Researchers use a special tool called a microtome to cut sections from a brain preserved in paraffin wax into tiny slivers 20-micromters thick.
BigBrain, a 3D digital reconstruction of a human brain, provides a first-ever high resolution view of the inner workings of the human brain that could lead to better understanding of how we think, talk, and feel.
The new tool, which is available for free to researchers in the scientific and medical community, is the first to map the anatomy of the brain to a resolution of 20 microns, which is smaller than a strand of human hair. That level of microscopic detail has scientists excited about what they might find as they start to delve deeper into how the brain works to better understand language, memories, sensory experiences and even why things go awry in conditions such as Alzheimer’s and dementia.
“Research has begun to realize that without really deep knowledge of the structures involved, we will never have an understanding of the data being produced by many of these other techniques and methods,” says Dr. Peter Stern, senior editor of the journal Science, which published details of the effort, during a teleconference about the project.
The virtual brain map was created by German and Canadian researchers, who assembled more than 7,400 painstakingly produced slices of brain, each 20 micrometers thick, from a deceased 65-year old female. They say it will serve as an atlas and ultimate reference for the various layers and cellular circuits that contribute to everything from movement to language, planning and memories.
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The reference brains that have existed before have generally not been able to provide microscopic level detail, and have stopped at about 1 mm resolution, the limit of MRI images. BigBrain, however, has the potential of providing a better understanding how the brain’s cells are assembled and interact with each other.
“This, if you’d like, is big science comes to the brain,” said the study’s senior author Dr. Alan Evans, a professor of neurology at the Montreal Neurological Institute at McGill University in Montreal, Canada in the teleconference.
According to Evans the new brain allows a completely new level of insight into the organization of the brain and how interactions between its various regions explain behavior and function. “We’ve raised the level of insight orders of magnitude beyond what was possible at the turn of the 20th century. This data set will revolutionize our ability to understand internal brain organization,” he says.
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The brain is part of the European Human Brain Project, which hopes to promote more collaboration among neuroscience researchers around the world. “When you are interested in a common neurodegenerative disorder like Alzheimer’s disease, you have the first-ever human brain model where you can look into details of the human hippocampus, which is the brain region extremely important for memory. You can look into brain regions which are connected with the hippocampus and play a major role in this disease, but you can also study how many cells you need to build up a cortical unit,” said senior author Dr. Karl Zilles, a senior professor at the Julich Research Alliance and the Institute of Neuroscience and Medicine at the Research Center Julich in Germany in the teleconference.
Having the virtual brain available without cost should also encourage more researchers to access and discuss what they find — to to mention provide them with common ground on which to base their investigations. “This is the basis for scientific discussions because everybody can work with this brain model and speak about the same basic findings and we can develop new methodical aspects based on th[is] common model of the human brain,” said Zilles.
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Other groups have produced similar maps of the mouse brain — the Allen Brain Atlas (ABA) is the largest public-access databases of all genes expressed in the mouse brain, and researchers responsible for that effort have begun to model the same information from human brains, using imaging techniques to identify and measure the activity of genes in about 1000 regions of the human brain.
“It is very important to have these tools and unifying coordinated frameworks for the study of the human brain as they have historically only been available for model organisms such as rodents and non-human primates,” says Ed Lein, an associate investigator at the Allen Institute of Brain Science, which launched the ABS. “As the [BigBrain] model is adopted by researchers and annotated for the underlying functional anatomy its value will increase as a framework for integrating data from different fields.”
The BigBrain dataset will be provided through the CBRAIN Portal with free registration.