Cell: An automated electron microscope platform has been developed to reconstruct the neural circuit map at high resolution

January 17, 2021 /--- ) How does the network of neurons connect to functional neural circuits? This has been a long-standing problem in the field of neuroscience.
To answer this basic question, researchers from Boston Children's Hospital and Harvard Medical School in the United States have developed a new way to study these neural circuits in a new study and learn more about their connections in the process.
results were published online January 4, 2021 in the Journal of Cell under the title "Resal of motor control circuits in adult Drosophila using automated transmission electron microscopy".
from Cell, 2021, doi:10.1016/j.cell.2020.12.013.
are widespread, but the connections between them are very small," said Dr. Wei-Chung Allen Lee of Boston Children's Hospital and Harvard Medical School, co-author of the paper.
, we have to develop new technologies to observe them at very high resolutions in true large sizes.
, his team developed an improved large-scale electron microscope process.
electron microscope is a technique first developed in the 1950s that uses accelerated electron beams to visualize and observe very small structures.
the problem with electron microscopes is that while it provides such a high image resolution, it has been difficult to study the entire neural circuit," Lee said.
to improve this technology, we developed an automated system called GridTape that is imaging at high resolution, but on a scale that covers neural circuits.
"GridTape: Automated, faster, cheaper electron microscope technology Traditional electron microscopes require the manual collection of thousands of tissue samples to the grid.
tissue is cut into 40 nanometer-thick slices, a thousand times thinner than a person's hair.
GridTape technology automatically collects samples, assigns a barcode to each slice, adds them to the conveyor belt, and then transmits them to the electron microscope like a movie projector.
advantage of using this technique is that each neuron in each tissue slice is marked.
explains, "As electrons pass through each slice, we can fine-tune each neuron."
and because all the slices are marked with barcodes, we know exactly where each of these slices comes from, so we can reconstruct the neural circuit.
this new technology allows us to conduct electron microscopy more quickly in an automated manner, at a high quality but at a reasonable price.
paper, the Lee team provided GridTape instrument design and software to enable the larger scientific community to access and afford large-scale electron microscopes.
fruit fly spinal cord: A case study team used their GridTape method to study the abdominal nerve cord of a black-berries, which is similar to the spinal cord.
it contains all the neural circuits that fruit flies use to move their limbs.
goal is to build a comprehensive map of the neural circuits that control motor function.
, "By applying this method to the entire abdominal nerve, we were able to reconstruct all the motor neurons it contained, as well as a large number of groups of sense neurons," Lee said.
process, they found a special class of sensory neurons in fruit flies that are thought to detect changes in load, such as weight.
, "These neurons are very large and relatively rare in number, and they are directly connected to the same type of motor neurons on both sides of the body," Lee said.
we think this may be a neural circuit that helps stabilize the body's position.
study, the team built a reconstruction map of more than 1,000 motor and sensory neurons.
, "It allows anyone in the world to access this dataset and look at any neurons they are interested in and ask which neurons they are connected to."
" future applications, given the ability to draw ever-larger neural circuits, Lee believes the technology could be used to study neural circuits in the larger brain and test predictions of nerve function and behavior.
team is now working on the technology in mice, and other researchers in the UK and Japan are applying it in several animal systems.
addition, the technology has broader potential uses in areas that require imaging large numbers of samples at very high resolutions.
"So, in principle, if people need to generate a lot of data, then various forms of electron microscopes can be improved by using this technique," Lee said, including DNA sequencing based on electron microscopes, or cryogenic electron microscopes that analyze protein structures.
(Bioon.com) Reference: 1.Jasper S. Phelps et al. Reconstruction of motor control circuits in adult Drosophila using automated transmission electron microscopy. Cell, 2021, doi:10.1016/j.cell.2020.12.013.2.GridTape: An automated electron microscopy platform