Engineered Rabies Virus Illuminates Neural Circuitry

Originally published by Hannah Thomasy, PhD, for the Scientist on June 14, 2024

Scientists turned a deadly virus into a crucial tool for understanding the wiring of the brain.

 

Rabies labeling helps scientists identify neurons in the primary visual cortex that connect to two different higher visual brain regions. Marina Garrett 

In 1906, pathologist Camillo Golgi and neuroscientist Santiago Ramón y Cajal won the Nobel Prize for their work on the structure of the nervous system. More than a century later, the puzzle of nervous system organization—the intricately tangled mess that results from each neuron’s connections to thousands of others—remains incomplete.

Yet, fully developing scientific understanding of these connections is crucial, said Edward Callaway, a systems neurobiologist at the Salk Institute. “If you don’t have some knowledge about how the different parts are interacting, there’s no way to generate a hypothesis about how they’re working together.” 


Neuroscientist Edward Callaway uses monosynaptic rabies virus tracing to map neuronal circuits in the cortex..Credit:Chris Keeney

Disentangling this complex network to create an orderly map of neuronal connections is a problem that researchers have been working on for decades. In the 1980s, researchers began searching for a marker that could function as a transneuronal tracer. They needed something that could hop across synapses, spreading from neuron to neuron efficiently enough to reach detectable levels even in cells connected across long distances. Luckily for the scientists (although perhaps unluckily for humanity in general), a handful of neuron-specializing viruses have evolved to do exactly that. 

Thanks to the work of pioneering virologists, neuroscientist Gabriella Ugolini, now at the Paris-Saclay Institute of Neuroscience, knew that herpes simplex virus 1 (HSV-1) preferentially infected neurons, and that it could spread across synaptic connections. Unlike a dye or a toxin, a virus would not need to cross synapses in large amounts because it could replicate to detectable levels using the host’s cellular machinery. In the late 1980s, she demonstrated that when injected into a peripheral nerve, HSV-1 spread across synapses to neurons in the brain.1 The virus-infected neurons could then be easily identified in sections of brain tissue using immunohistochemistry, providing a clear picture of the chains of connection.

Read more

 


Comments

Post a Comment

Popular posts from this blog

First map of every neuron in an adult brain has been produced for a fruit fly

Image
Originally published by UK Research and Innovation on October 2, 2024   3D rendering of all ~140k neurons in the fruit fly brain. Credit: Data source: FlyWire.ai; Rendering by Philipp Schlegel (University of Cambridge/MRC LMB). The first wiring diagram of every neuron in an adult brain and the 50 million connections between them has been produced for a fruit fly . This landmark achievement has been conducted by a large international collaboration of scientists , called the FlyWire Consortium , including researchers from the MRC Laboratory of Molecular Biology ( in Cambridge, UK ), Princeton University, the University of Vermont and the University of Cambridge . It is published in a pair of papers in Nature . The diagram of all 139,255 neurons in the adult fly brain is the first of an entire brain for an animal that can walk and see . Previous efforts have completed the whole brain diagrams for much smaller brains , for example, for that of a fruit fly larva, whi...
Read more

Research finds resin that destroys coronavirus on plastic surfaces

Image
O riginally published by University of Jyväskylä, on January 30, 2024 Studying the impact of rosin-functionalized plastic and standard LDPE on the structure of HCoV-OC43 using (A) TEM and (B) AFM in liquid. The scale bar corresponds to 100 nm and 1 µm in the TEM and AFM images, respectively. In panel B, the blue circle highlights a doughnut-shaped virus. (C) The histogram derived from the AFM images illustrates the average size distribution of the height of individual viruses after being flushed from their respective surfaces. Credit: Microbiology Spectrum (2024). DOI: 10.1128/spectrum.03008-23 Researchers at the University of Jyväskylä, Finland , are currently developing anti-viral surfaces to decrease the spread of infectious diseases. A recent study published in Microbiology Spectrum found that a resin ingredient is effective against coronaviruses and strongly decreases their infectivity on plastic surfaces. Viruses may persist on solid surfaces for long periods, which ma...
Read more