Guidelines for participating in fMRI experiments
Here are some general guidelines for your upcoming fMRI scanning session. Please read it carefully and follow the guidelines. Thank you very much for your cooperation.
The day of the scan:
- If applicable, remember to wear contact lenses instead of glasses.
- Do not drink excessive amounts of liquid, especially caffeine (a diuretic — an fMRI session seems much longer with a full bladder!).
- Do not wear any shirts with metal around the head (e.g., pullovers with zippers). Metal buttons and zippers on pants are okay.
- Do not use any hairclips and be prepared to remove jewellery.
- For women, if possible, do not wear an underwire bra (the metal can throw off the magnetic field). Sports bras are usually good and we have hospital gowns to change into if necessary. The clasps on the back of a regular bra are not a problem, but avoid wearing bras that have metal parts on the straps.
- Avoid wearing mascara (can contain metal flakes), hair gel and wet hair. Water in hair can throw off magnet signal.
- Make sure you know where you are going to meet the experimenter and what time you are expected to show up. For a map of Dept. of Radiology see here. If you drive, you can park in Lot 100, right next to the Radiology building (take a ticket to enter the gate). We will issue you a parking validation at the end of the experiment so you don’t need to pay for parking.
- Scanning on a MRI machine costs a lot of money ($550/hr). Every minute counts, so please show up on time. If anything comes up such that you cannot make your scheduled time, notify the experimenter as soon as possible. If we cancel well in advance we can avoid to be charged. Please be considerate.
While in the magnet:
- It is important you settle into a comfortable position on the scanner bed. If you notice anything vaguely uncomfortable before you get rolled into the magnet, tell the experimenter. Things that are slightly uncomfortable at the start become excruciating by the end. Once you are in place, you will maintain that exact position for 1-2 hours.
- As the bed is moving into the magnet bore, moving through the magnetic field may play tricks on your vestibular system and some people feel a bit dizzy. This is normal, and will subside shortly after the bed stops moving.
- Try not to change head or body position during a scan (while the magnet is beeping). If the head moves, it creates artifacts that are usually difficult if not impossible to fix. The position of body parts in the magnetic field distorts it. So if you cross your legs, scratch your head, open your mouth, yawn (inhale deeply), or shift your posture, it can lead to artifacts even if your brain doesn’t move. We try to keep runs as short as possible (usually around 5 minutes) so that you can stay in the same position the whole time.
- Swallowing can lead to head motion artifacts. If you can avoid swallowing during a scan, the data quality will be better. If trying not to swallow makes you gag or swallow suddenly, then it’s best to just swallow normally.
- Between scans (when the magnet is not beeping), you can swallow freely, however you still can not change your body position or scratch, etc. If you absolutely can’t stand it, then it is better to do those things between scans, but is highly discouraged. If it happens frequently, the session will be a waste. Millimeters matter; do your best not to do anything that will move your head from its original position.
- Try to stay relaxed throughout the session. If you tense up at the beginning of a scan, your head can drift as you settle down.
- If you notice anything weird with the experiment (e.g., visual display is upside down/left right reversed or you can’t see the display or the screen saver comes on partway through a scan) or have problems with the task (e.g., make mistakes, fall asleep), be sure to tell the experimenter after the scan in which it happened.
- You will be given a squeeze ball in case you need to stop the scan midway. You can use this if something goes wrong with the experiment (see above) or if you need to stop immediately for any other reasons.
- While in the magnet, you can hear us through an intercom system. We will give you some prompts/instructions as we move along the session. However, normally we do not need you to talk back to us, as you might move your head if you talk. We usually use the screen to display some prompts and let you to press the buttons to indicate responses. It’s not we don’t want hear from you; we just want to minimize any head motion.