For decades, functional magnetic resonance imaging, looking at changes in the brain's blood oxygen, has over-promised and under-delivered, which made it a punching bag in the science community. People in the field tried to claim changes in pretty pictures meant more neurons working and suggested that meant X part of the brain controls Y behavior. It was never a valid link.
By 2009,
a paper even showed how easy it was to use a dead fish to make interpretations about emotion, and achieve the sought-after "statistical significance." Gone was the promise of clinical information that might help with depression, cognitive decline, and brain disorders, and the reason was humans.(1)