Mice are widely used in biomedical research. Their brains contain approximately 100 million cells each in hundreds of different regions. The brain of a mouse is just over a centimeter in size, and weighs the same as a jelly bean. Mapmakers at the Allen Institute have described a new cartographic feat in the journal Cell : it is the first 3D map of the mouse brain.
This map would be the neuroscience equivalent of GPS. Instead of manually searching for a location on a paper map based on what you see around you, GPS (and this new brain atlas) tells you where a certain position is. The researchers divided the brain into small virtual blocks and assigned each block a unique coordinate. In addition, they used tiny electrical probes to capture the activity of hundreds of neurons at once in several different brain regions.
With data sets in thousands or millions of different pieces of information, that common set of coordinates identifies the corresponding brain landmarks for those coordinates. The data that fueled that 3D construction came from the average brain anatomy of nearly 1,700 different animals.
Historically, brain atlases were drawn in 2D, taking leaf-shaped views of the brain at different depths and aligning them. For some data sets, this form of brain mapping works well. But for modern neuroscience studies, which look at neural activity or cellular features throughout the brain, a 3D atlas provides better context.
According to Dr. Lydia Ng., Senior Director of Technology at the Allen Institute for Brain Science, a division of the Allen Institute: “In the old days, people defined different regions of the brain with the naked eye. Just as we have a reference genome sequence, we need a reference anatomy. “
As neuroscience data sets grow larger and more complex, owning a common spatial map of the brain becomes a priority, as does the ability to collectively and accurately record many different types of data in three-dimensional space for comparison. and correlate: The atlas is a necessary resource that will allow studies at the brain level in mice.
The researchers believe that future versions of the atlas will likely rely on machine learning or other forms of automation, rather than the laborious manual curation that was included in the current version.
Reference:
‘The Allen Mouse Brain Common Coordinate Framework: A 3D Reference Atlas’. Lydia Ng. May 07, 2020. DOI:https://doi.org/10.1016/j.cell.2020.04.007
