June 21, 2013
Researchers Create First Ultra-high Resolution 3-D Map Of Human Brain
redOrbit Staff & Wire Reports - Your Universe Online
Researchers in Germany and Canada have created a spectacular 3-D digital reconstruction of a complete human brain that reveals unprecedented detail.
The map, dubbed the BigBrain, has a spatial resolution just 20 microns "smaller than the size of one fine strand of hair" and represents the first time that human brain anatomy has been shown in such ultra-high resolution.
Until recently, reference brains did not show much beyond the macroscopic, or visible, components of the brain, the researchers said.
BigBrain is 50 times as detailed as previous efforts, said Katrin Amunts of the Institute of Neuroscience and Medicine in Jülich, Germany, the lead author of a report on the project in the current issue of the journal Science.
The sophisticated image processing methods used to create the map allow it to show an extraordinary view of the brain's microstructure, or cellular level.
The anatomical tool will allow for 3-D cytoarchitectonic mapping of the human brain, and serve as an atlas for small cellular circuit data, or single layers or sublayers of the cerebral cortex, the researchers said.
The project "has been a tour-de-force to assemble images of over 7,400 individual histological sections, each with its own distortions, rips and tears, into a coherent 3-D volume," said senior author Dr. Alan Evans, a professor at the Montreal Neurological Institute at McGill University in Montreal, Canada.
"This dataset allows for the first time a 3-D exploration of human cytoarchitectural anatomy."
BigBrain depicts the brain of a 65-year-old woman. It was preserved in paraffin after her death, and then sliced into 7,400 sections with a special tool called a microtome.
Next, 20-micrometer thick histological sections were mounted on slides, stained to detect cell structures and finally digitized with a high-resolution flatbed scanner so researchers could reconstruct the high-resolution 3-D brain model.
The resulting images reveal differences in the laminar pattern between brain areas.
The new map, which is part of the European Human Brain Project, serves as a powerful tool to facilitate neuroscience research and "redefines traditional maps from the beginning of the 20th century," said Dr. Amunts who is also director of the Cecile and Oskar Vogt Institute for Brain Research at the Heinrich Heine University Düsseldorf in Germany.
"The famous cytoarchitectural atlases of the early 1900's were simplified drawings of a brain and were based on pure visual analysis of cellular organization patterns," added Dr. Amunts.
Because of the sheer volume of this dataset, which took about 1,000 hours to collect, the researchers say that there will be a push by those who want to use it to develop new and valuable tools for visualization, data management and analysis.
"We plan to repeat this process in a sample of brains so that we can quantify cytoarchitectural variability," said Dr. Evans.
"We will also integrate this dataset with high-resolution maps of white matter connectivity in post-mortem brains. This will allow us to explore the relationship between cortical microanatomy and fiber connectivity," said Dr. Amunts.
"We are planning to integrate our receptor data of the human brain in the reference frame provided by the BigBrain," said senior co-author Dr. Karl Zilles, senior professor at the Jülich Aachen Research Alliance in Germany.
"We will also transfer high-resolution maps of quantitative data on the regional and laminar distribution of native receptor complexes to the BigBrain. This will allow us to explore the relationship between cortical microanatomy and key molecules of neurotransmission."
The fine-grained anatomical resolution will allow scientists to gain insights into the neurobiological basis of cognition, language, emotions and other processes, according to the study.
The researchers said they plan to extract measurements of cortical thickness in order to gain new insights into aging and neurodegenerative disorders. They also want to create cortical thickness maps to compare data from in vivo imaging, integrate gene expression data from the Allen Institute, and generate a brain model with a 1-micrometer resolution to capture details of single cell morphology.
The researchers have made BigBrain freely available to the broader scientific community through the CBRAIN Portal.