Pruning neuronal connections
5 Oct 2011 by Evoluted New Media
Specialist cells in the brain prune neuronal connections, shaping the way the brain is wired say researchers, who believe the finding may have important implications for neurodevelopmental disorders.
Researchers from the European Molecular Biology Laboratory (EMBL) in Monterotondo, Italy have discovered that cells called microglia prune the connections between neurons, swallowing up dead and dying neurons in injured brains.
“We’re very excited, because our data shows microglia are critical to get the connectivity right in the brain,” said lead author Cornelius Gross. “They ‘eat up’ synapses to make space for the most effective contacts between neurons to grow strong.”
The work – published in Science – involved introducing a mutation that reduced the number of microglia in the developing mouse brain.
“What we saw was similar to what others have seen in at least some cases of autism in humans: many more connections between neurons,” said Gross. “So we should be aware that changes in how microglia work might be a major factor in neurodevelopmental disorders that have altered brain wiring.”
The mutation only has temporary effects, so eventually the number of microglia increase and the mouse brain establishes the right connections – however this happens later in development that it normally would. Gross and his colleagues plan to find out if this delay has long term consequences. They also plan to investigate what microglia do in the adult brain where their role is essentially unknown.
Synaptic pruning by microglia is necessary for normal brain development
