Every day you wake up with a slightly less connected brain than the night before. New research in mice reveals that during sleep the connections between brain cells, which hold information learned throughout the day, undergo massive shrinkage. The process makes room for learning new memories while shedding weak ones. As author Marie Kondo would put it, this is the brain’s very own “life-changing magic of tidying up.”
“When we are awake, learning and adapting to the environment, synapses—or the connections between neurons—get strengthened and grow,” says neuroscientist Chiara Cirelli of the University of Wisconsin–Madison. “But you can’t keep growing the synapses. At some point, you will saturate them.