Six Kinds of Brain Scans: Peering Inside The Skull, Part Two

March 23, 2010 at 9:49 pm Leave a comment

In part one, we looked at three of the older ways to get a picture of what’s going on inside the skull.  EEG’s, which use electrodes on the scalp to measure electrical activity, CAT scans, which use XRay like radiation to reveal the physical structure, and PET scans, which use a radioactive injection to reveal areas of blood absorption in the brain.

MRI scanToday, we’re going to look at three more scanning technologies used by science and medicine –  technologies that are used not only for medical diagnosis, but heavily used in research, too.

MRI (Magnetic Resonance Imaging)

MRI’s were originally called NMRI’s, for Nuclear Magnetic Resonance Imaging, but the public was skittish about the  association with nuclear radiation exposure that the name conjured up, so the N was dropped.   The fears were ironic, because unlike PET and CAT scans, MRI’s don’t expose the patient to radiation at all.  Instead, they use a combination of a magnetic field and radio waves to harmlessly distinguish between different kinds of tissues, while a computer builds a picture based on the data.

Like CAT scans, MRI’s reveal the brain’s structure, but provide much more detailed and higher contrast results, and are able to distinguish more clearly between the density in a tumor, for instance, vs healthy brain tissue.

fMRI scan fMRI (Functional Magnetic Resonance Imaging)

fMRI’s are a specialized type of MRI scan that reveals blood flow and oxygen levels in the brain. The more active an area of the brain is, the higher the blood flow is to that region, and the more oxygen is used — so fMRI’s provide a sort of second-hand look at the activity levels within the brain. First produced in the 90’s, they’ve quickly become invaluable tools in neuroscience research, and are responsible for many of the advances made in our understanding of the brain.

You’ll see fMRI’s mentioned a lot in articles about brain fitness research. As useful as the results are within the studies, the way  the information is described sometimes lead us lay folk to over simplified ideas about the brain’s function being compartmentalized, rather than working as a whole.

MEG scanner MEG (Magnetoencephalography)

MEG scans are similar to one of the of the oldest methods, the EEG; . Both scans reveal brain activity based on the tiny electrical signals produced by active neurons.   But while EEG’s measure electrical waves coming through the skull, MEG’s measure the magnetic fields of those electrical signals.   The advantage? The skull interferes with accurate measurements of the electrical signals, but the magnetic fields are less affected.  MEG scans can show changes in the brain on the fly, almost in real time – something fMRI’s can’t do.  But MEG scans are more reliable in areas close to the surface of the brain, because the deeper you look, the more the other magnetic fields within the brain itself distort the results.

So there you go.

Six brain scanning technologies: EEG, CAT, PET, MRI, fMRI, and MEG.   Between them, they can measure electrical activity, bloodflow and oxygen use, and the physical structures of the brain.  In combination, they create a fascinating picture of  how the human brain functions and responds, as well as how it changes in structure.   Knowing just a little about them provides a deeper understanding of the research behind brain fitness recommendations, which is, of course, what you’re here for!

Have you ever had a brain scan?

I have to admit to moments when I really, *really* wanted to know exactly what was going on beneath that skull of mine!

Entry filed under: Supporting Science & Medicine. Tags: , .

Six Kinds Of Brain Scans: How Doctors Peer Inside Your Skull (part 1) Get Moving for Your Memory (even if you’re out of shape or physically limited)

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About This Blog


A healthy mind and brain is key to a healthy, active life. Come along for the ride as we explore the basics of brain health, with topics including:
  • Physical Exercise
  • Cognitive Training
  • Stress Management
  • Social Interaction
  • Sleep
  • Nutrition
  • A Sense of Purpose & Connection
Authored by Tori Deaux
Sponsored by Dakim Brain Fitness

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