" Recently, the search for what he calls " the splinters that make up different attention problems" has taken Castellanos in a new direction. First, he explains that your brain is far less concerned with your brilliant ideas or searing emotions than with its own internal " gyroscopic busyness," which consumes 65 percent of its total energy. Every fifty seconds, its activity fluctuates, causing what he calls a " brownout." No one knows the purpose of these neurological events, but Castellanos has a thesis: the clockwork pulses enable the brain's circuits to stay " logged on" and available to communicate with one another, even when they're not being used. " Imagine you're a cabdriver on your day off," Castellanos says. " You don't need to use your workday circuits on a Sunday, but to keep those channels open, your brain sends a ping through them every minute or so. The fluctuations are the brain's investment in maintaining its circuits online. "