Three-dimensional map of the brain pathways

March 31, 2012 12:42

The white matter of the brain, consisting of vascular bundles of axons, is not matted tangle of unordered and precise three-dimensional lattice, the complexity of which increases from the lower to the upper layers of the brain.

White matter pathways (photo authors of the study)

Researchers from the Massachusetts Institute of Technology (USA) together with European and Chinese colleagues have built a spatial map of the white matter of the brain. White matter consists of fibers which, in turn, are composed of long neuronal processes — axons. Signal is sent down the axon to the next cell, and bundles of axons can be a stretch to compare the tire with which computer components communicate. Axon fibers have the same function, linking, for example, the emotional centers with movement. Thanks axonal "tires" the brain can function as a unit.

It may seem that the white matter pathways form a tangled mass, completely unrecognizable tangle. What would be surprising given the diversity of pathways and the complexity of the brain. But it is not. The researchers used a diffuse spectral MRI to see the orientation of the nerve fibers. This type of imaging allows us to observe the active neural connections, with the help of researchers tracked the movement of water on the brain. The work was conducted with the brain and the living with the dead tissues of four primate species.

In the end, as the researchers report in the journal Science, instead of a disordered tangle they saw a structured three-dimensional lattice: the fibers going from front to back and left to right and top to bottom. As you zoom in, they created a curved honeycomb structure. Most of all, such a structure was shown in the deep layers of the brain, near the centers of memory and the formation of emotions. According to the observations of scientists, as we move from the depths of his brain to the outer layers of the original bare complicated scheme and acquired new parts. Distinctly all branching paths and deviations from the block diagram found near the gray matter of the cortex, responsible for complex cognitive functions such as language and fine and complex motor skills. That is, younger and more variable, flexible conductive part of the overall structure as it grows from a long hardcoded foundation.

The authors believe that the formation of a conductive grid is controlled by chemical signals in the future help to cope with potential problems. Reconfigure the pathways around the damaged area under the scheme can be much easier than trying to do it in a chaotic tangle of matted fibers.

It should be noted that the scientists were able to analyze the structure of white matter in only one quarter of the brain. In the future they are going to, of course, to "pass" in a way the whole brain. They do not exclude that this might come to light, and other geometric neuroanatomical structures. Moreover, some critics point to the fact that the authors have missed a little question, what is described in the cells of the axon lattice.

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