Functional MRI

In addition to structural imaging, MRI can also be used to visualize functional activity in the brain. Functional MRI, or fMRI, measures changes in blood flow to different parts of the brain. 

It is used to observe brain structures and to determine which parts of the brain are handling critical functions. Functional MRI may also be used to evaluate damage from a head injury or Alzheimer's disease. fMRI has been especially useful in neuroscience — "It has really revolutionized how we study the brain," Filippi told Live Science.