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Key Stage 5 Magnetic Resonance Imaging Watching the brain at work

Key Stage 5 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. baseline. activation state. These areas of the brain need more oxygen….

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Key Stage 5 Magnetic Resonance Imaging Watching the brain at work

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  1. Key Stage 5Magnetic Resonance ImagingWatching the brain at work www.oxfordsparks.net/mri

  2. If you wiggle your fingers… …there is more activity in these brain areas. www.oxfordsparks.net/mri

  3. baseline activationstate These areas of the brain need more oxygen… …which the blood delivers More blood flow More oxygenated blood Less distortion of magnetic field More fMRI signal www.oxfordsparks.net/mri

  4. FMRI signal These areas of the brain are active during movement, but not rest. An experiment rest move rest move rest move rest Task time www.oxfordsparks.net/mri

  5. The FMRI scanner looks at one brain ‘slice’ at a time… www.oxfordsparks.net/mri

  6. 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

  7. The trace shows that this voxel is relevant to the task. www.oxfordsparks.net/mri

  8. This voxel is not relevant to the task – it is a noisy voxel. www.oxfordsparks.net/mri

  9. 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

  10. fMRI signal The subtraction approach: vision grey colour grey colour grey colour grey Task: time View colour stimuli View grey stimuli (control) www.oxfordsparks.net/mri

  11. The subtraction approach: vision = - www.oxfordsparks.net/mri

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