The MRI scanner is a large, tube-shaped magnet that provides a strong magnetic field around your child. A radio-frequency coil is placed over the body part to be imaged, which will be the brain for the purposes of our studies. The magnetic field, along with the applied radio-frequency waves, will temporarily alter the alignment of hydrogen protons found in water molecules within the body. Computers then construct the images of the brain based on the radio-frequency signals emitted by the protons.