Brain complexity: newborn neuron migration (Introduction)

by David Turell , Thursday, October 06, 2016, 19:24 (2970 days ago) @ David Turell

The amount of migratory neurons in newborn humans is much greater than seen in other species and is part of our brain's uniqueness:-http://medicalxpress.com/news/2016-10-human-neurons-migrate-birth.html-"Researchers at UC San Francisco have discovered a previously unknown mass migration of inhibitory neurons into the brain's frontal cortex during the first few months after birth, revealing a stage of brain development that had previously gone unrecognized. The authors hypothesize that this late-stage migration may play a role in establishing fundamentally human cognitive abilities and that its disruption could underlie a number of neurodevelopmental diseases. -"Most neurons of the cerebral cortex - the outermost layer of the brain responsible for advanced cognition - migrate outward from their birthplaces deep in the brain to take up their positions within the cortex. Developmental neuroscientists have long thought that most neural migration ends well before an infant is born, but the new paper—published October 6, 2016 in Science—suggests for the first time that many neurons continue to migrate and integrate into neural circuits well into infancy.-***-"Several labs had observed that there seemed to be many young neurons around birth along the ventricles, but no one knew what they were doing there," said Paredes. "As soon as we looked closely, we were shocked to discover how massive this population was and to find that they were still actively migrating for weeks and weeks after birth."-"To determine whether these immature neurons - which the researchers dubbed "the Arc" - actively migrate in the newborn brain, researchers used viruses to label immature neurons in tissue samples collected immediately after death and observed that Arc cells move inch-worm style through the brain, much as neurons migrate in the fetal brain.-"Further histological studies of the cingulate cortex, a portion of the brain's frontal lobe, show that Arc neurons migrate outward from the ventricles into the cortex primarily within the first three months of life, where they differentiate into multiple different subtypes of inhibitory neurons.-***-"The new research suggests that inhibitory circuits in humans develop significantly later than previously realized. This postnatal migration is much larger than what is seen in mice and other mammals, the authors say, suggesting that it may be an important developmental factor behind the uniqueness of the human brain.-"The first months of life, when an infant first begins to interact with its environment, is a crucial time for brain development, Huang said. "The timing of this migration corresponds very well with the development of more complex cognitive functions in infants. It suggests that the arrival of these cells could play a role in setting up the basis for complex human cognition.'"-Comment: Research keeps finding new ways to show our brain is especially developed as compared to other animals.