An article in the MIT Technology Review explains diffusion tensor imaging, a variant of MRI that follows water molecules as they glide along axons. Why is this new wrinkle important? Because MRIs of many mentally ill patients look normal — diseases like schizophrenia may have their roots in the axons:
Conventional imaging techniques, such as structural MRI, reveal major anatomical features of the brain — gray matter, which is made up of nerve cell bodies. But neuroscientists believe that some diseases may be rooted in subtle “wiring” problems involving axons, the long, thin tails of neurons that carry electrical signals and constitute the brain’s white matter. With DTI, researchers can, for the first time, look at the complex network of nerve fibers connecting the different brain areas…
Following Lim’s lead, other neuroscientists have begun using DTI to study a host of disorders, including addiction, epilepsy, traumatic brain injury, and various neurodegenerative diseases. For instance, DTI studies have shown that chronic alcoholism degrades the white-matter connections in the brain, which may explain the cognitive problems seen in heavy drinkers…
Lim’s group has found, for instance, that healthy people with a genetic risk for developing Alzheimer’s disease have tiny structural defects in specific parts of the brain that are not shared by noncarriers. How these defects might be linked to the neurological problems of Alzheimer’s isn’t clear, but the researchers are trying to find the connection.
More from Dr. Kelvin Lim’s review of DTI (2002) and first DTI study of schizophrenia…