An international group of neuroscientists has sliced, imaged and analysed the brain of a 65-year-old woman to create the most detailed map yet of a human brain in its entirety. The atlas, called ‘BigBrain’, shows the organization of neurons with microscopic precision, which could help to clarify or even redefine the structure of brain regions obtained from decades-old anatomical studies. Researchers used a special tool called a microtome cut a human brain preserved in paraffin wax into 20-micrometre thick slivers and map its anatomical structure with high resolution.
“The quality of those maps is analogous to what cartographers of the Earth offered as their best versions back in the seventeenth century,” says David Van Essen, a neurobiologist at Washington University in St. Louis, Missouri, who was not involved in the study. He says that the new and improved set of anatomical guideposts could allow researchers to merge different types of data — such as gene expression, neuroanatomy and neural activity — more precisely onto specific regions of the brain.
The atlas was compiled from 7,400 brain slices, each thinner than a human hair. Imaging the sections by microscope took a combined 1,000 hours and generated 10 trillion bytes of data. Supercomputers in Canada and Germany churned away for years reconstructing a three-dimensional volume from the images, and correcting for tears and wrinkles in individual sheets of tissue. Since the BigBrain effort began in 2003, technology has advanced to enable researchers to scan human brain sections at a resolution of one micrometre. But completing another atlas at such a high resolution would create about 20,000 trillion bytes of data — more than the most advanced computers today could process efficiently.