How to see all cells in living brain tissue

An interdisciplinary group of physicists and biologists working in the research of brain cells has conceived a new and revolutionary technique of microscopy that, for the first time, allows to obtain images of all cells within a certain area of living brain tissue. It allows to obtain images of all living cells not labeled in a specific brain area, something that until now was impossible. This scientific breakthrough is the result of collaboration between research groups from the University of Bordeaux, the UPV / EHU and the Achucarro Basque Center for Neuroscience. This new technique will allow to expand the knowledge of the biology of the brain.

Image of the neuron labeled in yellow, surrounded by unmarked neurons (appear in white), using the SUSHI technique. Without this technique, the neurons that appear in white would not be seen. © Jan Tønnesen & Valentin Nägerl.

Microscopy is a basic tool in the investigation of the biology of any organism, since the elements that are studied, the cells, have a microscopic size and many times, nanoscopic. So far, the existing microscopy methods to investigate living brain tissue were limited to visualizing only the cells previously marked. However, due to technical limitations, not all cells in a given brain region could be labeled simultaneously, which has restricted vision, and therefore, the understanding we have of how brain cells, which are highly interconnected, organize and interact .

Dr. Jan Tønnesen (Sweden, 1977), researcher of the Ramón y Cajal Program in the Neurosciences Department of the UPV / EHU, and who works at the Achucarro Basque Center for Neuroscience is one of the authors of a work he has just published Cell, and in which they describe a new technique of microscopy, called "SUSHI", to improve the visualization of cells in living brain tissue.

The new technique SUSHI (acronym of "Super-resolution Shadow Imaging") allows to label in a pass the tiny space, full of liquid, that surrounds the cerebral cells, avoiding having to individually label all the cells that are to be analyzed .

Since this "label" also remains outside the cells, it produces a kind of negative image, which we can resemble the film of the old photo cameras. Thus, the negative image contains the same information about the brain cells as the corresponding positive image, but thanks to the fact that the labeling procedure is simpler, it is much easier to obtain this image and all the information it contains.

According to Dr. Tønnesen "The SUSHI technique is revolutionary because it allows us to simultaneously visualize all the brain cells in a certain region of the living brain tissue. Before we found blank spaces in the microscopy images, since we could not label all the cells at the same time. This fact was very limiting to us. From now on, with this technique we will be able to see all the cells of the study area that we place in the lens of the microscope, as well as their interactions, so that we can advance in our knowledge of the cerebral functions, both in the healthy organ, and when sick".

Reference:

Tønnesen J, Inavalli VVGK & Nägerl UV (2018) Super-resolution imaging of the extracellular space in living brain tissue Cell doi: 10.1016/j.cell.2018.02.007