Thursday, 07 Aug, 2008 Science

A usual scanning of a human brain presents a muted gray image, which one can distinguish quite easy by a series of complex folds. However, a neuroscientist working at Massachusetts General Hospital, in Boston, Van Wedeen, claims that such image is only a shadow of the actual brain. Recently scientists revealed the real structure of our brain, featuring accurately ordered tangle of nerve cells and the elongated projections linking the cells. It is worth mentioning that the image was kept secret until now.

Custom MRI (magnetic resonance imaging) is able to identify the main anatomical aspects of the brain. The procedure is mostly used to recognize stokes and brain tumors. However, the continuous development in the field of computing and processing algorithms made it possible for scientists to study the data obtained from MRI in totally new perspective.

One of the new ways to observe the brain in a new perspective is called diffusion spectrum imaging (DSI). The DSI applies magnetic resonance signals to identify the motion of water molecules in the brain. The water spreads along the length of axons, neural wires. With the help of such diffusion estimations scientists are able to observe the wires, building a meticulous image of the brain's connectivity.

In the field of medicine, specialists are starting to use the new technology in order to observe the brain before such surgeries as tumor removal. They map the brain to avoid vital fiber tracts.

Together with other researchers, Wedeen used the diffusion imaging for a clearer understanding of the structures that lie beneath human's ability to see, speak and remember. Besides, researches look forward to use the new techniques to better understand such diseases as schizophrenia and autism, which show abnormal wiring.

This video shows the image of a scanned dissected brain of a marmoset. After completing the 24-hour scan, scientists managed to produce a map that has a spatial resolution of 400 microns.

"The image quality and resolution are much higher than we can obtain in a living subject," says Wedeen.

The video shows a rotating brain where you can observe all the neural fibers in half of the brain: the spiky fibers resembling pins in a pincushion represent a part of the cerebral cortex. This brain of a marmoset does not include the folding which is typical for the human brain.

"The human brain would look 25 times as complicated. Every gyrus [fold] has its own story to tell," mentioned Wedeen.

Source: TechnologyReview.com

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