Nature “Brain imaging: fMRI 2.0”

This is a fog-free translation of the article “Brain Imaging: fMRI 2.0” from Nature magazine. Translated on request :D http://www.nature.com/news/brain-imaging-fmri-2-0-1.10365

Oxygen-rich blood has magnetic properties so they can use a giant magnet to track the flow of blood through the brain; this is called an fMRI. Where there is increased blood flow, this shows increased brain activity; decreased blood flow shows decreased activity. This is great because they used to have to inject radioactive stuff into you to track brain activity and now they don’t.

Because it measures blood flow in the brain and not what the brain is doing directly, it’s not perfect; it can’t tell what brain cells are actually doing. Also the fact that blood flow in the brain fluxuates naturally anyway can make interpreting results difficult and makes it easier to misunderstand or misuse the results.

They also don’t know whether blood flow shows what the brain is doing now, or what it’s preparing to do, or what it was doing, or some other things as yet undiscovered. It’s better to measure directly what brain cells are doing; so some people are investigating measuring the activity of each cell individually. They think they can do that because brain cells have electrical activity; and electrical activity produces magnetic activity. So with really sensetive magnets tuned just right, they might be able to measure it.

It’s hard to use fMRI pictures to tell what parts of the brain are associated with what and why, because you just get a general idea of “the front bit is doing something” – but you don’t know if it’s doing what you think it’s doing or reading the screen or imagining a holiday etc. Scientists want to find out how parts of the brain communicate with each other. Some folk are, instead of squashing all the data they get from an fMRI into one picture, looking at it bit by bit to see the pattern of activity. Looking at lots of patterns allows them to identify the brains response to certain things, so for example they know a certain pattern is a response to an image of a bird.

fMRIs pick up a lot of useless background noise that is meaningless, and this needs to be filtered from the meaningful data. Scientists are thus working on ways to get more meaningful data and less noise; some ways are by using stronger magnets or injecting a substance into the blood which reacts better to magnets. They are also working on the best ways to filter the meaningful data from the meaningless noise.

At the moment most fMRI data is an average of many, many scans of lots of people, which gives a better chance of spotting the pattern of what the brain is doing. Obviously it would be great if you could use an fMRI in a hospital setting to analyse an individual patient’s brain to see what is going on – not currently possible. Scientists are experimenting with collecting large samples of fMRI data on various people and using them as a comparison base, so they can compare one persons fMRI to this huge database and be able to tell what is going on. Right now, you can’t use an fMRI to analyse what is going on in one persons brain, because they can’t understand what it is saying without having lots of people to compare it to.

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Zurich studies suggest muscle fatigue signals, like disordered pain signals, start in brain

Us ME/CFS sufferers love good science. Not the decide-the-results-beforehand type of science that seems to pervade the world of ME research in the west; no, we like the kind of real work-out-what’s-happening science that actually investigates what’s going on! We appreciate real science. Unfortunately, due to the rapid deteriation of our brains (like glasses in a coffee-shop in January, they fog up pretty fast), it’s hard to read scientific articles and take in what they are saying. So, as an aid to myself as much as anyone else, I want to `translate’ some papers/medical articles etc. into a semi-readable form. Here goes!

This is a less confusing version of http://www.prohealth.com/library/showarticle.cfm?libid=16687: Zurich studies suggest muscle fatigue signals, like disordered pain signals, start in brain

So: They break down the ability to use your muscles into 3 areas: how much you want to use them, how tired they actually are, and how tired your brain thinks they are. In the past they have just been looking at the actual fatigue of the muscle, and not what the brain thinks is going on – but this study looks at what the brain thinks is going on instead.

First study:
In order for your brain to control your muscles, it needs to send signals to them and also receive signals from them, so it knows what is going on. The first study they did showed that when your muscles get physically tired, they send signals to your brain to tell it this. These signals are telling your brain that it shouldn’t be doing so much work. They then anaethitised the spinal cord (ie: put it to sleep/massive painkillers), and found that this interrupted some of the signals; so your brain doesn’t realise how tired your muslces are getting when it’s under the effect of a strong pain-killer.

Second study:
They used super-fancy equipment to take photos of the brain (basically an MRI which shows what parts of the brain are active). They took the images of the brain when the body had been doing enough strenuous exercise that the brain was about to tell it to stop. The active areas at that point should be the parts that are going to tell it to stop. It turns out that these parts are quite `basic’ ones which analyse threatening situations.

Third study:
They looked at how much communication was going on between these parts of the brain to work out what parts control what’s going on. They discovered that one part (‘insular cortex’) gets a lot more active the more fatigue messages are sent from the muscles to the brain. It gets active by communicating with the part of the brain which controls movement of the muscles. So, this shows that the insular cortex is controlling (to some extent) whether the brain thinks you are too fatigued or not.

Overall results:
The brain has a huge influence on muscle fatigue, in that it has to deal with the signals coming from the muscles and whether the muscles are too fatigued to do more work. This will hopefully help them to discover two things: 1) new ways to improve performance of muscles and 2) why muscles are perceived to be so fatigued with certain illnesses, when they can’t find much physical reason for it.