The 10 Brain Scan Commandments

By Neuroskeptic | March 13, 2013 10:31 am

Here at Neuroskeptic there’s a lot of talk about brain scanning, most commonly functional MRI. I’ve blogged about all kinds of studies, methods, criticisms and advances in fMRI technology. But what about the people on the receiving end – the volunteers?

What follows is meant to be half useful advice for participants, and half insight into the difficulties in running an fMRI study.

The 10 Commandments for fMRI Volunteers

1. Thou Shalt Turn Up…: Please. If you don’t, we’ll waste a lot of money (ballpark figure: $1000 an MRI scanning slot).

2. …On Time: If you’re late, the whole scanner schedule gets messed up. All the scans later in the day will be delayed, so our friends will think we’re jerks. Turning up really late could even alter the results of some experiments, because brain activity changes over the course of the day.

3. Thou Shalt Be Patient: Because your scan may be delayed (see #2).

4. Thou Shalt Not Fidget: Before the scan we’ll ask you to stay still, and we mean it. Any movement will affect our data. That camera that lets us keep an eye on you in the scanner? It’s partly for your safety, but also so we can spot if your fidgeting. If you do have to move, try and do it in the gaps between the scan sequences rather than in the middle of a test.

5. Thou Absolutely Shalt Not Sneeze: Really. It’s bad news for all concerned.

6. Thou Shalt Not Drink… any coffee or tea before the experiment. Caffeine affects the brain, you see. But then again, we don’t want you to go without caffeine you’d normally drink, because the withdrawal symptoms would also affect the brain. So, er, we’re in a bit of a bind, and neuroscientists disagree on what to do about this. We secretly wish all our volunteers were Mormon for this reason.

7. Thou Shalt Be Clever… enough to understand the instructions of the psychological tasks you’re asked to do, even if we’re terrible at explaining them.

8. …But Not Too Clever: If you ‘get’ the purpose of the task, we’re in trouble. We want brain activity caused by the test, not by thinking about the test. So just trust us, everything is exactly as it seems. We never try and mess with your mind. Honest.

9. Thou Shalt Be Metal-Free: We can’t MRI scan you if you might have metal around, on, inside, or otherwise about your body. Maybe you have jewellery or a piercing that you think will be easy to remove before the scan? Please check to see if it’s actually going to come off. If your wedding ring’s stuck on because you’ve gained weight, we’ll have a problem. I once spent 30 minutes trying to get someone’s earrings off.

10. Thanks: Seriously. We couldn’t do neuroscience without you!

CATEGORIZED UNDER: fMRI, funny, select, Top Posts, Uncategorized
  • SCH_Thurston

    11. Though shalt be honest with the experimenter. It’s really important for you to stay awake during the scan, but if you feel yourself getting woozy or you actually realize you just took a nap, please own up. Breaks are always possible!

    • Neuroskeptic

      Yep – that’s important. Volunteers also need to be ‘brave’ enough to point out when the researchers have made a mistake. We’re only human!

      I’ve seen it happen that there was something wrong with a task, and it only came to light after an especially confident participant flagged it up. Before that, the volunteers had noticed the blooper, but they’d not mentioned it because they thought it must have been intended.

  • SCH_Thurston

    Re. #4, if we accidentally tell you not to move your head during the scan, we really mean please don’t move any part of your body, except as is necessary to complete a task, such as pressing a button. Please adjust for comfort in between the scans, as already suggested, and make sure you let us know what you’re doing, per #11.

  • petrossa

    i once spent 30 minutes getting the earrings back in leaving my wife cursing and bleeding. So find another system

  • djlewis

    >> 8. …We want brain activity caused by the test, not by thinking about the test.

    I had an epiphany on reading this — why brain scanning, fMRI in particular, holds such fascination for neuroscientists themselves, not to mention the public and popular press — You. Can. See. Thought!

    Or you think you can (double entendre somewhat intentional).

    But consider this. You ask me to raise my right arm. I do that. You’ve just seen a thought! Seriously — think about it (another double entendre).

    Have a good day.

    • Barry Bayliss

      If asked to use a particular strategy for the task, use it as directed so that afterwards when examining the results we are comparing like for like.

  • Budgie Mitchell

    Hi Neuroskeptic, what do you think of stories like this, which purport to “read peoples minds” using functional MRI?

    Absolute scaremongering at its worst.

    • Neuroskeptic

      Well, articles like that are just exaggerated. The science in that case really is interesting and (in a very limited way) could be called ‘mind reading’ – but the article makes it sound much more impressive than it is. It’s just a study under carefully controlled conditions, it wouldn’t work in ‘real life’…although it might do, in about 20 years.

      • Budgie Mitchell

        How can an FMRI, which only measures blood flow, be used to determine neuron contents? I saw the example where the subjects were watching a parrot picture and the computer “guessed” what they were looking at, but that’s just mapping increased blood flow to a point in time on a video. How could an FMRI ever get down to neuron scale?

        Not forgetting the memory requirements for the system taking a snapshot of the neuron activity which would be surely in the (taken from WikiPedia 😉 – YottaByte scale?

        I’m a software developer, Moore’s law limit on a single CPU already has been reached, it would have to be a massively parallel supercomputer to record neuron activity on a second by second basis.

        • Neuroskeptic

          fMRI measures blood oxygenation & we know that this is altered by neural activation. You’re right that this can’t get down to the scale of one neuron – or even close.

          But it seems as though we don’t need to, because the brain activation associated with (say) a parrot vs. a chicken has a characteristic pattern, on a fairly large scale.

          This characteristic pattern is different for every individual person (and probably changes over time as well) but it’s possible to measure it. So even though you’re not measuring neural activity as such, you can tell roughly what the activity is…

  • Kanin Faan

    Think about it.

    • Rupert Faraway

      I think that’s a bit harsh. Some aspects of functions must be localised to a degree. What’s wrong with identifying them with fMRI? As long as you know the limitations of the technique, it can be useful. You can do a lot with fMRI – functional connectivity analyses for example. I don’t see how functional connectivity is phrenological.

  • Matúš Šimkovic

    0. Thou shalt not be left-handed.

    zeroth, because in case you are, you don’t have to bother reading the rest of the commandments

    • Neuroskeptic

      Heh. One day I want to run a study of left-handedness, just to see the smiles on the faces of the people who’ve been waiting years for a scan…

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  • toto

    Re: fidgeting, why not use head-fixing devices?

    And if fMRI is really that sensitive to fidgeting, then what exactly is the point of increasing resolution? I hear these fancy 7T magnets can get to column-level precision, but if it’s getting blurred simply by breathing movements…



No brain. No gain.

About Neuroskeptic

Neuroskeptic is a British neuroscientist who takes a skeptical look at his own field, and beyond. His blog offers a look at the latest developments in neuroscience, psychiatry and psychology through a critical lens.


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