How have brain-imaging methods such as PET and MRI affected neuroscience research and clinical care?

Techniques which capture pictures of the living human brain at work have become fundamental tools of neuroscience research and increasingly influence how doctors diagnose and treat brain disorders. Advent of "functional" imaging that looks at both structure and patterns of brain activity, galvanized the young field of cognitive neuroscience that investigates the interactions of brain, learning, and behavior. Clinical researchers are also beginning to employ brain scans to track changes underlying neurological diseases and measure effects of treatments.