Scientists at Emory University School of Medicine have uncovered how a structural component inside neurons performs two coordinated dance moves when the connections between neurons are strengthened.

The results are published online in the journal Nature Neuroscience, and will appear in a future print issue.

In experiments with neurons in culture, the researchers can distinguish two separate steps during long-term potentiation, an enhancement of communication between neurons thought to lie behind learning and memory. Both steps involve the remodeling of the internal "skeletons" of dendritic spines, small protrusions on the surface of a neuron that receive electrical signals from neighboring cells.

The results hint at why people with Williams syndrome, a developmental disorder caused by a deletion of several genes, including one that alters dendritic spine remodeling, have such an unusual blend of cognitive strengths and weaknesses.

The senior author of the paper is James Zheng, PhD, professor of cell biology and neurology at Emory University School of Medicine. The paper's co-first authors are graduate student Jiaping Gu, now a postdoctoral researcher at New York University, postdoc Chi Wai Lee and graduate student Yanjie Fan.

"We've been looking at the remodeling of dendritic spines, which is a fundamental process for reshaping circuits in the brain," Zheng says. "The anatomy of dendritic spines is altered in many diseases, such as fragile X syndrome and schizophrenia, as well as neurodegenerative disorders like Alzheimer's."

During the process of long-term potentiation, dendritic spines both enlarge and display a greater density of neurotransmitter receptors, the receiver dishes that allow neurons to detect the waves of chemicals other neurons are sending them.