every 2 seconds while you are performing a task). The length of the functional runs will vary for each experiment but usually takes 30-60 minutes.

During the experimental runs in the scanner, you will be asked to view stimuli through goggles and make responses to them using a computer mouse that will be in your hand. You will be able to have short breaks in between the experimental scans, but will remain lying in the scanner with your head in place.

Following the experimental runs, we will take some high-resolution (very detailed) images of your brain, which should take a total of about 15 16-20 minutes. During this time, you can just relax and close your eyes. We can play music for you through the headphones, so bring a favorite CD if you like.

We might have you put earplugs in your ears because the magnet makes loud knocking sounds while it is acquiring images. You will be wearing headphones with a microphone attached so that we can communicate with each other at all times.

After you come out of the scanner, you will be able to ask questions about what you did, and we can tell you what the experiment was about.

Be aware that a functional MRI scan is a medical procedure and when we reserve a scanning session on a hospital scanner, that time can cost us up to $1000, whether we have a subject or not. If you cannot keep your appointment, please let us know at the earliest possible moment (621-8618). Thank you for your cooperation.