Key Stage 4 Magnetic Resonance Imaging Watching the brain at work .
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Key Stage 4 Magnetic Resonance Imaging Watching the brain at work www.oxfordsparks.net/mri
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Transcript of Key Stage 4 Magnetic Resonance Imaging Watching the brain at work .
Key Stage 4
Magnetic Resonance Imaging
Watching the brain at work
www.oxfordsparks.net/mri
If you wiggle your fingers……there is more activity in these brain
areas.
www.oxfordsparks.net/mri
These areas of the brain need more oxygen…
activation statebaseline
More blood flow
More oxygenated blood
Less distortion of magnetic field
More fMRI signal
…which the blood delivers
www.oxfordsparks.net/mri
An experiment
rest move rest move rest move restTask FMRI signal
time
These areas of the brain are active
during movement, but not rest.
www.oxfordsparks.net/mri
The FMRI scanner looks at one brain ‘slice’ at a time…
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You can locate an area of the brain using X, Y, and Z co-ordinates.
The image is divided into
voxels. Voxels are 3D pixels.
www.oxfordsparks.net/mri
The trace shows that this voxel is relevant to the task.
www.oxfordsparks.net/mri
Colour Vision• FMRI does not give an
absolute measure, so you need to look at signal change.
• To isolate one brain function, compare the condition you are investigating to a control condition.
www.oxfordsparks.net/mri
The subtraction approach: vision
View grey
stimuli (control)
View colourstimuli
grey colour grey colour grey colour greyTask:fMRI signal
time
www.oxfordsparks.net/mri
The subtraction approach: vision
- =
www.oxfordsparks.net/mri
