Credit: Gerd Altmann / pixelio.de
Read aloud Scientists have identified a special kind of stem cell in the brain: they are used to form nerve cells that are responsible for the higher brain functions of mammals. So far, it had been assumed that all nerves of the cerebral cortex originate from the same stem cells. The discovery may provide long-term treatment options for mental illness, say Ulrich Mueller of the Scripps Research Institute in California and his colleagues. The cerebral cortex of mammals including humans is built up like an onion: neurons occupy different layers and are responsible for different tasks. The nerve structures of the deeper layers are responsible for the control of basic functions of the body. The control centers of the higher brain functions of mammals, however, lie in the outer areas. In humans, this top layer of the cerebral cortex is also the seat of the mind and thus the source of its unique abilities.

Special nerves? special origin

So far, scientists have assumed that in brain development, all different types of neurons of the cerebral cortex originate from just one type of stem cell. After their birth, they migrate outward, building up the layers of the cerebral cortex. According to this theory, only the time of formation determines the later function of the nerve cells. This refutes the current results of Ulrich Mueller and his colleagues: they were able to show in mice that the nerve cells of the uppermost layer of the cerebral cortex are derived from special stem cells, which differ from the mother cells of the other nerve layers.

In the evolution of humans, these stem cells probably played a particularly important role, the researchers say. Although the mouse already has comparatively high brain powers, which are due to the nerves of the cerebral cortex, but for the excellence of our thinking organ are far more of these? Intelligence cells? necessary. However, according to Mueller, the corresponding nervous upgrading in human evolutionary history also had a downside: if the neurons in the top layer do not properly connect, performance disorders such as autism or schizophrenia are the result. display

In this context, the current results could form the basis for new forms of therapy, the researchers say. Accordingly, laboratory cultures of nerve cells of the outer layer could be grown from the corresponding stem cells. These could then one day be transferred to patients for therapeutic purposes to compensate for missing nerve connections. Until then, it is still a long way, emphasize Ulrich Mueller and his colleagues.

Ulrich Mueller (Scripps Research Institute, California) et al .: Science, doi: 10.1126 / science.1223616 © science.de? Martin Vieweg

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