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Imaging Helps Scientists Zero In on Brain Disease at All Ages

SAN JOSE, California — Improved imaging techniques are helping scientists spot brain injuries in the womb and map out the borderland between aging and Alzheimer's disease, researchers reported at the 2015 AAAS Annual Meeting.

Functional magnetic resonance imaging (fMRI) and techniques like ultrasound are being refined and repurposed to look at ever-smaller structures within the brain, and to follow brain activity and metabolism as it happens, the scientists said.

 
Alzheimer's, aging, and schizophrenia all target different parts of the hippocampus, explains Scott Small of Columbia University. | AAAS/Carla Schaffer
 
Catherine Limperopoulos of Children's National Medical Center is using echocardiography and magnetic resonance imaging (MRI) to search for the earliest warning signs of brain injury in fetuses with congenital heart disease. | AAAS/Carla Schaffer

"For most of the time that I've been in this field, we've been very limited in the tools we've been able to use, largely tools that give us gross measurements of structure and very gross measurements of function," said William Jagust, who studies the neuroscience of aging at the University of California, Berkeley. "But in the last five or ten years we've really had an amazing ability to start looking at biochemistry and much more precise measures of brain function."

Jagust uses enhanced fMRI to look at aggregations of proteins such as amyloid-beta and tau, which have been associated with Alzheimer's disease, with the hope of seeing how the proteins grow and spread over decades in living brains.

"We have structural and functional measures that are showing changes [in the brain] before people have symptoms," Jagust said. "And now there's relatively good agreement that we can pick those kinds of things up with the current techniques."

Columbia University neurologist Scott Small has taken advantage of the increased resolution of fMRI to delve into separate sections within a part of the brain called the hippocampus. For the first time, Scott's research is showing how one structure can hold the roots of schizophrenia in youth, memory loss in middle age, and Alzheimer's in old age. "One can really begin to dissect out the hippocampus now, and show that why these different disorders are different, based on patterns of regional vulnerability," he said.

Scott and his colleagues can now identify "cell sickness" in the part of the hippocampus related to Alzheimer's disease. This previously invisible stage — before brain cells die in the disease — may be "an easier place to intervene" when treating Alzheimer's, Scott said.

The hope of earlier intervention guides Catherine Limperopoulos and her team as they combine ultrasound and fMRI to look for biochemical signs that a fetus is at risk for brain injury. In fetuses with congenital heart disease, for instance, the presence of lactate in the brain may be a sign that the fetus is low on oxygen.

Limperopoulos noted that there are few options to treat fetal brain injury in the third trimester, when many of these injuries occur. But she said her research is important to define where and when future therapies might be applied. "Our goal is to develop early and reliable biomarkers of injury before injury is consolidated, to see where this window is, and then work to develop ways to intervene."

Author

Becky Ham

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