During the filming of "Brains on Trial with Alan Alda," Alan made a special stop in a mock fMRI scanner to understand how it works and how scientists can glean insights. For more videos and other content, go to: brainsontrial.com/
So an fMRI can be used to see changes when we get a certain stimulus, like when we are asked a question, we see a clip or an image of something or when we hear a sound. What I'm more interested in is how they are sending media to a display (I'm assuming it's that rectangular piece that we see in this clip as part of the head cage) or headphones (as I saw in a clip) WITHOUT the device being affected by magnets. That's some fancy engineering that I want to understand. Aluminum wires? Plastic? Mirrors? What's actually happening?
Yes: mirrors, and often a projector system. The image is projected onto a series of mirrors and sometimes onto a plexiglass screen. The headphones are built from nonmagnetic components.
I, a researcher in the field, estimate that 95% (possibly all in humans) of all published fMRI studies are worthless. The reason is that subject motion creates signal variance that swamps the BOLD signal. Although motion correction algorithms are applied to the data they simply do not work well enough to reduce the motion variance to an insignificant value. Most researchers know this to be true but carry on regardless because their career depends upon doing so. Other researchers are simply ignorant of the artifacts that make this method junk.