Did You Know ...

... that researchers are working towards producing a map of the human brain?

In order to treat illnesses, researchers must firstly understand exactly how the organ in question works. While heart, kidney and lungs are now understood in great detail, the brain mainly remains a mystery. This is due to the high complexity and changeability of the network structures of its nerve cells. Moreover, the relationships between the nerve cells and brain functions are largely unknown. Scientists now wish to gain a better understanding of these interrelationships in order to treat neurodegenerative diseases such as Alzheimer's and Parkinson's.

A complete map of the human brain showing its approximately 100 billion neurons and its connections is still a distant goal. However, thanks to the development of new methods and tools in electron microscopy, the mapping of the 75 million nerve cells of a mouse's brain is now within reach. Reconstructing a three-dimensional image of the brain with very high resolution requires the preparation of very fine sections measuring from 30 to 50 nanometers. These are then imaged using an electron microscope, which was previously a painstaking and time-consuming task. The ZEISS MultiSEM 505 now makes this microscopic examination easier and much faster. It is the world's first scanning electron microscope to work with 61 parallel beams, as opposed to the single-beam microscope that was used previously. This extreme increase in the speed of electron microscope imaging enables large areas of the brain to be examined in the cubic millimeter, or even cubic centimeter, range. Such volumes previously took years to record and were therefore beyond the limits of the technologically feasible.

Neurobiologist Jeff Lichtman from Harvard University in Cambridge (USA) and his team are already carrying out experiments using the ZEISS MultiSEM 505, generating approximately 10 terabytes of image data per day. The images produced by this new microscope feature a pixel size of 4 nanometers. This data rate and high resolution means researchers will soon be able to map a mouse's brain fully, and possibly also that of a human in the not too distant future.

 

28 May 2015