Neuroscience Breakthrough

See-through 3D model that shows the axon (red), medium spinal motor neuron (green), and astrocyte converging at the synapse (yellow). Credit: Center for Translational Neuromedicine, University of Rochester and University of Copenhagen





Scientists have created one of the most detailed 3D images of the synapse, the important juncture where neurons communicate with each other through an exchange of chemical signals. These nanometer-scale models will help scientists better understand and study neurodegenerative diseases such as Huntington’s disease and schizophrenia.

The new study appears in the journal PNAS and was authored by a team led by Steve Goldman, MD, Ph.D., co-director of the Center for Translational Neuromedicine at the University of Rochester and the University of Copenhagen. The findings represent a significant technical achievement that allows researchers to study the different cells that converge at individual synapses at a level of detail not previously achievable.

“It is one thing to understand the structure of the synapse from the literature, but it is another to see the precise geometry of interactions between individual cells with your own eyes,” said Abdellatif Benraiss, Ph.D., a research associate professor in the Center for Translational Neuromedicine and co-author of the study. “The ability to measure these extremely small environments is a young field, and holds the potential to advance our understanding of a number of neurodegenerative and neuropsychiatric diseases in which synaptic function is disturbed.”

The researchers used the new technique to compare the brains of healthy mice to mice carrying the mutant gene that causes Huntington’s disease. Prior research in Goldman’s lab has shown that dysfunctional astrocytes play a key role in the disease. Astrocytes are members of a family of support cells in the brain called glia and help maintain the proper chemical environment at the synapse.

The researchers focused on synapses that involve medium spiny motor neurons, the progressive loss of these cells is a hallmark of Huntington’s disease. The researchers first had to identify synapses hidden within the tangle of the three different cells that converge at the site: the pre-synaptic axon from a distant neuron; its target, the post-synaptic medium spiny motor neuron; and the fiber processes of a neighboring astrocyte.   READ MORE...