Imaging the Brain – Matt Brookes – 14/5/12
14th May 2012
This week we’re back to normal! George managed to book a guest and we’ll be talking to Matt Brookes about imaging the brain, both with MRI and MEG.
Unless you’ve had your fingers in your ears while you’ve been here in Nottingham you’ve probably heard about MRI and Sir Peter Mansfield. You might even have undergone a scan! Back in the 1970’s he came up with a way to image slices through a subject instead of the object as a whole as previously.
In 2003 Sir Peter Mansfield along with Paul Lauterbur of the University of Illinois at Urbana-Champaign were awarded the 2003 Nobel Prize in Physiology or Medicine. Click the picture on the right for more detailed information about the Nobel Prize.
MRI has continued to advance and has become extremely popular as a way to image patients due to its unobtrusive nature and the fact that you can image soft tissue unlike x-rays.
Here at the University, Matt works on something called magnetoencephalography or MEG. Every electrical impulse that goes through the brain generates a magnetic field and this magnetic can be detected by extremely sensitive magnetic sensors called SQUIDs.
It has improved from just one sensor to over 300. This improved sensitivity means we can gather data rapidly and efficiently.
Tune in to find out more about what MEG does and what Science has been in the news this week!
On the show today:
The use of contrast agents in MRI allows you to better show different parts of the body, often the brain, when you have a MRI or MEG scan. MRI contrast agents alter the relaxation times of atoms and are usually gadolinium-based.
Functional medical imaging or FMI, is type of imaging that can measure changes in blood flow in the brain due to the difference in relaxation times of oxygenated blood and deoxygenated blood.
Although FMI is quick, MEG is better. FMI relies on blood getting to areas in the brain but that takes time, MEG measures the magnetic fields that are caused by electrical impulses. This means it can take near instantaneous measurements of changes in the brain.
For MEG to work, we need solve the inverse problem. This means we need to work out what currents have made the magnetic field that we have measured. However, this is somewhat impossible.
To solve this problem, we have to solve the forward problem. This is like the inverse problem but in reverse! Are you keeping up? I know, it’s confusing… If we assume there was an electrical impulse in the brain we can work out what magnetic field it would create outside the skull.
By doing this we can try and determine what impulses made the field we measured originally. It’s essentially fitting an answer to the problem.
A problem that we are trying to solve is brain computer interface. George is actually doing this for his final year project with Matt supervising!
By thinking of certain things, such as tapping your finger on your right hand and your left you create different neural patterns, this could possibly allow you to send a signal to the computer to tell a electric wheelchair to turn left or right.
Science in the News
Study finds psychopaths have distinct brain structure: http://uk.reuters.com/article/2012/05/07/us-brains-psychopaths-idUKBRE8460ZQ20120507
It’s a gas: dinosaur flatulence may have warmed Earth: http://uk.reuters.com/article/2012/05/07/us-climate-dinosaurs-flatulence-idUKBRE8460PB20120507