The complement system, where C4 resides, is known to play a key role in synapticpruning in the brain, which occurs with normal aging.
在正常衰老过程中，包括C4在内的补体系统在脑突触修剪起重要作用。
2
Although C4 had long been known for its role in the immune system, the researchers found that it was also instructing this process of synapticpruning.
C4在免疫系统中的作用已经为人们所熟知，但最新的研究发现它也控制突触修剪的过程。
3
"Babies are born with 100 billion neurons, " he says. "During the first years of life, some are salvaged and the others are left to wither. We call that synapticpruning.