• Question: How do you read minds with a magnet?

    Asked by anon-204429 to James on 5 Mar 2019. This question was also asked by anon-204422, anon-204920, anon-204393.
    • Photo: James Munro

      James Munro answered on 5 Mar 2019:

      Hi amburito and reaq!

      The short answer is: I use a MRI scanner. This stands for Magnetic Resonance Imaging. If we ignore the “Resonance” part, we can see that the machine uses magnets to take pictures.

      MRI scanners are huge machines that you might have seen on medical TV shows or in hospital. A patient lies in a tube which is surrounded by a giant powerful magnet. The one I use for my research is 60,000 times stronger than the earth’s magnetic field – so it is really strong. So strong that it needs to be totally covered in incredibly cold liquid helium to keep it working.

      Because the magnet is so strong, it can be used to detect tiny changes in magnetism inside the tube. Your blood is is not magnetic when it is full of oxygen, and becomes magnetic when that oxygen is used up. Your brain uses oxygen as fuel! So using MRI we can see which parts of the brain need fuel at different times by following the blood.

      By knowing what parts of the brain need fuel at different times, we can try to work out what the brain is doing. You could call this mind reading, using a magnet 🙂

      Great question – but a hard one to answer in a short form. I hope this made sense!

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