Key Stage 4 - MRI. Pupil worksheet. Watching the brain at work. Your task. Stage 1

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1 Pupil worksheet Background Key Stage 4 - MRI Watching the brain at work An MRI scanner uses magnetic fields to take detailed pictures of the brain. Doctors use the scans to help diagnose disease. Functional Magnetic Resonance Imaging (fmri) is a brain research technique. Scientists collect data from a grid of voxels (3D pixels) through the brain. These data show exactly which areas of the brain are associated with different activities. There is a strong magnetic field in an fmri scanner. This means we can detect changes in blood oxygen levels in different brain areas. This is how it works: If you wiggle your fingers, there is more activity in the cells in the areas of the brain that make this movement happen. These areas need more oxygen, which the blood delivers. The ratio of oxygenated blood: deoxygenated blood increases in these areas. Protons in oxygenated blood spin more slowly than protons in deoxygenated blood. This means that oxygenated blood distorts the magnetic field less than deoxygenated blood. Less distortion means that a higher signal is recorded. Question to discuss Will an increase in brain activity in a certain area of the brain cause an increase or decrease in the measured MRI signal? Why? Your task Stage 1 Design an experiment to find out which areas of the brain are associated with an activity, for example listening to music, watching a video clip, or singing. Choose your activity, and make up a scientific question to investigate. Identify the independent variable. The dependent variable is the MRI signal strength in each brain voxel. Identify the control variables Which variables will you keep the same, or control, so that you can compare data from doing and not doing the activity? If you did the experiment, a computer would compare changes in MRI signal strength across many brain voxels to find the most active areas. Stage 2 You will need volunteers for your experiment. They will need to be in the scanner for about 45 minutes, alternately doing and not doing your activity. Write an advert to recruit volunteers. In your advert, include: Stage 3 What you want to find out, and why. A brief outline of what fmri is, and how it works. The precautions you will take to keep volunteers safe. What the volunteers will have to do in the scanner, and how long it will take. To make sure you can compare the data from different volunteers, you will need to give them all the same instructions. Write a script to remind you what to say. Extension task Plan an investigation to isolate a very specific brain function such as speaking words or perceiving another person s emotion.

2 Help sheet 1 Stage 1 experiment design What we want to investigate Help sheet 1 Stage 1 experiment design What we want to investigate Our scientific question Which area of the brain is active when Our scientific question Which area of the brain is active when Task: Baseline: Lie still in the scanner Task: Baseline: Lie still in the scanner Dependent variable MRI signal strength in each brain voxel. Dependent variable MRI signal strength in each brain voxel. Control variables Which variables will you keep the same, or control, so that you can compare data from doing and not doing the activity? Control variables Which variables will you keep the same, or control, so that you can compare data from doing and not doing the activity? Results Graphs of changes in MRI signal strength in many brain voxels. Results Graphs of changes in MRI signal strength in many brain voxels. Analysis of results Analysis of graphs to find the most reliably active areas of the brain during the task. Colour these voxels on the brain image. Analysis of results Analysis of graphs to find the most reliably active areas of the brain during the task. Colour these voxels on the brain image.

3 Help sheet 2 Stage 2 Recruiting volunteers What we want to find out, and why. What fmri is, and how it works Safety notes An FMRI scanner includes a huge electromagnet. Objects made of magnetic materials move towards the magnet when it is switched on. If a volunteer has any magnetic metal in their body perhaps a tiny piece of steel in their eye the magnetic field makes it move. The moving object may damage the body. Magnetic fields also damage heart pacemakers. Heart pacemakers Magnetic or not? Magnetic metals iron and steel cobalt nickel Non-magnetic metals aluminium titanium copper How we will keep you safe What you will have to do in the scanner for seconds at a time. Objects people might have on (or in) them Object Metal Object in person Metal keys steel hip replacement titanium watch steel joint pin stainless steel hair steel tooth fillings mixture of mercury, clip coins steel, nickel, copper Questions to discuss steel fragment (eg in a welder) heart pacemaker Replacement hip silver, tin, copper steel various, including magnetic switch A Decide which objects are safe to take into the scanner. B Which objects inside a person may make having an fmri scan unsafe?

4 Help sheet 3 Stage 3 Script to read to volunteers Thanks! Help sheet 3 Stage 3 Script to read to volunteers Thanks! A reminder of what we want to find out, and why A reminder of what we want to find out, and why Final safety check Final safety check Detailed instructions of what to do in the scanner for seconds at a time. You will need to keep your head very still. Make sure you Detailed instructions of what to do in the scanner for seconds at a time. You will need to keep your head very still. Make sure you Please do not Please do not

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