Saturday December 15, 2007, 5:14 pm
It was widely known that synapse elimination occurs during normal development of a child's brain, but until now, no one knew how certain synapses were flagged for removal. Barres' team found that the brain-sculpting process was controlled by a component of the immune system known as the classical complement cascade.

Barres' team produced the first proof that the complement system also plays a role in the brain by showing that complement proteins bind to unwanted synapses, targeting them for elimination. Future studies will determine how the synapses are marked for death.