While Mednick's study focused on drug therapy, however, Muller and Sejnowski's took a systemic view on how sleep spindles work, and using new state-of-the-art brain-monitoring technology, were able to observe a more thorough view of sleep spindle patterns than ever before.
"You see a flow of activity going counter-clockwise over and over," Muller says. "That flow of activity flows at the exact speed that it takes to communicate from one point in the cortex to another by the wires, or the axons, between neurons."
So, different parts of your brain are communicating with each other, in highly concentrated ways throughout the night, as much as 15 times per second. Muller cautions that they need to continue doing more research, but: "We think we've found the way that neurons in auditory cortex can talk to neurons in visual cortex and link up all those pieces of information they've acquired during the day via this rotating wave of activity."