American researchers have succeeded at imaging a mouse brain at a scale previously unachievable. They describe their imaging tool in a recent publication in Cell. Jeff Lichtman, study senior author and researcher at Harvard University: "For people who are imagers, being able to see all of these details is wonderful.”
The scientists are strong believers in ‘bottom up-science’. This principle takes the data as a starting point for formulating a hypothesis. For the paper in Cell, they used data about the sensory part of a mouse brain that processes signals from the whiskers. Using a computer program, they assigned different colours and pieced apart each individual structure, like neurons, glial cells and blood vessels. The video below shows an example: the 3D reconstruction of thirteen axons that have a membrane-to-membrane apposition with a single spine originating from a central dendrite.
"The complexity of the brain is much more than what we had ever imagined", says study first author Narayanan Kasthuri, of the Boston University School of Medicine. "We had this clean idea of how there's a really nice order to how neurons connect with each other, but if you actually look at the material it's not like that. The connections are so messy that it's hard to imagine a plan to it, but we checked and there's clearly a pattern that cannot be explained by randomness."
The scientists envision many applications for their imaging technique, like comparing different human brains with each other or to that of other animals. Within the next couple of years they aim to create a national brain laboratory, to facilitate neuroscientists worldwide in new discoveries. Lichtman is certain this will happen: “Every time we look at this data we see something that we've never seen before.”
Credit: Kasthuri et al./Cell 2015
Sources: Cell, Eurekalert.
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