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Published byPeter Peterson Modified over 10 years ago
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Key Stage 4 Magnetic Resonance Imaging Watching the brain at work www.oxfordsparks.net/mri
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If you wiggle your fingers… …there is more activity in these brain areas. www.oxfordsparks.net/mri
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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
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An experiment rest move rest move rest move rest Task FMRI signal time These areas of the brain are active during movement, but not rest. www.oxfordsparks.net/mri
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The FMRI scanner looks at one brain slice at a time… www.oxfordsparks.net/mri
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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
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The trace shows that this voxel is relevant to the task. www.oxfordsparks.net/mri
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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
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The subtraction approach: vision View grey stimuli (control) View colour stimuli grey colour grey colour grey colour grey Task: fMRI signal time www.oxfordsparks.net/mri
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The subtraction approach: vision - = www.oxfordsparks.net/mri
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