Ok, if you would like to come through now.
What I would like you to do first of all is sit on the couch here and I will explain to
you what we are going to be doing.
Your head is going to be lying in this head collar here, the top of your head with a mask
over your face and then there is a mirror on top of that so when the couch is at this
height you'll be able to see the screen at the other end.
Ok, alright?
The test that they do in the MRI scanner take about an hour and there are various types.
The first case we acquire a structural image.
So this tells us the shape and the size and different tissue types in each person's brain.
Then we run a sequence which is called diffusion tensor imaging, or DTI, which allows us to
look at the white matter tracks that connect different parts of the brain together.
Hi.
Are you ok in there?
Hello.
Yes.
Ok.
Well I can hear you clearly.
Can you hear me clearly?
Yes.
That's great, well done.
So we have just got to check a couple of things before we start.
If you could squeeze that buzzer, I know you can, but just do it again for me.
That's lovely, thank you.
We then do a resting state scan where people again just lie still and relax and for that
we are measuring the changes in blood oxygenation, or blood flow, as the brain is at rest.
We also do several other sequences which have different MR contrasts that give us different
sensitivity to the amount of myelin in the brain.
So the myelin is the fatty tissue that is around those cells which also is impaired
as we get older.
Ok, we are just going to do the scan with the task now.
Is that alright?
Ok.
Ok, so you just need to remember each and every time you see checker boards on the screen
just press your index finger button once.
Each time you hear sounds just press again once and when there is a combination of checker
boards and sounds again you need to just press it once ok?
Well done.
We also do a very simple task where people see visual flashes, they hear tones, and they
press a key and this is called our sensory motor task.
It's a very easy task to do that allows us to trace out which parts of the brain are
active when we see things, hear things or do things.
And that same task we can also do in the MEG scanner so we can now, using the higher temporary
resolution MEG, we can look at how connectivity between the visual area, the audiometry area
and the motor area change over time.
So during that one hour of MRI they actually do a number of different scans which are all
tuned finely to detect different aspects of the brain's structure and resting sleep function.
Each time somebody comes for the first time they get a picture of their brain to take
away so I am just going to prepare that.
So again we've got the three sections but this is off the structural scan we just done.
I am just going to scroll down through the head, we're at the top of the head for the
moment, just coming to the top part of the brain and you can just see the folds of the
cerebrum at the top there.
The two hemispheres and the inter-hemispheric pressure providing the two hemispheres.
The right hemisphere on the left.
And then going on down through the brain we get to the ventricles there going down to
the ventricular area.
Down to the different parts, to the eyes, and then into the hydro part of the brain
and the cerebellum and you also have the brain there as well.
But for the image, we give them an image through the ventricular area of the brain.
And this is what they take away.
Is that clear?