Brain complexity: newborn neuron migration (Introduction)

by David Turell , Friday, October 07, 2016, 16:13 (2969 days ago) @ David Turell

Another article with more information:-http://www.the-scientist.com/?articles.view/articleNo/47207/title/Nascent-Neurons-Journey-Through-Newborn-Brain/&utm_campaign=NEWSLETTER_TS_The-Scientist-Daily_2016&utm_source=hs_email&utm_medium=email&utm_content=35506671&_hsenc=p2ANqtz--Rdr677la22p0c1MIqnVvnVi3HI3sGO09zQY7xglxUnAvXmPd5KGuSaShKAi9hNB-y5nYwsW-qmvAnCG9H0fotrlWN-Q&_hsmi=35506671-"The human cerebral cortex experiences a burst of growth late in fetal development thanks to the expansion and migration of progenitor cells that ultimately form excitatory neurons. For a fully functional brain, in addition to excitatory neurons, inhibitory ones (called interneurons) are also necessary. Yet scientists have not been able to account for the increase in inhibitory neurons that occurs after birth. Now, in a paper published today (October 6) in Science, researchers from the University of California, San Francisco (UCSF), have shown that there is a reserve of young neurons that continue to migrate and integrate into the frontal lobes of infants.-***-“'The fact that these cells can traverse such complicated territory and travel what are incredibly long distances—up to four centimeters—to get to where they need to go and contribute to circuitry well after birth is really astonishing,” said Alvarez-Buylla. -"The migratory cells decreased with increasing age, with very few cells detected by 7 months and none by age 6. The researchers also found that the number and subtypes of interneurons increased between birth and 5 months within a region of the cortex adjacent to the migration path of the newly born cells, suggesting that these migratory cells populate the cortex in infancy with various types of interneurons.
“The surprise is that the prenatal movement of neurons continues postnatally to accommodate such a big territory in the frontal lobe which is important for cognitive and emotional development and executive function,” Huang told The Scientist. “The human brain developed this clever mechanism to prolong the migration.”-"To Berninger's mind, the work highlights the power of observational research. The researchers “did not use particularly novel methods but rather followed their own lead that migration patterns in human infants differs markedly from those in other mammals, digging deeper than anybody else had before . . . to uncover this new picture of neuron migration in the human brain,” he wrote.-"For Fishell, the work implies that while these young neurons stop migrating by 7 months, they may provide a reserve of immature neurons in the brain for building new circuits throughout childhood and even into adolescence, when the cortex goes through major developmental changes.-"Alvarez-Buylla agreed. “Even after the cells get to their final location in the cortex, it may take months or years for them to fully mature which might coincide with key features of plasticity in human brain development,” he noted.-“'In one swoop, this study provides a new substrate neuronal population in which developmental, evolutionary, and functional changes may occur,” wrote neuroscientist Nenad Sestan of Yale University who was not involved in the work in an email to The Scientist. “And the timing of the appearance of these neurons suggests either their migration or their integration into neural networks, or both, may be regulated by external stimuli and/or experience.'”-Comment: This method of supplying enough neurons for the large frontal lobe to develop properly is amazing. Four centimeters of migration. How do they know where to go? What guides them to the proper spots? But obviously a large supply is needed to begin to plastically respond to the newborn as it experiences life and begins to be able to understand and reason. If evolutionary changes in an organ are driven by need where did the need come from to jump to a final Homo species to enlarge the frontal lobe? Previous species did not know what they did not know, i.e., the ability of H. sapiens brains to think. This huge gap in development occurred and then was learned to be used. The H. sapiens brain is the same as it was 200,000 years ago in volume but much more complex because it was given the ability to respond to use, by methods such as migration of neurons! Saltation. God.