MacArthur Fellows Program

MacArthur Fellows / Meet the Class of 2015

Beth Stevens

Neuroscientist

Assistant Professor of Neurology, F. M. Kirby Neurobiology Center, Boston Children’s Hospital

Department of Neurology, Harvard Medical School

Boston, Massachusetts

Age: 45 at time of award

Published September 28, 2015

Beth Stevens is a neuroscientist whose research on microglial cells is prompting a significant shift in thinking about neuron communication in the healthy brain and the origins of adult neurological diseases. Until recently, it was believed that the primary function of microglia was immunological; they protected the brain by reducing inflammation and removing foreign bodies.

Stevens identified an additional, yet critical, role: the microglia are responsible for the “pruning” or removal of synaptic cells during brain development. Synapses form the connections, or means of communication, between nerve cells, and these pathways are the basis for all functions or jobs the brain performs. Using a novel model system that allows direct visualization of synapse pruning at various stages of brain development, Stevens demonstrated that the microglia’s pruning depends on the level of activity of neural pathways. She identified immune proteins called complement that “tag” (or bind) excess synapses with an “eat me” signal in the healthy developing brain. Through a process of phagocytosis, the microglia engulf or “eat” the synapses identified for elimination. This pruning optimizes the brain’s synaptic arrangements, ensuring that it has the most efficient “wiring.”

Stevens’s discoveries indicate that our adult neural circuitry is determined not only by the nerve cells but also by the brain’s immune cells. Her work suggests that adult diseases caused by deficient neural architecture (such as autism and schizophrenia) or states of neurodegeneration (such as Alzheimer’s or Huntington’s disease) may be the result of impaired microglial function and abnormal activation of this pruning pathway. Stevens is redefining our understanding of how the wiring in the brain occurs and changes in early life and shedding new light on how the nervous and immune systems interact in the brain, both in health and disease.

Beth Stevens received B.S. (1993) from Northeastern University and a Ph.D. (2003) from the University of Maryland. She was a postdoctoral fellow (2005–2008) at Stanford University and is currently an assistant professor in the Department of Neurology at Harvard Medical School and the F. M. Kirby Neurobiology Center at Boston Children’s Hospital. She is also an Institute Member of the Broad Institute of MIT and Harvard. Her scientific papers have appeared in such journals as Neuron, Science, Proceedings of the National Academy of Sciences, and Nature Neuroscience, among others.

Photos

High-resolution photos for download. Photos are owned by the MacArthur Foundation and licensed under a Creative Commons license: CC-BY. Credit: John D. & Catherine T. MacArthur Foundation. Right-click on a link below to save the file to your computer.

For More Information

Website: stevenslab.org/

What's New

"Alumna Fights Debilitating Neurological Diseases with Science" thumbnail

"Alumna Fights Debilitating Neurological Diseases with Science"

Northeastern University
Beth Stevens, 2015 MacArthur Fellow
Read More
"Runs in the Family" thumbnail

"Runs in the Family"

The New Yorker
Beth Stevens, 2015 MacArthur Fellow
Read More
""Schizophrenia Gene" Discovery Sheds Light on Possible Cause" thumbnail

""Schizophrenia Gene" Discovery Sheds Light on Possible Cause"

Scientific American
Beth Stevens, 2015 MacArthur Fellow
Read More
"Immune System Offers Major Clue to Schizophrenia" thumbnail

"Immune System Offers Major Clue to Schizophrenia"

MIT Technology Review
Beth Stevens, 2015 MacArthur Fellow
Read More
"Big Idea: the Brain's Best-Kept Secret" thumbnail

"Big Idea: the Brain's Best-Kept Secret"

Popular Science
Beth Stevens, 2015 MacArthur Fellow
Read More